EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: oewean on January 10, 2024, 11:37:16 pm
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Siglent is releasing SDM4000A series multimeter in China.
6½ digit reading resolution (2,200,000 counts)
Maximum reading rate 50k rdgs/s, minimum sampling interval 20μs
DCV basic accuracy 35PPM
True RMS AC voltage and AC current measurements
Recorder function and digitizer function
5-inch touch screen, resolution 800*480
https://www.siglent.com/products-overview/sdm4000a/ (https://www.siglent.com/products-overview/sdm4000a/)
[attach=1]
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Appx 1200€ for the non scannercard version, will make appx 1400 "here".
Interesting..
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If I'm not mistaken, the SDM3065X is cheaper in Europe than in China. ¿Something to do with the price of american TE in China?
It's just a guess, but maybe the 346xA series from Keysight and the 6500 from Keithley are much more expensive/not sold in China, and as such Siglent has not strong competition.
I'd be surprised if someone is willing to buy the Siglent for €100 less than the DMM6500 TBH, which costs €1300-1500.
EDIT: Maybe for audio? It could work as a really high resolution scope up to (maybe) 25KHz. It has higher sampling rate than most audio interfaces.
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yep seems a Keithley DMM6500 clone at cheaper pricing .... scan card pricing is it the same card as the other siglent who have scan card options ?
we need a teardown, i want to know witch reference they use
but i hate the black trend ...
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The DMM6500 is currently sold for around €1450, the Siglent SDM4000 must be significantly lower. Especially since the long-term stability seems to be a little worse.
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yep seems a Keithley DMM6500 clone at cheaper pricing .... scan card pricing is it the same card as the other siglent who have scan card options ?
we need a teardown, i want to know witch reference they use
but i hate the black trend ...
It's not really at the level of the DMM6500, 50 KS/s is the sampling rate of the KS 34465a in digitizing mode. The DMM6500 has 1MS/s, 20 times higher.
The price is quite a bit lower than the KS, though. It would be interesting to see whether it is as programmable as the DMM6500. I guess they are trying to enter A brand pricing and margins territory. Too expensive even for "A-" tier IMO.
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If this new Siglent SDM4000A DMM is even close to the price of the DMM6500, why would anyone consider it over the Keithley?
The DMMs at this level are intended for accurate, repeatable, precise measurements and the Keithley DMM6500 and Keysight 34461-5A have demonstrated such over many years/decades of doing exactly this, these are the "Benchmark" DMMs in this territory, and relatively new unknown for Siglent.
Unless the SDM4000A becomes available at significantly lower cost, can't see knowledgable folks selecting it over the DMM6500.
Don't misunderstand, we aren't a Siglent basher, nor fanboy either, and have a significant repertoire of Siglent gear, including the SDM3065X which is a nice DMM, but doesn't compare with the DMM6500 nor KSs either, however is lower cost!!
Best,
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If this new Siglent SDM4000A DMM is even close to the price of the DMM6500, why would anyone consider it over the Keithley?
The DMMs at this level are intended for accurate, repeatable, precise measurements and the Keithley DMM6500 and Keysight 34461-5A have demonstrated such over many years/decades of doing exactly this, these are the "Benchmark" DMMs in this territory, and relatively new unknown for Siglent.
Unless the SDM4000A becomes available at significantly lower cost, can't see knowledgable folks selecting it over the DMM6500.
Don't misunderstand, we aren't a Siglent basher, nor fanboy either, and have a significant repertoire of Siglent gear, including the SDM3065X which is a nice DMM, but doesn't compare with the DMM6500 nor KSs either, however is lower cost!!
Best,
Siglent pricing is a strange thing, taken at first glance. The SDM is quite a bit cheaper in the western markets than in China. The SDS2000X-Plus is also a bit cheaper.
The 2000X-HD is much more expensive though. There, in China, the plus and the HD are quite close in terms of price.
I don't think it will cost as much here. Around 1.000 plus VAT is my guess, if it does come to US and EU. More than that will not sell much, if at all.
For hobbyists the DMM6500 has the old Keythley scanner cards going around for not too much money. We'll see.
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The Sigilent meters seems to have a 20 V high impedance range, which can make a difference for a few users.
It is also a bit unclear how good the meters is at higher sampling rates - the Keithley6500 is fast with the separate fast ADC, but AFAIK the front end is limited in the bandwidth, especially in some ranges.
50 kSPS only make really sense if the front end is also fast enough.
For the scanner part it would really be good if this would be a user option, but I am afraid there is the problem that already the connector for the scanner card would limit the maximum voltage.
The picture of the scan card on the web page still looks like the old one.
It is a bit early to say how much different the meter actually is from the old SDM3000 series. It could be as little as a new digital/display part and still the old analog side.
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Exactly.
It might be closer to the SDM3065X or closer to the vaunted keithley/keysight models.
We'll have to wait for a review...
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yeah could be some rev 2 of the actual model with cosmetic changes, UI changes ?
until we get internal views, we speculate ...
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Translations of the QuickStart and Datasheet
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From the datasheet, it's looks identical except for a few key upgrades and a touchscreen.
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Just found out about that meter. So they went from copying the keysight UI to copying the keithley UI. Let's just hope it is more intuitive than the DMM6500. I like that meter for the better digitising and graphing possibilities (compared to the KS34465A), but boy do I waste time in configuring it.
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DMM6500 ... but boy do I waste time in configuring it.
A benchtop DMM need anyway some time to reach thermal stability. In the meantime you have plenity to configure.
If you are refering to triggers, scanner, or other extended functions yes you need more time but this is a lab grade instrument not a pocket multimeter that you use to measure something faster.
Also this advanced functions can be scripted as application that can be stored on the scope an start when need them.
Keithley does not offer free software application as Siglent do (and Keysight with some limits). I found Siglent Easy DMM quite nice and useful.
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From the datasheet, it's looks identical except for a few key upgrades and a touchscreen.
What I've only just noticed is that the model designation has an "A" at the end. :-X ;)
X are always cost-effective devices, A are the Pro lines.
So I wonder what the significant difference is between the SDM3065X and this one, that it became a Pro model?
Possibly the use of pre-aged references this time?
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So I wonder what the significant difference is between the SDM3065X and this one, that it became a Pro model?
From website:
Larger 5" touch display.
2 GB flash
Webserver
Study of the datasheet vs SDM3065X is required for accuracy spec and drift for clues on ref stability.
It's a few months away......
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From website:
Larger 5" touch display.
2 GB flash
Webserver
That may be a reason for others, but not for me.
For me, this would be more of a "pro":
Study of the datasheet vs SDM3065X is required for accuracy spec and drift for clues on ref stability.
This is because the models from Keithley and Keysight, which are often quoted, basically have no better basic accuracy than the SDM3065X.
But less drift and correspondingly better stability.
I'm curious to see if I can hold back when the meter appears on our market. ;)
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I'm curious to see if I can hold back when the meter appears on our market. ;)
🤣🤣🤣
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I'm curious to see if I can hold back when the meter appears on our market. ;)
I have something for you that can be useful in the meantime... :-DD
[attachimg=1]
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Hello all,
Any idea when this will be available in EU?
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The "A" in the model name identifies Siglent's Pro series, as does the price.
This clearly competes with top dogs such as Keysight or Keithley.
You have to be careful not to throw it onto the rest of the market too early, not before the first teething troubles have been ironed out, because otherwise you run the risk of being considered a "burnt brand" in terms of Pro meters among the relevant customers.
In this respect, it is only to be welcomed if Siglent takes its time.
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Hello all,
Any idea when this will be available in EU?
Q4 IIRC.
Will hopefully get a little time with one next week while visiting Siglent HQ.
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The only feature that will really set it apart would be instant continuity. I went looking through a whole bunch of bench DMMs and most of them (actually, all but the cheapest ones) just suck at doing something simple like instant continuity. :popcorn:
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Oh Nico, for me that would be the last thing a precision measuring device should be able to do. ;)
There are cheap alternatives for that.
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Continuity is great on the 3000X models. I don't think they'd make it worse for a 4000A model. 🤷
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Continuity is great on the 3000X models.
No it isn't. It is way too slow for me.
Oh Nico, for me that would be the last thing a precision measuring device should be able to do. ;)
There are cheap alternatives for that.
But then I'd need two devices on the bench for a function which both have. That makes no sense.
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Continuity is great on the 3000X models. I don't think they'd make it worse for a 4000A model. 🤷
Actually is slower than on Keysight 34465A and Keithley DMM6500. Keithley is quite fast visually but the sound is lagging behind. On Keysight is opposite.
But for this task I'm always use a handheld DMM, not a bench one.
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Will hopefully get a little time with one next week while visiting Siglent HQ.
Please share as much as you can. Not only about the multimeter but also about the Siglent HQ.
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Continuity is basically instant for me. It works great, for me. I guess if you need it to tell the future, then that's another story. 🤣
Then again, I use gold-plated ProbeMaster probes, and as our dear friend Dave pointed out, the probes make a huge difference with continuity speed.
https://www.youtube.com/watch?v=uV9mW0rpRxg (https://www.youtube.com/watch?v=uV9mW0rpRxg)
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Probemaster tips are the best I know so far and I know some of them by principle. ;)
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I made a quick/lazy demo:
https://www.instagram.com/p/C-fj3d6u_su/ (https://www.instagram.com/p/C-fj3d6u_su/)
There's a small fraction of a second between the sound of the tips clicking together, and the beep from the DMMs. It's barely perceivable.
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That delay is long enough for me to get bored / annoyed. Seriously.
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That delay is long enough for me to get bored / annoyed. Seriously.
:-DD :-DD :-DD
Show us your faster continuity tester!
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That delay is long enough for me to get bored / annoyed. Seriously.
Exactly. This is slow.
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Exactly. This is slow.
Show us your faster continuity tester!
I see talk, but no proof. 😉😉
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You don't know anything either, do you?
It has to beep before you touch it, otherwise it's no good. 8)
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Continuity speed/performance is not subjective but entirely quantifiable with just a AWG.
SDM3000 range tests from a little over a year ago and methodology thanks to Joe Smith:
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg4840136/#msg4840136 (https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg4840136/#msg4840136)
Discussion is not required but real repeatable data is...... :P :box:
:popcorn:
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You don't know anything either, do you?
It has to beep before you touch it, otherwise it's no good. 8)
Hey, I already mentioned continuity testers that can tell the future! 🤣
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So to give some numbers about continuity beep minimum contact period of some of my meters:
(hand) Fluke 179: 0.2ms
(bench) Keithley DMM6500: 3ms
(hand) Uni-T UT123T: 13ms
(hand) eevblog 121GW: 40ms
(bench) Siglent SDM3055: 50ms
(bench) Keysight 34465A: 400ms
So, yes, handheld is normally faster, but there are exceptions.
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That delay is long enough for me to get bored / annoyed. Seriously.
:-DD :-DD :-DD
Show us your faster continuity tester!
You can ofcourse try to make fun out of pure fanboyism but the way the continuity works on many bench DMMs is just too slow for what I use continuity for. Not only when measuring continuity between two points (for which I take 3 quick measurements). When doing reverse engineering I swipe a probe across a row of contacts quickly. That just won't work when there is a delay due to software defined continuity.
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You can ofcourse try to make fun out of pure fanboyism but the way the continuity works on many bench DMMs is just too slow for what I use continuity for. Not only when measuring continuity between two points (for which I take 3 quick measurements). When doing reverse engineering I swipe a probe across a row of contacts quickly. That just won't work when there is a delay due to software defined continuity.
I'm not making fun at all! It's just funny to me when people say ~30ms is slow. I get that some handhelds are faster, but I've never found anything in the sub-50ms range to feel slow. But also, a lot of people say it's slow without specifying what they consider acceptable. More importantly, which device they currently use that is faster, and what that measured speed actually is.
So to give some numbers about continuity beep minimum contact period of some of my meters:
(hand) Fluke 179: 0.2ms
(bench) Keithley DMM6500: 3ms
(hand) Uni-T UT123T: 13ms
(hand) eevblog 121GW: 40ms
(bench) Siglent SDM3055: 50ms
(bench) Keysight 34465A: 400ms
So, yes, handheld is normally faster, but there are exceptions.
How was that Fluke measured? That seems too amazing. 😉
I want a DMM6500, but it's out of my budget. I'd buy two more SDM3065Xs before buying it considering that the SDM3055X-E is really better than what I generally need.
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How was that Fluke measured? That seems too amazing. 😉
With an AWG directly driving the input of the DMM. 1Hz cycle, 50 Ohm output impedance, H=5V, L=a couple of mV negative (as 0V was seen as over 10 Ohms). Yes, I should use a FET or so, but this was a quick set up, and easily tuned to the DMMs.
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How was that Fluke measured? That seems too amazing. 😉
With an AWG directly driving the input of the DMM. 1Hz cycle, 50 Ohm output impedance, H=5V, L=a couple of mV negative (as 0V was seen as over 10 Ohms). Yes, I should use a FET or so, but this was a quick set up, and easily tuned to the DMMs.
That's cool. I should try that with my meters.
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Some tests:
AN8002 7.2ms (latching)
AN8008 7.2ms (latching)
BM869s 0.2ms (not really audible under that)
SDM3045 (3055X-E) 50ms (misses very few beeps down to 40ms)
34461A 15ms (latching, sometimes beeps twice per pulse under 50ms or so)
34401A 9ms (latching) very few lost pulses down to 6ms
WH5000A 3ms (latching)
UT181A 2ms (latching)
MTX 3282 10ms, non latching, not really audible under 15ms.
1Hz, levels adjusted to 2-10 Ohms depending on the DMM, varying pulse width. Tested for 10 seconds or so to check for lost pulses when approaching the limit of each one.
Really, the Siglent is nothing special. You might argue it is good enough for your use case, but it is worse than almost any other DMM. I'd say the sample is a good mix, from bottom of the barrel to high-end.
A bunch of edits. Formatting and typos.
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Fascinating....
How do you measure the time in ms in such a test?
Do you have a trigger in your ear that triggers it?
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How do you measure the time in ms in such a test?
Do you have a trigger in your ear that triggers it?
Why would anyone need that? It's an audible cue. If it stops giving a beep each second, it's not giving a beep. It's not a precision measurement because it's not a precision function.
The time in ms is given by the SDG1062X. When the pulse according to the AWG is too narrow for the meter to give an audible beep, I dial it to be wider, with ms resolution, unless lower than a millisecond.
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...
(bench) Keysight 34465A: 400ms
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34461A 15ms (latching, sometimes beeps twice per pulse under 50ms or so)
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How did these two meters get such vastly different readings? I would presume that (at least for continuity) they would share identical circuitry. Hell, considering the price difference you'd hope the 34465A would at least perform slightly better.
Or is this perhaps because of the test method? i.e.:
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Actually is slower than on Keysight 34465A and Keithley DMM6500. Keithley is quite fast visually but the sound is lagging behind. On Keysight is opposite.
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That one measures the continuity to beep, and the other to display update rate?
1Hz, levels adjusted to 2-10 Ohms depending on the DMM, varying pulse width. Tested for 10 seconds or so to check for lost pulses when approaching the limit of each one.
With an AWG directly driving the input of the DMM. 1Hz cycle, 50 Ohm output impedance, H=5V, L=a couple of mV negative (as 0V was seen as over 10 Ohms). Yes, I should use a FET or so, but this was a quick set up, and easily tuned to the DMMs.
Because seeing these it seems you guys both use similar measurement methodologies.
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@Kwakneurder
There was a firmware update which improved it vastly.
Continuity was completely unusable when I bought it, but it became decent after an update, can't remember which one.
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How do you measure the time in ms in such a test?
Do you have a trigger in your ear that triggers it?
Why would anyone need that? It's an audible cue. If it stops giving a beep each second, it's not giving a beep. It's not a precision measurement because it's not a precision function.
The time in ms is given by the SDG1062X. When the pulse according to the AWG is too narrow for the meter to give an audible beep, I dial it to be wider, with ms resolution, unless lower than a millisecond.
That's only halve of the story, there still could be a noticeable delay/latency between when the continuity is detected until the beeper beeps.
I'd rate that at least as important.
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How do you measure the time in ms in such a test?
Do you have a trigger in your ear that triggers it?
Why would anyone need that? It's an audible cue. If it stops giving a beep each second, it's not giving a beep. It's not a precision measurement because it's not a precision function.
The time in ms is given by the SDG1062X. When the pulse according to the AWG is too narrow for the meter to give an audible beep, I dial it to be wider, with ms resolution, unless lower than a millisecond.
In that case you are not really measuring response time (time between detection and giving a beep) but the minimum detection time. While the minimum detection time is useful, it is only 1 part of the big picture. A better test would be to use a microphone and measure the time between the short and the tone being produced by the beeper.
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How do you measure the time in ms in such a test?
