Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

[Neper]

Just received my second SDM3045X because I found the continuity beeper to be very low in volume. The beeper in the replacement is just as low. Not exactly loud on high, quite low on MID and practically inaudible on low. Seems a bit odd to me, especially since there's effectively no difference between low and off.

Can someone confirm that this is the same on all of them?

[mawyatt]

LM399 is not the reason for this warm-up drift.
LM399 will be fully up to specs in less than 10 seconds  and pretty much perfect in 30 seconds
It is rest of meter reaching thermal equilibrium.
New meters have fan that speeds up the process by mixing air.
34401A is fan-less design.. It has to distribute temperature passively...

Agree, the two 34401As we have take longer to reach equilibrium at the expense of having no fan. The KS34465A takes longer than the SDM3065X to stabilize which is usually 30~45min, while the 3065A stabilizes in under 30 min.

If Siglent kept the LM399 powered during the soft OFF meter state, we could benefit from the LM399 long term aging quicker

All the DMMs are so good it's hard to complain about much, however the lack of a fan in the 34401A is worth the startup stabilization "wait" IMO

This begs the question, "what would happen if the SDM3065X fan were disabled"

Best,

[2N3055]

This begs the question, "what would happen if the SDM3065X fan were disabled"

Best,

Question has been posited few times, for several different DMM with fans..

I wouldn't recommend it, because they are not designed for stale air inside. In addition to reference, ADC and sensitive front end path, rest of the meter runs hot in comparison. Some parts (PSU for instance) might run too hot.
Also, without airflow, sensitive parts would develop larger and different thermal distribution patterns.

Few brave ones experimented and reported some improvements in low frequency noise and some shift in calibration.
Nobody did serious long term characterization of reliability, accelerated aging etc..

I spoke with some people from Keysight once, and info was that fan helps keep instrument more stable in wider temperature range and power on stabilization faster. Pretty much only downside is acoustic noise.

[mawyatt]

We'll I'm not "brave enough" just yet. Makes sense that LF noise would improve without random airflow, and cal would be incorrect because critical components would be at different running temperatures.

Best,

[eloso]

I have an SDM3045X purchased new two months ago.

Off is silent, Low is, well, low but clear, Mid is louder and is a comfortable setting for me, High is more or less the same volume as Mid but it is a higher pitch and is perceived as being somewhat more strident than Mid although as careful listening reveals Mid and High to be more or less the same actual volume.

I am satisfied with the dettings and happy to use mine on Mid.

Regards

Eloso

[et328]

I have an SDM3045X purchased new two months ago.

Off is silent, Low is, well, low but clear, Mid is louder and is a comfortable setting for me, High is more or less the same volume as Mid but it is a higher pitch and is perceived as being somewhat more strident than Mid although as careful listening reveals Mid and High to be more or less the same actual volume.

My 11 month old 3045x is very similar. High level is annoying, mid is perfect.
Beeper sound seems to come from the side panel vent holes, so if @Neper has those partially blocked with other devices, beeper sound might be more attenuated than with desktop installation.

[Neper]

No, the DMM was standing free in the middle of my workbench when I checked this. Low here is simply inaudible. There's a very faint click when making or breaking contact but no tone.

[movie]

Hello,
maybe somebody has an explanation?

After warm up of my SDM3065X and short circuit on the input terminals the display shows 000.0027 (+-3) mVDC (Range Auto 200mV, 10PLC, Auto Zero On). If I switch Auto Zero to "Off" the reading is 000.0001 (+-2) mVDC. So the Auto Zero function does not help in real.

movie

[TurboTom]

Maybe there's an inductively coupled AC signal present at the input terminals of the meter that may not cause a DC reading but affect the auto zero function? How did you short out the input? How long are the leads used?

[klausES]

Yes, the bridge must be quite direct and short in three places behind the dot (no cable in between) and it must have good contact surfaces quality.
Is the AC filter function on or off ? What is changing by your filter on or off ?

[movie]

Thanks for your hints!

The short circuit bridge is about 3-4cm banana gold plated+high quality measuring stripe. In order to check the Filter influence I switched to ACV. The reading here is 000.0940 mVAC (+-30). The filtersetting has no influence.
The "REL" button of cause eliminates any offset and leaves only the noise.
Ok. on that low levels some noise or thermoelectric effects are expected but does my observation match with the experience of other users of the SDM3065X?

movie

[Bad_Driver]

I see the same effect with my SDM3065X, using a massive 4-plug, golden plated short.
Autozero, 10 or 100 PLC, 10 Mohms or Hi-Z - no difference. About 0.0010 mV + noise

But my 34401A behaves the same way and shows a little bit more difference to zero.

Maybe the result of our electro smog environment?

[Kleinstein]

The Auto zero can only compensate the offset throung the internal switching path. From small temperature gradients on the PCB and at the terminals there can be a small residual offset from thermal EMF. There may be a calibration constant to compensate for most if it, but this may not be perfect and the temperature gradients can change.  Some meters allow to do the zera adjustment independent from a full calibration.

