Siglent SDL1000X/SDL1000X-E Electronic Load

[pmendiuk]

Hey all,
Are there any SCPI commands to clear C-Add and the accumulated mAh in Battery test?  I looked through the programming manual and didn't find anything other than reading the value.

[tautech]

Firmware update issues:
https://www.eevblog.com/forum/testgear/siglent-sdl-1030x-e-firmware-upgrade-(usb)-problem/

Seemingly stemming from incompatible USB stick format.

[Self Bias]

I got myself an SDL1020X-E after debating the Rigol DL3021 for a while. The siglent seemed to be much more stable with dynamic loading and generally better in hardware, so I chose that one. With the advice provided here on how to increase resolution and the power limit, and the same going for the Siglent SDS2000X+ that I also own, I think I can give something back.

I was fairly annoyed to see that both the set current and the readback values were off quite a bit. This may have to do with the hardware being X-E instead of X as someone mentioned on here, but the annoying part was that I couldn't find a way

So, I put @tv84's dump into the hex editor and looked around. There is a number of relevant commands to be found which I partly tried:

SYSTem:CALibration:MODE: Can be set to 1 by writing 1 or On. If done while the load is active, it will become inactive, but the On/Off button will stay lit. Resets to 0 after powercycle. I could not observe any changes whether active or not. Can be read with a question mark.
CALCLS:*: Deletes the calibration values. Possible subcommands are VOLTage, CURRent, RESistance, EXTV, MONItor, ALL. Effect becomes visible immediately. The reset is not written to memory though, see below.
CALibration:* Possible subcommands are DATA, EXTV, MONItor, STorage. I played around with DATA a lot to try and see if I can write calibration values, but I couldn't. I tried tuples like 1,1 ; 1,1,1; etc., I tried adding "W" for write - no luck. EXTV I didn't try. MONI crashed the unit a few times. STorage probably stores the temporarily changed calibration values, e.g. after using one of the CALCLS commands - didn't test it.

The following two commands read the calibration values back:
CALibration:CTRL?: Control calibration. In my unit, the response was 0.000668,1561,0.002856,1563,0.000084,794,0.000502,815 .
CALibration:MEAS?: Readback calibration. In my unit, the response was 0.000669,1269,0.002862,1269,0.000084,827,0.000502,786 .
CALibration:RES?: Produces no response.

I tried to interpret these and didn't fully succeed yet. What I found out:
1. A float and a 2-byte unsigned int belong together.
2. The order is as follows: Voltage Low, Voltage High, Current Low, Current High. This corresponds to the 36V/150V and 5A/30A ranges.
3. CTRL is for controlling the target voltage in CV and the load current in CC (and probably CR, CP) modes.
4. MEAS is the readback for the display. In CR and CP modes, this probably affects accuracy as the control loop will likely operate on these, so CTRL and MEAS calibrations work in tandem for those.
5. The firmware might support a hardware loop or some other form of calibration for CR mode, but doesn't expose it or it wasn't fully implemented. Therefore, RES calibration is not available.

I could not get calibration to work using these commands, so I did something else: using @atimos' post about FLASH:READ, I dumped the flash and looked for the values given by CAL:CTRL? and CAL:MEAS?. Success: The entire calibration data is within Offsets 0d-63d. I will use decimal addressing from here on as it's used for the SCPI commands.

I tried to make a memory map, but for that, I need to give those variables a name. And that's where I failed. I'm mostly through calibrating the unit, but it was at least 30% guesswork and modifying variables to observe their effect.
I assume the float is a kind of offset as it tends to shift values in both the low and high end of a range. But at some point it becomes linear. The int value could be a linear correction, but it seems that the offset is neither for all values nor does it define the maximum value. My current guess is that the offset isn't actually a data value (ADC result), but the point within the range at which a specific data value occurs. This means that the linear correction shifts with the offset. I have no mathematical proof and it sounds a bit convoluted, so I hope there is a better explanation. It's also weird that the int changes linearity and the float changes the offset, most systems I've seen and written do the opposite. To make things even more complicated, there seemed to be a squared component in the calibration: With the "right" settings, the measured values were off at the low and high end of a range, but correct in the middle.
The int and float are stored in little endian formats. I can provide a python script to decode the dump directly, I just need to finish that memory map. For those who want to take a look themselves:

CTRL V LOW starts at 0d with four bytes for the float value. At 4d two bytes for the int follow. Then there's two unknown bytes (see below).
CTRL V HIGH starts at 8d.

It seems that the calibration data is grouped by voltage/current rather than MEAS/CTRL, so there's a jump:
MEAS V LOW starts at 16d.
MEAS I LOW starts at 24d.
CTRL I LOW: 32d
CTRL I HIGH: 40d
MEAS I LOW: 48d
MEAS I HIGH: 56d

There are also oddities: between two range calibration values, there is a gap of two bytes. For most ranges those are 00 00, but for one it isn't. Modifying the bytes does not produce any noticeable change.