Do you have a trigger in your ear that triggers it?
Why would anyone need that? It's an audible cue. If it stops giving a beep each second, it's not giving a beep. It's not a precision measurement because it's not a precision function.
The time in ms is given by the SDG1062X. When the pulse according to the AWG is too narrow for the meter to give an audible beep, I dial it to be wider, with ms resolution, unless lower than a millisecond.
That's only halve of the story, there still could be a noticeable delay/latency between when the continuity is detected until the beeper beeps.
I'd rate that at least as important.
That is true. I can try and test that although I'm not sure how.
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I think these tests are all useless unless they're conducted in an agreed upon and repeatable way. If variables aren't consistent, then comparison results are meaningless.
How is the the AWG set? Share a screenshot.
What is the threshold on the DMM?
I can set my AWG Period to 1ms, 1Vrms, and raise the threshold on the SDM3045X to 1kΩ, and that gives a constant beep.
For everything I tried, the main thing that stopped the SDM3045X from beeping faster is if the threshold is too low compared to the signal from the AWG.
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About the KS34465A: mine is on the latest FW, and also by hand testing, it is unusably slow. Maybe I got a hidden (read: SCPI) setting wrong. Found nothing related on the KS itself: one can only set beep on/off, no thresholds, nothing. Maybe another owner can confirm?
But hey, this topic is getting out of hand, it is supposed to be about the SDM4000A. And I'm partly guilty. This beep thing is more a subject for the DMM excel sheet.
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But hey, this topic is getting out of hand, it is supposed to be about the SDM4000A. And I'm partly guilty. This beep thing is more a subject for the DMM excel sheet.
Maybe we need a separate thread on this subject.
About SDM4000 I think his meaning is to offer a a real challenge to the market players while SDM3065X make competition only by price.
I hope we will see soon if 4000 will succeed.
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Hello all,
Any idea when this will be available in EU?
Q4 IIRC.
Will hopefully get a little time with one next week while visiting Siglent HQ.
And I did. ;D
Release is postponed a little and reasons for such will be obvious in time. ;)
Nice DMM it is and I spent some time investigating UI usage with Touch and front panel controls and made some suggestions for improvements that were readily accepted.
Unfortunately with many new and new to me instruments to inspect, the chance to use for real measurements did not arise.
However, as these are to use a color and touch display, would the ability to define a readout color benefit those users with color vision restraints/issues ?
We discussed such and need feedback.....
:popcorn:
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Hmmm, that doesn't look so bad after all... 8)
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Indeed it looks good to me.
Release is postponed a little and reasons for such will be obvious in time. ;)
You know the public of this forum: we like numbers :)
Unfortunately with many new and new to me instruments to inspect, the chance to use for real measurements did not arise.
You know the public of this forum: we like lists :)
However, as these are to use a color and touch display, would the ability to define a readout color benefit those users with color vision restraints/issues ?
I prefer possibility to use a mouse (attached to a rear USB port) to a touch display ... colors IMHO are always usefull (and I have color vision issues).
Anyway thank you for the nice photo.
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However, as these are to use a color and touch display, would the ability to define a readout color benefit those users with color vision restraints/issues ?
I prefer possibility to use a mouse (attached to a rear USB port) to a touch display ... colors IMHO are always useful (and I have color vision issues).
It has rear USB A port and while I did not test, all the existing touch instruments support mouse usage so expect these SDM4000A to have this too as webserver capability is offered also.
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Why is showing such a high value on DC Volt auto scale? It was set on High impedance?
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i would love they get rid of the leading zeroes ..... on any ranges
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i would love they get rid of the leading zeroes ..... on any ranges
Same ugly behavior as on SDM3065...
so they can for shure tell it is a 6.5 digit gear O;)
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i would love they get rid of the leading zeroes ..... on any ranges
Yes, no leading zeros please. And make sure that number font is such, that digits positions do not change even by one pixel across ranges, +/- input (like on LCD segment display). Otherwise displayed numbers will be "jittery".
However, as these are to use a color and touch display, would the ability to define a readout color benefit those users with color vision restraints/issues ?
We discussed such and need feedback.....
:popcorn:
Different colors are useful. There are immediate applications - 1) better visibility due to customization, 2) different colors for current/voltage (user set, off course), 3) different colors when using multiple DMMs at once.
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Hello all,
Any idea when this will be available in EU?
Q4 IIRC.
Will hopefully get a little time with one next week while visiting Siglent HQ.
And I did. ;D
Release is postponed a little and reasons for such will be obvious in time. ;)
Nice DMM it is and I spent some time investigating UI usage with Touch and front panel controls and made some suggestions for improvements that were readily accepted.
Unfortunately with many new and new to me instruments to inspect, the chance to use for real measurements did not arise.
However, as these are to use a color and touch display, would the ability to define a readout color benefit those users with color vision restraints/issues ?
We discussed such and need feedback.....
:popcorn:
Please, at least no dull yellow with bright green as in SDS800X-HD's traces. Just google "deuteranopy" and look at the images, you will understand our pain :-DD
The leading zeros tell you the range and limitations of the measurement from a mile away. Won't bitch if they are removed, but they are ugly and useful.
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i've seen in some software
the leading digits before the decimal point / separator had some pale blue"ish" color, and after the dot = white ??
the digits don't look like the most ugliest ones in the dm858 ... to mimic nixies grid tubes, man this sucks, give me one, i'll toss it right away
this meter does look like an keithley DM7500 serie loll only miss the left right arrows buttons, and the front back switch
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Hello all,
Any idea when this will be available in EU?
Q4 IIRC.
Will hopefully get a little time with one next week while visiting Siglent HQ.
[...]
Release is postponed a little and reasons for such will be obvious in time. ;)
[...]
Any news regarding the release date in EU?
Thank you.
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Any news regarding the release date in EU?
A few months yet and reason for the delay will be apparent in time. :-X
Nice DMM.
I played with one for maybe 30 minutes while at HQ a few weeks back and suggested a couple of minor improvements to the UI they could make.
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Would be interesting to experience how well this new SDM4000 compares to our KS34465As and DMM6500, the SDM3065X we have is Ok but doesn't get used very often as we prefer the KS or DMM6500 for most use cases.
Nothing generally "wrong" with the SDM3065X but it's compared to the KS and DMM which have decades of refinement and in actual use this shows!!
Best,
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Would be interesting to experience how well this new SDM4000 compares to our KS34465As and DMM6500, the SDM3065X we have is Ok but doesn't get used very often as we prefer the KS or DMM6500 for most use cases.
Nothing generally "wrong" with the SDM3065X but it's compared to the KS and DMM which have decades of refinement and in actual use this shows!!
I can say the UI is very different and will require some small learning curve for those used to the 3000 models.
SDM4000A has physical, touch/mouse and webserver control, although I didn't get a chance to have it connected to a PC.
I was mainly interested in UI usability using the touch or physical controls in turn and mixing them up a little.
It worked well and IMO just some minor tweaks were needed, mainly for better visibility/highlighting of user selections made.
The option to change the readout digit color was also suggested but not sure if that might be implemented or not, I hope it does.....
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Would be interesting to experience how well this new SDM4000 compares to our KS34465As and DMM6500, the SDM3065X we have is Ok but doesn't get used very often as we prefer the KS or DMM6500 for most use cases.
Nothing generally "wrong" with the SDM3065X but it's compared to the KS and DMM which have decades of refinement and in actual use this shows!!
I can say the UI is very different and will require some small learning curve for those used to the 3000 models.
SDM4000A has physical, touch/mouse and webserver control, although I didn't get a chance to have it connected to a PC.
I was mainly interested in UI usability using the touch or physical controls in turn and mixing them up a little.
It worked well and IMO just some minor tweaks were needed, mainly for better visibility/highlighting of user selections made.
The option to change the readout digit color was also suggested but not sure if that might be implemented or not, I hope it does.....
We never quite got used to the UI on the 3465X coming from the KS34465A and DMM6500, so maybe the 4000 will behave different/better in this respect. Touch Screen and Webserver should be welcome improvements IMO.
Best,
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Hi everyone, new member, long time lurker. I was wondering if anyone has any more good resources on the Siglent SDM4065A/SDM4065A-SC? I have received information it should be available in Europe in the (early) second quarter, I'm in the market for a new DMM and might hold out for this one if it seems worth it.
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It does seem like a good meter. I have absolutely no need for another DMM, but I want one anyway. It will look pretty next to my Keithley/Keysight meters. 😉
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Hello,
was at EmbeddedWorld and got my hands onto it.
Short but thorough video at
https://youtu.be/3N_oN7XVDCc
To be short: I like it. Handles well, the touchscreen is responsive, and there will be a scanner option also.
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To be short: I like it. Handles well, the touchscreen is responsive, and there will be a scanner option also.
It's the same scanner card that the 3000 series uses.
From your video, it's pretty clear Siglent bought a Keithley to study before designing this. Kinda like how they clearly had a Keysight for the 3000 series. 😉
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Main thread for these models to be released before not too much longer:
https://www.eevblog.com/forum/testgear/new-siglent-multimeter/ (https://www.eevblog.com/forum/testgear/new-siglent-multimeter/)
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To be short: I like it. Handles well, the touchscreen is responsive, and there will be a scanner option also.
It's the same scanner card that the 3000 series uses.
From your video, it's pretty clear Siglent bought a Keithley to study before designing this. Kinda like how they clearly had a Keysight for the 3000 series. 😉
Hi,
this is interesting - sounds plausible. I am not too familiar with the Siglent family.
As for the Keithley - definitely. But this is the name of the game...
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Main thread for these models to be released before not too much longer:
https://www.eevblog.com/forum/testgear/new-siglent-multimeter/ (https://www.eevblog.com/forum/testgear/new-siglent-multimeter/)
Other thread completely went to sleep ;(
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Well, wake him up if there's any news. ;)
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Main thread for these models to be released before not too much longer:
https://www.eevblog.com/forum/testgear/new-siglent-multimeter/ (https://www.eevblog.com/forum/testgear/new-siglent-multimeter/)
Other thread completely went to sleep ;(
Which is quite normal when the only units in the wild are with beta testers and they're bound to NDA's. :-X
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Damn NDA’s, really curious how it will compare to my DMM6500, what’s better than 1 6.5 DMM? Should be available April probably, hopefully.
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Requested https://www.eevblog.com/forum/testgear/siglent-sdm4065a(-sc)/ (https://www.eevblog.com/forum/testgear/siglent-sdm4065a(-sc)/) be merged into this thread.
OP is agreeable.
That was quick. :o
Merge done, thanks Mods. :clap:
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HOT news!
The 🔥NEW🔥 6.5 Digit DMM from Siglent, here on the desk for full review.
https://www.youtube.com/watch?v=OsjHRk-q2oU (https://www.youtube.com/watch?v=OsjHRk-q2oU)
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The SDM4065A has been on my radar since last year ... anyone know if SMB client functionality is planned?
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All that is missing now is a teardown. Curious to see the improvements
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Also curious about fan noise and startup time.
Really happy to see they implemented a fast continuity tester, silly as that may be. It's just nice not to have to switch to another device for that
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All that is missing now is a teardown. Curious to see the improvements
This is a sealed demo Unit that needs to go back to Siglent,
i was already very happy i could test is this soon,
but i will request Siglent if i may open it and break the seals, maybe it can be done before it goes back, if allowed,
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Also curious about fan noise and startup time.
Really happy to see they implemented a fast continuity tester, silly as that may be. It's just nice not to have to switch to another device for that
Sart-up time is about the same as the SDM3065X maybe 1 second longer.
fan noise is the same SDM3065X, so on the desk you hear it a bit, in the stack not over-noising the other equipment..
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I did test the boot time , but it did not make it into the review video.
SDM3065X-SC vs SDM4065A-SC
https://www.youtube.com/watch?v=c1-CONoQ6H8 (https://www.youtube.com/watch?v=c1-CONoQ6H8)
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Not terrible, but of course the GDM-9061 in the back trolls the hell out of them 😀
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Nice video Tony :-+
Also wish to see the internals, especially how they compare with the SDM3065X. Wonder if Siglent is using an "aged" LM399, or ADR1399, and how they solved the excessive long drift at startup issue?
Best
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So, considering the, oh so sensible and reasonable, trade policies in the US of late, this will come in around $3000. I'm sure they will fly off the shelves!
How much of the Keithley is made in China?
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HOT news!
The 🔥NEW🔥 6.5 Digit DMM from Siglent, here on the desk for full review.
Nice video!
One note: All of the Siglent 3000 series DMMs also have continuity threshold settings. Your Keithley DMM is even better and has both range and threshold settings for continuity. Separating the range and threshold is the best method because it gives the fastest response at any threshold level.
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How much of the Keithley is made in China?
The entire unit, packaging and manuals included.
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How much of the Keithley is made in China?
The entire unit, packaging and manuals included.
Well, that puts future stock of the DMM6500 up to about $4,200. Makes the Siglent look like a bargain!
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I'm a little surprised at how inexpensive the new series is; I wasn't expecting that. :-+
They are only slightly more expensive than the previous models, so one would actually expect a price reduction for the previous models.
(https://www.eevblog.com/forum/testgear/new-siglent-multimeter/?action=dlattach;attach=2547594;image)
(Sources: Meilhaus.de /Batronix.de)
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HOT news!
The 🔥NEW🔥 6.5 Digit DMM from Siglent, here on the desk for full review.
https://www.youtube.com/watch?v=OsjHRk-q2oU (https://www.youtube.com/watch?v=OsjHRk-q2oU)
Hello!
Nice video.
Just please make sure to somehow note that it does have Digitizer function, like I posted in comment on YouTube.
This is one function that is not available on older models.
Best
Siniša
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From the specs it is well possible that there is very little (if any) change to the analog board hardware. The main change is for the screen, case and UI and a little more memory. The ADC in the SDM3065 is already capable of providing the higher speed.
The faster warm up phase hints on at least some change - could be as change in the air flow / case to avoid a hot spat or a changed part.
For a relatively empty instrument with a fan it is unusual to take 3 or 4 hours for warm up.
To a large part it is a question of taste if the old or new UI is more convenient. Not everybody likes the bluish color and touch screen.
For the pricing the step from the normal to the scanner version got quite a bit smaller.
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To a large part it is a question of taste if the old or new UI is more convenient. Not everybody likes the bluish color and touch screen
In the short time I had to play with one last August at HQ, focus was using it without any need of touch or mouse.
Certainly 100% possible was my findings and asked for some minor improvements in improving highlighting of selections within the UI.
The blue font does little for me and have also requested a user color palette .....isn't it a color LCD display ?
I recommend all owners of these ask Siglent to provide at least a simple range of colors for the displayed digits.
This may also be useful for those that have a rack of these meters for better measurement duty identification.
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I am not a fun of touch screens ... but I like the mouse is available.
Deep bench, tool well away from work area, test leads and mouse readily available.
The big screen helps.
Colors are for sure welcome.
I recommend all owners of these ask Siglent to provide at least a simple range of colors for the displayed digits.
Yeah .. first become a owner than ask :)
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I placed my order, should be somewhere end of next week it arrives, maybe week after that latest. Let's see what it can do 8)
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Siglent responded to my teardown request, and it is a NO
The demo could be slightly different inside, less well finished, because it is a early demo unit
later models build to go to customers will be better finished and they don't want to have wrong pictures going around.
So we need to wait for someone to break it seal from a real sales channel unit.
maybe i go for one myself
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Wonder if Siglent is using an "aged" LM399, or ADR1399, and how they solved the excessive long drift at startup issue?
Are these “pre-aged” LM399s available for purchase from the manufacturer, and if so, with what suffix?
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Wonder if Siglent is using an "aged" LM399, or ADR1399, and how they solved the excessive long drift at startup issue?
Are these “pre-aged” LM399s available for purchase from the manufacturer, and if so, with what suffix?
Don't think so, recall HPAK did this themselves, probably Keithley and others also.
Best,
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When I got my SDM3065, I left it powered on for two or three weeks to allow some aging. I recently ran my 34401a, my Keithley 2000, and my SDM3065 for a few hours, and in the end, all three showed almost the same reading down to the last digit.
However, I learned that cleaning the terminals with a cotton swab and isopropanol can improve accuracy by a few ppm.
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The problem with the LM399 reference is the still noticable drift in the first 100 hours or so of operation. In the SDM3000/4000 it would be not just the reference but likely also the divider after the reference that can show some initial drift. So the logical way would be to give the complete meters a few days or a week of burn in before doing the final calibration before delivery.
For the user the problem is that one kind of gets an extra 10-20 ppm of extra uncertainty for the initial calibration. This reduces the trust in the initial calibration and a typical later calibration without values would not help with this. So if one wants to imporve on this later one should consider loging the drift from the very start when you get the meter. Once used for some 10 hours or so it can already have drifted quite a bit.
