New Siglent SDM4000A series Multimeter

[tonyalbus]

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

[Martin72]

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?

[mawyatt]

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,

[Bad_Driver]

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.

[Kleinstein]

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.

[bdunham7]

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. 

[mawyatt]

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

[Martin72]

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...

[KungFuJosh]

I do not have a measuring device that can measure significantly below 10 ppm...

yet 😉

[Kleinstein]

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.

[tonyalbus]

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.

[tonyalbus]

[Furna]

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

[tonyalbus]

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.

[Furna]

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

[tautech]

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.

[tonyalbus]

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

[tautech]

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

[Furna]

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 ...

[tonyalbus]

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  ) 
for me it seemed only useful in production environments where you meseure many tempratures
So what is your use?

[Furna]

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  ) 
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?

[tautech]

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

[tonyalbus]

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....

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)

[Martin72]

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

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.

[Kleinstein]

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.