One big annoyance is that at least in the low current range, the set current is dependent on the Slew Rate. With 0.5 A/us, my set current is now correct to at least 1 mA. with 0.01 A/us, the current is too high by at least 20 mA across the range. I have no idea what technical reason could cause that as I would assume that CC drives the load FETs with a constant voltage generated by a DAC. Does anyone else have that issue?

One big disadvantage of directly writing the calibration values to the memory is that they only come into affect after a restart. So every time you change a value, you need to reboot, making the whole process very tedious. Maybe someone can find a way to reload the calibration data. With a three day old unit, the effect of that is:

[See attachment, I can't seem to get inline pictures to work.]

But don't worry, the startup counter can be reset too. It is a two byte int located at 236d. To reset it, all you need to do is
FLASH:WRITE 236,0
FLASH:WRITE 237,0

To set it to a reasonable value, write something to 236d and zero to 237d.

[Dirk C.]

Firmware update:

2023/3/23    1.1.1.22R1      1. Modify the BUG of the fan false trigger protection function

https://www.siglenteu.com/service-and-support/firmware-software/dc-electronic-load/#sdl1000x-series

Dirk

[mawyatt]

Anyone know if Siglent plans on releasing a Calibration procedure similar to the one for the SDP3303X?

Best,

[pmendiuk]

I have been testing various ACDC power supply modules from Amazon and I had a 12V 600W power supply fail in a spectacular fashion with a 50A combined load.  I had a 25A CC load (300W) with a "upgraded" firmware (1.1.1.21R2) SDL1020X-E and a KP184 set at 25A CC load (300W).  The KP184 didn't flinch and is still functioning normally.  The SDL1020X-E provided no load after the failure so I pulled the metal cover off to take a look.  I didn't see any obvious carnage so I powered the unit back up and it was functioning normally again about 30 minutes later.  I started testing again today and the SDL1020X-E seemed to be fine until I turned on the additional parallel load with the KP184.  The SDL1020X-E load current dropped after ~5 min to about 2mA and there has been no "recovery" as before.  I'm suspecting that the previous power supply failure was likely not a good experience for the load MOSFETs unless someone has some other ideas?

[tautech]

Had a discussion with a customer just a day or 2 back about his load....some lesser known Asian brand that I never noticed but to cut a long story short its negative terminal was mains earth bonded and as such had destroyed some projects he was working on.....put him right off the thing. 

We all need keep our eyes open for such bad design. 

[pmendiuk]

Had a discussion with a customer just a day or 2 back about his load....some lesser known Asian brand that I never noticed but to cut a long story short its negative terminal was mains earth bonded and as such had destroyed some projects he was working on.....put him right off the thing. 

We all need keep our eyes open for such bad design. 

There are no load output earth ground connections in my relatively new KP184, but I have no experience with the older units.

If someone would have asked me which load seemed more robust I would have previously said the SDL1020X-E.  I would like to get the schematic for the SDL1020X-E and see what happened to it.

[Self Bias]

The SDL1020X-E load current dropped after ~5 min to about 2mA and there has been no "recovery" as before.

Did you try turning it off and on again?

No seriously: The SDL performs a self test at boot. I don't have my unit here at the moment, but I think it could be triggered from the System menu as well - though I'm not sure if that actually runs the test or just shows the results.

One of the items tested is "Load", which I would assume are the FETs. Would be interesting to see if that test fails in that state.

[mawyatt]

Request for tautech.

Rob, could you ping Siglent about a user means to calibrate the SDL1000X ?

We've read the post about writing specific cal numbers to specific memory locations, but that seems risky for our case.

Ours is considerably off in Voltage and Current readings relative to our many DMMs.

Just recently we needed to validate a Korad KWL102 (30V/30A) power supply for a client/colleague, the Korad agreed well with our KS34465A or DMM6500, however the SDL load wasn't doing as well which required us to monitor the setup with a pair of DMMs. This is the type of usage that the SDL should be able to handle without the need for additional support equipment where one can rely on the Voltage & Current readings directly from the SDL.

Anyway, a ping to Siglent home base for a SDL User Calibration Routine would be greatly appreciated.

Best, 

[TheDefpom]

Request for tautech.

Rob, could you ping Siglent about a user means to calibrate the SDL1000X ?

We've read the post about writing specific cal numbers to specific memory locations, but that seems risky for our case.

Ours is considerably off in Voltage and Current readings relative to our many DMMs.