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The problem with the LM399 reference is the still noticable drift in the first 100 hours or so of operation. In the SDM3000/4000 it would be not just the reference but likely also the divider after the reference that can show some initial drift. So the logical way would be to give the complete meters a few days or a week of burn in before doing the final calibration before delivery.
One issue with aging references is that it isn't just the aging that is important, characterization and culling of non-optimal specimens is also part of the process. You can't easily do the latter if they're already soldered to the board. I suppose this is one good reason to use sockets like some HP models.
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One issue with aging references is that it isn't just the aging that is important, characterization and culling of non-optimal specimens is also part of the process. You can't easily do the latter if they're already soldered to the board. I suppose this is one good reason to use sockets like some HP models.
Seems like this might be a good opportunity for someone with small company to acquire, age and characterize these popular references.
Best
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Don't think so, recall HPAK did this themselves, probably Keithley and others also.
That would definitely explain why their 6.5 digit meters are still significantly more expensive.
Given the surprisingly small price difference between the SDM4065 and the SDM3065, this will not be the case there, i.e., “normal” references will be used. ;)
I don't think it's such a big deal if you're aware that the meter can still drift in the early stages.
I ran my SDM3065X continuously for over a month, then for 2 weeks, 2 hours on and 1 hour off.
I think it has “stabilized,” but I'm not sure, because to know for sure, I would have to log it with a signal that drifts significantly less than the reference in the meter or the meter itself as a whole.
My replica Elektor reference should have 10 ppm, which should be sufficient, but I am uncertain because I do not have a measuring device that can measure significantly below 10 ppm....wahhh... ;)
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I do not have a measuring device that can measure significantly below 10 ppm...
yet 😉
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Aging and selecting the refererences would add some costs, but it is not that bad.
For the sigilent meters it is however not just the reference drift. With a SD ADC chips they also have a voltage divider to bring the 7 V to some 2.5 V to 5 V that the ADC can work with. That part and the ADC chip itself can also show initial drift. So for such a design it would be more a burn in for the complete meter.
Another option could be to have the burn in at the customer and plan for an re-adjustment after 1 year or so.
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Hi, i received mine today SDM4065A ...
After work i will make some pictures. (also inside)
The question if the scannercard will fit or not in a normal version is simple. (NO)
the bay is not there, so No... so GPIB clearly goes with that extra USB connection and not with that module as before.
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[attach=1]
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So you bought the non SC version ... the slot/bay is not even there.
I really do not understand this choice :(
EDIT
I mean I do not understand Siglent choice
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The question has been, can one use a ScannerCard in a non -SC version, because in the SDM3000 the slot was always there.
Siglent always said No to this, because of missing wiring inside, but still many have questioned that, because of the slot.
Now there is no confusion... not a bad choice at all from Siglent i think.
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I would have preferred to have the choice to buy the SC card as an add on in a second time in case the need arises.
Missing wiring inside ... produce 2 board versions ... for sure they did the math.
It is just that I don't understand their math :)
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The question has been, can one use a ScannerCard in a non -SC version, because in the SDM3000 the slot was always there.
Siglent always said No to this, because of missing wiring inside, but still many have questioned that, because of the slot.
Now there is no confusion... not a bad choice at all from Siglent i think.
Not only, there is no hardware frame installed in SDM3000 models to support the scanner card, only in the -SC models.
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Yes i see your point...
What maybe happened, that they later thought of the scanneercard and then realized they needed the 'extra 4-wire' to the slot. that before was only used for GPIB
last minute design desission? who knows...
at least the confusion is gone now..
can't wait to open it
EDIT: what tautech says :) its even more missing in a normal version
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I would have preferred to have the choice to buy the SC card as an add on in a second time in case the need arises.
Missing wiring inside ... produce 2 board versions ... for sure they did the math.
It is just that I don't understand their math :)
Current maths for SDM3000-SC models, the SC version additional cost is less than an additional scanner card by itself.
In other words, you get the scanner card and HW and wiring loom for less than the cost of an extra scanner card.
Dave asked about this a while back so we looked at SDM3000-SC pricing:
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg5021944/#msg5021944 (https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg5021944/#msg5021944)
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Current maths for SDM3000-SC models, the SC version additional cost is less than an additional scanner card by itself.
In other words, you get the scanner card and HW and wiring loom for less than the cost of an extra scanner card.
The result of my math is I am now evaluating the SDM4055A-SC instead.
Anyway I still have a couple of weeks before a final choice ...
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Current maths for SDM3000-SC models, the SC version additional cost is less than an additional scanner card by itself.
In other words, you get the scanner card and HW and wiring loom for less than the cost of an extra scanner card.
The result of my math is I am now evaluating the SDM4055A-SC instead.
Anyway I still have a couple of weeks before a final choice ...
i wonder what is your use for the SC ? i had one in my SDM3065-SC, end i endedup not using is very much, (also i have enough DMMS to do it without scanning :palm: )
for me it seemed only useful in production environments where you meseure many tempratures
So what is your use?
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Current maths for SDM3000-SC models, the SC version additional cost is less than an additional scanner card by itself.
In other words, you get the scanner card and HW and wiring loom for less than the cost of an extra scanner card.
The result of my math is I am now evaluating the SDM4055A-SC instead.
Anyway I still have a couple of weeks before a final choice ...
i wonder what is your use for the SC ? i had one in my SDM3065-SC, end i endedup not using is very much, (also i have enough DMMS to do it without scanning :palm: )
for me it seemed only useful in production environments where you meseure many tempratures
So what is your use?
That is exactly the point; currently I have no use in mind ... anyway I would prefer, if the need arises, just buying the scanner card instead of n. new multimeters.
EDIT
Really? Do you have so many multimeters to replace a 16 ch. scanner card?
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The decision should be made with consideration of the SC capabilities and limitations:
https://int.siglent.com/u_file/download/24_03_28/SC1016_Datasheet_DS60030-E02A.pdf
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Really? Do you have so many multimeters to replace a 16 ch. scanner card?
Sadly yes... a very bad case of TEA and its not only DMM's i love counter too... its bad....bad.... :palm:
btw i have 2 videos or so about the 3065 scanner card on my channel, i made a breakoutbox (not very beautiful, but very useful)
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The question has been, can one use a ScannerCard in a non -SC version, because in the SDM3000 the slot was always there.
Siglent always said No to this, because of missing wiring inside, but still many have questioned that, because of the slot.
Now there is no confusion... not a bad choice at all from Siglent i think.
I think that's good, because it clarifies whether or not it would be possible to “upgrade.”
Although it was already clear here that it wasn't going to work out:
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg5020930/#msg5020930 (https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg5020930/#msg5020930)
It's not just “2...4” cables, there are missing connectors, the mechanical mount, and probably components on the circuit board, and finally, the meter also has to “know” that it's an SC model, which means you would then have to access the firmware.
No, the way it is now with the 4000 series is better.
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I think the main reason for not allowing a user upgrade to the SC version is likely the voltage rating of the connector used for the scanner. So already having the connector installed could limit the maximum safe voltage. Another point could be just the costs of the parts with only few units actually changed to the scanner version.
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Really? Do you have so many multimeters to replace a 16 ch. scanner card?
Go look at one of Tony's youtube videos and you can see for yourself. 🤣
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I think the main reason for not allowing a user upgrade to the SC version is likely the voltage rating of the connector used for the scanner. So already having the connector installed could limit the maximum safe voltage. Another point could be just the costs of the parts with only few units actually changed to the scanner version.
Personally, I think it was a crappy design choice that they shouldn't have hung on to for the new meters. The 3000 series was clearly a copy of Keysight's meters. Adding on a card there was probably an afterthought that changed a no card design.
Now, the 4000 series is clearly attempting to copy Keithley. The difference being that Keithley's system makes upgrading addon cards simple. The DMM6500 and DAQ6510 share the same analog board, but allow for two different types of scanner cards. Siglent should have followed this philosophy and made the SC card simply an optional upgrade. Why bother with 4 production lines, when you can do two? It makes no sense to me. They could have offered with and without the SC card as a simple optional addon.
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Really? Do you have so many multimeters to replace a 16 ch. scanner card?
Sadly yes... a very bad case of TEA and its not only DMM's i love counter too... its bad....bad.... :palm:
btw i have 2 videos or so about the 3065 scanner card on my channel, i made a breakoutbox (not very beautiful, but very useful)
Really? Do you have so many multimeters to replace a 16 ch. scanner card?
Go look at one of Tony's youtube videos and you can see for yourself. 🤣
I watched the one about SDM4065A-SC ... and yes I noted a few devices around but I didn't take the time to count the DMMs.
Indeed I noted he modified the DMM Check Plus adding SMA connectors ... nice one.
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I noted a few devices around but I didn't take the time to count the DMMs.
I think the fact that it would take time to count all the DMMs tells you everything you need to know. 🤣
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Closer look, also the rubber bumper changed compared to the Demo model.
notches have changed.
[attach=1]
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Some quick shots... need new glasses, no clue what i am shooting.. can't get into the lab right now, but at least we have a quick look.
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more
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more
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If this new Siglent SDM4000A DMM is even close to the price of the DMM6500, why would anyone consider it over the Keithley?
The DMMs at this level are intended for accurate, repeatable, precise measurements and the Keithley DMM6500 and Keysight 34461-5A have demonstrated such over many years/decades of doing exactly this, these are the "Benchmark" DMMs in this territory, and relatively new unknown for Siglent.
One reason is china is very hard to be independent of the "western market". Worst case scenario is china invades Taiwan, everybody gets angry at china, china builds a big wall around itself and then stops interacting with the rest of the world. I'm not sure how realistic this scenario is, but china is also not a "normal" country.
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@tony:
Very good, then I don't have to open mine... ;)
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ohhh they use their own SOM module ... lm399 a classic
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Is it normal for new Siglent equipment availability in USA to be delayed or is this a chump thing?
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Is it normal for new Siglent equipment availability in USA to be delayed or is this a chump thing?
Probably the latter. US prices went up recently on the US Siglent site. I purchased a Siglent SPD4000X before the tariffs kicked in, and it is now 15% more., which is very reasonable. Not everything went up though. SDS800X HD did (5%), but SDS1000X HD did not (which is also reasonable). SDM3045X remained the same, but SDM3065X increased by 15%. I am curious what the SDM4000A is going to be. I originally thought the SDM4065A would be sold for around $980 (slightly less than $1000), but I now think it will be at least $1120.
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Is it normal for new Siglent equipment availability in USA to be delayed or is this a chump thing?
No it's not normal and until the tariff dust settles there will be some uncertainty.
Just keep an eye on the US website.....sorry I don't have any insider knowledge.
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https://www.batronix.com/versand/siglent/alle-multimeter.html (https://www.batronix.com/versand/siglent/alle-multimeter.html)
Batronix has the 4055A and 4065A in stock. With the current special offer for the SDM3065X, you can choose between the 4055A and the 3065X, with a difference of just $3...
Higher precision vs. more modern design.
Why not both... 8)
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Why not both... 8)
Because of the bank account.
I am curious to see the internals of the 4065A-SC ...
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It looks pretty much the same as tonyalbus's, except that the mechanic for the card has been added, along with the connections.
Oh, I didn't really want to open it...
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It looks pretty much the same as tonyalbus's, except that the mechanic for the card has been added, along with the connections.
Oh, I didn't really want to open it...
Thank you ... yes the board looks exactly the same; even the scanner card data connector is present ...
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I will test the scanner card function soon.
Personally, I would like a second scanner card with fewer channels but higher voltage resistance.
Then it would also be suitable for work.
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I will test the scanner card function soon.
Personally, I would like a second scanner card with fewer channels but higher voltage resistance.
Then it would also be suitable for work.
Thanks for sharing your pictures,
i see your inside fuse has a cover, while mine has not, maybe because of those cables close by.
and you have an extra fuse in the back
Did your seal also say: Calibration void and not Warranty void? when seal broken?
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Hi,
Yes, it's now on everything, on my SDG6000X, SSG3000X...
Siglent must have ordered the wrong seals and now they're just using them up. ;)
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Hi,
Yes, it's now on everything, on my SDG6000X, SSG3000X...
Siglent must have ordered the wrong seals and now they're just using them up. ;)
I think they finally ordered the correct seals. 😉
Lots of countries don't allow warranty void stickers, because they can't invalidate the warranty for doing basic service.
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Hi,
Yes, it's now on everything, on my SDG6000X, SSG3000X...
Siglent must have ordered the wrong seals and now they're just using them up. ;)
I think they finally ordered the correct seals. 😉
Lots of countries don't allow warranty void stickers, because they can't invalidate the warranty for doing basic service.
AFAIK warranty void stickers are illegal in the USA; they are not explicitly illegal in EU but are probably not enforceable due to the law governing the warranty.
I good sum-up at https://www.ifixit.com/News/74736/warranty-void-stickers-are-illegal-in-the-us-what-about-elsewhere (https://www.ifixit.com/News/74736/warranty-void-stickers-are-illegal-in-the-us-what-about-elsewhere)
I appreciate Siglent opted to "lightly discourage" the practice of looking inside something that you *own*.
I guess they have the full right to declare the calibration voided if the sticker is broken ...
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I guess they have the full right to declare the calibration voided if the sticker is broken ...
Probably every TE manufacturer or cal lab uses cal void if opened stickers.
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Probably every TE manufacturer or cal lab uses cal void if opened stickers.
Surprisingly (to me) the one that doesn't is Fluke. They have little round stickers that go over the actual CAL button if it is externally accessible, but that's it. If you send something to them for calibration, it comes back with a little peel-off sticker (like from the DMV) that is still on the form so you can leave it there or put it where you want. The bench meters have a little outline where it is supposed to go but putting it there does not obstruct any screws or anything. Now if I send the same meter to Joe's All-Pass Calibration Lab and Sticker Store, I'll get it back looking like it is wrapped in crime scene tape.
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As far as I could tell from the photos, the new 4065 uses the same ADC and the same reference as the 3065. Otherwise, the two devices are quite similar.
What’s interesting is the digitizing mode, which is a feature of the ADC used. It would be great if someone could test it, especially regarding the temporal consistency of the sampling intervals.
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Do they come with any calibration certificate?
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it comes with [Certificate of Calibration]
1 sheet A4/letter, which basicly says:
Appearance test, Function test, safety test and calibration
done on fluke 5522A , at date, time, temp, sn.
it passed calibration [OK]
signed by engineer
Like this: https://www.siglenteu.com/operating-tip/faq-calibration-traceability/ (https://www.siglenteu.com/operating-tip/faq-calibration-traceability/)
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Today, my 10V reference arrived, which will serve as a “placeholder” until my adjustable reference is finally calibrated.
Equipped with ADR1399, burned in for 4 weeks, calibrated with a 7.5 digit meter.
I ran it together with the SDM3065X and the SDM4065A-SC for an hour at a room temperature of 20.8°C.
Both meters show slightly higher readings, in the case of the SDM4065A by around +14ppm, which is not bad. ;)
(Provided that the calibration of the reference can be relied upon)
I will log the progress over several hours with the test controller program at the weekend.
Oh, and the Brymen is performing quite well in the higher resolution mode.
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The test has been running for over an hour now, let's see how long I leave it running today.
What you can see is that the two settled down in the first 20 minutes or so.
I should mention that I had “burned in” the 3065X for about 6 weeks and also had the SDM4065 in continuous operation for about 3 weeks.
What's interesting is that both meters measure the voltage higher. I actually had the impression that people had complained about the opposite in the SDM3000X thread. ;)
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What's interesting is that both meters measure the voltage higher. I actually had the impression that people had complained about the opposite in the SDM3000X thread. ;)
You can tweak the Cal, well at least in the SDM3065X and this User adjustment was added for owners to adjust precisely for drift as the DDM reference ages.
IIRC this feature is in the Utility menu.
I liked at anytime you could return to the factory Cal.
Guessing SDM4000A has it too but I don't remember checking for it when at HQ.
Defpom did a video on adjustment which should be linked in the OP of the SDM3000X thread.
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The test has been running for over an hour now, let's see how long I leave it running today.
What you can see is that the two settled down in the first 20 minutes or so.
I should mention that I had “burned in” the 3065X for about 6 weeks and also had the SDM4065 in continuous operation for about 3 weeks.
What's interesting is that both meters measure the voltage higher. I actually had the impression that people had complained about the opposite in the SDM3000X thread. ;)
Stability already looks better on the 4000. You might want to change the scale to zoom in a bit.
What was the temp and RH for the ref cal?
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@Rob:That's a good idea, Rob, but I'll leave that to others when I send the meter in for its first calibration after factory calibration.
The calibration will cost around €150, which is worth it to me.
I have now finished logging after a little over 4 hours.
I think the results are more than acceptable.
I have also attached the log export.
