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| How to calibrate Siglent SPD1000X / SPD3303X / SPD3303X-E series power supplies? |
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| 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:
--- Quote from: Bad_Driver on January 07, 2022, 10:48:30 am ---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 --- End quote --- 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, |
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