Just recently we needed to validate a Korad KWL102 (30V/30A) power supply for a client/colleague, the Korad agreed well with our KS34465A or DMM6500, however the SDL load wasn't doing as well which required us to monitor the setup with a pair of DMMs. This is the type of usage that the SDL should be able to handle without the need for additional support equipment where one can rely on the Voltage & Current readings directly from the SDL.

Anyway, a ping to Siglent home base for a SDL User Calibration Routine would be greatly appreciated.

Best,

Did you have the sense connections hooked up (and turned on)? It makes quite a difference.

[mawyatt]

Request for tautech.

Rob, could you ping Siglent about a user means to calibrate the SDL1000X ?

We've read the post about writing specific cal numbers to specific memory locations, but that seems risky for our case.

Ours is considerably off in Voltage and Current readings relative to our many DMMs.

Just recently we needed to validate a Korad KWL102 (30V/30A) power supply for a client/colleague, the Korad agreed well with our KS34465A or DMM6500, however the SDL load wasn't doing as well which required us to monitor the setup with a pair of DMMs. This is the type of usage that the SDL should be able to handle without the need for additional support equipment where one can rely on the Voltage & Current readings directly from the SDL.

Anyway, a ping to Siglent home base for a SDL User Calibration Routine would be greatly appreciated.

Best,

Did you have the sense connections hooked up (and turned on)? It makes quite a difference.

Not using external sense connections at moment. We just had a reasonably large error (~10mv) when reading unloaded or lightly loaded (10ma) voltage relative to a pair of DMMs, one sensing source and another sensistng load (SDL) input. Both DMMs agree, the SDL is off.

Current reading is also off with SDL relative to DMMs. The DMMs we use are either KS34465A (have 3), DMM6500, HP34401A or a AG34401A, and sometimes a SDM3065X (which we need to do the cal routine you kindly created, as it's off relative to all the other DMMs which agree very well, including the 2 old 34401A which show remarkable consistency, however we don't have the proper Cal equipment in house). 

Maybe later we'll try with the remote sense, but don't expect this should matter with no load or very light load as little current is flowing and we are using quality #10AWG cables with spade lugs and give plenty of time to thermally stabilize.

Anyway, thanks for the suggestion.


Edit: For example, just turned things on with SDL and a KS34465A sensing the SDL input directly across the input Knobs, a HP34401A sensing the output (source) of a new KWL102 which is set to 10.000V. The SDL is set to 1000 ohms load and the KS34465A reads 10.00006, the HP reads 10.00007V and the SDL reads 10.0066 to 10.0100 bouncing around a lot, unloaded similar result with SDL significant last two digits bouncing. Output of KWL102 is really clean for a switcher, however we get similar result using a SDP3303X.


Best,

[tautech]

Request for tautech.

Rob, could you ping Siglent about a user means to calibrate the SDL1000X ?

We've read the post about writing specific cal numbers to specific memory locations, but that seems risky for our case.

Ours is considerably off in Voltage and Current readings relative to our many DMMs.

Just recently we needed to validate a Korad KWL102 (30V/30A) power supply for a client/colleague, the Korad agreed well with our KS34465A or DMM6500, however the SDL load wasn't doing as well which required us to monitor the setup with a pair of DMMs. This is the type of usage that the SDL should be able to handle without the need for additional support equipment where one can rely on the Voltage & Current readings directly from the SDL.

Anyway, a ping to Siglent home base for a SDL User Calibration Routine would be greatly appreciated.

Best,

Did you notice there's a new Service manual ?
https://int.siglent.com/u_file/download/23_04_12/SDL1000X%20Series%20Service%20Manual_E01B.pdf

While it does not include adjustment procedures there is a section for performance validation where it could be useful to have some data from your unit to forward to the engineers and also check if your unit still meets datasheet spec. See P15

Should you need forward results/tables slip them to me by email please Mike.

[mawyatt]

Did you notice there's a new Service manual ?
https://int.siglent.com/u_file/download/23_04_12/SDL1000X%20Series%20Service%20Manual_E01B.pdf

While it does not include adjustment procedures there is a section for performance validation where it could be useful to have some data from your unit to forward to the engineers and also check if your unit still meets datasheet spec. See P15

Should you need forward results/tables slip them to me by email please Mike.

No didn't know about the Service Manual, thanks we'll take a look.

Best,

[Self Bias]

Using the Sense input made a good difference for me too. Also I wouldn't use any setting but 2^14 for averaging.
On my unit, I have crimped fork connectors to the sense wires and connect them directly to the input posts for normal use. This already eliminates some error and seemed to make the reading a little more stable.

[Detlev]

I just measured my SDL1030X, the values look good here. Picture 1 with no load and picture 2 with 1A load. I can live with these deviations quite well. The SDL could be better at ampere.

A possibility for calibration would still be very good.

