Electronics > Repair

Rigol DP811 (DP800 series) voltage accuracy

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terrance:
My DP811 output and measurement voltage are very off. Then I did a painful calibration, just months after, it went off again. The spec is 0.05% + 10mV, actually It generates 9.82V at 10.000V setting, and itself reads 10.003.
I'm thinking weather do another calibration or tear it apart and see what's wrong with it.   :-BROKE

geeze! it has 61 points to calibrate!

terrance:
 |O |O |O
I calibrated 61 voltage points, and 10 ADC points. Power cycle DP811. It still generates 9.82V at 10.000 setting.

So I poked around, after click "Sense" to "off" and then "on", the output voltage magically jumped to 10.000V ......
 :-//

RoGeorge:
Your complaint makes me think you are trying to calibrate manually, which would be painfully slow to do, and inaccurate/prone to errors and typos during inputting the measured values.

The calibration can be automated, so the best way is to use all available points.  For a totally off/miscalibrated situation, there might be useful to fully calibrate 2-3 times, for an incremental accuracy increase.

It is essential to leave the instrument idle at least half an hour to reach thermal equilibrium, same for the measuring multimeter.  Use very high quality wires/probes.  If the temperature/humidity varies a lot from what it was during the calibration, then recalibrate more often.

Yours, with almost 200mV error after calibration is very off, might be defective.

I have a DP832 that I've recalibrated a couple of years ago.  It was possible to make it with 1mV and 1mA accuracy over all the voltage and current ranges, on all 3 channels.  It did shifted over years, and from summer to winter, but not much, a few mV or mA at most, even when at full range.

Calibration for DP832 is about the same as for DP811, both are from the same DP800 family of power supplies.  Found the program that served as a model to calibrate my DP832, though I had to adapt it to my DMM model, a Metrix mtx3283:  https://www.eevblog.com/forum/testgear/rigol-dp832a-automatic-scpi-calibration-script/

If you didn't try yet, search for

--- Code: ---DP800 calibration site:eevblog.com
--- End code ---
maybe you find a ready made tool.  Beware some of the calibration documents might be incomplete, or wrong, from the period when the calibration procedure from Rigol was not yet available.

terrance:
ah, noice! Thanks!  :-+

I use Linux, so a shell script is perfect. I can use my UT61E+, with a simple python program to read measurements.

terrance:
DP811 has wider voltage range, 0-40V, and 61 V DAC points. I need to modify the script.

first thing, voltage calibration points:


--- Code: ---0.4
0.7
1.3
2.01
2.3
3.2
3.8
4.0
4.9
5.5
6.5
7.6
8.2
8.6
9.0
9.9
10.6
10.9
11.9
13.1
14.0
14.8
15.4
16.5
17.4
17.8
18.1
18.7
19.5
20.3
20.8
21.8
22.4
22.8
23.2
24.2
25.7
26.0
27.2
28.1
29.2
30.0
30.6
31.0
31.5
32.1
32.7
33.5
34.7
35.2
35.9
36.6
36.9
37.8
38.1
38.7
39.6
40.0
40.5
41.3
42.0
--- End code ---

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