Author Topic: Automated DP832 Calibration  (Read 4428 times)

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Offline PeDre

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Re: Automated DP832 Calibration
« Reply #50 on: April 28, 2020, 06:03:46 pm »
Hello Wolfgang,

you write on your website, screen copies do not work with DP832. The SCPI command is ":SYSTem:PRINT? BMP" and works with my DP831.

Peter
 
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Offline JDubU

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Re: Automated DP832 Calibration
« Reply #51 on: April 28, 2020, 06:05:17 pm »
Wolfgang:

Will you be sharing your Arduino SCPI-based appliance code?
 

Offline Wolfgang

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Re: Automated DP832 Calibration
« Reply #52 on: April 28, 2020, 06:11:09 pm »
Hi Peter,

thanks for the tip ! I try it on my DP832 and let you know if it works.
 

Offline Wolfgang

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Re: Automated DP832 Calibration
« Reply #53 on: April 28, 2020, 06:20:45 pm »
Hi Peter,

works perfectly. I also tried PNG, but that does not seem to work, so I stayed with BMP. Thanks again !
 

Offline Wolfgang

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Re: Automated DP832 Calibration
« Reply #54 on: April 28, 2020, 06:21:47 pm »
Wolfgang:

Will you be sharing your Arduino SCPI-based appliance code?


Yes, under GPL V3. Just cleaning it up a little bit.
 
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Offline Wolfgang

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Re: Automated DP832 Calibration
« Reply #55 on: April 28, 2020, 06:46:04 pm »
Wolfgang:

Will you be sharing your Arduino SCPI-based appliance code?


I just uploaded it onto the webpage. Have fun !
 
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Offline Gandalf_Sr

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Re: Automated DP832 Calibration
« Reply #56 on: April 30, 2020, 04:51:39 pm »
I just bought a second DP832 from Tequipment.net.  I have 2 main workbench areas and I unburdened myself of a Siglent SPD3303X-E a few months back.  Just sold some stuff on eBay and decided I would try and boost the economy so the deal is done  :)
If at first you don't succeed, get a bigger hammer
 

Online tv84

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Re: Automated DP832 Calibration
« Reply #57 on: April 30, 2020, 09:38:55 pm »
Hi Peter,

works perfectly. I also tried PNG, but that does not seem to work, so I stayed with BMP. Thanks again !

Wolfgang,

Look here. Maybe you'll find others that interest you.

BTW, it only saves in .BMP mode.
« Last Edit: April 30, 2020, 09:44:47 pm by tv84 »
 
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Offline Wolfgang

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Re: Automated DP832 Calibration
« Reply #58 on: April 30, 2020, 11:10:25 pm »
Thanks !,

I'll add some when I find time and I have collected some feedback.
I plan to put all the instruments in a DB instead of into the program as now.

For what I have (DP832(A),DG1000Z Series, DL3021A, DS1000Z Series, DSA800 Series, M300)
everything worked now except the M300, but you dont have that either.

The better parts in your list (3000/4000/5000/7000/8000) I dont have, but could be added to the list for other users.

Please report errors if you find any.

regards
  Wolfgang DL1DWG
 

Offline czecht

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Re: Automated DP832 Calibration
« Reply #59 on: June 20, 2020, 08:23:07 pm »
I have just the DP831, so I don't know if the DP832 hack works also on DP831.
I do not understand the commands you are talking here about - since I'm newbie and most of the time I don't know what I'm doing, sorry, I need any help I can get.
Because of financial limitations, I can't get a better one, I need to update mine as much as I can, but on youtube they are all talking about DP832, not much about mine DP831.
Thank you very much!
Tony
 

Offline Gandalf_Sr

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Re: Automated DP832 Calibration
« Reply #60 on: June 20, 2020, 08:29:47 pm »
I don't know for sure but I'm guessing that the 'magic' USB drive will allow the DP831 to be converted to an higher hardware-compatible model.  But what does the 831 do that the 832 doesn't?
If at first you don't succeed, get a bigger hammer
 

Online mjkuwp

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Re: Automated DP832 Calibration
« Reply #61 on: June 21, 2020, 01:50:34 pm »
Regarding Python and the IDE.  this is what I have done on several machines and it works:
1. download Python from the Python site python.org and install.
2. do not use Virtual Environments.