Have a nice day
Detlev

[mawyatt]

Detlev,

That's better than what we are seeing with our SDL1000X.

BTW do you see the last couple digits bouncing around on the 150V range, even with 2^14 averaging we still see this.

Thanks for showing

Best,

[mawyatt]

Using the Sense input made a good difference for me too. Also I wouldn't use any setting but 2^14 for averaging.
On my unit, I have crimped fork connectors to the sense wires and connect them directly to the input posts for normal use. This already eliminates some error and seemed to make the reading a little more stable.

That's a good idea with the sense line crimped with the heavy current cable if that's what you are doing, good idea either way. We have some heavy 10AWG & 12AWG flex cable on order for making up some 30A cables for upcoming testing and may make up a pair with the sense lines crimped with the lug. This should effectively move the supply or load "reference terminals" to the cable lug end whichever way it's connected, and not have to deal with two lugs on one terminal which is often a problem with some terminals.

Best,

[TopQuark]

Have never been really happy with binding posts on DC loads, when virtually everyone uses banana plugs anyways. I was tired of the custom adapter cables I DIYed dangling around, and I wanted something a bit beefier than the PCB adapter boards out there (e.g. https://www.tindie.com/products/labshack/dc-electronic-load-banana-plug-adapter-pcb-only/)

I ended up cutting a couple of parts out of 1mm thick solid copper sheets, and soldered 4mm safety banana jacks onto it. I did have to snip away the lower right rubber bumper to have it fit properly, but the binding posts extends beyond the bumper, so it wasn't going to do anything anyways. 

I quite like this little accessory, it is quite solid and resistance should be as low as it gets. There is a possibility the binding post may come loose and the copper parts will short out, but I have wrenched hard on the binding post with a pair of Knipex Cobra, think I should be good.

[tautech]

Early in this thread a member found binding post caps that take banana plugs.
First pics here and a couple posts later a link to where he got them from on Aliexpress.
https://www.eevblog.com/forum/testgear/siglent-sdl1000xsdl1000x-e-electronic-load/msg2539641/#msg2539641

[TopQuark]

Early in this thread a member found binding post caps that take banana plugs.
First pics here and a couple posts later a link to where he got them from on Aliexpress.
https://www.eevblog.com/forum/testgear/siglent-sdl1000xsdl1000x-e-electronic-load/msg2539641/#msg2539641

That looks nice, bit I still prefer to have safety jacks that take shrouded plugs, especially when the other side of the cable is hooked up to a power supply under test, which may or may not take accidental shorts very well. 

[Mortymore]

No...there's a point beyond which I can't believe this is my problem. Not only does my computer and network work perfectly with four other Siglent instruments (and dozens of other devices), but if I touch the IP configuration on the SDL configuration page the ethernet wakes up, and this time doesn't go back to sleep again. That would make no sense if it were a problem with my switch or router. I just don't know why no one else is experiencing the same thing. It really smells like an uninitialized variable in the firmware to me, and I just happen to have a bad value stored there. Currently I have my router set to always assign the same IP address based on the MAC address (and it's the same address I was using as a static IP before), and things work perfectly. That's added evidence it's not my computer, cabling, or switch.

Thanks for the suggestions, though. At some point I'll try my SDL with a completely different environment - different cables, router, switch, computer - just to make sure it has to be the unit.

Rob

I recently bought a SDL1020X-E and configured it with static IP, as are my other Lab devices with LAN connection, and none had issues. But when using for the first time, EasyDSL stopped logging after 30 minutes. Then I recall have read something about it and revisited this thread.
Now all devices have IP reserved by MAC address in the router, and are DHCP enabled, and everything seems to work fine.

I agree that there must be some issue with the ethernet connection on the SDL. But in this case it can be overcome. 
Thanks for the tips.

NOTE: As mentioned before, the trend time in the EasySDL is wrong and Siglent should release a new software version.

[tautech]

Banana lead capable input terminals were mentioned in some other thread so followed an old link in this thread to find they are still readily available:
https://www.aliexpress.com/item/32778229464.html

[Mortymore]

I have IKEA shelves (BERGSHULT / GRANHULT ) over my workbench and they are 30cm deep and that's too short for the SLD1000X, so I made an extended support with an MDF board.

For now, I've installed a pair of banana terminals for sensing wires that run from de SDL rear terminals. The next thing to do when I have the time and the material needed, is to add below the display a pair of BNC connectors for I and V monitoring, to this connections be also easily available at the front.

[Mortymore]

Bought some silicon wire 12AWG and 18AWG, 4mm banana plugs, M6 spade terminals, and alligator clips to make a proper cable with sensor wires, mainly to test 12v Lead Acid batteries, 5Ah to 20Ah or so.