How to calibrate Siglent SPD1000X / SPD3303X / SPD3303X-E series power supplies?

[MartyMacGyver]

The other day I got myself an SPD3303X-E (now converted to an SPD3303X). However, I had some questions:

https://www.eevblog.com/forum/testgear/spd3303x-e-(unmodified)-curious-behavior-when-outputs-are-on/

The thread quickly turned to the question of how to calibrate these devices. I'd try dumping memory, etc, but there's no place to dump it to (unlike other Siglent devices there is nowhere to plug in a flash drive).

I installed NIVIEW and EasyPower and can connect to the device via USB (how I upgraded it) and I can use EasyPower's CmdCommandDlg to send SCPI commands to the device and get responses.

From a thread on the commands it appears to support, I found the following:

Code: [Select]

--Short Cmd-----------Long Cmd------------Set-Get-----Extended v1---------Extended v2--------
**READID                                  X
*CALCLS                                   X
*CALRCL                                   X
*CALST                                    X
*CPU                                          X
*DEL                                      X
*IDN                                          X
*LOCK                                     X   X
*RCL                                      X
*READALL                                      X
*SAV                                      X
*UNLOCK                                   X
*UPGRADE                                  X
CAL:CURR            CAL:CURRENT           X         CALIBRATION:CURR    CALIBRATION:CURRENT
CAL:VOLT            CAL:VOLTAGE           X         CALIBRATION:VOLT    CALIBRATION:VOLTAGE
CH1:CURR            CH1:CURRENT           X   X
CH1:VOLT            CH1:VOLTAGE           X   X
CH2:CURR            CH2:CURRENT           X   X
CH2:VOLT            CH2:VOLTAGE           X   X
CLREEPROM                                 X
CURR                CURRENT                   X
DHCP                                      X   X
FACTORY                                   X   X
GATE                GATEADDR              X   X
IDN-SGLT-PRI                                  X
INST                INSTRUMENT            X   X
IP                  IPADDR                X   X
IPST                                      X   X
MAC                                       X   X
MASK                MASKADDR              X   X
MEAS:CURR           MEAS:CURRENT              X     MEASURE:CURR        MEASURE:CURRENT
MEAS:POWE           MEAS:POWER                X     MEASURE:POWE        MEASURE:POWER
MEAS:VOLT           MEAS:VOLTAGE              X     MEASURE:VOLT        MEASURE:VOLTAGE
OUTP                OUTPUT                X
OUTP:TRACK          OUTPUT:TRACK          X
OUTP:WAVE           OUTPUT:WAVE           X   X
SCDP                                      X
SRLN                                      X   X   
SYST:ERR            SYST:ERROR                X     SYSTEM:ERR          SYSTEM:ERROR
SYST:STAT           SYST:STATUS               X     SYSTEM:STAT         SYSTEM:STATUS
SYST:VERS           SYST:VERSION              X     SYSTEM:VERS         SYSTEM:VERSION
TIME                TIMER                 X
TIME:SET            TIMER:SET             X   X
VIRKEY                                    X
VOLT                VOLTAGE                   X

I found *unrelated but interesting* SCPI calibration commands for a different PSU in another forum:

https://www.diyaudio.com/forums/equipment-and-tools/281868-source-firmware-software-programmable-power-supply.html#post4503727

Siglent seems to use a subset of typical SCPI commands, possibly with very different options.

The interesting commands are likely the ones starting in `*CAL` and `CAL:` here. However, every actual setting I've tried leads to a `SYSTEM:ERROR?` output of `9  Data out of range` (beeping accompanies such errors most of the time).

Code: [Select]

`*CALST` works with no errors
`CAL:CURR 0.00` gives the error but doesn't beep
`CAL:CURR 0.000` gives the error and beeps
`CAL:VOLT 0` and every permutation I've tried gives the error and beeps

Given that, I'm not even sure those arguments are sufficient or correct (I tried adding an extra number with and without commas to no effect.

Not sure what `*CALCLS` and `*CALRCL` are about. I suspect they (with `*CALST`) represent the set of "store/clear-stored/recall" operations, but I've no idea what context those are used in.

I'm told that a password (as mentioned for the unrelated PSU) isn't required.

`FACTORY?` is by default off, but I've tried this process with `FACTORY on` with no greater success (nor any other obvious effect).

Other commands I've tried from the list are effective to their purpose, so I know I'm on the right track, but I'm not sure what the process, command order, and command arguments are to achieve success with calibrating this.

(And yes, this was calibrated from the factory before I bought it but I'd like to fine-tune it, especially now that it's using an extra decimal place of precision. Besides, it's very useful knowledge.)

[tautech]

[ outdated reply removed ]

From a later post the Service manual is now available with Cal procedures outlined:
http://old.siglentamerica.com/USA_website_2014/Documents/manual/SPD3000X_Service_Manual.pdf

[MartyMacGyver]

So far it's been... educational. I'm making use of PyVISA as the EasyPower CmdControlDlg is pretty painful.

Edit: It doesn't seem to be worth the effort without more information.

I saw your other post but thought it was just an old version of EasyPower - but clearly EasyTest is something else entirely, and I'm not sure where to get that...

I'll dig through the SDG scripts you referenced.

If I must contact Siglent directly, is there a preferred/expedient way? (PM me that answer if you prefer.)

That said, calibrations don't last forever: all the devices used to calibrate this have their own cal due date, yet the PSU itself does not (at least, not anywhere on the cal sheet). So how long is a factory calibration supposed to be good for, and what is one supposed to do after that time period?

[tautech]

Where are you Marty as your profile gives no clues ? 

Inquires to any of the branches will go through to local tech support that can answer most questions but of course this cal info shouldn't be in the public domain so that users don't brick their equipment. 
Generally cal is valid for 12 months however after looking through the SPD documentation a week or two for you I couldn't find any recommended cal interval. 

[Rerouter]

The scripts Tautech linked are for the signal generators, Which work on a very different process to the power supply (doesn't reference any of the command for it)

Siglent seem to "borrow" definitions for commands from other manufacturers in places, so this may be a good place to start
http://literature.cdn.keysight.com/litweb/pdf/5959-3362.pdf

[MartyMacGyver]

Where are you Marty as your profile gives no clues ? 

Inquires to any of the branches will go through to local tech support that can answer most questions but of course this cal info shouldn't be in the public domain so that users don't brick their equipment. 
Generally cal is valid for 12 months however after looking through the SPD documentation a week or two for you I couldn't find any recommended cal interval. 

Ah, I never got around to filling that out - fixed it. I'm in the USA.

I appreciate the info you've been able to help with so far. Hopefully I can get this completed soon.

[tautech]

All the public contact info is here:
https://www.siglentamerica.com/contact-us/

The scripts Tautech linked are for the signal generators, Which work on a very different process to the power supply (doesn't reference any of the command for it)

Yes and they use Pysion for calibration however the SW and HW needed is listed in their service manuals whereas we don't have service manuals for SPD PSU's..........yet......not even on the Chinese website. 

Might shoot an email off to see if there's one available.

[MartyMacGyver]

All the public contact info is here:
https://www.siglentamerica.com/contact-us/

Sounds good!

Edit: It's been interesting but as the original issue was the device acting strangely (there were a couple other glitches I didn't write down) and not being too well-calibrated to begin with (just comparing the two channels), I think I'm going to exchange it and cross my fingers.

[tautech]

It's been interesting but as the original issue was the device acting strangely (there were a couple other glitches I didn't write down) and not being too well-calibrated to begin with (just comparing the two channels), I think I'm going to exchange it and cross my fingers.

So are you saying it doesn't meet the datasheet spec ? 
Please check the accuracy spec listed on P4/5
http://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SPD3303X_DataSheet_DS0503X-E01A.pdf

[MartyMacGyver]

The outputs were a little off, not sure if at the edge of spec or just outside of them. There were a few glitches when I first got it, particularly involving the displayed readings (sometimes they'd be WAY off for no apparently reason).

After lots and lots of trying to figure it out and rectify it, it's only that much worse now. Rather than beat my head against the wall anymore this weekend, I'll look at my options next week and go from there (seller RMA, manufacturer, or credit card coverage). It's already eaten a solid day and that's enough given the lack of information.

[tautech]

I saw your other post but thought it was just an old version of EasyPower - but clearly EasyTest is something else entirely, and I'm not sure where to get that...

Well after a few minutes hunting it seems like here:
https://sourceforge.net/projects/easytest/

With a link to here:
https://github.com/EasyTestTeam/EasyTest

So it might seem all we need now are the Calibration scripts. 