Edit: Room temp 21.3°C, RH 48%
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@Rob:That's a good idea, Rob, but I'll leave that to others when I send the meter in for its first calibration after factory calibration.
The calibration will cost around €150, which is worth it to me.
Well good luck with a Cal lab ! :horse:
One major US one didn't even know SDM3000 were adjustable and recommended they should be binned when outta spec ! :palm:
Cal (Performance Verification) is one thing, adjustment is another and when they don't have the script to auto adjust from their Fluke calibrators, manual adjustment seems just not worth the trouble. :horse:
Good ones are hard to find.....
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Good ones are hard to find.....
That's true, but I have other options due to my job. ;)
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The manual states HISense/LOSense input protection limitations as:
2. Sampling (HISense and LOSense) terminal
HISense and LOSense are used for 4-wire Resistance measurement. Two protection limitations are defined:
- HISense-LOSense protection limitation: 200 Vpk.
- LOSense-LOSense protection limitation: 2 Vpk.
Shouldn't last line be referencing LO terminal? i.e.,
- LOSense-LO protection limitation: 2 Vpk.
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The senseLo limit still makes little sense. Of cause it should be relative to the normal Lo terminal and not itself. In addition it should be well more than 2 V as protection limit. 2 V would be more a sensible number for the limit for the meter to still get correct readings - could still be less. Chances are Sense Lo would have a similar 200 V protection limit. From the PCB pictures I would even expect a higher limit before damage is done. The more critical one could be the high side terminal in ohms mode, that may not withstand ESD or similar spikes that well.
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Shouldn't last line be referencing LO terminal? i.e.,
This came up in regards to the SDM3000X series, and was reported to Siglent who acknowledged it was an error.
https://www.eevblog.com/forum/testgear/sdm30xx-input-terminal-protection-limitation/ (https://www.eevblog.com/forum/testgear/sdm30xx-input-terminal-protection-limitation/)
In the SDM3065X User Manual edition UM06036-E01B from May 2017 it stated:
2. Sampling (HIsense and LOsense) terminal
HIsense and LOsense are used for 4-wire Resistance measurement. Two protection limitations are defined:
- HIsense-LOsense protection limitation: 2000Vpk.
- LOsense-LOsense protection limitation: 2Vpk.
In the SDM3065X User Manual edition UM06036-E02B from Feb 2022 it now states:
2. Sampling (HI Sense and LO Sense) terminal
HI Sense and LO Sense are used for 4-wire Resistance measurement. Two protection limitations are defined:
- HI Sense-LO Sense protection limitation: 200Vpk.
- LO Sense-LO protection limitation: 200Vpk.
So apparently this correction was missed when they created the SDM4065A User Manual (as of edition EN01A it is same as UM06036-E01B):
2. Sampling (HISense and LOSense) terminal
HISense and LOSense are used for 4-wire Resistance measurement. Two protection limitations are defined:
- HISense-LOSense protection limitation: 200 Vpk.
- LOSense-LOSense protection limitation: 2 Vpk.
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LOSense-LO 200Vpk looks better. There are also some spelling mistakes in the manual, somebody should go check that.
Looking through the manual I don't see any reference to using both sense and force terminals to measure two voltages and show ratio V1/V2 on the screen (like in some HP/Agilent/KS DMMs).
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The SDM3000 /4000 come with a somewhat odd front end to get a 20 V with only a +-15 V supply for the analog part. This requires having the COM terminal not at ground, but moving it with the input. With this configuration it is not easy to use the sense input as independent inputs. It would at least come with some limitations (e.g. reduce the ranges to half) and extra effort (switch to a mode where COM is ground). In this case it makes sense to not offer the ratio function.
In contrast with the HP/KS and Keithley meters COM is equal to circuit ground and there is relatively little extra effort (mainly software) to use the sense inputs also for a 2nd voltage.
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Some spelling errors in manual that needs fixing
Binning Munual (on DMM display, p122)
Menu > Help > Teach support :-DD (in manual, p29, p126)
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LOSense-LO 200Vpk looks better.
I'm not sure this correction is, well...correct! I don't have this meter, but on similar meters you'll see that the LO-sense and LO (force) actually have low impedance between them, not a direct connection but not anywhere near isolated. This is a factor that limits the test lead resistance in 4W mode--it can't be very large or the LO-sense-to-LO current will become a factor. Thus in these meters the LO-sense-to-LO (force) voltage really is limited to something very small because the current would become excessive at higher voltages. IDK if this applies to the specific DMM we're discussing here, but if someone could measure between those two terminals using a DMM with a fairly high compliance voltage then maybe we'd know.
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The SDM3000 /4000 come with a somewhat odd front end to get a 20 V with only a +-15 V supply for the analog part. This requires having the COM terminal not at ground, but moving it with the input. With this configuration it is not easy to use the sense input as independent inputs. It would at least come with some limitations (e.g. reduce the ranges to half) and extra effort (switch to a mode where COM is ground). In this case it makes sense to not offer the ratio function.
I'm not clear on the construction of the input as you describe it, I would have thought they would just float the supplies of the input buffer and that doesn't really float the COM terminal, does it? In any case, the input limitation markings on the front of these meters are almost identical to what is on the front of an HP34401A and IIRC we're all pretty sure that once upon a time Siglent took a very close look at the 34401A! The 34401A has low impedance between the two LO terminals and in the ratio mode, those two terminals have to be shorted. Presuming that the SDM3000/4000 also have low impedance there--as implied by the markings--then I'm not sure why ratio would be difficult as it would only involve switching the input buffer between the two HI inputs.
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The protecion levels are kind of industry standard. The SDM3065,4065 , HP34401 and most other 6 digit meters have protection via resistance of some 100 K to limit the current. For enough voltage rating the resistors are usually chains of equal values. The specs for the normal voltage input sometimes looks a bit optimistic, with relays that have limited voltage specs. Some meters seem to turn off a relay to prevent over heating the resistors. However his is more like a longer time thing.
For this reason KS has some supension on the specs and use for high voltage.
On the other side with the Sigilent meters the protection for the sense input often looks nearly as good as the main input. So chances are the 200 V specs there would have some reserve. The problem in the ohms more is more the current source that is usually through the main input - this may well not like a full 1000 V.
The question of a ratio measurement is a different thing. They are just reusing the sense terminals. With the 34401 the sense terminals are from the HW side not that different from the normal input. The HP meter use AZ switching at the input and get a kind of differential reading this way. The normal voltage is input and COM=GND or for 4 wire ohms sense H and sense L as the 2 readings in the AZ loop.
Sense low has no pre-charge and thus more switching spike, but would still be an input used for the low side and assumed to be low enough in impedance externally to absorb the current spike. One still wants a way to define the relative voltage between the main input and the 2nd voltage to measure. The direct link from Sense L to COM would be the obvious solution, but there could also be some voltage difference.
With the limited supply in the sigilent meters the COM terminal can not be directly linked to the supply ground. It is very likely driven to the opposite if the main input,as this is the way to get a 20 V high impedance input and at the same time a differential signal to drive the differential ADC.
This limits the available input range between COM and the sense terminals. As an example, if there are 20 V between the normal input and COM, the COM would be at some -10 V relative to the supply and thus little headroom (maybe some 3 V) for a negative voltage between COM and a sense input.
The system with moving the COM signal relative to the supply ground is an elegant way to get a larger range and differential signal, but it is not compatible with easy electronic switching between more inputs. So it would be quite some effort to add an ratio mode to the SDM3065, while it is easy (no extra HW needed) for the 34401.
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I don't have either Siglent meter to look at nor a schematic (does anyone?) but I'd still like to know if I'm correct about the LO-sense having low impedance to the LO (force) terminal.
As for the floating or bootstrapped voltage supplies for the 20V-range input buffer, are you saying that there is only one +/-15V voltage supply for the entire in-guard input circuitry? Other similar systems that I have schematics or information for use a separate bootstrapped supply for the 20V input buffer and then immediately divide it by 10 and send it to the 2V (or so) ADC. There typically is no "common" for this bootstrapped supply, but if you take the average of the two to be your common, then that will indeed be offset from the LO input by approximately the input voltage. But in the examples I'm aware of, this has no implications for the relationship between the COM/LO (force) and any other part of the system.
The 34401A requires an external short between the two LO terminals to take an accurate ratio reading. Shorting those terminals in 4W ohms mode gives you a sort of 3W setup that still takes fairly accurate resistance readings. What happens if you short the two LO terminals on the Siglents and take either voltage or resistance readings? I'm guessing you can read +/-20 V just fine this way.
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AFAIK there are no open schematics for the SDM3065 around. I also don't have such a meter, just looked at photos. These show clearly just a single +-15 V regulated supply for the input section and the unregulated voltage should also have not much headroom as the heat sinks a quite small.
As far as one can see the input is kind of differential. I could not see all the details, but it looks like some buffer (may also work as amplifier) than 2 dividers and buffers at the ADC inputs. So this really fits the idea of driving the low side (COM terminal). Signal switching is with CMOS MUX chips (ADG1208/1209) and these would not have enough supply range to alow a full +-24 V relative to ground.
A configuration with driving the low side is a bit unconventional, but it makes absolute sense for a ADC chip with differential inputs. It may be a bit mind twisting, but the circuit itself is not to complicated and having a 20 (24) V range is nice. I have a somewhat similar configuration for my DIY DMM, though with a single ended ADC. So I know the limitations that come with this configurations.
There should be no low impedance link from sense Lo to COM in the meter. There should be at least the chain of resistors (some 100 K) from the protection. Some meters have a clamp for only a relative low voltage (like 2 diodes) for sense low, but this could also be higher.
It should be fine to connect the sense low terminals or a sense terminal to COM and still do the full voltage reading. One could however run into issues if one applies a voltage (like 5 V) relative to COM - one would than expect a current ( 10s of µA) at the sense inputs with some input voltages at the main input. Also the 34401 has not low impedance link. It just wants a reasonable low impedance (like < 10 K) external link, so that the switching spike can be absorbed.
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... and I finally received my 4065A ...
[attach=1]
@Martin72 just to not reinvent the wheel: I guess for TestController you just copied&pasted the SDM3065 + IDN string modification. Am I right?
Did anyone already submitted the modification to HKJ?
Thank you
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... and I finally received my 4065A ...
(Attachment Link)
@Martin72 just to not reinvent the wheel: I guess for TestController you just copied&pasted the SDM3065 + IDN string modification. Am I right?
Did anyone already submitted the modification to HKJ?
It wasn't exactly that simple, I made the definition. I'll share it here, and if it works, then I'll share in the TC thread. Needs more testing before that, and I don't have one of these (yet?).
Do you have the regular version, or the -SC?
Thanks,
Josh
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... and I finally received my 4065A ...
(Attachment Link)
@Martin72 just to not reinvent the wheel: I guess for TestController you just copied&pasted the SDM3065 + IDN string modification. Am I right?
Did anyone already submitted the modification to HKJ?
It wasn't exactly that simple, I made the definition. I'll share it here, and if it works, then I'll share in the TC thread. Needs more testing before that, and I don't have one of these (yet?).
Do you have the regular version, or the -SC?
Thanks,
Josh
Thanks to you indeed Josh.
I have the regular version.
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Thanks to you indeed Josh.
I have the regular version.
Try the attached and let me know how it goes. I made 3 different versions. ;)
Thanks,
Josh
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Try the attached and let me know how it goes. I made 3 different versions. ;)
It is working since 20 minutes without a glitch.
I am currently measuring the AC mains (togheter with BM2257).
I know; boring and not th ebest use of a 6.5 digit multimeter anyway the first and fastest thing to measure I had at hand ...
I'll switch to something else in an hour or two.
Completely unrelated to TestController: I found the network interface unresponsiveness even to a simple ping after I was playing with it for a while.
I power cycled the device to have the network working again ... currently no idea how to reproduce it.
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If that glitch happens again, try hitting the shift key (assuming it works the same way as the others) to switch to Local control again before reattempting remote control.
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I think the attached file is the one that worked for Martin. @Martin72, have you modified the file at all? Or is it running fine as is?
Thanks,
Josh
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If that glitch happens again, try hitting the shift key (assuming it works the same way as the others) to switch to Local control again before reattempting remote control.
Local control was working perfectly ... it was just the network not working.
I played with EasyDMM-X - no issue
Switched back to Local and took a few measurment - no issue
I played with the Web interface - no issue
Switched back to Local and took a few more measurement and played around a few menu - no issue
I tried to connect with TC ... no connection but Local was working ...
Tried to ping -> no reply
Then I power cycled.
Let's see; I'll pay some attention ...
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Hi @Josh,
I hadn't changed anything.
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Local control was working perfectly ... it was just the network not working.
I played with EasyDMM-X - no issue
Switched back to Local and took a few measurment - no issue
I played with the Web interface - no issue
Switched back to Local and took a few more measurement and played around a few menu - no issue
I tried to connect with TC ... no connection but Local was working ...
Tried to ping -> no reply
Then I power cycled.
Let's see; I'll pay some attention ...
If it happens again, and pinging doesn't work, try something else like *IDN? or *CLR or *RST and see if that does anything for you.
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Local control was working perfectly ... it was just the network not working.
I played with EasyDMM-X - no issue
Switched back to Local and took a few measurment - no issue
I played with the Web interface - no issue
Switched back to Local and took a few more measurement and played around a few menu - no issue
I tried to connect with TC ... no connection but Local was working ...
Tried to ping -> no reply
Then I power cycled.
Let's see; I'll pay some attention ...
If it happens again, and pinging doesn't work, try something else like *IDN? or *CLR or *RST and see if that does anything for you.
Found how to reproduce 8)
Software ver: 0.0.0.18
Start condition: fresh new configuration, dhcp.
Action to reproduce: set screensaver (I used 15 min). Immediately after (or few minutes later) Menu->Utility->Store/Recall->RestoreFactory/OK
Symptom: network becomes unavailable. Device does not respond to ARP.
Recovery: perform a second "RestoreFactory" or "Lan OFF/ON" or "LXI reset"
The behaviour is not consistent ... every few RestoreFacotry it happens also without setting ScreenSaver ...
Anyway not a big issue
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Some spelling errors in manual that needs fixing
Binning Munual (on DMM display, p122)
Menu > Help > Teach support :-DD (in manual, p29, p126)
Ehm ... it's not only a matter of spelling ...
[attach=1]
:o
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It can happen. ;)
Furna, were you able to establish a successful connection with TC?
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It can happen. ;)
Furna, were you able to establish a successful connection with TC?
[attach=1]
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Also the 34401 has not low impedance link. It just wants a reasonable low impedance (like < 10 K) external link, so that the switching spike can be absorbed.
I'll reply to that when I return home in 2 weeks. The two LO terminals don't have a simple low-resistance connection, there are semiconductors or something involved. However, IIRC, if you put any significant voltage there, like 10V, I you'll get a large current. The maximum lead resistances for 4W ohms are <<<10k, and for ratio measurements anything less than a complete dead short will produce some error. But I don't have one available so I'll have a closer look when I do.
You have an interesting theory on the Siglent design, the only suggestion I have is my previous request for someone to measure that impedance using a DMM with fairly high (10V?) compliance voltage.
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The maximum voltage at sense Lo for 4 Wire resistance is likely in the lower range, that use gain for the main amplifier. The limitation would be not so much the voltage at sense low, but the range for sense Hi is limited (some 120 mV) and if a significant part is lost at sense lo there is not much range left.
For protection the sense input have some 24 K of series resistance.
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Any tear-downs of these?
Curious about the internal Thermal/PCB design, type Reference and ADC utilized.
Best
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Any tear-downs of these?
Curious about the internal Thermal/PCB design, type Reference and ADC utilized.
Best
See reply #130 Mike.
Tony gave us a few pics:
https://www.eevblog.com/forum/testgear/new-siglent-multimeter/msg5900438/#msg5900438 (https://www.eevblog.com/forum/testgear/new-siglent-multimeter/msg5900438/#msg5900438)
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Does anyone know the password for user calibration for the SDM4065, weird it does have a password
i want to play with this a bit,, when all goes wrong i set it back to factory.
Rob maybe? @tautech
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Does anyone know the password for user calibration for the SDM4065, weird it does have a password
i want to play with this a bit,, when all goes wrong i set it back to factory.
Rob maybe? @tautech
No idea, actually never had one across my desk but first suspect would be the PW to get into the DSO Developers options. :popcorn:
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No, it's not. ;)
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I was also going to play with user calibration a bit today ... DMM Check Plus r8 just arrived this morning.
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I was also going to play with user calibration a bit today ... DMM Check Plus r8 just arrived this morning.
DMM Check plus after travel to you is not good enough to serve as reference to adjust SDM4000.
I would only make a calibration ( defined as measuring up all the test points, 10 times in a row, and writing down detailed results)
And do that every month.
