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eez-open / psu-firmware

Firmware for programmable bench power supply EEZ H24005
https://www.envox.eu/bench-power-supply/psu-firmware/
GNU General Public License v3.0
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False attempt to calibrate current without load connected #190

Closed romain145 closed 6 years ago

romain145 commented 6 years ago

Expected behavior

When calibrating Ch1 MID point current, I should be able to enter the value I measured: 2.492 (A).

Actual behavior

The screen displays an error "Value out of range".

How to reproduce

Enter 2.492 for current MID point calibration.

prasimix commented 6 years ago

Possible duplicate of #160. Trace log on serial is needed to check values.

romain145 commented 6 years ago

Current [0-5A] MID point: **TRACE [2017-12-09 18:23:10]: Voltage range: 0.000000 - 40.000000V **TRACE [2017-12-09 18:23:10]: ADC=0.191949 **TRACE [2017-12-09 18:24:13]: ADC check failed: level=2.425000, adc=-0.005169, diff=2.430169, allowedDiff=0.475000

Current [0-5A] MAX point: **TRACE [2017-12-09 18:25:50]: ADC check failed: level=4.800000, adc=-0.005322, diff=4.805322, allowedDiff=0.475000

Current [0-500mA] MID point: **TRACE [2017-12-09 18:27:03]: ADC check failed: level=0.242500, adc=-0.000502, diff=0.243002, allowedDiff=0.095000

Current [0-500mA] MAX point: **TRACE [2017-12-09 18:27:55]: ADC check failed: level=0.480000, adc=-0.000486, diff=0.480486, allowedDiff=0.095000

Channel 2 Current MID point: **TRACE [2017-12-09 18:29:17]: Voltage range: 0.000000 - 40.000000V **TRACE [2017-12-09 18:29:17]: ADC=0.234834 **TRACE [2017-12-09 18:30:30]: ADC check failed: level=2.425000, adc=-0.005322, diff=2.430321, allowedDiff=0.475000

Also, clicking "Change" after setting a calibration value doesn't re-enable the output.

prasimix commented 6 years ago

Do you have load connected during current calibration?

romain145 commented 6 years ago

Yes, but it seems that my load impedance was way too low for the PSU. I'm trying with a 1 Ohm load now and went through the calibration!

For some calibration, clicking "Change" after setting a calibration value doesn't re-enable the output.

prasimix commented 6 years ago

Yes, but it seems that my load impedance was way too low for the PSU. I'm trying with a 1 Ohm load now and went through the calibration!

You mean your load is too high, since measured current is zero. Use resistor that is lower then about 4 Ohms as it's clearly stated here.

For some calibration, clicking "Change" after setting a calibration value doesn't re-enable the output.

Please be more specific. Which "Change" button/option?

romain145 commented 6 years ago

The multimeter was correctly measuring the current so I'm not sure what the deal was... Indeed, by using a 1-4 Ohm load, the calibration procedure runs just fine. Great job !

The Change option is working, I noticed I blew the low amp range fuse on my multimeter (EEVBlog BM235). The multimeter case is rated 600mA, so I used it for the 500mA calibration; however, Dave fitted a 400mA fuse...

Closing