[MartyMacGyver]

... and the calibration equipment necessary. I now have a better appreciation for electronic load testers, one piece of equipment I am least likely to ever have a reason to buy (unlike the rest of this stuff I have handy).

(Edit: also, good find! I hunted for several minutes trying to find it, but I also assumed it was Siglent-specific so that influenced my search parameters.)

[tautech]

On the matter of Service manuals for these Siglent PSU's, English manuals for SPD3303C and SPD3303X/X-E are currently being prepared and should be online and available to download within a few weeks.

I have a 900KB copy for SPD3303C if anyone wants/needs it.
PM your email and I can send it.

[arturfra]

Any news about spd3303x service manual or the procedure how to calibrate it? On mine i’ve the issue on the right part, if i set example 8.000 volt it say me 8.006 sigh! Anyone knows how i can solve this issue? Thanks

[tautech]

Any news about spd3303x service manual or the procedure how to calibrate it? On mine i’ve the issue on the right part, if i set example 8.000 volt it say me 8.006 sigh! Anyone knows how i can solve this issue? Thanks

Nothing is up online yet sorry.....and yes I do check for the X/X-E service manual every few days.

[dkggpeters]

Any news about spd3303x service manual or the procedure how to calibrate it? On mine i’ve the issue on the right part, if i set example 8.000 volt it say me 8.006 sigh! Anyone knows how i can solve this issue? Thanks

I have a SPD3303X-E that is hacked and if I put something like 8.000v is will say in the lower screen something like 8.003 ish.  When I actually measure the voltage is is within .001 of my input value which will read 7.999 or 8.001 on the DM.  It is of no concern to me since is is only about .0125%.

[tautech]

On the matter of Service manuals for these Siglent PSU's, English manuals for SPD3303C and SPD3303X/X-E are currently being prepared and should be online and available to download within a few weeks.

I have a 900KB copy for SPD3303C if anyone wants/needs it.
PM your email and I can send it.

The SPD3303X/X-E Service manual is finished and should be online soon. It's a 2MB file and if anyone is desperate for it please PM your email to me and I can send it on through.

[Gian2975]

Hi to all,
I have a problem on my SPD3303X-E power supply.
I converted to the X model.
Now I have this problem:
The power supply is no longer calibrated, I have an error of about 200mv
I lost the serial number

I am looking for the service manual to see if I can correct this problem.

I can't explain why the serial number has changed, it never happened to me.

Help is appreciated.

Best regard
Gianfranco

[tautech]

@ Gian2975
Yes you have made some error and maybe a recalibration might fix it. I dunno.
Got your PM so I'll email that SM to you soon.

Maybe try rolling the firmware version back to an earlier one and check for accuracy again.
Good luck.

[Gian2975]

I thank tautech for the help given to me.
Fortunately having the necessary tools I was able to perform an even more accurate calibration.

Now the last step remains, I would like to restore the serial number.
Could someone help me?
Suspicion is a command to be used under the calibration software.

Every help is appreciated

Thank you

[tv84]

Could someone help me?

Send the SCPI command:

:SRLN <serial_number>

[Tjuurko]

Сalibration method with SCPI command list:
http://old.siglentamerica.com/USA_website_2014/Documents/manual/SPD3000X_Service_Manual.pdf

Chapter 3  Calibration channel parameters

[tautech]

Great, thank you.....I only checked the websites for this service manual a couple of days ago.
Edits need be made in earlier posts...........

[ArthurDent]

I was looking at a photo of the back of the Siglent SPD3303X power supply and it looked vaguely familiar. Here is that photo next to a drawing from the manual of my slightly older GW Instek PSM-2010 power supply. I'd say that these were made by the same company. Not unusual to see a lot of rebranding on a lot of different types of test equipment. 

[tautech]

I was looking at a photo of the back of the Siglent SPD3303X power supply and it looked vaguely familiar. Here is that photo next to a drawing from the manual of my slightly older GW Instek PSM-2010 power supply. I'd say that these were made by the same company. Not unusual to see a lot of rebranding on a lot of different types of test equipment.

For these 2 PSU's I doubt very much they're even closely similar except for a rear on view.
Quite a bit of Siglent's equipment is rebranded however off the top of my head I'm not aware of any of their PSU's.

Wanna do a 'I'll measure mine if you measure yours' ? 

Actually there's no need to get that personal as here's the SPD3303X measurements: 225(W)×143(H)×278(D) mm

[ArthurDent]

It probably isn't fair to compare the two power supplies because although I'm sure the Siglent is good, the PSM-2010 is, in my opinion, a far better supply which probably accounts for its price being about 3 times the Siglent. 

[tautech]

It probably isn't fair to compare the two power supplies because although I'm sure the Siglent is good, the PSM-2010 is, in my opinion, a far better supply which probably accounts for its price being about 3 times the Siglent.

Sure, but this is not about mine is better than yours however checking the PSM-2010 specs I see its attractiveness for some. Can you series or parallel the 2 outputs ? Is each output isolated from the other ?

[chickenHeadKnob]

Arthur --

 They don't look the same at all. check positions of case screw holes (not including the fan mount as those are a standard)  and other details like the mains voltage switch which are design elements a rebrander would not change.

[kahuna0k]

Ok, I've been able to calibrate voltage in both channels without problem, and now it is looking much better. But with current I have a problem. When I clear the calibration parameters for CH1, at 0.100mA I get no current at all through the electronic load, the multimeter is even measuring -0.0013mA. I'm able to adjust the 'b' parameter without problem and in fact at 2.5A everything matches to the mA, but when I start to go down in current, it starts to diverge, at 200mA I read 70mA and at 100mA I read 0. Any clue what should I do? I've tried several times, calibration only display current, only setting current and both values at the same time, with no change. I always start the calibration by clearing the values with

*CLCLS 2
*CLCLS 3

then set the display current values with the corresponding

CALibration:CURRent ch1,1,0.000   (I've also tried with -0.0013)
CALibration:CURRent ch1,2,2.3687 (or whatever I measure, usually after clearing the values I always get to 2.3687A)

and the same for setting current

CALibration:CURRent ch1,3,0.000
CALibration:CURRent ch1,4,2.3687

Any clue? Voltage calibration was so easy and effective, but I'm lost with this 0A at 0.100mA setting. I've also tried with a very small value, 0.0001 or something like that, just in case 0 is not a nice number for the firmware.

Thanks!

[kahuna0k]

Answering to myself for the record. The points you choose for the calibration are arbitrary. The manual uses 0.1A and 2.5A for point 1 and 2 but you can use whatever, and the formula Y=a*X+b would be adjusted using the current value of X and the provided value of Y. I just used 0.2A and 2.5A and now the thing is precise to the mA. Great PSU!

[sjm]

From a later post the Service manual is now available with Cal procedures outlined:
http://old.siglentamerica.com/USA_website_2014/Documents/manual/SPD3000X_Service_Manual.pdf

Oh yeah, yesterday I was able to calibrate my (hacked) SPD3303X-E to have almost 1mA/1mV accuracy on all levels of output.

I used my bench DMM and now the requested, PSU self-measured and DMM measured voltages and currents are nicely lined up.
On some voltages, the PSU is almost comparable to some lower quality voltage references.   

The description of the calibration process in the manual is maybe a bit hard to read and not so logically written at times, but after some thinking and testing it out a few times, yeah it works.
It is important to keep the power output enabled while inputting the calibration commands!

Thanks a lot! Now I can sleep better!   


BR, -sjm

[tautech]

A little something that is endorsed by the factory....SPD3303X/X-E units in series mode in series !

[Elasia]

A little something that is endorsed by the factory....SPD3303X/X-E units in series mode in series !

Interesting, what do they say about two units in series but internally in parallel mode?

[oz2cpu]

i have the same "problem" this one is the best of all my units
SET SAY 2.010
OUT SAY 2.012
but in reality there is 2.008

it is not a big deal, right now,
but those are the true X version, not a hacked upgrade, I did pay 140 Euro EXTRA pr unit for that extra precision,
so i did expect the readouts and setpoints to be a lot more spot on.
also they drift 2mV the first hr, they are turned on, that i did not expect either.

[oz2cpu]

look at the attached spec sheet.
the last digit that the X version provide, is just resolution, not accuracy,
since it can be up to 10mV off, and still be within spec.
so it seem a bit odd, to make and sell a version X, with this extra digit,
 

[Peter_O]

Did the FW upgrade to SPD3303X_V1.01.01.02.07R2_EN with an "upgraded" 3303X-E yesterday. At first glance the calibration stays well within specs.

[oz2cpu]

some of you with a SPD3303 might find this video interesting ?

https://youtu.be/BBW8dv2ImOc

Noise ? or low frequency instability ?
or just the regulation loop ?

why is it not on a super cheap supply ?

