Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

[Kleinstein]

It is sometimes convenient to measure voltage and current at the same time (e.g. power going into a regulator, or to measure the U/I curve for a part to test, like a zener diode). One could use 2 meters, but a single meters saves space and the handheld meters usually don't have a PC link. However there is a principle limit in the accuracy from a shared terminal. The reading may still be more accurate than the reading at the usual power supplies.

[bateau020]

Would the need to measure DCV and dca at the same time be a real situation?

From your question I read: "You are using the tools in the wrong way."
Short reply: It would be wrong indeed if I always need the utmost precision and control. And that is not the case.

Longer reply:

Apart from "is a bug that hangs a specific appliance/tool important" (in my opinion yes, any bug that requires manual intervention is a critical bug), yes, V+I measurement via a DMM is something that I at least frequently need.
One cannot always rely on a PSU or an SMU, plugging in a DMM is much more versatile.
And yes, of course, 2 separate DMMs, one for V and the other for I can be better: better logging, better control over settings, name it. But having it all on 1 screen, even with the limitations that go with it, is good enough in many situations. For me at least.

[Peter_O]

easiest way I found to reproduce this: just switch on the meter, set to DCV (auto), press dual, then DCI, the meter clicks and hangs.

Same here: SDM3055 with 1.01.01.25

[TheDefpom]

🔴 TOP SECRET Siglent SDM3065X Multimeter Calibration Procedure - No.891

[Algoma]

Received a new SDM3055 a few days ago. Included leads sure have inconsistent contact when simply shorted together. Continuity beeper sounds like its trying to send morse code as the resistance measurement randomly flashes values all over the low end of the scale, eventually finally settling on a proper expected low value after a few seconds. Rub them together and they produce a really scratchy sounding continuity beeper...

Switched to using my Brymen BM786 Gold Plated leads and the SDM3055 works perfectly at first touch, instantly holding a proper low value.



Left side where Samples(1-4) from the included leads, taking a few seconds to settle on each..
Right side were Samples (5-8) using the leads borrowed from my EEVBlog Brymen BM786 that instantly held the value.

I can't see anything wrong with the Siglent leads, they look normal and clean, and they probe as being in proper condition, but they're sure giving troubles getting a stable reading at low resistance values, even with manual range to lowest range, it still randomly flashes anything from overload to a proper value for a few seconds before finally settling on a proper reading. Behavior presists in the two lowest ranges, I guess its poor conductivity along with the very low test current this meter uses on the lowest range.

[bdunham7]

Included leads sure have inconsistent contact when simply shorted together.

Clean the tips with alcohol.  If you need another set of leads, look at ProbeMaster.

[tautech]

Excellent webpage by Defpom for SDM User Cal CSV file creation:
http://www.thedefpom.com/siglent_sdm_calibration.php

Carefully follow his instructions and use appropriate quality references to build your own SDM Cal files to compensate for accuracy drift as these bench meters references age.
Video above also linked on his webpage for guidance on how User Cal works.

Added to OP.

[Kleinstein]

For the calibration in the non AZ mode the measurement points should be not so far appart in time.  For an instrument that may show some dirft I would measure more like   200 mV / 20 V / 200 mV and than average the 2 readings at the 200 mV point.
For the AZ mode this should not matter as much, but would still be the better way.

Having the low end test points at around 1% FS is a bit odd. The reason behind this may be a output cross over error of an amplifier stage, that may cause some INL error near zero.  On the other hand one would still want an accurate 0 point.

The way with the extra CAL files as CVS files is nice as one naturally saves the calibration.

[TheDefpom]

The 0 crossover can be touchy on the 3065x, the 3055 and 3045x don’t have a 0v adjustment and are done at +- half scale instead (ie -100mV and +100mV), which does solve that problem.

[TheDefpom]

Hi All,
I have been continuing to tinker with my new Siglent SDM calibration file generator, I have added a few more features today.

The main change is the site will store the calibration data when you generate the files.

If you supply your units serial number (it is optional) then it is stored with the data which allows you to come back later on and retrieve the LAST calibration data that you generated, so if you need to just tweak something a little bit you can just reload your last data and change the bit that needed adjusting, rather than having to re-enter everything again (nobody wants to have to do that!).

To be clear, the ONLY reason I am storing the serial number is to allow this retrieval feature to exist, originally I was only going to use it to append to the file names in case multiple units are being calibrated.

[TheDefpom]

Latest video showing a bit more information about the calibration files and my calibration file generator, with extra details especially for the SDM3045X and SDM3055 versions.

[Dbldutch]

Hi all,

I have discovered a weird phenomena with my SDM3055X dated from March this year.
Software 3.01.01.07, hardware 02-02-00-05-00.

I'm measuring a variable DC supply with an output between 0-200V with the DMM.
I use a RIGOL DS2072A to look at the ripple of the supply, that's how I found out.

The DC supply is based on the Harrison/HP/Agilent method, so the "+" is actually the common ground, and the "-" is the varying negative going supply.
I'm connecting my DMM with the Red lead to the "+" of the supply, and the Black lead to the "-" of the supply.
Sounds complicated, but is maybe important. With this setup I'm measuring a positive voltage on the DMM.

With the DC supply off, I see pulses appearing on the DSO as soon as I switch on the DMM, so even before it finishes to boot.

It get's even stranger. When I now turn on the DC supply and adjust the output to 150V and higher, pulses appear on the DSO as well.

When I disconnect only the black lead from the DMM, everything is clean again, same when it is off.
Disconnecting only the red lead makes no difference.

Now for the grand finale...
When I reverse the two DMM leads to connect to the supply, and now measure a negative voltage, everything is clean.

The DSO and the DMM are connected to the same powerblock and so have the same earth ground.
The DC supply is grounded through the DSO probe connection. I have a 240VAC 50Hz mains.

[UPDATE] What I forgot to mention is that my DC supply has no capacitor on the output. This is important because just adding a 1uF film capacitor fixes the problem. This is why most of you problably won't see it when there is some capacitance involved.

I'm puzzled by this is. Luckily I found the cause because I already spend several hours trying to find the problem in the DC supply.

Has anybody seen this, can verify this or provide an explanation?

[Peter_O]

+1 for the Bryman BL21S2-T4SC silicone test leads with gold plated tips.

First time my 3055 reacts as expected with ohm measurement and continuity check. 

I tried polishing and alcohol with siglent and 'keysigth' steel tip test leads before - with some but not groundbreaking success.

[Algoma]

The Leads included with my SDM3055 have been a complete failure when testing any sensitive and low level signals. They look good, but perform unusually poorly, even with cleaning.

Perhaps it may have been a bad batch with the tip plating process, or something at the socket end.

My Brymen leads perform flawlessly on the SDM3055... Even a pair salvaged from an old cheap junk meter are giving me better results at the moment when used on the SDM3055.

[joeyjoejoe]

Does anyone know if custom Thermistor definitions can be added? I'm able to modify existing ones, but I'd like to add a new one. Did not find anything in the manual to suggest it's possible.

[tautech]

Does anyone know if custom Thermistor definitions can be added? I'm able to modify existing ones, but I'd like to add a new one. Did not find anything in the manual to suggest it's possible.

Here's a little info on custom sensors:
https://www.eevblog.com/forum/testgear/sdm3045x-versus-dm3058e-sensor-input-4-20ma/

[joeyjoejoe]

Thanks. Sounds like SDM3055 users need to hope and wait for a firmware update?

[tautech]

Thanks. Sounds like SDM3055 users need to hope and wait for a firmware update?

Which version are you on ?
Latest is V1.01.01.25

Sorry we don't have any in stock to check the 3055 state of play for custom sensors but the other models have it.

[HKJ]

Does anyone know if custom Thermistor definitions can be added? I'm able to modify existing ones, but I'd like to add a new one. Did not find anything in the manual to suggest it's possible.

One way to handle custom sensors is a PC program. TestController can handle a NTC easily and works with any of the supported DMMs.

[joeyjoejoe]

I'm on 1.01.01.20R2

[tautech]

I'm on 1.01.01.20R2

You need update !

[joeyjoejoe]

I don't disagree But it sounds like it won't add custom thermistor values.

[tautech]

I don't disagree But it sounds like it won't add custom thermistor values.

Latest update is most important as it's supposed to fix boot freezes once and for all. It should also align the feature set to the other models.
As I said we don't have stock to check what custom sensor settings are available in 3055 but I would strongly recommend you do the update:
https://int.siglent.com/u_file/download/21_08_06/SDM3055_1.01.01.25_EN.zip

[joeyjoejoe]

Ok, on the latest now

No change for thermistor. If you do see something in the coming months please ping this thread I'll try to keep an eye out as well.

[tautech]

Ok, on the latest now

No change for thermistor. If you do see something in the coming months please ping this thread I'll try to keep an eye out as well.

Have a close look again at the other thread and this post. You should be able to define, modify and save a sensor and have it to recall.
https://www.eevblog.com/forum/testgear/sdm3045x-versus-dm3058e-sensor-input-4-20ma/msg3757376/#msg3757376

Then success mentioned here:
https://www.eevblog.com/forum/testgear/sdm3045x-versus-dm3058e-sensor-input-4-20ma/msg3793610/#msg3793610
Yes I know that's a 3065X but the 3055 should be able to do that too.