At one point measurements will settle and become very stable.
You will never know if changes were because of DMMCheck or meter.
Until an independent high quality calibration on both is performed and then you will know.
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No, it's not. ;)
I hit exactly the very same wall ... moreover the device freezes and I need to power cycle with the button.
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I was also going to play with user calibration a bit today ... DMM Check Plus r8 just arrived this morning.
DMM Check plus after travel to you is not good enough to serve as reference to adjust SDM4000.
I would only make a calibration ( defined as measuring up all the test points, 10 times in a row, and writing down detailed results)
And do that every month.
At one point measurements will settle and become very stable.
You will never know if changes were because of DMMCheck or meter.
Until an independent high quality calibration on both is performed and then you will know.
Thank you, I am aware of DMM Check plus limitations ...
Since a user calibration does exists on my SDM4065A (I can switch between user calib and factory calib) and since the user calibration is far away from the reference 5V I was going to play with it ... but hit the password wall (and subsequent freeze of the device).
IMHO something definitely worth to singal to Siglent.
Going back to calibration ... the idea is to wait a few months (I would say beginning of January 2026) and send both device for calibration (for the DMM adjustment included).
Enough time for stabilization.
The plan is easy to realize if I do not relocate to Italy before that date ...
BTW anyone knows a good lab that offers services to non commercial entities in Italy?
EDIT: I just learned that DMM has a trim pot so will ask the lab if they can adjust the DMM check plus too.
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Thanks Rob anyway you always respond very fast! @tautech
indeed thats not it.
tried also with the date 2025.06.21 for today and chatgpt thought it was 112112
so i send now a support ticket to siglenteu, i wanted the original calibration report also.
when i know, you know :)
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i just want to play with is, and use my WRYtech PDVS2mini and my DMM6500 and the GDM6091 , they all agree.
and for other ranges i can use my old Fluke 5101B with the two Keithley/GW-Intek
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Tony, did you also got the freeze of the device after inserting a wrong password?
Thank you
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Tony, did you also got the freeze of the device after inserting a wrong password?
Thank you
The first few times not (i think, i did not notice in my memory) , but after 2 time yes
also the [wrong password] window is sometime behind the soft-key-board,
after [enter] it just shows still the keyboard, until you click [close] and than the [wrong password] window appeared
and a power cycle is needed also with mine
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Same here, reported to siglent.
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May I ask you how did you report?
Standard Siglent EU "contact us" form or did you contacted the seller?
Thank you
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I know someone at siglent support, that would be more direct.
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Thanks Rob anyway you always respond very fast! @tautech
indeed thats not it.
tried also with the date 2025.06.21 for today and chatgpt thought it was 112112
so i send now a support ticket to siglenteu, i wanted the original calibration report also.
when i know, you know :)
Tried the SN# or the word SIGLENT ?
Anyone looked in the Help files in the chance the PW is there ?
After visiting Siglent last August and seeing their instrument Cal lab and the rows and rows of automated Cal equipment, adjustment of any reasonably new instrument in my view is questionable however any precision instrument with a reference will over time drift.
Again in my view isn't it better to concentrate efforts into measuring/logging any initial drift until it stabilises before attempting adjustment ?
Still, User Cal in any instrument should be an 'available to all' feature and not behind a PW wall.
Instead when entering User Cal a massive OSD warning is all that is needed and the ability to recall the factory Cal.
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Memory is relatively cheap and usually large enough to keep quite some of the calibration history. So the option for a reset to a previous setting should be possible.
A PW protection makes some sense, but the users should have the default password. So the owner can decide to enable an effective protection. This is how it is usually done.
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After visiting Siglent last August and seeing their instrument Cal lab and the rows and rows of automated Cal equipment, adjustment of any reasonably new instrument in my view is questionable however any precision instrument with a reference will over time drift.
Again in my view isn't it better to concentrate efforts into measuring/logging any initial drift until it stabilises before attempting adjustment ?
I see it a bit more pragmatically.
Siglent's initial calibration ensures that the devices are within their specifications.
Subsequent (external) calibrations confirm this or not.
The parameters drift at the beginning, of course, but as long as they do so within the specified tolerance, it is only of academic interest, at least to me.
The fact that I burned in my SDM4000A for three weeks is purely for sporting reasons. ;)
In real-life testing, you should choose a measuring device with a tolerance that is well below that required for the measurement tasks, so that you never find yourself in a situation where you have to question the measurement results.
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Anyone tried the obvious passwords...?
SDM4000
SDM4000A
SDM4065
SDM4065A
4065A
4065
6504
A6504
4000
4000A
1234
4321
1111
abcd
dcba
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I tried 1234 and I would also try all the other obvius ones ... if the device does not freeze and need a power cycle to return functional :-//
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Thanks Rob anyway you always respond very fast! @tautech
indeed thats not it.
tried also with the date 2025.06.21 for today and chatgpt thought it was 112112
so i send now a support ticket to siglenteu, i wanted the original calibration report also.
when i know, you know :)
Tried the SN# or the word SIGLENT ?
Anyone looked in the Help files in the chance the PW is there ?
After visiting Siglent last August and seeing their instrument Cal lab and the rows and rows of automated Cal equipment, adjustment of any reasonably new instrument in my view is questionable however any precision instrument with a reference will over time drift.
Again in my view isn't it better to concentrate efforts into measuring/logging any initial drift until it stabilises before attempting adjustment ?
Still, User Cal in any instrument should be an 'available to all' feature and not behind a PW wall.
Instead when entering User Cal a massive OSD warning is all that is needed and the ability to recall the factory Cal.
It is just to play with to try to get it the same as my DMM6500 GDM9061 and the WRYtech who all agree on most tempratures on 1 or 2 digits.
Thats what a user call is for i would think. and you can just set it back to factory cal at any time.
The Factory call is near good ~13ppm so yes within specs. compared to my other stuff of which i am sort of sure off :)
The strange thing is, the User-Call is very off, i would assume/expect it to be same as factory when arriving new.
which is not the case with my meter, and i received it new, it was not the old Demo one from the video.
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[...]
The Factory call is near good ~13ppm so yes within specs. compared to my other stuff of which i am sort of sure off :)
The strange thing is, the User-Call is very off, i would assume/expect it to be same as factory when arriving new.
which is not the case with my meter, and i received it new, it was not the old Demo one from the video.
I confirm; Facotry-call is well within specs.
The User-call is way off.
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For whatever reason, no password is now requested...
Yes, the values differ drastically, but that's not so bad because you want to correct them anyway.
That's the whole point of personal calibration, otherwise you wouldn't need it.
However, I would steer clear of it for two reasons:
-As long as there is no documentation available on how to do it.
-You don't have the appropriate references that are sufficient for calibrating a 6.5 digit meter.
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The password is requested when you select Recili, not before
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The password is requested when you select Recili, not before
Correct ... when you select Recali
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Yepp, my fault. ;)
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Things starts to look better ;)
Unfortunately I cannot tell what has changed since the 10V reference just arrived a couple of hours ago.
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This perfect match... ;)
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Things starts to look better ;)
Unfortunately I cannot tell what has changed since the 10V reference just arrived a couple of hours ago.
Room temperature?
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Things starts to look better ;)
Unfortunately I cannot tell what has changed since the 10V reference just arrived a couple of hours ago.
Room temperature?
When I took the photo it was 26.5°C; now 26.8°C
DMMCheckPlus cal. certificate report 5V room temp 21.3°C
TEN389 unfortunately does not report root temp.
DMMCheckPlus meanwhile drifted to previously measured 5.00004V
TEN389 looks more stable and drifted to 10.01649
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Just got my 4065A a couple of days a go, and been playing around with it. Nice to have such a comprehensive multimeter! 8)
But there are quite a few bugs that i have encountered so far. So the firmware could use some improvement still.
Here is a weird bug:
2W resistance: Turn on Auto Ranging and Auto Zero. Short the input leads to create zero ohms. The instrument shows about ~0.007 ohm. All ok so far. Then remove the short. You would expect the meter to measure open "overload" in the 100Mohm range. But nope. Mine shows about 0.014 ohm (slight fluctuating) and sometimes tries to switch to the 200k range, before going back to the 200ohm range. When i disable Autozero, the measurement functions correctly again. This only happens on auto range, when using fixed ranges everything works correct.
And another bug/issue? On 2 wire resistance, when i just plug in the upper test lead, the meter already measures ~20Mohm. When i unplug the upper test lead the meter measures >100Mohm. This might be an earthing related issue here in the lab to be honest, but yeah this makes measuring anything above 20Mohm impossible.
The whole datalogging and digitize functions are a bit unreliable. I had instances where the digitize function would continuously alternate between the true value of the signal and zero volt, when i was just measuring 5V from my lab supply. Exports to csv from both the datalog and digitize would sometimes result in the same incorrect values. I dont have a way to reliably reproduce this problem.
It isnt really clear when you are in Continuous acquire mode that you are also recording, at what speed, and where in the recording memory you are exactly. You can save the recording from the Acquire menu, but in order to delete/reset the recording you have to go in to the Trend view. But in trend view you cant save them, you have to go back to Number view -> Acquire. A bit messy if you ask me.
The Start value in the CSV export had a bit of a weird notation. For example:
"Start date:,2025-09-05,Start time:,14:15:08.3.375781"
Is it showing milliseconds or what?
And maybe it would be nice to have better options to navigate (zoom, scroll, etc) through Histogram and Trend view?
And as a final issue, windows keeps nagging about the usb stick needing to be repaired after it has been used in the sdm4065a. There seems to be no data corruption however.
That is what i have so far :box:
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And maybe it would be nice to have better options to navigate (zoom, scroll, etc) through Histogram and Trend view?
Agree
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SDM4055A arrived and now with a chance to spend a little time with it since last August when we played briefly with SDM4065A at Siglent HQ before release.
First thing was to set time to NZ where I noticed there is also a setting for NTP time if connected to your LAN. :-+
Screenshot grabbed remotely using the webserver.
(https://www.eevblog.com/forum/testgear/new-siglent-multimeter/?action=dlattach;attach=2664829)
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New one is already released SDM4075A 7 1/2 digits with 50000 rdgs/s.
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New one is already released SDM4075A 7 1/2 digits with 50000 rdgs/s.
:-+
Chinese webpage:
https://www.siglent.com/products-overview/sdm4075a/ (https://www.siglent.com/products-overview/sdm4075a/)
Chinese datasheet:
https://www.siglent.com/wp-content/uploads/2025/09/SDM4075A-Datasheet_CN01A_.pdf (https://www.siglent.com/wp-content/uploads/2025/09/SDM4075A-Datasheet_CN01A_.pdf)
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I'll take one. ;)
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I'll take one. ;)
Spot this option ?
(https://www.siglent.com/wp-content/uploads/2025/09/Interface.png)
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I'll take one. ;)
Spot this option ?
I do like the rear jacks, but I'm guessing that's not going to be on the -SC version. I'd prefer the rear jacks though, I'm not going to replace my DAQ6510. ;)
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I'll take one. ;)
it is have LTZ1000 and adc ftom SDM4065 ?
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So i was trying to do some device sleep current measurement with a SDM4065A and i was a bit disappointed with the zero offset that came with this multimeter. So im running at the 2A DCI range and i first tried to measure the zero current level by just shorting the input. Im reading a zero level of about 380uA. Hmm, yeah when you are trying to measure microamps sleep current of say a microcontroller or something, having an offset of 380uA seems like a lot. But ok, it seems to be within spec of the meter.
Maybe i was just expecting a little bit better calibration out of the box? :o
The next histogram shows the results over a couple of minutes of measuring. It has a nice span of just 35.7uA, a std dev of 5.2uA and a distribution as you would expect. It even shows the distinct converter steps.
[attachimg=1]
Anyway, we can obviously use REL mode to zero out the measurements. And as expected that puts the zero level in the right spot with just minor fluctuations.
The span, std deviation and distribution curve all look similar to the non-REL measurement so no problems here.
[attachimg=3]
But then the SDM4065A has an AutoZero option. But what the hell is that supposed to provide us?
- It does not zero out the measurement at all, i get an average remainder of 85uA still
- The measurement noise increases a lot! A span of 122uA, std dev 24.8uA, and the curve is all over the place
- It obviously adds lag because of the additional zero measurement in between each normal measurement
[attachimg=2]
So my question is, is there something wrong with AutoZero, or what is the purpose of it?
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Sidenote: i do realize the 2A range on the sdm4065a might not be the most accurate of the ranges. The 200mA range actually has way better specs and indeed shows less offset by default. I guess that is just a result of the hardware architecture.
The AutoZero noise and offset problem however is still present on the 200mA range.
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The SDM3065 or 3055 are known to use a TIA for the lowest current range(s). With such a configuation not current should use an open input and not a shorted pinputs. The current ranges should be similar to the 200 mV range, possibly even less voltage for full scale. So the 2 A range can be relatively noisy.
The SDM3065 uses a AD8622 (pA range bias low drift BJT based amplifier, a bit like an improved AD706), likely as initial buffers for the inputs. It is not so sure if these buffers are included in the AZ loop. One should be able to see if it is included: if the AZ cycle includes it, one would see spikes in the input current from AZ switching. If not there would be essentially no AZ switching spikes.
The input buffer could some low frequency noise and thus not so great 200 mV range.
The wrong zero in the current ranges could be a problem with the calibration. It may also need quite some warm up time to stabilize.
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The wrong zero in the current ranges could be a problem with the calibration. It may also need quite some warm up time to stabilize.
Warmup time wouldn't be the issue, the problem remains even after 4 hours of uptime.
But yeah I'm thinking calibration might be the problem. So the DCV ranges are all pretty well zeroed out by the factory cal with shorted input leads. Like +1 or +2 counts across the ranges. Its just the DCI and ACI ranges that have this high offset. Its a pretty consistent ~38 counts or ~380 counts depending on the range. So with 2A it has +380 counts offset, 10A has +38 counts. These 2 ranges seem to use the same internal pathway in hardware (same amplifier or shunt resistor?), so it makes sense the offset is also scaled by a factor of 10 between these 2 ranges. The same applies to the 200mA and 20mA ranges, they both utilize the same path. And again for the 2mA and 200uA range.
So what zero offset do other users of 4065A or 3065A get in DCI?
The User manual mentions a "User" calibration option. So you can switch between Factory calibration and User calibration. But my user calibration has obviously never been performed, so it is completely wrong at the moment (its off by like -19000 counts or something in DCI 2A). And the menu doesn't allow you to execute a user calibration without a password. There is also no documentation available for user calibration, so its a bit of a mystery to me. Seems that Siglent still needs to do some work in this area. There is a file menu where you can browse for calibration files (.cal) but i have no idea how to use that.
This is literally the only thing the User Manual mentions about calibration:
The multimeter provides two calibration modes: Factory and User .
- Factory: Perform factory calibration.
- User: Perform user-defined calibration.
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The instructions for the user calibration for the SDM3065 seem to only allow for a full calibration, not a partial calibration, especially not a separate zero adjustment. One may get away with editing an existing cal file, but this would still need a good one to start with. With the adjustment points it would still be difficult to change only the zero point. One still has the possibilty to use the rel. function. So zero before use. This may be the way to go, especially if the zero is also drifting somewhat (e.g. use an extra BJT based amplifier outside an AZ correction).
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But ok, it seems to be within spec of the meter.
Maybe i was just expecting a little bit better calibration out of the box? :o
That is the crucial point.
As long as the values are within the tolerance range, everything is OK.
The meter is working correctly, and any calibration laboratory in the world would confirm that everything is fine with the device.
This can and may fluctuate over time; as long as it is within the specified tolerance, there is nothing to complain about.
If you need more accuracy, you will have to buy a better device.
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That is the crucial point.
As long as the values are within the tolerance range, everything is OK.
The meter is working correctly, and any calibration laboratory in the world would confirm that everything is fine with the device.
This can and may fluctuate over time; as long as it is within the specified tolerance, there is nothing to complain about.
If you need more accuracy, you will have to buy a better device.
But then the question remains, shouldn't AutoZero correct for this offset? Isn't that what that function is for?
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AutoZero, or what is the purpose of it?
Pag.36 of the manual:
When the state of "Auto Zero" is ON:
The multimeter internally disconnects the input signal and measured circuit after each
measurement, and takes a zero reading. It then subtracts the zero reading from the preceding
reading (displaying the difference between the measurement value and zero value during the
measurement), in order to reduce the impact of offset voltage from input circuit on measurement
result.
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Maybe AZ needs to be improved in the firmware?
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With the AZ part the question may be what part of the circuit is included. The AZ switching can not be all the way to the input - there is at least the protection in front and this can add some offset from thermal EMF. Other meters also choose to have the AZ switching only for parts of the circuit. E.g. with the Keithley 2000 (and likely also 2002) there is an zero drift buffer at the input and AZ switching only from after the buffer. So an offset of the input would not be corrected. There is still an extra zero adjustment for the input part that needs a short at the terminals and is usually done during adjustment / calibration.
Normally the AZ part is not that complicated. There could still be firmware issue, like insufficient waiting time when switching.
The issue may be more with the adjustment / calibration procedure, that AFAIK does not include zero but uses 2 small voltages at testpoints. It there is an ussue (e.g. with the calibrator) it can lead to a zero that is off.
Using the REL function to zero before use is usually a good work around. For really sensitive measurements it is anyway good practice to check the zero.
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New one is already released SDM4075A 7 1/2 digits with 50000 rdgs/s.
Shit... I purchased a Keithley DMM7510 a few weeks ago.
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With the AZ part the question may be what part of the circuit is included. The AZ switching can not be all the way to the input - there is at least the protection in front and this can add some offset from thermal EMF. Other meters also choose to have the AZ switching only for parts of the circuit. E.g. with the Keithley 2000 (and likely also 2002) there is an zero drift buffer at the input and AZ switching only from after the buffer. So an offset of the input would not be corrected. There is still an extra zero adjustment for the input part that needs a short at the terminals and is usually done during adjustment / calibration.
Yeah i guess that makes sense.
So i think the whole AutoZero is a bit pointless then. If it just adds noise, doesnt fully compensate for offset (not like REL or proper calibration), and makes the sampling much slower, its just not worth it. Yeah it could compensate for drift while making long measurements, but to be honest i dont think the meter drifts all that much in short timespans of minutes to hours. Maybe if you have wildly fluctuating temperatures its a different story, dont know...
Perhaps Siglent should have implemented a self-cal function on the 4065A. But since they didnt, they should definitely work on getting that User Calibration function working properly!
Then again, I guess the whole firmware is still a bit alpha. Maybe they are just working on getting the 4075A released first and then start working on refining the firmware. You would expect this whole calibration thing would be even more important on a 7.5 digit meter, right?
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New one is already released SDM4075A 7 1/2 digits with 50000 rdgs/s.
Shit... I purchased a Keithley DMM7510 a few weeks ago.
Oh darn, looks like Scott is gonna have at least two 7.5 digit meters. :-DD
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With the SMD3065 / 4065 the value of AZ mode may indeed be limited. The SD ADC chip already has quite good zero drift specs. With many MS-ADCs the ADC itself has quite some zero point drift and there is also low frequency noise. For these it absolutely makes sense to use the AZ mode. With longer integration (e.g. 50 PLC) it can already reduce the noise by suppressing much of the 1/f noise.
It depends on how it is implemented - the HP meters have AZ switching usually only the protection and a little signal switching before the AZ part. So they can compensate for most of the zero drift. It is mainly the thermal EMF from the protection that can't be corrected.
I have some hope that the 4075 could be a reason to improve on the calibration / adjustment points so that 0 V is included.
Quite some of the specs (especially speeds) still look similar to the 4065 and chances are it would be the same ADC, but with a better reference.
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There is a firmware update to version 0.0.0.20 (Release Date 10.10.25) available for the SDM4065A from Siglent, solving at least problems I had with setting the vertical scale of the trend chart (uA/nA input was not possible, had to type as mA value 0.xxxxxx).
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8/19/2025 0.0.0.20
1. Supports SMB and NTP functions.
2. Optimized noise after AZ is enabled.
3. Optimized noise after 100PLC is enabled.
4. Supports saving readings, statistics, and histograms in the scanner card function.
5. Supports relative value settings, statistics, and histograms in the dual display function.
6. Bug fixes
a) System crashes when entering the wrong password during recalibration.
b) Statistics occasionally show 0 in math.
c) Fixed an issue where overload values were recorded during probe-hold.
d) The digitizer would freeze at certain sampling rates and readings.
e) Device malfunctions occurred when using the scanner card's universal remote control command function.
f) File path errors when browsing when holding readings.
g) Selecting uA in current mode did not work.
I think Siglent is following this thread! :o :D
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I can confirm that the AutoZero noise has been improved. Compared to my previous measurements at 2A DCI, im getting about a 45% reduction in noise (~13.4uA stddev vs 24.8uA). But this is still twice as much noise compared to non AutoZero mode.
Still a welcome improvement i would say :)
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I think Siglent is following this thread! :o :D
Looks like it... ;)
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I can confirm that the AutoZero noise has been improved. Compared to my previous measurements at 2A DCI, im getting about a 45% reduction in noise (~13.4uA stddev vs 24.8uA). But this is still twice as much noise compared to non AutoZero mode.
Still a welcome improvement i would say :)
The AZ mode trades more short time noise for less drift and less low frequency noise.
To really compare one would want to look at the allan deviation curve. There is usually a cross over time from which on AZ mode is better.
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The AZ mode trades more short time noise for less drift and less low frequency noise.
To really compare one would want to look at the allan deviation curve. There is usually a cross over time from which on AZ mode is better.
True, but i dont see the meter drifting that much in the span of hours or days (which i assume is the timespan where most of the data logging is done). That cross over point is probably way beyond that. Unless there is maybe temperature drift influence i suppose?
Anyway, i did some more measurements today, including some CSV exports of captured data. I see they fixed the timestamp bug in the CSV file that i mentioned earlier. It now properly displays the start timestamp with milliseconds, microseconds and nanoseconds (!) :)
I am a bit puzzled though by the available memory for storing measurements in Normal mode (so not Digitize or Datalog). It appears the data just keeps logging and logging forever. The trend plot and histogram keep plotting correctly to well over 100 million samples! That is actually amazing! :-+
But no idea where the limit is to be honest...? (im up to 197M as we speak...) Maybe until that 512MB internal Ram is full?
So for histogram you obviously dont need to store all of the samples, but what about the trend plot and stddev calculation? Is siglent doing some smart sample decimation for the trend plot to keep the screen data valid? Interesting!
*** New bug report ***
When trying to save acquired samples in Normal mode (not Digitize or Datalog) to a USB stick you only get 2 million samples maximum in the CSV file. I assume that this 2M number is what is stated in the user manual. But here is the thing: If the meter has acquired more than 2M samples (as shown in the statistics window), the CSV file becomes corrupt. You do get the 2M samples in the CSV file, but at a random location the timestamps become corrupt (even negative timestamps). Im not yet sure what happens to the data, i will try to analyze that in more detail later.
Note: If the meter has acquired less than 2M samples, the CSV file is correct.
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With more conventional DMMs with MS ADC the cross over where AZ mode gets better than non AZ can be quite low, like 1 or 10 seconds.
The later the cross over, the more sensible to use non AZ mode. I don't know the front end details, but in the SDM3065 there are AZ OP-amps directly at the ADC and it looks like AD8622 BJT based low bias OP-amps at the input. The current ranges may have extra amplification and may not be the best example for judging the meter. Where the cross over happens can also depend on the range.
Already 2 M data points in a CSV file is quite a lot. One rarely need such long datasets. 197 M points would not really fit in 512 MBytes, even with just 24 bits and no compression. One can calculate the std. dev. without saving all data. It only need a few more sums independ on the number of points.
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Having Samba is very convenient to directly save to network share...
Also web control (VNC) is too, because when doing something sensitive where you don't want to come close too much you can nicely have things under control from afar..
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Ah yes i see there exists a Running std deviation method, that would solve that issue.
And for the trend plot, as you say it is virtually impossible to store all those samples in memory and plot them on the chart. So there must be decimation going on, at least for the higher sampling frequencies (in my test I was running at 50ks/sec). I assume it is something similar to peak-detect mode of a scope.
Already 2 M data points in a CSV file is quite a lot. One rarely need such long datasets.
True, but it is nice to know the limitations. And obviously if you do exceed the limit by accident you wouldn't want the data to become corrupted in the CSV. With 50ks/s you reach that limit in just 40 seconds.
What would be the preferred behavior with this 2M limitation?
Should the meter only memorize the first 2M data points after the start of an acquisition, and ignore subsequent measurements?
Or should it behave more like a 2M FIFO, so you always store the last 2M measurements?
Tbh i dont care which implementation is chosen, but it should at least be clear for the end user, so you know what data you end up with.
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What is being discussed here is free running Auto meter mode and data from that process.
But there is Log mode where you set timing and length (time/number of samples) and that one will capture deterministic number of samples.
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Having Samba is very convenient to directly save to network share...
Unfortunately the Samba client implementation in firmware ver. 0.0.0.20 does not support encryption of the data transport channel.
I had to revert to "Desired" from the "Required" settings on my NAS for the transport channel in order to mount a share.
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Whatever method they choose, they should make it so it exports the data uncorrupted. Even 1M points is too much in a CSV, unless you're using a script to do something with the data.
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In firmware ver. 0.0.0.20 the NTP address is not saved between reboots.
It always reverts to ntp.pool.org
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Hi,
I am very much interested in acquiring this meter. I have a question for an owner of this meter - I am interested if when in diode mode it continuously beeps if there is a short and if it shorts beep during a normal reading - where there is a normal voltage drop reading. As far as I've seen pictures with menus I assume you can set the long short beep, but there is no video or mention about the short beep.
Thank you very much!
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Alientek DM40 and Brymen BM788BT works like you want, generate short beep on functional diode and continuous beep on broken one. Alientek can identify Schottky diode, under 0.02V continuous, between 0.02V - 0.45V two short beep, 0.45V - 0.75V one short beep, 0.75V - 1.45V three short beep. Brymen see only normal diode. Both meter communicate over Bluetooth and have phone app. For Brymen Windows software is not yet ready but you can write your software, protocol communication has been released.
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I'll answer the actual question...
I am interested if when in diode mode it continuously beeps if there is a short and if it shorts beep during a normal reading
In the menu, you can switch the buzzer on/off, change the volume, and set the threshold above which no acoustic signal is emitted.
The diode measurement is very fast; no short beep is generated when measuring the diode path.
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I know the man and what he want to do so, my post wasn't really off topic. I think he will appreciate both answers. He may still want/buy SDM4000A.
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Perplexed by the lack of full, or at least more in depth, reviews after 7 months form initial show and tell. Folks seem to have non demo versions available. Checking outlets in the US still either not available, backlisted, or out of stock. What was the reason for delay that would become obvious in time? I still totally don't need it but money is burning a whole in the pocket...
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Perplexed by the lack of full, or at least more in depth, reviews after 7 months form initial show and tell. Folks seem to have non demo versions available. Checking outlets in the US still either not available, backlisted, or out of stock. What was the reason for delay that would become obvious in time? I still totally don't need it but money is burning a whole in the pocket...
You can thank the orange turd in the oval office for that. Tariffs are not helping international trade.
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Is that it, just tariffs? Tariff situation does suck, but I did not see any major disruptions on other similar products from the far East. Also, looking at SDM3065X at Siglent NA, ships in 2-3 days. However, SDM4065A "Inventory Available on or about 02/05/26". Three months out, wow! Are you suggesting all other items were well stocked out from before April's fools day? Anyway, just wanted to hear if there was anything else going one besides the tariff situation. I'd rather not hear about it, than hear about it and not be able to get it, haha.
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I'd rather not hear about it, than hear about it and not be able to get it, haha.
lol! Yeah, it is a tease.
I'm sure most of the previously available items were well stocked before the tariff nonsense. Think about this- how many units will they ship to stock a country on a new device? In that case, the tariffs make a huge difference. I'm just speculating beyond that, I dunno how the supply is, but I know from somebody on the inside that the tariff situation has had a major impact on bringing in new devices.
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Is that it, just tariffs? Tariff situation does suck, but I did not see any major disruptions on other similar products from the far East. Also, looking at SDM3065X at Siglent NA, ships in 2-3 days. However, SDM4065A "Inventory Available on or about 02/05/26". Three months out, wow! Are you suggesting all other items were well stocked out from before April's fools day? Anyway, just wanted to hear if there was anything else going one besides the tariff situation. I'd rather not hear about it, than hear about it and not be able to get it, haha.
NA has been slow in adopting the SDM4000A series, noticeably slow from where I sit.
I've always suspected the US tariff situation was the reason as I cannot imagine another.
Unless they had a lot of SDM3000 models they needed to shift first. :-//
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He doesn't really want to buy the SDM, he wants a Keithley, but because he can't afford the Keithley, he would go with a clone (SDM40xx) :)
The truth is that none of these models work in diode mode the way I want... I really don't understand why manufacturers do not implement this diode mode beep function, it's not like it has been patented by Fluke...
Anyway, highly disappointed.
About stocks, they are available in the EU. The 4065v is in stock and 4055 has a 7 days lead time.
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I really don't understand why manufacturers do not implement this diode mode beep function
Perhaps because it makes little sense to implement something like that.
What is the point of the short beep?
To test diodes “blind”?
I wouldn't do that; I would always check the forward voltage as well, and then you don't need an audible signal if you're looking at the display.
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Right now SDM4055A and SDM4065A are in stock at welectron.com with shipping from Germany.
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NA now shows "Inventory Available on or about 12/22/25". Today is 12/22 so I guess it is more "about" than "on".
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NA now shows "In Stock: will ship in 1-3 days", yay!
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Wow, NA now "Inventory Available on or about 03/11/26" I guess they only snuck in a few units, or everybody and their mother ordered one. Was a big enough window. Got mine, which is all that matters :-)
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Not a lot of videos about this meter online, so adding one. Maybe not the most interesting feature, but playing around to see how well it can read and follow dBm readings on a 50Ω load, outputting a sine wave out of my SDG2042X into the SDM4065A with a 50Ω thru BNC adapter.
https://youtu.be/d6ZgsBna0v4
Found that the SDM4065A follows very well up to its ACV bandwidth of 300KHz and decently (+/- < 1 dB) to 1MHz. Not shown in the video, you can go up to 2MHz and 3MHz, but beyond that it saturates and has a hysteresis returning down in frequency that finally resets once you drop to 1MHz. So very safe to use up to 1MHz I think.
By comparison my trusty Fluke 289 follows noticeable less closely and only up to 100KHz point zero, and is way off for values below -10 dBm or -20 dBm.
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Here is another video showcasing the SDM4065A DCV digitizing abilities. Using SDG2042X to output a 0dBm square wave at 100Hz, 1KHz, 2KHz, 3KHz, and 5KHz. Still image below for context (shows 1KHz).
https://youtu.be/z_CfiXbHOLM
The SDM4065A does 50 KSa/sec but the -3dB bandwidth is 10KHz. The video reflects this. Once you go above 1KHz the lack of odd harmonics within the 10KHz bandwidth degrades the square wave significantly (as expected). Does exactly what it says on the tin.
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Nice looking DMM, Congrats :-+
Nice display, you can easily see the under sampling effects on the squarewave.
Best
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It is odd to see the undershoot before the rising edge. This not what one would expect from a DMM, because the ADC is not classical sampling, but a SD type that is more integrating. So there should normally be no digital reconstruction / interpolation filter for the display, like with a DSO.
Some ringing could well be from the analog front end. The version with a driven negative side to get the 20 V high Z range is a bit prone to ringing.
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Symmetric ringing before & after is interesting, very scope like.
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Looks like Siglent is using SineX/X reconstruction, maybe they borrowed some of the DSO folks to help with the DMM development!!
Best
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8/19/2025 0.0.0.20
1. Supports SMB and NTP functions.
2. Optimized noise after AZ is enabled.
3. Optimized noise after 100PLC is enabled.
4. Supports saving readings, statistics, and histograms in the scanner card function.
5. Supports relative value settings, statistics, and histograms in the dual display function.
6. Bug fixes
a) System crashes when entering the wrong password during recalibration.
b) Statistics occasionally show 0 in math.
c) Fixed an issue where overload values were recorded during probe-hold.
d) The digitizer would freeze at certain sampling rates and readings.
e) Device malfunctions occurred when using the scanner card's universal remote control command function.
f) File path errors when browsing when holding readings.
g) Selecting uA in current mode did not work.
I think Siglent is following this thread! :o :D
Did our PD checks on a unit today and when correcting the time clock from Shenzhen to NZ time I noticed the new NTP feature and as I had a LAN connection nearby, enabling auto DHCP and NTP time was just a couple of screen touches and hey presto the correct time was set. :clap:
Too easy.....the NTP server address was already entered at the factory. :-+
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So, I have been complaining to Siglent about my SDM4065A DCI range being out of spec on the zero level, see my old post (https://www.eevblog.com/forum/testgear/new-siglent-multimeter/msg6061195/#msg6061195). Initially in that post i said the offset was still in spec, but actually it wasn't. By the way, me complaining to Siglent about this problem was back in november, over 2 months a go... Nice work Siglent support team! |O.
Ive told them that if they could finally get the user calibration function working on the 4065 i would at least have a solution. Im still baffled why the 4065 firmware is in such a poor shape at this point...
And then i came across a video from Defpom...