I've never tried using Python from the Windows Store.

I've done a lot with Python and Pycharm and do my development for in-house engineering tools on Windows and then most often the project is eventually run on a Raspberry pi.

in PyCharm you may need to point each project to the location of your Python interpreter.
[File][Settings...][Project:yourproject][Project interpreter] and then browse to your python.exe file.

PyCharm is an awesome tool, I think is a really good aid for productivity.

After a Raspberry Pi computer is running I sometimes use Visual Studio Code to edit over ssh via the tools that software provides.


 

Online alank2

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Re: Automated DP832 Calibration
« Reply #62 on: June 26, 2020, 07:14:01 pm »
Does anyone know if any of the calibration scripts for the DP832 support th Fluke 8845A?
 

Offline garrettm

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Re: Automated DP832 Calibration
« Reply #63 on: July 10, 2020, 11:03:42 pm »
Does anyone know if any of the calibration scripts for the DP832 support th Fluke 8845A?

My Telnet script using Ethernet works with the Fluke 8845A and 8846A, as it was written and tested using a Tektronix DMM4050 (rebranded Fluke 8846A). The script is written in Java and is pretty simple to use, less to configure and set up than the Python script in my opinon.

My script as well as the Python scripts use standard SCPI commands to control the instruments. So I'd wager your Fluke will work with the Python script if you prefere to go that route.

I've attached my script if you would like to use it. If you do, run "test_run.bat" in the complied directory first to check your setup. Then, if everything worked okay, run "calibrate.bat". Read the "Example Output of Cal Routine.txt" to see what a successful calibration looks like and what options to select.

 
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Online alank2

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Re: Automated DP832 Calibration
« Reply #64 on: July 11, 2020, 01:30:27 am »
That looks awesome - thanks garrettm I'll give it a try.
 

Online alank2

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Re: Automated DP832 Calibration
« Reply #65 on: July 11, 2020, 08:21:44 pm »
I installed Java for windows 10, but it says:

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: TelnetTest ha
s been compiled by a more recent version of the Java Runtime (class file version
 57.0), this version of the Java Runtime only recognizes class file versions up
to 52.0

I also tried to download the JDK 13 and install it as well.

Any ideas?
 

Online alank2

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Re: Automated DP832 Calibration
« Reply #66 on: July 11, 2020, 09:07:24 pm »
Ok, I go the java worked out.

Ran the test, here are the results:

Should these values be this far off?  The display of the power supply (DP832) did show a much closer number when the steps were selected to the meter and not what the steps are...

Code: [Select]
---------------------------- START OF TEST ---------------------------

Please disconnect all cables from the DMM

Enter 1 to begin automated voltage readback tests
1

Testing remote voltage measurement
meas val:  0.0015v
meas val:  0.0015v
meas val:  0.0015v
meas val:  0.0015v
meas val:  0.0015v

Testing local voltage measurement

Please check that instrument is in DC volts, 10npcl, local mode

Enter 1 to begin automated current readback tests
1

Testing remote 1A to 10A current measurement
meas val: -0.0001A
meas val: -0.0001A
meas val: -0.0001A
meas val: -0.0001A
meas val: -0.0001A

Testing local current measurement

Please check that instrument is in DC current, 10npcl, local mode

Enter y to test reading output of PSU cal points or n to skip
y

---------------------- SELECT READBACK TEST TYPE ----------------------

Note 1: If you're having trouble with voltage or current calibrations
performing a full voltage + current calibration will fix this

Note 2: Automated current calibration requires DMM with >= 3A range

Enter value of desired test type for ch1

0: skip ch1 test
1: voltage + manual current test
2: voltage + automated current test
3: voltage test (automated entry)
4: current test (manual entry)
5: current test (automated entry)
2

