Products > Test Equipment
How to calibrate Siglent SPD1000X / SPD3303X / SPD3303X-E series power supplies?
<< < (11/27) > >>
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  |O

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 :P

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 |O

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 :P

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 :o 

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 :P

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 :-DD

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,
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod