Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X

[tautech]

Scott, do you think Test Controller would be another solution for MarkKn ?
https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/

Did you do a description for Dual measurements with HKJ ?

[TheDefpom]

Scott, do you think Test Controller would be another solution for MarkKn ?
https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/

Did you do a description for Dual measurements with HKJ ?

I didn't write the SDM device driver as that was done by someone else (I did the SDL1xxxx series, SDP1xxxx series devices). The SDM driver is pretty comprehensive BUT doesn't have the dual mode function at the moment, maybe I should look to see if I can add it, I will have to look in the manual to see if there are any SCPI commands for dual mode.

[tautech]

Interesting, for all SDM3000 models there are 2 programming manuals:
https://int.siglent.com/upload_file/user/SDM3045x/SDM3045X_Remote_Manual-RM06034-E01A.pdf

SDM3055:
https://int.siglent.com/upload_file/user/SDM3055/SDM3055_RemoteManual_RC06035-E01A.pdf

And for your SDM3065X Scott:
https://int.siglent.com/upload_file/user/SDM3065X/SDM3065X_Remote_Manual_RC06036-E01A.pdf

And this they all share:
https://int.siglent.com/u_file/document/SDM%20Series%20Digital%20Multimeter_ProgrammingGuide_EN02A.pdf

[TheDefpom]

well, it seems dual mode is not even covered by the SCPI commands... there is no remote option I can find.

[tautech]

well, it seems dual mode is not even covered by the SCPI commands... there is no remote option I can find.

Good. 
We can't have the engineers have a quiet western holiday break now can we ? 

Questions asked on Siglent's private forum........

[tautech]

I have an SDM3055 that I bought used on eBay (so no dealer purchase history). On two separate occasions it has bricked due to the well-known "freeze on boot" problem. Each time I recovered by using the microSD card (opening the case and soldering the two magic pads together). The most recent time it was already running the V25 firmware that was supposed to have solved this problem. Unfortunately, after this recent recovery the unit has been set back to factory defaults. The *IDN? command returns:

Siglent Technologies, ,0123456789,1.01.01.25

and the factory calibration appears to have been deleted (my voltage measurements are noticeably wrong).

I'm guessing Siglent is not going to want to fix this under warranty since it has a cracked case, modifications, and no purchase history. Is there any way to recover from this? I can deal with the bad *IDN? string, but how do you get it recalibrated? I don't have access to the necessary equipment to do it myself. I live in the US (California).

Thanks!

Email sent. Apparently NA branch have the knowledge/tools to fix this.

[Mortymore]

Having recently bought a SDM3055, here's some things I'd like to note.

The meter I received does not have a back faceplate with the "extension card option". Not that it matters to me, but the pictures I've seen everywhere doesn't match.



Measuring ambient temperature around 20ºC is 1.5...3ºC above. Tends to converge over time, but still 1...1.5ºC off
The last 2 digits could be omitted since they are always jumping all over, and are useless.
And... why is 'ºC' and 'ºF' lettering, different from the rest of display, like 'K' 



The EasyDMM display has an error above the button 'Cont', because it should show 'diode' not 'freq'



I would prefer the second reading in dual mode to show up like the "Measure value" in temperature mode. Bigger numbers.  The 'range' display could be placed above that or at the top next to 'Auto trig'. The way it looks now, it's like a sticker to patch a mistake

In the dual mode, I'm unable to place frequency or period as a second reading of each other. I'm probably being clumsy but in dual mode I always manage to double display frequency or period.

Unlike what's stated in the datasheet, my SDM3055 is a not a 240,000count. 
Regularly is a 220,000 count  , but it acts weird in dual mode, behaving like a 999,999count   
In 'single mode' display, it always jumps to the next range when reaching 220,000 count if in auto-range, or overflows if in manual-range.

Use cases in Dual mode ----------------------------------------------------------------------------------------------------------------------------------------------

Up to 999.999mVAC - 999,999 count


Up to 9.99999VAC - 999,999 count


But the really weird behaviour is when in dual mode mVDC+mVAC it jumps from 200mV scale to 1000V though it still displays it's in 200mV range, but showing 000.220v, ignoring the 2v range were it should be if 200mV was overflown.

Below 220mVDC - 220,000 count


When 220mVDC is overflown -



Don't know if all this was known, since I have to admit that I didn't read all the thread, but as I have the latest firmware version 1.01.01.25, seems that are some bugs left to correct.

Conclusion: It's almost perfect. 

[tautech]

Having recently bought a SDM3055, here's some things I'd like to note.

The meter I received does not have a back faceplate with the "extension card option". Not that it matters to me, but the pictures I've seen everywhere doesn't match.

It seems efforts to reduce confusion has only increased it. 
SC models are the only units with holes in the rear these days and the few we've sold haven't come with an additional cover plate.

I would prefer the second reading in dual mode to show up like the "Measure value" in temperature mode. Bigger numbers.  The 'range' display could be placed above that or at the top next to 'Auto trig'. The way it looks now, it's like a sticker to patch a mistake

Dual mode display was enlarged in very early firmware and maybe if there's further support for this it can be looked at again.

In the dual mode, I'm unable to place frequency or period as a second reading of each other. I'm probably being clumsy but in dual mode I always manage to double display frequency or period.

Please see the Dual display chart on P41 in Users manual:
https://int.siglent.com/upload_file/user/SDM3055/SDM3055_UserManual_UM06035-E02A.pdf

[TheDefpom]

The bug in easyDMM for diode mode was something I found and told Siglent about years ago when I did a multimeter review and looked at software, I’m surprised it is still there, something for you to pass along Rob.

[Mortymore]

In the dual mode, I'm unable to place frequency or period as a second reading of each other. I'm probably being clumsy but in dual mode I always manage to double display frequency or period.

Please see the Dual display chart on P41 in Users manual:
https://int.siglent.com/upload_file/user/SDM3055/SDM3055_UserManual_UM06035-E02A.pdf

Thanks tautech 

I tried all options on the table, and put the results on the chart.

The ACI (main) + DCI (dual) caused the DMM freeze in 2 times when only DC current was present. When I measured a test circuit with AC+DC the DMM worked as expected.

What came as surprise was the fact that if AC current is the being measured as the main display function, frequency or period can't be in dual display mode, but the inverse is possible. The chart is inverted for me.

Still... no matter how I tried, just can't get frequency and period at the same time (one as main and the other in dual). Just one at a time, or the same at the same time. 

[mushroom]

Measuring ambient temperature around 20ºC is 1.5...3ºC above. Tends to converge over time, but still 1...1.5ºC off

I don't want to hijack this discussion, but I've been waiting to read about this issue for a while. It's been discussed in this thread, with no clear answer. The placement of the cold source was evocated... Not really understanding the temperature probe calibration, I didn't attempt anything. Temperature readings are wrong by the same amount. I tested with 3 thermocouples, two being new (the one that came with the EEVBlog BM786, another that came with the Brymen BM079 ammeter), and a 25 years old one. Is there something that can be done ? (SDM3045X with the "chinese fake 3055" hack, the hack making no difference in temperature readings).

[tautech]

Does no one ever RTFM these days ? 
P35 in the manual for temp measurement describes how to adjust the meter to get temps more accurate.

[Mortymore]

Does no one ever RTFM these days ? 
P35 in the manual for temp measurement describes how to adjust the meter to get temps more accurate.

Been there.

There's nothing to adjust or set, stated in page 35 neither in page 88.
As far as I can tell, the DMM only displays a table with the corresponding measured value vs temperature, but it can't be edited. 
One can only set the type of thermocouple.
If it can be manipulated through commands or some other way, I haven't cheeked, and don't recall to have seen it mentioned.

EDIT: I haven't checked the service manual though

[mushroom]

Does no one ever RTFM these days ? 
P35 in the manual for temp measurement describes how to adjust the meter to get temps more accurate.

I wrote "Not really understanding the temperature probe calibration...".
This means I read, but didn't 100% understand : english is not my native language (Didn't you notice ? Seriously ?).
Explanations were unclear to me ; having other tools for temperature measurements, I gave up instead of messing things up. I don't even know the exact type of probes that came with my other meters, and anyway I can live without temperatures on a bench DMM !

[tautech]

Does no one ever RTFM these days ? 
P35 in the manual for temp measurement describes how to adjust the meter to get temps more accurate.

Been there.

There's nothing to adjust or set, stated in page 35 neither in page 88.
As far as I can tell, the DMM only displays a table with the corresponding measured value vs temperature, but it can't be edited. 
One can only set the type of thermocouple.
If it can be manipulated through commands or some other way, I haven't cheeked, and don't recall to have seen it mentioned.

EDIT: I haven't checked the service manual though

Nothing in SM, just checked so sent mail to HQ.

[Mortymore]

@tautech Thanks for your efforts, as usual. 

Adding a thought on the subject...