[tautech]

some of you with a SPD3303 might find this video interesting ?

https://youtu.be/BBW8dv2ImOc

Noise ? or low frequency instability ?
or just the regulation loop ?

why is it not on a super cheap supply ?

Any AC ripple from the cheap SMPS is likely influenced by the 2V AC voltage accuracy spec of the SDM3055:

20 KHz – 50 KHz = +1.0% of reading + 0.05% of range
P5 in the datasheet:
https://int.siglent.com/upload_file/user/SDM3055/SDM3055_DataSheet_DS06035-E03E.pdf

Whereas the SPD3303X is a linear PSU therefore any ripple is 2x mains frequency and measured result will be more accurate. Comparisons such as this need be done with a scope so to properly see the full noise/ripple picture. 

[oz2cpu]

YES that is exactly what i would expect too,
how ever the result is just the opposite, the SPD3303X is the one with more "jitter" but less noise

[oz2cpu]

the SDM3055 voltmeter can reveal the odd stepped voltage signal from the SPD3303

so something is affecting the voltage in a special stepped way, however the levels of this is insanely low !!
it is 50uV so there is now way to see this with a normal scope.

just to verify my test setup, i connected the cheap MINLEAF NPS605W
and saw the stepped surve is compleetly gone,

by the way . WOW I am happy about the SDM3055 voltmeter

[oz2cpu]

side by side compare picture

[mawyatt]

Successfully upgraded the just received (from Saelig) Siglent SPD3303X-E to a SPD3303X following the procedures outlined by folks here with much thanks 

After the latest firmware install and then the mentioned upgrade today, we did the calibration per the Service Manual. This took a few tries to understand and get the calibration in order since we don't have a precision load and just used the KS34465A DMM current shunt and wiring as a "load" for the current calibration. Used 1V and 20V for the voltage cal and 100ma and 2A for the CH1 current cal and 200ma and 2A for the CH2 current cal, CH2 would not produce an output current much below 200ma, so this was selected as the lower cal point for CH2. As mentioned above by kahuna0k you don't need to use the exact service manual values, since this is just fitting a y = mx + b  linear equation for both voltage and current. However you do need a known accurate DMM and why we chose our most accurate DMM.

Eventually everything came together and the cal was completed, and to our delight the PS shows a very stable 10.000 volt output as shown. No attempt was made to shield the PS from the cycling AC, or anything else and the test leads were a half combination of twisted pair banana to banana, to the supplied banana to gator clips for total ~6 foot length from PS to DMM (indeed, not an optimum calibration setup).

Image below is from KS34465A DMM with PS set to 10.000VDC.

Best,

[sjm]

Just a quick update: I upgraded my previously hacked SPD3303X-E with the new and shiny official firmware for SPD3303X and the upgrade worked flawlessly.
After the upgrade, I decided to calibrate my psu once again, while I was at it. Used the Linux command line SCPI tool for that, over my LAN.

    

BR, -sjm

[tautech]

ex Factory manual adjustment PDF attached.
In short form of the calibration procedure from the service manual.

[AdiGital]

Hello all.
I'm having a weird problem issuing calibration commands (for X-E in X mode)

1. Connection via ETH using EasyPower and PuTTY
2. Communication works as the unit responds
3. Sending commands *CALCLS 0/1 makes the channel "uncalibrated" - showing and outputting wrong values
4. Sending commands CALibration:VOLTage ch1,1,0.980 and CALibration:VOLTage ch1,2,24.450 does nothing but beeps.

Restarting the unit brings correct values as I didn't send the *CALST

I think I've searched all I could find. I'm following the manual provided here (thank btw!)
I'm using a new unit that came with 07R2 version. I downgraded to 05 X-E, then used the modified 05 X. Then finally used official 07R2 X.
Hardware version is V3.0

Hope the problem is only between the chair and the keyboard.

[mawyatt]

Be very careful with the self calibration of the SPD3303X-E that's been augmented to a SPD3303X. Follow the cal procedures explicitly and do not deviate. We didn't and caused a fixed current limit offset, that it not recoverable by any means so far, and the factory hasn't provided any help after numerous pleas.

We have two SPD3303X-E that are working fine and been calibrated per procedure, and another that has a 119ma current limit offset on channel 1 and a 95ma offset on channel 2 which basically makes it worthless for our needs (precision lab type use).

Best,

[AdiGital]

I'm not sure what eventually did it but I was able to send the commands in the end. The calibration worked.

I installed and used NI Max. It behaved the same way initially - beep after CALibration:VOLTage... Then I started playing with VISA Test Panel configuration, namely enabling Termination Character as '\n'. It worked but now it also works without this option. It could also be I was using "Write" and now "Query" (assuming I'm writing to the instrument). I don't want to experiment too much as per what mawyatt warned about.

Both channels' outputs and readings are now aligned and accurate to single mV - measured with SDM3055.

[BreakingOhmsLaw]

We have two SPD3303X-E that are working fine and been calibrated per procedure, and another that has a 119ma current limit offset on channel 1 and a 95ma offset on channel 2 which basically makes it worthless for our needs (precision lab type use).

I have started a thread about a working procedure here:
https://www.eevblog.com/forum/testgear/siglent-sds3303x(-e)-calibration-fw1-01-01-02-07r2-best-practice/
The service manual is flawed in my opinion. Please try if this approach fixes your problem.

[mawyatt]

Thx, will do

Best

[BreakingOhmsLaw]

Thx, will do

Best

Update: Procedure is updated & tested for all values now. This should fix your unit hopefully.

[mawyatt]

Update, I've tried your procedure over 5 times without any change in the CH1 and 2 Offset Current limit. Tried using NI and EasyPower over Ethernet and no luck, nothing seems to remove this current offset. Tried using *CALCLS 8 (supposed to erase all calibration coefficients and set all channels to default values) a few times as well, same result 

With what you've found with the cal procedure, and the problem we're having with this unit doesn't give one much confidence in using these supplies for lab type bench work, well at least they don't have any overshoot at turn On or Off

Anyway, thanks for the effort and hope no one else gets stuck with this type of Offset Current Limit issue

Best,

[BreakingOhmsLaw]

The issue with the current limit procedure in the manual is, that the unit actually has to be actively limiting the current during calibration. Depending on how screwed the calibration is, a low setting like 100mA (as the manual suggest) actually limits the unit to just a few mA because the DAC is basically alredady just outputting 0 Volt to the circuit.
If you choose a setting (like my 500mA / 2.5A recommendation) where the unit is actually actively limiting the current (so you see an actual current >200mA), then the formula for the correction factor has a chance of doing its job.  It needs two points on a straight line. If one of those points is on the 0-line (you'll measure something like 5mA), the calculated correction value is wrong.

[mawyatt]

Understand the linear fit, and how this should work. The basic problem is that the Current Offset can not be removed by any means, even using the *CALCLS 8 which should reset all channel parameters to default.

Nothing we've done has changed this base offset current. What this offset does is without anything connected (0 current) the Current Limit must be set to >120ma on CH1 and >90ma on CH2 for the supply to go into Constant Voltage mode because the zero output current "reading" is ~120ma CH1 and ~90ma CH2 without supplying any output current. If you supply an output current then the current reading is the mentioned offset plus the actual output current.

In use you must mentally subtract the base current offset from the supply reading and set the CC mode to a desired current limit + this offset. We've tried to correct this so many times with this supply that the EEPROMs are probably exceeding their number of write cycles, and spent countless hrs/days trying to correct this problem

Not sure if this is a unique supply problem, hardware failure, firmware failure, or built-in design flaw but up to now unrecoverable, and why I would not recommend anyone deviate from the calibration procedures.

Also extremely disappointed in that Siglent factory has ignored multiple requests for help, and not even a factory response. If one intends to do self calibration I would steer clear of these supplies until the factory decides to address the issues you've found since one might end up with another big and heavy brick like we now have

After these cal problems, I've become somewhat disillusioned with the SPD3303X-E and considering replacing the two "good" supplies with something more trustworthy. We have some very expensive developmental electronics powered from these supplies and a single hiccup or incorrect output setting or reading could destroy 10X the supply cost, so this is an Open Door for Mr Murphy to set in  

Anyway, thanks for looking into this calibration issue.

Best,

 

[BreakingOhmsLaw]

Okay, I understand your problem now. That's one sick puppy you have there.
I assume you have already tried this with the latest firmware (Release Date 02.05.21 ).

For company use, Siglent would not be high on my list of lab equipment solely for the lack of B2B sales. Nothing gets you support faster than a sales rep hell-bent on keeping you happy for your next order. We use R&S, Gossen Metrawatt and Delta Electronica.