The 3065X appears to have nice user calibration function that can selectively be applied to individual ranges and modes. Exactly what i need! So why doesn't the 4065A have this function yet? Siglent, if you are paying attention, this is what we expect for the 4000 series multimeters as well!
https://www.youtube.com/watch?v=8gZZg605ioI (https://www.youtube.com/watch?v=8gZZg605ioI)
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So what are your zero offsets in DCI mode?
Cant be as poor as mine i hope?
[attachimg=1]
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Enable AutoZero..
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Enable AutoZero..
Done that, please read my original post explaining the situation.
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The picture looks like AZ mode on, but also Rel mode active. It may get better with Rel off or after a new manual zero via the Rel function.
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In that picture both AutoZero and Rel are off. On my SDM4065 I get about the same reading. However, turning AutoZero on improves by almost to orders of magnitude. Separately turning Rel on, by itself, also gets to the last digit shown.
Not sure this bothers me at all.
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Yeah the picture is with Autozero and Rel off. Its kind of hard to see with the blue colors.
On my SDM4065 I get about the same reading.
So that is interesting, this could indicate the factory calibration process isn't sufficient to meet specifications? It's maybe a structural problem?
I suppose this isn't a big deal for everyone, we all use our equipment in different ways. But to me having a proper zero calibrated DCI mode is important. I like to measure battery powered microcontroller circuits, so having a large dynamic range with the ability to also measure very low currents accurately (sleep currents) and doing it with a fast sample rate is a requirement. So no autozero for noise and speed reasons, and preferably also no Rel mode.
I mean, isnt it odd that my Brymen multimeter is better zero calibrated than the SDM4065A? In fact i cant remember ever having any multimeter (handheld or bench) that had any significant offset on the DCI range.
Now what everyone should care about is the lack of user calibration with the current state of the firmware. And that is what i like to see changed here. That would solve my problem at least and would help other people in the future as well. And Siglent has proven that they can do it, given the implementation on the 3065X.
I kind of wonder if they are holding back with SDM4065A firmware development until the SDM4075A sees the light of day?
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The picture looks like AZ mode on, but also Rel mode active. It may get better with Rel off or after a new manual zero via the Rel function.
ON is blue and OFF is gray, so on that photo it looks reverse.
Both Autozero and Rel are OFF on that photo.
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I mean, isnt it odd that my Brymen multimeter is better zero calibrated than the SDM4065A? In fact i cant remember ever having any multimeter (handheld or bench) that had any significant offset on the DCI range.
It is not. On Brymen you simply do not see those 2 last digits.
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On my Fluke 289 in mA setting shows "0.000 mADC", but also occasionally "0.001 mADC" and sometimes "0.002 mADC". Whereas in µA setting shows "0.01 µADC" or "0.02 µADC" sometimes. All with leads laying on desk. I don't think much of these as a problem, for my use cases.
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I mean, isnt it odd that my Brymen multimeter is better zero calibrated than the SDM4065A? In fact i cant remember ever having any multimeter (handheld or bench) that had any significant offset on the DCI range.
It is not. On Brymen you simply do not see those 2 last digits.
Small offset is always present, that is not news. Not seeing last 2 digits is fine.
Some multimeters deliberately show fake zero with low input AC V or AC current (IIRC, Hioki models). Not sure about this Brymen model, but at least compare both DMMs on the same AC/DC setting.
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Got a used Fluke 85RF probe and testing on Siglent SDM4065A to make sure the probe is not blown. Supposed to measure only 0.25-30Vrms from 100KHz-500MHz, but was able to go down to -5dBm and right above 10KHz fairly accurately. Detects peaks (diode rectifier) and outputs VDC equivalent to sine Vrms, so will be off for non sinusoidal signals (but still good for a ballpark).
Nice that SDM4065A does dBm math on VDC! My Fluke 289 only does dBm math on VAC. Extends SDM to see beyond its 300KHz rated (1 MHz tested) AC bandwidth.
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So what are your zero offsets in DCI mode?
Cant be as poor as mine i hope?
You can't compare any 6.5 digit bench meter to a lesser digit DMM, especially not a handheld.
How are you shorting the inputs? 4-wire short?
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How are you shorting the inputs? 4-wire short?
For DCI and ACI zero measurement, you leave the connections open without any leads attached, as shown in the picture. This prevents any antenna or inductive loop that could cause unwanted current flow in to the input terminals. Someone else pointed out to me that shorting the input leads is not good practice for measuring the zero point of DCI and ACI.
Im going to quote Siglents specifications here, just to point out the obvious. Its the 90day spec for the DCI 2A range:
0.080+0.005 Accuracy ± (% of Reading + % of Range)
Nowhere in the specification does it say this specification requires Autozero to be turned on, as one would expect.
So doing the math for my previous example: (0.08% * 380u) + (0.005% * 2A) = 100.304uA
So the specification says the accuracy should be within 100.304uA. But I'm measuring 380uA when it should theoretically be exactly zero. So my meter is out of spec by a factor of 3.8
And so if Vsilves says his meter is showing the same offset, then it is clear that this is not an isolated case, but it could be a structural problem.
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For accurate measurements one should have the AZ mode on. If one needs to use the non AZ mode one should at least use the REL function before the measurement to get a valid zero.
To some degree the meter chould do at least an internal zero (like in AZ mode) when changing range or function in the non AZ mode. Some meters do this, but the SDM4065 seems to not do this (or has it disabled by default).
Usually the accuracy specs are for the AZ mode - they may just have missed that point here.
Some multimeters deliberately show fake zero with low input AC V or AC current (IIRC, Hioki models). Not sure about this Brymen model, but at least compare both DMMs on the same AC/DC setting.
A few (usually cheap) meters (even more common with balances) indeed fake a zero or have an enlarged zero bin that is split as +0 and -0. In part this was an issue with dual slope ADCs, that have very good DNL, except at 0.
The zero with AC measurements is a different topic. The analog RMS converters just don't work at very low voltage like < 0.1%. There is also the issue with meter internal noise and subtracting that in a correct way. Users would complain of the meter sometimes shows negative RMS readings. To be fully honest they should show the 0 in a different way than normal, like as 00 or 0 0 .
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Hi,
Results from my SDM4065A-SC, 10PLC, auto-zero on, input short-circuited.
All manual ranges, once without, once with rel function.
I don't see any problems with the meter.
Martin
EDIT:
Auto-zero was off, measurements will be repeated.
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Here's the same thing, now with auto-zero.... :P ;)
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Results from my SDM4065A-SC, 10PLC, auto-zero on, input short-circuited.
All manual ranges, once without, once with rel function.
I don't see any problems with the meter.
Thank you for the detailed measurements. You say you dont see any problems, but your meter is also out of tolerance when not using Autozero. It confirms the measurements i made earlier.
Obviously you can Rel out the zero point, but that is bad practice for current measurements, since you are now just shifting the entire calibration (so basically everything else is measuring wrong now). Rel should only be used when you want to make a true relative measurement, not as a band-aid for a bad calibration.
And sure, Rel is typically used to subtract unwanted probe / lead capacitance or resistance when measuring Capacitance or Resistance, so effectively zeroing out those measurement modes. But in those cases, the calibration isn't affected, you are just making a true relative measurement.
Autozero is not something i like to use, because it has it own drawbacks as mentioned earlier. Even as Kleinstein said, Autozero is a tradeoff; less drift vs more noise and lower speed. So for accurate measurements i'd rather rely on having Autozero switched off.
Now what is interesting from the Defpom video i posted earlier is that the SDM3065X has a separate calibration for each mode and range with and without Autozero. So there is no reason why the zero point calibration would be out of tolerance when not using Autozero. Take a look at the 4:26 mark in the video:
https://youtu.be/8gZZg605ioI?si=3r1mO64nqXR1L-BL&t=267
Interesting right? Assuming the same applies to the 4065A...
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Hi,
According to the calibration protocol I have for my model, everything is fine.
If the measurements were performed with auto-zero (not specified), this shows even more clearly that there is no problem with using this function.
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Using the REL function is not effecting the calibration. It only substracts an offset, that can especially be present in the non AZ mode. So if there is a good way (open input for current) to get a zero, using the rel function is a good way. Especially with old meters it was standard practice to check and maybe adjust the zero before use.
If the meter has so much offset as shown, one should use the rel function (or the AZ mode).
It depends on the meter, function and time frame whether one wants the AZ mode or not. Some meters kind of need AZ mode (e.g. HP34420, 3458), while others can get away without (e.g. Datron 1281). Usually shorter time windows for an experiment prefer non AZ mode, while over a long time AZ mode is usually better.
From the little I know about the front end, I would expect the SDM4065 to be relatively good in non AZ mode, but it would still profit from AZ for longer times (e.g. > 5 min).
The rather high offset in non AZ mode points to a poor calibration / drift since then. Many meters automaticly correct at least what they can internally with a function change. This is kind of a nice feature that the SDM40xx is missing.
If not using the REL function is kind of needed for the non AZ mode.
It is a bit odd that the specs are not more specific about AZ mode and use of REL for the offset.
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Using the REL function is not effecting the calibration. It only substracts an offset, that can especially be present in the non AZ mode. So if there is a good way (open input for current) to get a zero, using the rel function is a good way. Especially with old meters it was standard practice to check and maybe adjust the zero before use.
I strongly disagree. That offset that you are subtracting when using REL mode is applied everywhere. So all those calibration points that Siglent so delicately measured and programmed are now also out by that same offset. And having all the calibration points out by 380 counts (as in my example) is not up to standards if you ask me. Sure, percentage wise it is better to have that offset at a high level calibration point than at the zero point, but it is still just shifting the problem.
Rel should never be a replacement for a proper calibration.
The rather high offset in non AZ mode points to a poor calibration / drift since then.
Exactly!
According to the calibration protocol I have for my model, everything is fine.
If the measurements were performed with auto-zero (not specified), this shows even more clearly that there is no problem with using this function.
Thank you, this is actually quite insightful. From what i gather from your calibration report and the Defpom video, it appears that Siglent doesn't use a zero level calibration point for their calibration procedure. I'm not sure which calibration points Siglent uses exactly for the DCI ranges, since the defpom video only shows DCV and your calibration report only shows a +40% of range and a -107.5% of range verification (which i doubt are the only calibration points for the a single DCI range, i'd expect at least 4 points like the defpom video shows). But if they are not using a zero level calibration point, then that might explain why the meter could be measuring a wrong zero level, even when the calibration was performed correctly at Siglent. That could imply that there is some kind of non-linearity in the system somewhere...? Or it could be drift?
Well, im curious to see what Siglent's response is. If they could just implement that user calibration function in the 4065A, just like the 3065X has, i would be happy.
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The technical data sheet for SDM4065A states "After 90 min warmup and at 100 PLC integration time" and the shown picture had 10PLC. I think I matched your 10PLC so will have to try again with no leads and 100PLC when I get home.
With "90 days at TCAL ± 5C" the expectation is Error: 0.080% reading + 0.005% of range = 0.0001 A according to my calculation. But I think that may not apply to the zero point based on Google Gemini (see below).
Gemini: "Yes, a small offset in the DCI (DC Current) ranges—especially high-current ranges like 2A—is perfectly normal for 6.5-digit multimeters like the Siglent SDM4065A, even immediately after a professional calibration. At the 6.5-digit level, even microscopic temperature differences between the shunt resistor and the internal circuit board create tiny voltages (Thermal Electromotive Forces). The absolute "zero" is the most volatile point on a 6.5-digit meter. It can shift slightly due to changes in ambient temperature (even by 1C), humidity, or the magnetic environment of your lab bench."
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Have not had 90 minutes warm up time to try the 100PLC DCI yet.
Overall, I find the UI of the SDM4065A rather rudimentary, in line with a 0.4 release. The little use of the rotary knob, and the inability to zoom horizontally bug me slightly. I did find auto vertical scale, which saves me having to press "rescale once" repeatedly. However, I am quite happy with the performance and value. Of course, there is nothing wrong with the SDM4065A. The only thing wrong would be my expectation that it does everything everybody may ever want or thinks they need.
Ultimately, having SCPI interface like other Siglent devices, allows one to build custom interfaces for custom testing scenarios, and that matters a lot more to me than the actual UI in the nice screen that I find myself squinting on most of the time.
Here is an example of what I mean by custom test interface using a few lines of Python (using Fluke 289 and Fluke 85RF probe). When I have time, I plan to see how many samples per second this puppy can provide (SDM4065A).
https://youtu.be/s2ykCpWX0KA
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Here is an example of what I mean by custom test interface using a few lines of Python (using Fluke 289 and Fluke 85RF probe).
What did you use to connect the 289 to your computer?
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I bought this for $20 bucks from China, which took a couple of weeks. It is like a generic optocoupler to micro-USB serial interface board stuffed inside a 3D printed plastic part, and a second 3D printed part that locks to the first one. No USB cable or anything else provided. The assembly fits into the Fluke 289's void between the meter and its stand on the back, (instead of locking perfectly to the opto port as I thought it would), but works fine. Would like it to have some more weight and close the gap better, but works no issues at 115200 baud on MacOS. It was pretty easy to research the Fluke serial command interface (in these forums mostly).
https://sandboxelectronics.com/?product=opto-isolated-usb-ir-adapter-for-fluke
I have never used FlukeView Forms software.
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@S13
I just got my SDM4065A on Wednesday (FW 0.0.0.20), so haven't had much time to collect this data as of yet; although the meter has been powered on fully since then (21.0C ambient). I replicated your setup (2ADC range, 10 / 100PLC, AZ on / off) and see some similarities:
With AZ ON, 100PLC, and no REL, I am seeing <= +0.000045ADC. I have attached a picture for reference.
With AZ OFF, 100PLC, and no REL, I am seeing larger zero offsets around -0.000080 ADC, up to -0.000145 ADC, which is odd in comparison. Slightly out of spec it would seem. my 200mA range doesn't seem to be significantly different than the values I stated earlier.
I will put together some more data soon, but my quick testing has numbers very similar to @Martin72 's post with the auto-zero enabled. Other than that, meter seem to be in spec for the most part.
Edit: Apologies, my pictures keep rotating themselves.
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Thanks that is very helpful!
Yes it seems your SDM4065A is somewhat better calibrated, but still slightly out of spec. Anything above 100uA in the 2A range is too much deviation.
I will relay this information back to Siglent.
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but still slightly out of spec.
(..)I will relay this information back to Siglent.
I must admit, I haven't fully understood the problem yet.
The specifications do not mention what the meter should display when no measuring current is flowing.
And that's what's happening here right now.
Basically, the offset is being looked at, and it's not specified at all (or I overlooked it).
The specs indicate accuracy in %, and zero cannot be expressed as a percentage.
All SDM4000A units come with confirmation that they comply with their tolerances.
I don't think this is cheating.
Or rather, I know it isn't, because I have the complete protocol for my SDM4000A.
I would therefore prefer to measure known reference currents and then worry if these measurements were outside the tolerance range.
But as I said, I don't want to rule out the possibility that I haven't understood the problem.
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@Martin72
Not sure I understand the point made either, just wanted to chime in that I see the same behavior. I certainly don't see the offset showing in current measurements I made, but maybe I'm also missing something here?
Correct me if i'm wrong, but wouldn't the most effective metric be measuring the zero offset with a 4W short installed on the front terminals? Because as of now, the meter's accuracy isn't spec'd for open terminals (ie no DUT?)
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Not sure I understand the point made either, just wanted to chime in that I see the same behavior. I certainly don't see the offset showing in current measurements I made, but maybe I'm also missing something here?
Correct me if i'm wrong, but wouldn't the most effective metric be measuring the zero offset with a 4W short installed on the front terminals? Because as of now, the meter's accuracy isn't spec'd for open terminals (ie no DUT?)
To clarify, you don't see any issue with real measurements, correct?
This is an important note:
The specs indicate accuracy in %, and zero cannot be expressed as a percentage.
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I must admit, I haven't fully understood the problem yet.
The specifications do not mention what the meter should display when no measuring current is flowing.
And that's what's happening here right now.
Basically, the offset is being looked at, and it's not specified at all (or I overlooked it).
The specs indicate accuracy in %, and zero cannot be expressed as a percentage.
No, the accuracy of the SDM4065A is specified as a "percentage of reading" and a "percentage of range". This is important. For higher level measurements, the "percentage of reading" is dominant and for lower level measurements (such as near the zero level) the "percentage of range" is dominant.
So the accuracy of values near or at the zero level can be perfectly specified, and Siglent did just that.
For the 2A range the numbers are as follows (90 day spec):
percentage of reading = 0.08 (%)
percentage of range = 0.005 (%)
Example for measuring the zero level we get: (0 * 0.0008) + (2 * 0.00005) = 100uA accuracy
Example for measuring 1A we get: (1 * 0.0008) + (2 * 0.00005) = 900uA accuracy
So what Siglent did is specify the full range from +2A to -2A, and everything in between, zero included. As one should by the way.