-------------------- VOLTAGE READBACK ROUTINE --------------------

Please connect DMM voltage input to ch1 output of PSU

Enter 1 to begin automated voltage readback
1

ch1 DAC-V readback
step  0, cal point:  0.2v, meas val:  0.0119v
step  1, cal point:  0.5v, meas val:  0.3104v
step  2, cal point:  1.2v, meas val:  1.0007v
step  3, cal point:    2v, meas val:  1.7894v
step  4, cal point:  3.2v, meas val:  2.9779v
step  5, cal point:  4.1v, meas val:  3.8682v
step  6, cal point:  5.2v, meas val:  4.9582v
step  7, cal point:  6.9v, meas val:  6.6497v
step  8, cal point:  7.5v, meas val:  7.2426v
step  9, cal point:  8.7v, meas val:  8.4378v
step 10, cal point: 10.1v, meas val:  9.8239v
step 11, cal point: 11.8v, meas val: 11.5075v
step 12, cal point: 12.6v, meas val: 12.3022v
step 13, cal point: 13.5v, meas val: 13.1974v
step 14, cal point:   15v, meas val: 14.6870v
step 15, cal point: 15.8v, meas val: 15.4879v
step 16, cal point: 16.5v, meas val: 16.1856v
step 17, cal point: 17.3v, meas val: 16.9773v
step 18, cal point: 18.5v, meas val: 18.1661v
step 19, cal point: 19.1v, meas val: 18.7651v
step 20, cal point: 19.9v, meas val: 19.5579v
step 21, cal point: 20.2v, meas val: 19.8532v
step 22, cal point: 20.8v, meas val: 20.4471v
step 23, cal point: 21.8v, meas val: 21.4467v
step 24, cal point: 22.4v, meas val: 22.0422v
step 25, cal point: 22.7v, meas val: 22.3420v
step 26, cal point: 23.9v, meas val: 23.5388v
step 27, cal point: 24.3v, meas val: 23.9386v
step 28, cal point: 25.7v, meas val: 25.3328v
step 29, cal point: 26.9v, meas val: 26.5311v
step 30, cal point: 27.9v, meas val: 27.5246v
step 31, cal point: 28.5v, meas val: 28.1186v
step 32, cal point: 28.9v, meas val: 28.5138v
step 33, cal point: 29.8v, meas val: 29.4050v
step 34, cal point: 30.2v, meas val: 29.8022v
step 35, cal point:   32v, meas val: 31.5926v

ch1 ADC-V readback
step  0, cal point:    0v, meas val: -0.1861v
step  1, cal point: 0.05v, meas val: -0.1374v
step  2, cal point:  0.1v, meas val: -0.0878v
step  3, cal point:  0.5v, meas val:  0.3101v
step  4, cal point:    1v, meas val:  0.8039v
step  5, cal point:    5v, meas val:  4.7599v
step  6, cal point:   10v, meas val:  9.7236v
step  7, cal point: 12.8v, meas val: 12.5013v
step  8, cal point:   20v, meas val: 19.6557v
step  9, cal point:   30v, meas val: 29.6043v
step 10, cal point:   32v, meas val: 31.5924v

-------------------- CURRENT READBACK ROUTINE --------------------

Connect ch1 output to DMM 10A current input

Enter 1 to begin automated current readback
1

ch1 DAC-I readback
step  0, cal point:  0.1A, meas val:  0.0862v
step  1, cal point: 0.25A, meas val:  0.2358v
step  2, cal point:  0.5A, meas val:  0.4855v
step  3, cal point:  0.8A, meas val:  0.7837v
step  4, cal point:    1A, meas val:  0.9828v
step  5, cal point: 1.25A, meas val:  1.2307v
step  6, cal point:  1.5A, meas val:  1.4785v
step  7, cal point: 1.75A, meas val:  1.7257v
step  8, cal point:  1.9A, meas val:  1.8756v
step  9, cal point: 2.15A, meas val:  2.1228v
step 10, cal point: 2.35A, meas val:  2.3225v
step 11, cal point:  2.5A, meas val:  2.4712v
step 12, cal point: 2.75A, meas val:  2.7187v
step 13, cal point:    3A, meas val:  2.9663v
step 14, cal point:  3.2A, meas val:  3.1632v

ch1 ADC-I readback
step  0, cal point:    0A, meas val: -0.0129v
step  1, cal point: 0.01A, meas val: -0.0028v
step  2, cal point:  0.1A, meas val:  0.0861v
step  3, cal point:    1A, meas val:  0.9827v
step  4, cal point:    2A, meas val:  1.9741v
step  5, cal point:    3A, meas val:  2.9662v
step  6, cal point:  3.2A, meas val:  3.1631v

---------------------------- END OF TEST ----------------------------
 

Offline garrettm

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Re: Automated DP832 Calibration
« Reply #67 on: July 11, 2020, 09:38:02 pm »
Those values look fine. These are the raw values used internally, so don't worry if they don't match the cal point exactly. Negative readback values are also not uncommon near zero for the ADC and DAC cal points.