Bob Pease's rule that the power supply should be the single most reliable piece of equpment in your lab still applies. If you look at old pictures from his bench, you'll only find top shelf PSUs ever. He even famously disencouraged engineers from building their own PSU, stating:
"Especially for a ‘hacker bench,’ you'll want a safe and reliable supply. A ‘hacker supply’ on a ‘hacker bench’ will just need fire-extinguishers."
Nothing to add there. Amen.

[mawyatt]

Very sick puppy indeed

Tried with 2.05 and 2.07 versions, same results.

I couldn't agree with Bob Pease anymore, folks that skimp on power supplies are just playing Russian Roulette with whatever they are working on. Murphy is just laughing and grinning

I've said this for many years that the single most important piece of equipment on your bench is your power supply. Exactly why I am concerned about these two other SDP3303X-E we have and are using, the third is this one with the current offset problem and will likely just become a paperweight 

Best,

[blurpy]

With Siglent trying to enter the pro marked, I wonder why they don't just fix this issue rather than risk the bad reputation and loss of future sales.

[mawyatt]

This is the worst product I've used from Siglent

The SDS2000X+ are stellar performers, the SAA3021X+ is very nice as is the SDG2042X, the SDM3065X and SDL1020X-E are OK, and these SDP3303X-E PSUs are at the bottom of the list. The UI is not well done with the "fine" button and arrow keys (usage makes no sense, frustrating, and potentially error prone), and why they placed the output jacks at non-standard spacing is inexcusable! However, the output voltage is clean and accurate (on two we have) without overshoot and these shortcomings can be overlooked which we've done in favor of a good, stable, clean, accurate output.

Now with the issues of self calibration and the ability to completely screw up the accuracy from a calibration mishap, which is evidently totally unrecoverable, and the lack of any factory response, even if negative, these PSUs are now considered "Buyer Beware" category. As attractive as these PSUs were from a price performance standpoint, these issues seriously take away from that perspective.

Siglent may be falling into the trap that has consumed so many others. They have a stellar SDS2000X+ product, other good products, but seem to be ignoring some lower level products/customers in favor of the movement into the "Pro" ranks. Classic example of forgetting who they are, why they got to where they are, and overstepping their bounds having to sacrifice factory present customer/product support to support the big step into the "Pro" ranks.

At least they are still paying attention to the SDS2000X+ as it's likely a cash cow, and need the income to support the "Pro" developments. Suspect engineering is way overstretched and no time to handle any support and/or present customer/products.

Siglent has introduced a new "Pro" level 2 and 4 port VNA (5000 series), new "Pro" level MSO (6000 series), and soon a new "Pro" level AWG (7000 series), all in less than a years span. That's way too many/much advanced product releases in such a short time frame for a company like Siglent IMO, likely severely straining the engineering/management side of the company.

Time will tell

Back to the PSU, are the GW Instek PSUs capable of self calibration?

Best,

[BreakingOhmsLaw]

Well, the one thing that makes it absolutely useless for any serious lab use is, that you CANNOT DISABLE the beep when it goes in to CC mode. WTF Siglent?

Helloooooo, Siglent? Anybody home?
Some people use CC continuously. As in ALL THE TIME.
For example to charge a battery.
Do I really need to open the unit and remove the bloody piezo beeper to shut the damn thing up?
Please someone tell me there's a secret button to make it stop.

[C.J.S.]

Well, the one thing that makes it absolutely useless for any serious lab use is, that you CANNOT DISABLE the beep when it goes in to CC mode. WTF Siglent?

In my experience the PSU only beeps when it goes in CC mode in combination with a very low output voltage. If you load the output of the PSU with a DMM in Ampere range connected to ground, you will get the beep. But if the output voltage is above a certain threshold voltage, the PSU does not beep. I don't know the exact threshold voltage, but I think it is below 1V. I expect that when using the PSU to charge batteries with the PSU in CC mode, it will not produce a beep.

[CDN_Torsten]

What beep?
The only time my unit beeps is during boot.

Operating in CC mode with Vout <<1V results in no beeping...

[CDN_Torsten]

The UI is not well done with the "fine" button and arrow keys (usage makes no sense, frustrating, and potentially error prone), and why they placed the output jacks at non-standard spacing is inexcusable!

The UI fine/arrow keys are the WORST implementation I have ever used.  It confuses me every time.  On what planet is this arrangement normal?
...and then there is the spacing of the output jacks.

[BreakingOhmsLaw]

Well, the one thing that makes it absolutely useless for any serious lab use is, that you CANNOT DISABLE the beep when it goes in to CC mode. WTF Siglent?

In my experience the PSU only beeps when it goes in CC mode in combination with a very low output voltage. If you load the output of the PSU with a DMM in Ampere range connected to ground, you will get the beep. But if the output voltage is above a certain threshold voltage, the PSU does not beep. I don't know the exact threshold voltage, but I think it is below 1V. I expect that when using the PSU to charge batteries with the PSU in CC mode, it will not produce a beep.

You are right. I was using an electronic load, and that obviously nearly short circuits it. On higher voltages it does not beep.
Still, this should be configurable IMHO.

[Bad_Driver]

I have to agree with all the negative feedback.
Now I own 5 Siglent devices and Santa Claus announced the arrival of an SSA3021X+ (thanks to SWMBO).

But I'm unhappy with the SPD3303X-E.
Yes, it produces DC, low noise and it has a hard power switch. But this is all positive what I see....

- the UI is a nightmare. (usage of arrow keys and "Fine" key and rotation knob)
- the weak binding posts are so cheap and unreliable
- the provided "software" looks like a DOS-program from the 90s
- the missing of an energy measurement function (mAs or Ah) - a simple multiplication!

still my both RIDEN 6018 have a much better user interface. 

Conclusion:  the SPD is heavily overpriced!
I'll keep it because it's paid with an not awaited small gratification from my employer as Amazon gift card.

[oz2cpu]

EXACTLY.. odd random low frequency regulation noise,
see more here :
https://youtu.be/BBW8dv2ImOc
and see that attached picture, when comparing to a dead cheap ebay psu

anyone figured out how to fix this ?

[Bad_Driver]

Hi oz2cpu,

I will try it, what load have you used? Open output, low R or SDL1020??

B.D.

[oz2cpu]

just open, no load, and about 2V since in this range my voltmeter got very high resolution, and can reveal the problem,
play with the time roll setting, and see how it looks
you got SDM 3055 ? or even better ?
I tried this many times, back and forward, just to prove it is not SDM 3055,
I constantly get the same result.
if any one will find the bug inside the psu, i will be happy to open and perform mod,
also we should inform siglent, so they can improve the design.

By the way : i got a few ideas for software improvements SPD3303X
in parallel mode : turn other screen off, and show the correct ADDED current, and the total power correctly..
today it display halve of the current and power in ch1 and the other halve in ch2

same problem in series mode !!
suggestion : turn ch2 display off.
and display the new total voltage, new total power..

I happen to use series and parallel mode a lot, so this not smart.

[Bad_Driver]

ok I own the SDM3065 but I‘m just starting  a business trip, so I can try it not before end of the week.

I found another benefit of the SPD, it is not as deep as the Rigol PSU and since I have very limited space
this was one of the main decision criteria.

B.D.

Edit:

I was curious about your findings and did a quick test.

First finding:
Standard deviation (noise) increases with load (ohmic resistor)

Second Finding:
My 40 year old east german anlog PSU has at 2 volts about 10 times lower noise than the SPD3303 !!
Photos will follow when I return.

I have a Low Noise Amplifier on the bench for this kind of measurements, around Xmas I can do a deeper dive into Siglents noise floor with FFT 

[Bad_Driver]

As promised here my measurements of the SPD3303X. See photos and read STD value.

#1 warming up
#2 no load
#3 4 ohms resistor (0.5 A)
#4 2 ohms resistor (1 A)
#5 my 40 years old east german analog PSU

But I‘m not sure that this is the whole story, I tried to see the noise on the scope but my bench setup seems to suffer from grounding problems, I catch a lot other noise. It needs further investigations.

