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Rigol DP832 - Firmware list and bugs

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garrettm:

--- Quote from: skander36 on March 17, 2020, 10:02:02 pm ---@garrettm
It will be more easy to verify the status of calibration if the displayed read value is displayed in real values , not scientific .

--- End quote ---

Thats easily doable. I just need to convert the string to a double then print that using printf to format in volts. I'll probably truncate or round at the 4th decimal place since the PSU can only adjust / readback 3 decimal places. The current format is literally what the DMM sends back.

Before I do that though, I want to try testing out new cal points. I've been focusing on using standard low voltage VCC values for the cardinal points. This way, the voltages that are most likely to be used will have tighter accuracy. For instance 1, 1.2, 1.8, 2.4, 2.7, 3, 3.3, 3.6, 4, 4.2, etc. Then switch over to 0.5 volt increments after that and then 1 volt increments.

Let me know what you think. I plan on doing <= 53 cal points per parameter. Hopefully we can fine tune the linearity doing this. I also need to write another script to measure and plot the output and figure out the programming vs output error to see if we can measure an improvement.

garrettm:

--- Quote from: JDubU on March 17, 2020, 08:02:51 pm ---The DMM has a 10 Meg ohm input resistance.  Even if the leads had a total of 1 ohm resistance, the voltage drop would be half a microvolt.

--- End quote ---

Any 6.5 digit DMM at or below 10 or 20 volts (depending on % overranging) will have >= 10 gigohm input impedance at DC. So negligible loading error.


--- Quote from: McBryce on March 17, 2020, 05:40:35 pm ---If I had the results you're showing here I'd be worried. It's saying that the output is quite a bit higher than it should be unless those cables you're using have absolutely no voltage drop? Which is unlikely.
McBryce.

--- End quote ---

The DP832A can only program upto the third decimal place, and after very recent calibration is maybe within +-2 counts at best. So
Gandalf_Sr DMM reading is actually excellent. The programming error is only around 0.3 counts. I can't see how that is bad in any way.

skander36:
I also planned by myself to edit list with calibration points from thread with bash script. Tommorrow I will make time for this.

garrettm:

--- Quote from: skander36 on March 17, 2020, 10:26:44 pm ---I also planned by myself to edit list with calibration points from thread with bash script. Tommorrow I will make time for this.

--- End quote ---

I decided to do the print format edit first. Now everything is lined up and prints out values in volts and amps. So no mucking about with annyoing scientific notation. I also reduced the settling time to 2 seconds for volts and 3 seconds for current. This is in anticipation of the larger cal point arrays, which will make the calibration take longer.

Let me know if you have any problems with new changes and thanks for using the script!

UPDATE: There was a minor typo in TelnetTest that I fixed. It would cause the DMM to report an error because of an unfinished measuremnt. Accidentally called readDMM() instead of dmm.read() inside the for loop. Whoops.

McBryce:

--- Quote from: JDubU on March 17, 2020, 08:02:51 pm ---
--- Quote from: McBryce on March 17, 2020, 05:40:35 pm ---
--- Quote from: Gandalf_Sr on March 16, 2020, 08:44:44 pm ---Here's a picture of my calibrated DP832(A) sending 5.000V to my 34461A :D

--- End quote ---

If I had the results you're showing here I'd be worried. It's saying that the output is quite a bit higher than it should be unless those cables you're using have absolutely no voltage drop? Which is unlikely.

McBryce.

--- End quote ---

The DMM has a 10 Meg ohm input resistance.  Even if the leads had a total of 1 ohm resistance, the voltage drop would be half a microvolt.

--- End quote ---

Doh, for some reason my brain hid the 3 zeros between 5 and 13 on the meter. I read 5.013V. Need more coffee.

McBryce.

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