AFAIK the SDM3068 uses an AZ OP at the input and an SD ADC chip. This gives the question on what the AZ mode on such a meter actually does. The AZ mode may only apply to parts of the front end and may not include the first amplifier. For the 34401 and most HP meter the AZ function is obvious : swtich the input to a short or low resistor and than subtract the zwero reading. With meters that have an AZ OP at the front (e.g. Keithley 2000, 2002) this no longer that obvious and some do the AZ swtiching only after a buffer at the input.

[TheDefpom]

Autozero is also interesting as it is actually calibrated as a seperate mode, so if you turn auto zero on/off you are actually switching to some different calibration constants.

[TheDefpom]

I have been working for the past few days to make some software for MacOS which can send SCPI commands and also control the SDM30x5 series of multimeters.

I still have a lot to do but I am able to control my SDM3065X with my Mac and get readings from it.

So far I have two windows, one for sending SCPI commands and viewing the responses, and one to actually control the SDM3065X, which can change modes etc.

Once I have the software polished enough I will share it, I should be able to compile the software to work on windows too.

[HKJ]

I have been working for the past few days to make some software for MacOS which can send SCPI commands and also control the SDM30x5 series of multimeters.

I still have a lot to do but I am able to control my SDM3065X with my Mac and get readings from it.

So far I have two windows, one for sending SCPI commands and viewing the responses, and one to actually control the SDM3065X, which can change modes etc.

Once I have the software polished enough I will share it, I should be able to compile the software to work on windows too.

You don't need to make any software to control the DMM from a MAC, TestController also works on MAC and Linux.
The command line in TC allows you to type SCPI commands directly to the device, put I believe most people uses the predefined commands.

TC get even more useful when you connect multiple devices to it, i.e. a PS and maybe a load and let it control voltage or current while logging the result.

[TheDefpom]

As I had spent many many hours attempting to find without any luck a MacOS software that actually works, is free, and has a GUI, I decided to make my own.

Do you have a URL for that software so I can at least look at it, the search I just did failed to turn up anything.

[HKJ]

As I had spent many many hours attempting to find without any luck a MacOS software that actually works, is free, and has a GUI, I decided to make my own.

Do you have a URL for that software so I can at least look at it, the search I just did failed to turn up anything.

On this forum: https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/
Main page with download link: https://lygte-info.dk/project/TestControllerIntro%20UK.html

You will have to install Java before you can use it.

[TheDefpom]

Well it looks like I've been wasting my time for the past three days.... why did I never look at this !

I just tried it out and it seems to do what I want, has a popup display and all the direct controls the same way I did it... thanks for pointing the software out to me, it is pretty polished and already does way more than I had planned to build into mine.

I might still tinker around with mine just to finish it off and get it to where I wanted seeing as the one you suggested is based on Java... who knows how long that will be supported by operating systems.

[HKJ]

I just tried it out and it seems to do what I want, has a popup display and all the direct controls the same way I did it... thanks for pointing the software out to me, it is pretty polished and already does way more than I had planned to build into mine.

The software has been around for some time as can be seen from the forum thread and during that time it has seen many improvements. My main purpose for this software never was to control or log from a single DMM, but to control, log and chart a automatic test setup based on multiple devices from different brands.
One of the nice details is that anybody can add new SCPI (and many other) devices to it (I did not add the Siglent meters) fairly easy.

I might still tinker around with mine just to finish it off and get it to where I wanted seeing as the one you suggested is based on Java... who knows how long that will be supported by operating systems.

Java is one of the most used computer languages in the world and has a open source implementation (Open JDK). I believe it will last a long time.

[Bad_Driver]

Test Controller is really a fine piece of software! As mentioned above I used it for the warming up test run
with the SDM3065X and my HP34401A. And it is very handy and easy to use.
And HKJ‘s software found a great community of contributors for new devices. I need more time for a deeper dive
into the script capabilities of it but it will be worth it!

[HKJ]

I need more time for a deeper dive into the script capabilities of it but it will be worth it!

You only need scripting for automatic testing and even some of that can be done from a popup (LogEvent & ParamSweeper).
For more simple stuff (Restoring TC & device configuration) TC can write its own script and you can modify them if you want.

[oz2cpu]

SDM3065x green power led breathing, while powered off,
to show standby mode i suppose ??
how to stop this ?
permanent marker ? or black paint ?
who do this unit need an led anyways ?
the display will tell you the unit it on.. if you dont see anything on the display it is off, duh..

[TheDefpom]

SDM3065x green power led breathing, while powered off,
to show standby mode i suppose ??
how to stop this ?
permanent marker ? or black paint ?
who do this unit need an led anyways ?
the display will tell you the unit it on.. if you dont see anything on the display it is off, duh..

The unit has a screen saver mode... so the LED is there in case the screen is turned off.
I have live with my 3065X for a few years now, honestly the LED doesn't bother me, it also pulses when the unit is sleeping too.

[PartialDischarge]

I like this meter except for the relay switching at around 2V when the leads are picking up noise..