[oz2cpu]

thanks alot, I think what you see, is the same i see
the SPD3303 got :
quite warm up time before stable (you did warm up your multimeter a few hrs before starting the SPD warm up test ? we need to be fair here.
two different types of ac noise
one sine wave shaped very slow (also visible on your curves)
and one sharpedged pulsed, much faster (also visible on your curves)
is it possible to lock ? the vertical scale on your SDM 3065 ?
so it is same as mine ? and same time scale too ?
I am getting ready reperform my tests, but first i run a 2hr SDM 3055 warm up, so we know it is the SPD we see..

if you want to prove the SDM is performing stable, take a 1.5V AA cell, set the centre, and min max points, same as what we do for psu tests.
I also got a real old analog psu. mine is only 35years old, i will also see its power up, and warm up time, just for fun,
its refferance might just be a normal zener diode

[oz2cpu]

more : i came up with those settings, for more fair and more controlled compares:

power on warm up, 5mV full scale, 1800 sec full scale
this is my right unit SPD3303X ch1

[oz2cpu]

here my 35 years old justy kit powersupply

power on warm up, 5mV full scale, 1800 sec full scale

so clearly much worse, when it come to power up time :-)

[oz2cpu]

short term stability

0.2mV full scale, 10 sec full scale is the best to see this..
this is my right unit SPD3303X ch1
I use the manual set low and hi, for 0.2mV full scale, this was i can compare the curve, fair

[oz2cpu]

my old psu :

short term stability

0.2mV full scale, 10 sec full scale

see this is alot more stable, free from short term noise :-)

[mawyatt]

Here's the GPP4323, then the SDP3303X-E (augmented to a 3303X) and a very old linear EMCO. All set to ~2V. Note the GPP (1st) and SDP (2nd) have a vertical span of 200uv on the SDM3065X, the EMCO (3rd) span is higher at 700uv and not as stable as the GPP or SDP.

Best,


Edit: Added SD (RMS) over a 5 min time span, GPP ~53uv, SPD ~31uv and EMCO ~76uv

[Bad_Driver]

Wow, so much information on the last Sunday before Xmas!

I have to prepare the upcoming weekend for my three children (and to setup a new XBOX X so far) and for my very old
parents too and 4 days in business as well  And I‘m the chief of the kitchen (and the related food shopping drives)

Let‘s see what I can repeat with your settings this week.

One remark (you see my findings in the SDM-thread):
The SDM3065 settles down in a view minutes compared to my HP 34401a, I’m pretty sure that the warming up
curve comes from the SPD3303 but I will double check this.

It makes sense to use TestController again for this, more post processing capabilities and easier overlay of different measurments. I need more free time for the bench!!!!!! 

[mawyatt]

Also noticed the long period to stabilize for the 34401A. Think this is because they don't have a fan, while the other high end modern DMMs all have fans which help achieve thermal equilibrium quicker.

Best,

[oz2cpu]

bad driver, you cant use the auto range.. need to make it 200uV always, else the curves will confuse us :-)

here is the left unit, maybe we should just come down back to earth :-)
noise of 0.1mV is NOT bad, not at all..

[C.J.S.]

maybe we should just come down back to earth :-)
noise of 0.1mV is NOT bad, not at all..

And well below the ripple+noise spec of ≤1mVrms（5Hz ～ 1MHz).
Although you would need an AC mV meter with adjustable bandwidth to measure this ripple+noise spec.

[Bad_Driver]

Ok, I used a boring TEAMs meeting to do a first measurement.

Siglent SDM3065, 2 V DC, 10 PLC, Auto-Zero, !0 Mohms
TestController software, 1 reading per second, 12 min

first photo: raw data
second photo: average over 20 readings

As stated by oz2cpu we see a kind of oscillation.

Edit: Pics in better quality

[mawyatt]

This does seem to have a low frequency and much higher frequency content in the waveform. An FFT on the data should revel the details and show these.

Best,

[oz2cpu]

exactly fft will tell us, and then it can be fixed (by modding or by siglent update the design?)
however if sample time is too low ? the resulting fft could fool us
this is why i played so much with recording time / sample interval

(all this amimated me to look into making a super nice stable and noise free reference for my test equipment experiments)

[Bad_Driver]

I started a 2h (3 measurements/sec) recording, than we have about 20.000 samples.
Has someone a suitable software for FFT by the hand?
I will provide the file as attachment asap.

Edit:
2h record, 3 Measurements/sec attached - feel free to do the FFT
(file renamed to txt, CSV-format)

[Bad_Driver]

ok, I've done a short self learning session regarding FFT with Excel.

Attached my first step. It needs deeper investigation and I'm considering a new series with 1 PLC / 50 readings per second.
As we learned it needs external triggering to get fast readings. I do not have time these days, maybe someone else can try it.

x=frequency, y=amplitude
As expected some peaks.
Any comments?

[oz2cpu]

in the quest to understand what is a good powersupply, i found a few more of my old things...

this one Oltronix stabpac mca 5-3 is from 1973 at least that is what I see written on the schematic
it is very hard to date this exact unit, from its serial number ? when was they sold ? start ? stop year ?
video detail : https://youtu.be/pspuqOsWG44
now see this power on curve from cold.. +/- 1mV scale..
also : its noise and regulation is in the crasy low, wtf :-)
cant even see 0.1mV drop when load change from 0-3A
it is possible... just saying

[Bad_Driver]

Hi oz2cpu

I saw your video regarding this old PSU, very impressive!

Since Santa Claus put a new toy (SSA3021X+) under the tree I didn't‘ spend more time with the SPD these days.

Yesterday I got an very old idea in mind for the simplest check at least (don‘t lough plz!) I connected the PSU outputs DC-BLOCKED
with the LF-input of my batterie powered speaker system (avoiding grounding problems) to listen to any noise - nothing!

I have to put more efforts in it, I was impressed in your video how good automatic triggering of your SDM3055 runs (the green flashing dot on the top left), with the 3065 it is a night mare…. as mentioned in the SDM thread I tried as suggested external triggering but did not get what I expected.

[oz2cpu]

>I saw your video regarding this old PSU, very impressive!

thanks alot, i had a lot of fun and work out of the making of that video, (if you like teardown videos, see my youtube)
if anyone ever seen this type of zener implementation before ?? please post link ?
I really like to know more about this genius opamp design.

>SSA3021X+
HAHA lucky you.. I got one too, super happy about it

>Yesterday I got an very old idea in mind for the simplest check at least (don‘t lough plz!) I connected the PSU outputs DC-BLOCKED
>with the LF-input of my batterie powered speaker system (avoiding grounding problems) to listen to any noise - nothing!

no one is laughing, this is a perfectly good idea,
I only see one problem : it reveal only noise in the audio range, that type of speaker system can handle,
small pc desk top speakers, are like 100Hz to 10kHz
if you cant hear anything, add more gain ? external opamp ?
actually such noise amp, headphones, could be used to debug alot of things.
but most problems with emc, switchmodes, regulation , stability, is not in the hearable range, either 0-100Hz or over 10kHz..

> I was impressed in your video how good automatic triggering of your SDM3055 runs (the green flashing dot on the top left)
I am not sure i understand what you mean ?
auto trig, is just freerun mode, the meter is not synced to anyting,
I just resently had an SDM3065 for loaner, did not see any problems with it, when my 3055 came back from repair, i had to let it go,
i actually missed it a bit, due to its one more digit resolution in low ohm range, and that is where i play the most at the moment

[mawyatt]

"thanks alot, i had a lot of fun and work out of the making of that video, (if you like teardown videos, see my youtube)
if anyone ever seen this type of zener implementation before ?? please post link ?
I really like to know more about this genius opamp design."

Yes this is a very old and clever technique, National even had a hybrid reference that used it back in ~70s. If you can find the old National Linear Databooks, it's shown in those. Almost all the zener based references use it.

Best,

[2N3055]

Bootstrapping zener like that by supplying it with self regulated voltage is used a lot.  Speaking of Walt Jung, he used it in his super low noise PSUs. OTOH, it might seem common now, but whoever though of it first to create what is basically a recursive regulator (in software parlance), that was quite clever...

[oz2cpu]

exactly 3055, it is clever designed,
and the performance speak for it self as explained in the video,
lets challenge any of your brand new, ultra expensive powersupplies, are they just as stable ?
from cold power on and a few hrs ahead ??

I have designed electronic products for 35 years
maybe i did not pay too deep attention to details, when i came to voltage zener refferences :-)
I have not seen this coupling before,
dont you just love it, when something as normal as a teardown, ends with wisdom,
It must be named something ? there must be a tech sheet puplished ?

[mawyatt]

Like 2N3055 mentioned, likely called a "Bootstrap Regulator or Reference". This has two stable voltage states, zero and the zener referenced, the 2 resistors and diode force the opamp into the desired zener state. The old 1N821 thru 1N829 series reference diode circuits used this technique as well.

Best,

[Bad_Driver]

The trigger problem is described in

https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg3466342/#msg3466342

With the SDM3065 you easily see it with the scope connected to Trigger Out. Thats why I fiddled with external trigger etc.
to get constant readings for FFT.