The thermocouple tables provided in the SDM3055 probability match this reference tables:
https://www.thermocoupleinfo.com/thermocouple-reference-tables.htm

Given that generally thermocouples have linear behavior, 2 points will suffice to determine the slope, 0ºC and 100ºC

0 ºC can be attained with an ice bath, mixing in a thermal container smashed ice, filled with water just to reach the top of the ice

100 ºC will no be exactly what we are looking for, since boiled water could be used, and the temperature dependes on altitude or pressure

To check your altitude: https://whatismyelevation.com/
To check the temperature at water boils for a given altitude: https://www.omnicalculator.com/chemistry/boiling-point-altitude

More on thermocouples: https://www.omega.com/en-us/resources/thermocouple-hub

So, if the meter has to be calibrated, not being an expert on the subject, I'd say that the DMM should just ask for correspondence voltage-temperature for this 2 points (0º C or F, and temperature for boiling water ºC or ºF). Provided this 2 point for a given type of thermocouple the DMM would extrapolate the complete table.

That would be the simple calibration possible, for the thermocouple used during the process. Noting that, even from the same type, can be slight deviations between thermocouples. If you have several thermocouples, verify for yourself that deviations between them probably will happen.
Without calibration, Siglent's best option was to "follow the tables".

Just my 2 cents

[tautech]

Without calibration, Siglent's best option was to "follow the tables".

7 lines in your table yet 8 definitions in the meter Temp menu. 

Ideally we'd like Siglent to offer us at least a couple more user definitions and a simple method to define and save custom sensor definitions.
They do similar in other products so why not the SDM ?

Not yet heard back from HQ.

[Kleinstein]

The curve for the different TC types are usually known (unless one uses a non standard one). Most sensors use the type K. So no real need to measure the slope (if it is linear at all).

A weak point with the standard banana plugs is the cold junction compensation. Depending on the plugs / connectors used there can be some offset, as the actual cold juntion is usually outside and the sensor for the cold junction temperature is inside the meter. The exact desing and thermal conditions can introduce some offset, depending on the probe construction. So ideally one would have a way to adjust an offset (some up to 1-2 K equivalent voltage).

It is mainly the high temperature type B TC that don't really care and may even get away without cold junction compensation (the curve is essentially horizontal near room temperature).

Custom sensors could be a thing with NTCs. These are available with different resistance and different beta values.

[skander36]

The DMM allow creating a custom sensor profile using a calibrated measuring device (as Mortymore have).

[Mortymore]

I don't have the option "Custom Sensor" 

It's not mentioned in the manual either, but somehow it rings a bell... cause my mind tells me I read about it some time ago, somewhere.
Probably in this thread. Have to check that. But I don't see that option in my meter, anyway. 

EDIT: Could that be an option in other meters in the SDM3000 series, but not for the SDM3055?
@ skander36, which meter do you have?

EDIT2: Seems that a similar situation was addressed about a 4-20mA custom sensor, missing from SDM3055: https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg3869129/#msg3869129

EDIT3: After some reading... seems that the 3055 guys are still waiting for that option 

[skander36]

Sorry, I missed the fact that you have a 3055 model. Mine is a 3065X.
This might be the cause. I didn't know that 3055 does not have this option. Anyway this option wasn't in the 3065 prior to 3.01.01.03 if I'm remember correctly.

[Martin72]

Finally I got the "permission" to order four bench meters..
And finally a very last question:
What seriously speaks against the SDM3045X ?
I would just need the accuracy and bandwidth of a Fluke87 for the desk.
Nothing more...
Oh, and it should work stable, no freezings, no stuckings, just switching on and work with it, every day.
Could the SDM3045X handle this or not?

[BillyO]

Oh, and it should work stable, no freezings, no stuckings, just switching on and work with it, every day.
Could the SDM3045X handle this or not?

I've not seen too many reports of those problems with the SDM3045X.  If you don't have to buy them all immediately you could try one for a while to see if it meets your needs.

Also, consider the SDM3055.  It's only 26% more yet gives a half order of magnitude better resolution/precision.  I have had mine for several months and use it everyday without any problems.

[tautech]

Finally I got the "permission" to order four bench meters..
And finally a very last question:
What seriously speaks against the SDM3045X ?
I would just need the accuracy and bandwidth of a Fluke87 for the desk.
Nothing more...
Oh, and it should work stable, no freezings, no stuckings, just switching on and work with it, every day.
Could the SDM3045X handle this or not?

No problem if latest firmware is installed.
There are some idiosyncrasies with this model which to properly understand you need study this:
SDM3045X Ranging issues and why:
https://www.eevblog.com/forum/testgear/siglent-sdm3045x-enough-is-enough/

[Armin308]

Recently got my self an sdm3065x-sc, and I gotta say that the fan is a bit loud for my taste. Has anyone tried to replace it with a noctua yet? If so, how did it go? I accidentally ripped the warranty sticker off when taking it out of the plastic bag it...     
So I thought ill give it a try, but dunno how its going to affect the accuracy of the meter