Leaving a portion of the range unspecified in terms of accuracy would be bad practice. Certainly they could have done that, but then they would have needed to specify that in the datasheet - which they didnt.
If i interpreted that datasheet wrong, or Siglent made a typing error in the specifications or whatever, i would assume Siglent would have pointed that out to me by now, its been 3 months... So, im left to assume that Siglent knows something is not right here, they just dont know how to solve it yet...
Maybe some users with other 6.5 digit meters can do some comparisons here? Like how does the 34465A or DMM6500 perform at the DCI zero point? Ages a go i worked with an Agilent 34410A, and that thing was pretty much spot on as far as i can remember. But maybe im remembering it better than it actually was...
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The HP/KS meters have the accuracy specs for the AZ mode. This way they have much less issues with an offset for the zero reading.
Even if in non AZ mode, most (if not all) of the HP/KS meters do an auto zero once at the start, when changing the function (and maybe range). So even the non AZ mode should not have much extra offset.
The rather large offset in the non AZ mode that the Sigilent meters show is more some unconvenience. If accuray matters use the AZ mode or do a REL step.
There seems to be an issue in the adjustment procedure that they did not adjust the value right. Could be as simple as doing the adjustment in AZ mode and this way never adjusting the offset for non AZ mode. At least for the user adjustment the odd procedure with cal points at some +-5% instead of 0 could also contribute.
A question would be if the offset in non AZ mode is also there when coming from AZ mode.
Another point could be testing if the offset is different between a meter turned on from cold, or a meter that was on, than turn off shortly and than turned on again. This could effect a zero procedure that is done in the power on test. Maybe that step is done too early, before the zero is settled.
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The HP/KS meters have the accuracy specs for the AZ mode. This way they have much less issues with an offset for the zero reading.
Even if in non AZ mode, most (if not all) of the HP/KS meters do an auto zero once at the start, when changing the function (and maybe range). So even the non AZ mode should not have much extra offset.
Yes, that would be a better procedure i guess.
There seems to be an issue in the adjustment procedure that they did not adjust the value right. Could be as simple as doing the adjustment in AZ mode and this way never adjusting the offset for non AZ mode. At least for the user adjustment the odd procedure with cal points at some +-5% instead of 0 could also contribute.
I agree.
Including a 0 level cal point could probably fix the entire issue if that indeed is missing from the factory calibration.
A question would be if the offset in non AZ mode is also there when coming from AZ mode.
Another point could be testing if the offset is different between a meter turned on from cold, or a meter that was on, than turn off shortly and than turned on again. This could effect a zero procedure that is done in the power on test. Maybe that step is done too early, before the zero is settled.
Yes that would be interesting to test. Maybe someone else is willing to test this? Otherwise i will have a go at it when i have access to my 4065A again, but that still takes a couple of weeks.
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Not sure I understand the point made either, just wanted to chime in that I see the same behavior. I certainly don't see the offset showing in current measurements I made, but maybe I'm also missing something here?
Correct me if i'm wrong, but wouldn't the most effective metric be measuring the zero offset with a 4W short installed on the front terminals? Because as of now, the meter's accuracy isn't spec'd for open terminals (ie no DUT?)
To clarify, you don't see any issue with real measurements, correct?
This is an important note:
The specs indicate accuracy in %, and zero cannot be expressed as a percentage.
No, zero issues with real measurements, all functions seem to be bang on and well within accuracy specs after 96H of power on.
Yes that would be interesting to test. Maybe someone else is willing to test this? Otherwise i will have a go at it when i have access to my 4065A again, but that still takes a couple of weeks.
Let me give this a try.
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I turned the SDM4065A off and then on again, took all these results at the same time. The 34461A just came back from Pylon and while the DCV failed gain verification, the current ranges passed perfectly fine. It was cold booted. The 8845A has been on for a long while, warm boot. I will post a cold boot of the SDM4065A later once it has cooled.
Worth noting: 34461A's and 8845A's have a zero point for calibration as per the cal manuals
I apologize for shoddy photo editing skills, and the image was too large to post on the forum:
https://imgur.com/a/ouf20wB
-Tyler
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We did a quick test, just turned meters on (no warm up) and set to 10NPLC, Statistics, nothing connected.
All 3 KS34465As read below 3pA, DMM6500 13pA, DQM6510 -73pA, and SDM3065X -10nA.
BTW we pull no punches, what you see is what we measured, be that from Siglent, HP, Agilent, Keysight, Rigol, Keithley, Tektronix and so on. The Keysight's are noted for their low current capability, and the Keithley's for their low ohms capability, why we have both types.
Best
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What percentage of 0 would you say those measurements are off by? ;)
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Now finally with some time to play but only with a SDM4055A for comparison....065A models all sold out.
No shorting link but instead used a Pomona 50 Ohm Banana pass through...thought better than a banana cable acting as a antenna ! :horse:
In DCV mode from cold startup ~0.400mV indicated that steadily fell to very near zero in ~20 minutes.
DCI is now near zero also.
No Rel setting used and all other settings are as new from box.
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Now finally with some time to play but only with a SDM4055A for comparison....065A models all sold out.
No shorting link but instead used a Pomona 50 Ohm Banana pass through...thought better than a banana cable acting as a antenna ! :horse:
In DCV mode from cold startup ~0.400mV indicated that steadily fell to very near zero in ~20 minutes.
DCI is now near zero also.
No Rel setting used and all other settings are as new from box.
Rob,
Believe for "zero current" you should use an "open circuit" like we did with nothing attached to the banana jacks. Also use the statistics function to show an average zero offset current with better resolution, at least that's what we did with the SDM3065X we have, and the other DMMs we mentioned.
Best
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Now finally with some time to play but only with a SDM4055A for comparison....065A models all sold out.
No shorting link but instead used a Pomona 50 Ohm Banana pass through...thought better than a banana cable acting as a antenna ! :horse:
In DCV mode from cold startup ~0.400mV indicated that steadily fell to very near zero in ~20 minutes.
DCI is now near zero also.
No Rel setting used and all other settings are as new from box.
Rob,
Believe for "zero current" you should use an "open circuit" like we did with nothing attached to the banana jacks. Also use the statistics function to show an average zero offset current with better resolution, at least that's what we did with the SDM3065X we have, and the other DMMs we mentioned.
Best
Now open input DCI, use the clock from previous screenshots to calculate the time of power ON.
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Now finally with some time to play but only with a SDM4055A for comparison....065A models all sold out.
No shorting link but instead used a Pomona 50 Ohm Banana pass through...thought better than a banana cable acting as a antenna ! :horse:
In DCV mode from cold startup ~0.400mV indicated that steadily fell to very near zero in ~20 minutes.
DCI is now near zero also.
No Rel setting used and all other settings are as new from box.
Rob,
Believe for "zero current" you should use an "open circuit" like we did with nothing attached to the banana jacks. Also use the statistics function to show an average zero offset current with better resolution, at least that's what we did with the SDM3065X we have, and the other DMMs we mentioned.
Best
Now open input DCI, use the clock from previous screenshots to calculate the time of power ON.
Interesting it uses "Speed" instead of PLCs. 1nA Is small compared to the near 8.6nA I could see on my 4065. Were your measurements jumping around quite a bit with that setup? Or were they staying stable?
Edit: Just did the cold startup and measured AZ off on DCI. Surprised to see that DCV starts up at +000.8614mVDC which starts to drop after heating up. The 2A range is still reporting exactly as warm boot at around -0.000110ADC, and 75nADC on the 200uA range. In all seriousness, my measurements are not showing these offsets with cables connected, and accuracies seem to be within spec so not sure why this is a large issue again, since it's still a percentage of 0, which is 0.
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Now finally with some time to play but only with a SDM4055A for comparison....065A models all sold out.
No shorting link but instead used a Pomona 50 Ohm Banana pass through...thought better than a banana cable acting as a antenna ! :horse:
In DCV mode from cold startup ~0.400mV indicated that steadily fell to very near zero in ~20 minutes.
DCI is now near zero also.
No Rel setting used and all other settings are as new from box.
Rob,
Believe for "zero current" you should use an "open circuit" like we did with nothing attached to the banana jacks. Also use the statistics function to show an average zero offset current with better resolution, at least that's what we did with the SDM3065X we have, and the other DMMs we mentioned.
Best
Now open input DCI, use the clock from previous screenshots to calculate the time of power ON.
Interesting it uses "Speed" instead of PLCs. 1nA Is small compared to the near 8.6nA I could see on my 4065. Were your measurements jumping around quite a bit with that setup? Or were they staying stable?
I looked for a PLC setting in this SDM4055A but it wasn't obvious.
The display was going all over the place (within reason) when cold but kept clocking down as it warmed and when finally warm varied to only a count or 3nA from 0.0A.
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Hi,
I'd like to add a comment to your interesting DCI offset investigations.
When I compare the 4055 vs the 4065 using their datasheets, I see that they differ in their DCI shunt resistors.
In their 200uA (lowest) DCI range, the 4065 apparently uses a 125 ohms shunt (explanation follows) while the 4055 uses 40 ohms.
I am quite sure that they both measure the voltage drop across that resistance to arrive at the current through it, so the 4055 sees only about 1/3 of the voltage which the 4065 sees, therefore any input circuitry voltage offset errors would contribute 3 times more to the DCI offset error on the 4055.
Therefore I am somewhat surprised that the 4055 has the same 0.005% of range offset error spec'd for its 200uA range, since it is about 3 times more sensitive to offset errors due to its lower current shunt resistor value.
Explanation for the 4065 current shunt value: apparently the 2mA and the 200uA range use the same shunt. For the 2mA range tha datasheet says the voltage drop is less than 250mV. From that I calculate R_shunt = 250mV / 2mA = 125 ohms.
So actually one could view the 4065 DCI 200uA range as a 25mVDC range (!) scaled by the shunt resistor value to display DC current.
That kind of explains why there is more counts offset error spec'd as is in the 200mV DC range - for the 4065, you end up having 100 counts specified offset error on the 200uA range after a 90 minute warmup (200uA*0.005%=10nA=100 counts).
Btw, the comment about the readings being "all over the place" during the first minutes after power-on in not very reassuring to me (I am just now considering to purchase a 4065A-SC). Was this with autozero active? I cannot tell from the screenshots - a pity this is not shown, as there are unused softkeys which could have been populated with an autozero ON/OFF function. Also what about the NPLC - really strange that this setting is not easy to determine - it is really important (SLOW/FAST is insufficient - it must be possible to set the integration time to an integer multiple >=1 of the mains supply cylce period).
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Btw, the comment about the readings being "all over the place" during the first minutes after power-on in not very reassuring to me (I am just now considering to purchase a 4065A-SC). Was this with autozero active? I cannot tell from the screenshots - a pity this is not shown, as there are unused softkeys which could have been populated with an autozero ON/OFF function. Also what about the NPLC - really strange that this setting is not easy to determine - it is really important (SLOW/FAST is insufficient - it must be possible to set the integration time to an integer multiple >=1 of the mains supply cylce period).
All over the place = 10 counts or so, steadily diminishing until this SDM4055A reached datasheet operating temp accuracy spec.
After reaching temp, 1-3 counts variation is all I saw, DCV or DCI....remember this is in uV or nA.
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The low current range of the SDM3055 (and likely also SDM4055) is different from the high current ranges: it uses an transimpedance amplifier. This give a separate and often lower offset - one may even get a separate offest in AZ mode. In addtion a shorted or 50 ohm loaded input for the current measurement would be a problem and could give non zero readings from the voltage offset of the TIA part.
The SDM4055 voltage part front end is also different from the SDM4065, as it does no support a 20 V high impedance mode and thus no extra divider stage after initial buffers.
For a comparison the offset of an SDM3065 could be more relevant, as it very likely is essentially the same front end.
The point is the non AZ mode and fixed higher current range (e.g. 2 A).
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@ Kleinstein: Thanks for this insight.
Do you happen to know if 4065 also uses TIA for DCI ?
edit: I just realized I could have answered that myself by looking at the "Measurement Method" section in the datasheet (answer is no TIA).
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Btw, the comment about the readings being "all over the place" during the first minutes after power-on in not very reassuring to me (I am just now considering to purchase a 4065A-SC). Was this with autozero active? I cannot tell from the screenshots - a pity this is not shown, as there are unused softkeys which could have been populated with an autozero ON/OFF function. Also what about the NPLC - really strange that this setting is not easy to determine - it is really important (SLOW/FAST is insufficient - it must be possible to set the integration time to an integer multiple >=1 of the mains supply cylce period).
I fail to understand several things written here.
Firstly, it was demonstrated that SDM4065A on boot settles faster than any other meter, including "legendary" ones.
Secondly, Mike demonstrated that with AutoZero on, it has same or less offset than 34465A from Keysight.
Thirdly, of course you can easily set NPLC.
Fourth, of course you can easily set AutoZero right there on the screen.
NPLC, Rel and AutoZero are right next to each other on the screen.
Tautech has shown an image from different instrument.
I also attach Euramet guideline on calibration of multimeters. You will see that use of AutoZero is recommended for good accuracy. Also you will see that calibration of zero point is not mandatory but left to instrument designer to choose.
In general, I see here that many are posting stuff that is overreaction to how these long scale instruments work and are used.
Also, every instrument will have some individual idiosyncrasies, that will create need for every single instrument to be used slightly differently.
That is usually because they were designed to achieve slightly different things, in slightly different ways.
SDM4065 is a graphical DMM with added fast sampling. It has many usability features that other meters do not. It is not Keysight 3485A, nor anybody pretends it to be.
It also has 2200000 scale, so for measurement on, say, 12 V systems it will give one digit of precision more than Keysight or Keithley.
Like any instrument, it will excel at some things, and be simply good enough at others.
It was already demonstrated that it has comparable (or better) measurements than other meters twice the price. And better usability features. And touch screen.. And many other things that might or might not be of use or importance to user.
User need to choose what is important to them.
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One more note.
In Menu->Utility->System setup there is a Cali button.
Inside Cali screen, there is an option to choose Factory or User calibration.
Please make sure that it is the Factory calibration being selected here. Otherwise, you will have basically uncalibrated instrument.
That is how it is set by default, and if you didn't mess with it it should be Ok.
But if someone did play with it and has large offsets, check here.
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Thanks all for the replies!
I apologize for shoddy photo editing skills, and the image was too large to post on the forum:
https://imgur.com/a/ouf20wB
There you have it, your unit seems to be way better calibrated than mine! Your unit it showing near zero with Autozero On, with only a couple of counts out on most ranges. That is exactly what i would expect! But it is just not the case for my unit sadly...
Compare that to my unit with Autozero On, it still has an offset off 86 counts:
[attachimg=2]
An obviously this is even worse with Autozero Off (but the lesser noise is soooo much nicer...):
[attachimg=1]
Note that the noise in Autozero mode has improved a bit with the last firmware update. These images were made with the older firmware.
So i think we can conclude that the offset that some people see in DCI range is not due to hardware architecture issues, it is just a matter of a bad calibration. That is actually sort of a relief.
In Menu->Utility->System setup there is a Cali button.
Inside Cali screen, there is an option to choose Factory or User calibration.
Please make sure that it is the Factory calibration being selected here. Otherwise, you will have basically uncalibrated instrument.
Yes i am running factory cal. With the User Cal the offsets are way way worse and also all other modes and ranges are completely out as expected.
Im just going to wait until Siglent implements the User Calibration feature, because this part of the firmware is not implemented yet.
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The noise for the non AZ mode looks really good. On the other side the noise for the AZ mode looks poor: it normally should be 1.4 or 2 times higher at most. With the rather long window ( e.g. some 400 seconds for 2000 points at 10 PLC) to looks at could be even lower than the non AZ mode.
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Another oddity I noticed when performing the DCI tests with no leads connected is that starting with the 200uA, increasing it sometimes triggers "Current Overprotection!" warning to show on the display. Seemed to happen at 2mA and 20mA ranges. It seems somewhat random though, not always on the same ranges.
Anyone else see something like this?
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I had that too. I think it's caused by switching between the internal measuring ranges.
As long as it's not displayed permanently.... ;)
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Know this thread is about the 4000 series, but would like to see the comparisons with the SDM3065X with Zero Current (Open Circuit) Histograms and Average and SD results.
We've never been able to get the SDM3065X Histogram to behave/display the way we liked, probably operator error, altho we are running the latest firmware (12R1).
Here's an example using Auto and Manual Histogram settings of a Zero Current on 200ua range (DMM6500 is 10ua range and KS34465A is 1ua range).
Think we'll also post this on a SDM3065X thread, but would be interested in seeing how the new SDM4000X displays a Zero Current Histogram.
Best