I know that the audio check has very limited BW. For PSU measurement I built a Low Noise preamplifier ( 10 Hz…. 100 kHz) some weeks ago
and with my 192 kHz, 24 bit semi professional external sound card and the software AudioTester you can do FFT up to 90 kHz. For higher frequencies -> SSA3021X/SVA1032X   

Unfortunately my design (2 stage OP amp for 60 dB) tends to oscillate and now I have a 3 stage design on the bench but not finished.

[2N3055]

Like 2N3055 mentioned, likely called a "Bootstrap Regulator or Reference". This has two stable voltage states, zero and the zener referenced, the 2 resistors and diode force the opamp into the desired zener state. The old 1N821 thru 1N829 series reference diode circuits used this technique as well.

Best,

Absolutely correct,  it probably originated with old ref zener diodes as a solution to run them at very specific zero tempco current, combined with hand picked good stability resistor..
But since even LM399 has some current dependency, it is used with LM399 too, to make it even more stable...
Walt Jung used it to make his quiet linear regulators have excellent PSRR by virtue of feeding voltage reference with already regulated voltage... It's a gift that keeps on giving :-)

[mawyatt]

I have not seen this coupling before,
dont you just love it, when something as normal as a teardown, ends with wisdom,

Very powerful learning experience, even for older folks

Recall tearing down the HP3325 Function Generator when it first arrived way back, and curious how they achieved the ultra linear triangle waveform. They used a couple ECL gates and a fixed 100MHz (think it was 100) crystal oscillator for one gate input, the other input came from the frequency synthesizer which used the same 100MHz as a reference. The ECL gate output pulse width @ 100MHz varied as the frequency difference and was low pass filtered by a passive LC filter into an almost prefect triangle wave, which was amplified and offset scaled accordingly. Brilliant design concept!!

Best,

[Bad_Driver]

I wanna come back to our SDP3303X.

I have to admit that it is not possible to get constant readings with the SDM3065, the time deviation between the readings during recording is very high - doesn't care if I use EasyDMM, USB-disk, internal recording which is missing a time stamp. Also external triggering doesn't help. Do the 3055 users have the same problem?

Once again, Siglent, shame on you!

So I used my 25y old 34401a, connected via Agilent GPIB-adaptor and the old but free software "Agilent DMM". I got very constant readings @ 16.5 Hz with 1 PLC and a far better FFT analysis of the SPD3303X output.
Voltage = 1 volts since this fits best to the 1V range of the 34401a. FFT was done with EXCEL. Both devices are running for 24 hours.

You see now much better the oscillating (yes, it is still in specs) of the output, I think it comes from a internal feedback loop of the regulator.
I'm interested what you think?

[oz2cpu]

is it recalculated to HZ the bins ? of the fft ?

and YES i also belive it is regulation loop that is not performing uptimal,
any one got a schematic ? come on siglent, we offer to fix this for you, for free,
so this super nice supply, can be 10 times better performance :-)

[Bad_Driver]

Yes, X is in Hz. Linear looks better than in Log.
A schematic would be helpful.

oz2cpu, can you be so kind to check the behavior of your 3055 during recording with respect to the time intervals?
Siglent should be able to get thinks done as a 25y old HP-DMM....

[oz2cpu]

i will be happy to help,
please tell me the most easy methode to test/reveal the time interval issue,
it is something i did not dig into yet,
so i need a little bit for dummies how to :-) 

[Bad_Driver]

Very easy, connect DMM to EasyDMM, settings for faster reading (1 PLC or so), No AutoZero and record some minutes.

Export to EXCEL, normalize Time Stamp (I think you must do a division by 1E6 or so to get seconds) and calculate the time intervals between readings.

With the SDM3065 the intervals have a deviation of more than 50% from one to the other, with the HP34401 the deviation is about 2%.
Than you can try to use external triggering with about 10 Hz to see if there is some improvement.

[oz2cpu]

i assume i need to input a known signal, with a known repeat freq ?
also ethernet and my routers and switches and my pc involved, is not a realtime envoiment
and cant be thrusted to the last ms.
 

[Bad_Driver]

No input signal can be DC (our SPD maybe). You get only a reading if the SDM is ready.
I assume network connection is better than usb, but every kind of connection is fast enough for some hundred bytes per second.
You can also try the same with recording to usb-disk as well.

[oz2cpu]

this is my first time using the record to usb stick feature :-)
I am sorry but it is a bit confusing,
I dont know if it is running or not, how to start or stop..
+2V -2V squarewave 0.1Hz

Mode,Time(s),Value
DCV,0.1224640012,-1.980109E+00
DCV,0.3224929869,-1.980099E+00
DCV,0.5225350261,-1.980221E+00
DCV,0.7225729823,-1.980194E+00
DCV,0.9232320189,-1.980166E+00
DCV,1.1231570244,-1.675675E+00
DCV,1.3231680393,4.330368E-01
DCV,1.5232470036,1.899562E+00
DCV,1.7232489586,1.979141E+00
DCV,1.9232670069,1.979064E+00
DCV,2.1233971119,1.979092E+00
DCV,2.3234310150,1.979073E+00
DCV,2.5233540535,1.979068E+00
DCV,2.7234768867,1.979066E+00
DCV,2.9235060215,1.979098E+00
DCV,3.1234118938,1.979249E+00
DCV,3.3235540390,1.979335E+00
DCV,3.5234611034,1.979267E+00
DCV,3.7234780788,1.979239E+00
DCV,3.9236209393,1.979196E+00
DCV,4.1235442162,1.979189E+00
DCV,4.3235640526,1.979174E+00
DCV,4.5237011909,1.979143E+00
DCV,4.7236280441,1.979153E+00
DCV,4.9236412048,1.979187E+00
DCV,5.1237788200,1.979096E+00
DCV,5.3237118721,1.979051E+00
DCV,5.5237450600,1.978988E+00
DCV,5.7238807678,1.978893E+00
DCV,5.9238147736,1.978840E+00
DCV,6.1238241196,1.857547E+00
DCV,6.5433020592,-1.980423E+00
DCV,7.4235730171,-1.980176E+00
DCV,7.6235952377,-1.980146E+00
DCV,7.8236031532,-1.980107E+00
DCV,8.0236463547,-1.980106E+00
DCV,8.2237596512,-1.980206E+00
DCV,8.4237136841,-1.980117E+00
DCV,8.6238460541,-1.980151E+00
DCV,8.8238334656,-1.980220E+00
DCV,9.0238161087,-1.980155E+00
DCV,9.2239456177,-1.980105E+00
DCV,9.4238948822,-1.980061E+00
DCV,9.6239099503,-1.980061E+00
DCV,9.8240585327,-1.980089E+00
DCV,10.0240192413,-1.980048E+00
DCV,10.2240056992,-1.980011E+00
DCV,10.4241542816,-1.980070E+00
DCV,10.6240949631,-1.980055E+00
DCV,10.8252677917,-1.980056E+00
DCV,11.0251789093,-1.974333E+00
DCV,11.2252397537,-1.307193E+00
DCV,11.4253664017,1.053806E+00
DCV,11.6252880096,1.962226E+00
DCV,11.8253135681,1.979114E+00
DCV,12.0254421234,1.978924E+00
DCV,12.2253580093,1.978975E+00
DCV,12.4253692627,1.979014E+00
DCV,12.6254377365,1.979111E+00
DCV,12.8254461288,1.979105E+00
DCV,13.0254764557,1.979070E+00
DCV,13.2255163193,1.978966E+00
DCV,13.4255256653,1.978929E+00
DCV,13.6255464554,1.978772E+00
DCV,13.8255786896,1.978756E+00
DCV,14.0256805420,1.978708E+00
DCV,14.2256231308,1.978740E+00
DCV,14.4257678986,1.978772E+00
DCV,14.6257085800,1.978803E+00
DCV,14.8257331848,1.978868E+00
DCV,15.0258588791,1.978925E+00
DCV,15.2258081436,1.978895E+00
DCV,15.4258232117,1.978820E+00
DCV,15.6259517670,1.978818E+00
DCV,15.8258924484,1.978791E+00
DCV,16.0259170532,1.978506E+00
DCV,16.2260551453,1.645835E+00
DCV,16.4259834290,-5.011422E-01
DCV,16.6259975433,-1.910020E+00
DCV,16.8260555267,-1.979830E+00
DCV,17.0260810852,-1.979768E+00
DCV,17.2261085510,-1.979764E+00
DCV,17.4261226654,-1.979775E+00
DCV,17.6261367798,-1.979843E+00
DCV,17.8267440796,-1.979848E+00
DCV,18.0266151428,-1.979829E+00
DCV,18.2266178131,-1.979847E+00
DCV,18.4267959595,-1.979837E+00
DCV,18.6266841888,-1.979698E+00
DCV,18.8266925812,-1.979707E+00
DCV,19.0267677307,-1.979766E+00
DCV,19.2267646790,-1.979769E+00
DCV,19.4267768860,-1.979799E+00
DCV,19.6269245148,-1.979892E+00
DCV,19.8269100189,-1.979952E+00
DCV,20.0268516541,-1.979956E+00
DCV,20.2270088196,-1.979872E+00
DCV,20.4269199371,-1.979882E+00
DCV,20.6269474030,-1.980007E+00
DCV,20.8270702362,-1.979978E+00
DCV,21.0269870758,-1.845071E+00
DCV,21.4470748901,1.978747E+00
DCV,22.3273601532,1.978798E+00
DCV,22.5275154114,1.978814E+00
DCV,22.7274436951,1.978876E+00
DCV,22.9274597168,1.978843E+00
DCV,23.1276111603,1.978771E+00
DCV,23.3275279999,1.978939E+00
DCV,23.5275440216,1.978910E+00
DCV,23.7276000977,1.978854E+00
DCV,23.9276371002,1.978866E+00
DCV,24.1276683807,1.978937E+00
DCV,24.3277091980,1.978940E+00
DCV,24.5277252197,1.978922E+00
DCV,24.7277297974,1.978934E+00
DCV,24.9277763367,1.979013E+00
DCV,25.1277961731,1.978926E+00
DCV,25.3278236389,1.978762E+00
DCV,25.5279483795,1.978718E+00
DCV,25.7278919220,1.978830E+00
DCV,25.9293479919,1.979036E+00
DCV,26.1293487549,1.846035E+00
DCV,26.5514125824,-1.980106E+00
DCV,27.4316883087,-1.979922E+00
DCV,27.6341247559,-1.979897E+00
DCV,27.8318672180,-1.979915E+00
DCV,28.0318107605,-1.979855E+00
DCV,28.2319431305,-1.979865E+00
DCV,28.4318809509,-1.979834E+00
DCV,28.6319141388,-1.979810E+00
DCV,28.8320484161,-1.979816E+00
DCV,29.0319805145,-1.979913E+00
DCV,29.2320022583,-1.980012E+00
DCV,29.4321346283,-1.979985E+00
DCV,29.6320552826,-1.979882E+00
DCV,29.8320922852,-1.979778E+00

is this what you want ?
also how about all sorts of settings ?
fast, med, slow ?
auto range ?
trigger auto, and delay auto, samples / trigger ??
here is a new file, much longer recording,
webx dot dk / siglent / csv_data_1.csv

[Bad_Driver]

This looks much better as what is possible with the SDM3065! Every 0.2 sec a reading!
Thanks for your efforts!

Can you please try again with lower DMM resolution to see what will be the fastest acquisition frequency?

[Bad_Driver]

Sorry, didn‘t answer your question.
No auto range, fast reading, trigger auto, trigger delay=0 -> let‘s see what is possible.

[oz2cpu]

exactly.. got it
please reload the link,
just added 3 new files, about 5 mins, 5V dc, in slow, medium, fast.
the fun thing is all modes save a lot of digits into the file ..

[Bad_Driver]

I got the file. I will have a look tomorrow and do some comparisons with the 3065X.

[Bad_Driver]

The SDM3055X behaves as expected! Very constant readings, in slow mode 5 Hz, in fast mode about 72 Hz!

So I'm pretty happy to spend 800 € for the SDM3065X with very weird and crappy acquisition behavior.   

I try to compare your readings with the SDM3065 for the SDM threat, hope that Siglent takes care of this issue (Tautech where are you??).

I did a FFT with your slow readings, I assume this is not the SPD3303X??? (X = frequency/Hz)

[oz2cpu]

>I did a FFT with your slow readings, I assume this is not the SPD3303X??? (X = frequency/Hz)

nope it is the oldie Oltronix_stabpac_mca_5-3 the most stable voltage i got :-)

I can make a slow-mode file SPD3303X tomorrow, just booted it up
I let the voltmeter stay on, all night too, this way they will be as stable as possible,
how long file do you think I need to record ?
only slow ? or also the other modes ?

[Bad_Driver]

Plz try to make a file with 4096 readings. This is the limit for EXCEL FFT.

[oz2cpu]

so this is the plan, agree ?

DC source : Siglent  SPD3303X set for 5.000 no load, been powered on for 24hrs at least.
slow 4096 points needed, 4096/5 = 819 sec, 13,6 mins
medium 4096 points needed, 4096/50 = 82 sec, 1,36 mins
fast 4096 points needed, 4096/92 = 44 sec, 0.74 mins

i add atleast a few secs, so we are sure you get over 4096, maybe it is a good idea to take double the length, and perform the test two times ?
see if results align ?

PS: how do i get the excel fft ? please email it to me, my email is my user name at gmail so that is easy to remember :-)
note : i have a hard time importing this CSV format, my excel dont accept the format.

[Bad_Driver]

Follow this advice to get exact 4096 readings to usb. For best resolution 2 volts DC I think.
https://siglentna.com/operating-tip/sample-and-store-sdm3000/

For FFT I send you the information via mail tomorrow.

Edit: Please adopt the advice so, that datas are written direct to USB-disk, internal recordings will not have any time stamp. 
Very old failure (I can‘t beliefe that this shall be a feature) in the firmware.

[oz2cpu]

here we go, refresh the link

I added slow, medium, fast,
2V and 5V same SPD3303X
the record length should be over double the min required, this means it is possible to make two fft pr test, and see if results are the same

[Bad_Driver]

I have started with the analysis but no results before Friday. Tomorrow I get my (3rd) vaccination.

[Bad_Driver]

With help of oz2cpu data acquisitions I calculated 2 new FFTs of the SPD3303's output oscillations.
oz2cpu and I recorded with our DMMs (oz2cpu: SDM3055X, medium speed; me SDM3065X, 0.05 PLC) after warming up DMM and
SPD for more than 24 hours more than 4000 values for further FFT with EXCEL.

I discovered some interesting findings for the SDM3055X and 3065X but I will them post in the Siglent SDM topic later.
Long story short: SDM3055X behaves much better with recordings (with regards to sampling frequency accuracy) but
not perfect, SDM3065X is (big surprise!) only useable with high sampling frequencies up to 600...2000 Hz.
This is the reason for the fewer (smoother looking) data's in my measurement, there is no additional information in the spectrum above 20 Hz (up to 1000 Hz).

Attached you see both FFTs with nearly the same result. There are not only some oscillations in the low-Hz range but up to 18 Hz as well with the SPD3303X. My former low-f FFT:
https://www.eevblog.com/forum/testgear/how-to-calibrate-siglent-spd1000x-spd3303x-spd3303x-e-series-power-supplies/msg3916976/#msg3916976

[mawyatt]

Good news on the rogue SDP3303X-E that had the current offset mentioned much earlier. We sent this to Siglent NA before the Holidays and just received the repaired unit. After 1/2 hour warm up, ran some quick tests for output voltage and current limit. Everything is Spot On, even lower current limits below 20ma, so we can now put this back in service with the intended use

Don't think we'll be attempting a self calibration on this unit tho 

Thanks Siglent NA (Jason)

Best,

[mawyatt]

With help of oz2cpu data acquisitions I calculated 2 new FFTs of the SPD3303's output oscillations.
oz2cpu and I recorded with our DMMs (oz2cpu: SDM3055X, medium speed; me SDM3065X, 0.05 PLC) after warming up DMM and
SPD for more than 24 hours more than 4000 values for further FFT with EXCEL.

I discovered some interesting findings for the SDM3055X and 3065X but I will them post in the Siglent SDM topic later.
Long story short: SDM3055X behaves much better with recordings (with regards to sampling frequency accuracy) but
not perfect, SDM3065X is (big surprise!) only useable with high sampling frequencies up to 600...2000 Hz.
This is the reason for the fewer (smoother looking) data's in my measurement, there is no additional information in the spectrum above 20 Hz (up to 1000 Hz).

Attached you see both FFTs with nearly the same result. There are not only some oscillations in the low-Hz range but up to 18 Hz as well with the SPD3303X. My former low-f FFT:
https://www.eevblog.com/forum/testgear/how-to-calibrate-siglent-spd1000x-spd3303x-spd3303x-e-series-power-supplies/msg3916976/#msg3916976

Wonder if this is something to do with the feedback loop that uses the ADC readings to correct the output, assuming Siglent has incorporated this type of error correction loop? If they did, then the cycle time between read and correction might be within the FFT spectrum you've shown.

Do recall Dave mentioning a high resolution SD ADC chip in his teardown video, these tend to be slow and their sample rate would fit the FFT artifacts. Would be interesting to hear from someone that has the schematic, or knows how this PS is implemented.

Best,

[blurpy]

Good news on the rogue SDP3303X-E that had the current offset mentioned much earlier. We sent this to Siglent NA before the Holidays and just received the repaired unit.

Really nice! Any idea what they did to fix it? Clear an eeprom and recalibrate perhaps?

[Bad_Driver]

Had a short look into Dave's video. The ADC is a AD7792 (3-channel, 16/24 bit) and the reference is a ADR03.
If they have done the regulation feedback loop in "software" than they should be able to fix it with a firmware update.

[mawyatt]

Good news on the rogue SDP3303X-E that had the current offset mentioned much earlier. We sent this to Siglent NA before the Holidays and just received the repaired unit.

Really nice! Any idea what they did to fix it? Clear an eeprom and recalibrate perhaps?

Agree, really nice they did this under warranty since I had "augmented" the X-E to an E. Our only cost ($50) was shipping to Siglent NA

No idea what they did.

Best,

[mawyatt]

Had a short look into Dave's video. The ADC is a AD7792 (3-channel, 16/24 bit) and the reference is a ADR03.
If they have done the regulation feedback loop in "software" than they should be able to fix it with a firmware update.

Siglent may have implemented a "Dual Loop" with a continuous feedback loop and another feedback loop formed with the ADC where this becomes more of an output voltage update and now behaves as a sampled data feedback in parallel with the continuous loop.

Agree the loop formed with the ADC should be affected by firmware.

Best,

[Bad_Driver]

I found some time to setup my high-end audio interface (Terratec DMX6 Fire USB) to measure the noise spectrum above 10 Hz of the SPD3303X.
(it's a night mare since all the drivers are from the good old XP/win7...8 decade)

Attached the results. Graph 1 is channel 1 @ 2 volts, no load. Graph 2 is channel 2 @ 2 volts, no load.
Nearly identical. Above 3 kHz is nothing of interest in the spectrum ( I did it up to 90 kHz with "AudioTester 3.0; 192 kHz sampling rate, 24 bits).

Please note that the levels of the spectrum are in calibrated "dBV". Overall the SPD is in specs. There is no dependency to the level of output voltage.
End of the week I can try it under load.

[oz2cpu]

I am so happy you look into the odd regulation loop noise,
if this is a sw or hw issue, i dont know,

I have been "playing" with SPD3303 today, i did find optocoupler drivers on both sides, running 5 times
hotter, than all other opto driver transistors, so i figure they do run some kind of hi speed link there too,

since I keept remembering the too hot parts, in the EEVblog 828 see at 26 mins
and i run my SPD3303 most of the time in week long experiments
i was looking for a way to , fix the hot parts, and to dimm the display (mine are very bright)

I gave up on the display dimm, looks like impossible to do, i digged all the way to the display it self,
there is just no way to get access to the led wires and put in a resistor.

I did however fix the too hot parts, since i fixed both psu in one go, made the video during the 2nd psu fix,
so i knew what to do fast and easy.
it is all explained here:

https://youtu.be/nvGxl44cNno

incase anyone want access to all my hires pictures of all details inside SPD3303
get the 490MB zip here
webx.dk/siglent/SPD3303PICS.ZIP

[Bad_Driver]

During the last firmware update I learned that there is a new hardware revision of the SPD3000.
(firmware update was only for new hardware release)
Has someone an idea what was improved?

[BreakingOhmsLaw]

During the last firmware update I learned that there is a new hardware revision of the SPD3000.
(firmware update was only for new hardware release)
Has someone an idea what was improved?

The SPD3303X(-E) had an issue with a bridge rectifier overheating, causing the unit to reset frequently under load. The issue is common. So far, Siglent has been repairing them under warranty as far as users here report. Funny enough, in Dave's teardown from years ago, he already noticed that hot rectifier.
https://www.eevblog.com/forum/repair/siglent-spd3303x-e-rebooting/msg4340536/#msg4340536

[oz2cpu]

you might want to see this one
https://youtu.be/nvGxl44cNno

it is about how to modify the psu, so its life time will be much longer

[Peter_O]

Never tried to calibrate mine.

acc. to siglenteu the 3.0 FW is the newest one: SPD3303X Firmware_V1.01.01.03.10 (Release Date 09.02.22 )

https://www.siglenteu.com/service-and-support/firmware-software/dc-power-supplies/#spd3303xx-e-series

[BreakingOhmsLaw]

So, a a quick update on this:
My SPD3303 suffered from the fault that it starts resetting after a while. This is due to the overheating bridge rectifier that Dave found in his review.
I've bought mine from siglent.eu webshop in the Netherlands.
Sent it for repair, got it back around three weeks later from Siglent Germany, repaired. Fault report stated "replaced faulty bringe rectifier".

Can't complain about their service.

[ono]

I was calibrating my "upgraded" SPD3303X-E today according https://www.eevblog.com/forum/testgear/how-to-calibrate-siglent-spd1000x-spd3303x-spd3303x-e-series-power-supplies/msg2131678/#msg2131678 on macOS using PyVISA and I got stuck on CALibration:VOLTage SCPI command producing beep despite I was sending perfectly fine commands. So essentially I experienced same thing as described by OP @MartyMacGyver.

Since I wiped voltage and stored wiped values with *CALST prior putting new calibration values, I thought I just screwed my power supply badly and it will show garbage voltage readings from now on. 

But then I started reading around the web if there is a some easier way to access SCPI command line, and yes you can connect to port 5025 (see https://www.siglenteu.com/operating-tip/instrument-socket-and-telnet-port-information/) to have telnet like console. (On Linux/macOS you can use nc 192.168.xxx.yyy 5025). Using this connection method all CALibration:VOLTage got accepted (no beep) and I was able to perform all calibration steps (V reading, I reading, CC) I have now great calibrated device that is at most 1-2mA off from my HP 34401A and Stamos S-LS-60 (aka Korad KEL102) with current readings and CC regulation. Previously CC was off by 8mA with small currents.

Also power cycling the unit is absolutely not necessary. New calibration values start to work immediately upon changing the voltage or current setting. *CALST is only needed to make them persist after power off.

Since others may trip on this as well I decided to post my solution here, despite this thread is pretty old. @BreakingOhmsLaw you could consider updating your instructions recommending direct TCP port 5025 telnet/nc access as the most reliable way that does not require any software.

[BreakingOhmsLaw]

Since others may trip on this as well I decided to post my solution here, despite this thread is pretty old. @BreakingOhmsLaw you could consider updating your instructions recommending direct TCP port 5025 telnet/nc access as the most reliable way that does not require any software.

Thanks! Updated the procedure.
https://www.eevblog.com/forum/testgear/siglent-sds3303x(-e)-calibration-fw1-01-01-02-07r2-best-practice/msg3819530/#msg3819530

[MathWizard]

I haven't had any problem with my hacked 3303x, besides one time I damaged the select-able 5V rail. But I've hardly stressed the PSU, most stuff I've powered was pretty low power, and for fairly short duration tests/etc.


But my cables and connectors aren't the best, and can sometimes drop a few mV or more, I know that's usually fine. But has anyone looked at the circuits in detail, and thought about adding voltage sensing out at the DUT ?

 I'm not sure what would be involved with that, maybe too much stuff would have to be changed.

I only have one, brandname bench PSU (I made one too) so I'm in no rush to open it back up, but I did want to mod the 3rd rail a bit, I think by adding some warning LED's or some protection that was not added, or something, I can't remember, I mapped some of the circuit when I fixed it ages ago.

[mawyatt]

The 3303X is quite a nice supply for the bench, we have three to support our work. We haven't experienced any of the use issues that would make us think about using these for development work with expensive sensitive ICs. The voltage and current settings are accurate and they don't have any nasty overshoots, however having remote sense capability would be nice.

Think the new Siglent supplies tautech mentioned awhile back may have this feature.

For very high current needs we have the Korad KWR102 and 103, which feature remote sensing. We created "special" cables for these which have sense leads built in, this works quite well and gives us an accurate voltage at the cable ends, even with higher currents (30 amps!).

Best,

[tautech]

Think the new Siglent supplies tautech mentioned awhile back may have this feature.

They will.

[MathWizard]

Yeah I guess getting or making some better cables would help. I need some better banana plugs.

But this reminds me, all my main gear, which is Siglent stuff, needs to be opened up and cleaned with the vacuum and toothbrush, or compressor. My 1204X-E, AWG and DMM have never been opened or cleaned in 3-4 years, and I did some house renovations, so I'm sure they have dust in there. I guess all their warranties are up.