From what I see, you are good to go if you want to calibrate using the Java script.

If you want to compare your test output with another PSU see the "Example Output of Test Routine.txt". It's the output of the test with my DMM and PSU.

P.S.

It also looks like there is a typo for the unit symbol for the current readback (V instead of A). I could also simplify the test routine: some of the prompts are carried over from the calibration script but aren't really needed for running the test.
« Last Edit: July 11, 2020, 09:50:19 pm by garrettm »
 

Online alank2

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Re: Automated DP832 Calibration
« Reply #68 on: July 11, 2020, 09:41:07 pm »
Thank you - I will move forward to calibration!
 

Online alank2

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Re: Automated DP832 Calibration
« Reply #69 on: July 11, 2020, 10:21:27 pm »
Wow garrettm, that did an amazing job.  I checked all 3 channels in 1V steps and there is only a place or two where it deviates by more than 1mV, and when it does, the meter on the DP832 matches the DMM.  Thanks so much for the script and posting it - you are awesome!
 
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Offline garrettm

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Re: Automated DP832 Calibration
« Reply #70 on: July 11, 2020, 10:31:15 pm »
Glad to help and thanks for trying out the script.
 
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Online alank2

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Re: Automated DP832 Calibration
« Reply #71 on: July 17, 2020, 10:45:09 pm »
garrettm - I've got another question - I got a second DP832 and it seems to have an odd issue where one of the calibration steps has a LOWER voltage than the one before it!

Any thoughts on this?  Shouldn't step 1 be around 0.3V higher than the step 0.

ch2 DAC-V calibration
step  0, cal point:  0.2v, meas val: -0.0705v
step  1, cal point:  0.5v, meas val: -0.0720v
step  2, cal point:  1.2v, meas val:  0.4447v
step  3, cal point:    2v, meas val:  1.2543v

ch2 ADC-V calibration
step  0, cal point:    0v, meas val: -0.1565v
step  1, cal point: 0.05v, meas val: -0.0899v
step  2, cal point:  0.1v, meas val: -0.0228v
step  3, cal point:  0.5v, meas val:  0.4982v
step  4, cal point:    1v, meas val:  1.0005v
 

Offline bson

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Re: Automated DP832 Calibration
« Reply #72 on: July 18, 2020, 03:48:11 am »
If I recall we originally made the calibration skip the first point since it might be negative.  But clearly there can be more than one negative point, so the calibrator should keep stepping the output by the negative readback plus a few mV until it gets positive.  So if it sees -70mV, step up the output by perhaps 75mV and check.  Repeat until it's positive.  The reason is negative outputs are almost certainly clamped and not part of the linear output range.  It might be a good idea to shift the entire calibration scale by the offset.  If 80.0mV produces 3.5mV, the offset if 80 - 3.5 = 76.5mV.
« Last Edit: July 18, 2020, 03:55:45 am by bson »
 

Offline garrettm

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Re: Automated DP832 Calibration
« Reply #73 on: July 18, 2020, 06:04:59 am »
@alank2 the routine is written verbatim as described by tooOldForThis, though from what bson points out we could certainly improve the script.

As is--negative readback values and all--the script still works and calibrates just fine. Maybe not perfect 1 mV or mA accuracy across the entire output, but it seems okay from my testing.

That said, I do like the idea of finding the zero output point and using this value as an offset to add to the default cal point values. Should be pretty easy to do: First check the min cal point readback value. If non-negative do nothing. Else if negative, step up from the minimum cal point in 1 mV or mA increments until a readback value >=0 is reached, set this as the offset value and add it to all cal points.

@bson, do you think the above would work okay? Also should the default maximum cal point (i.e, full-scale cal point) not be exceeded? Or should we clamp at the full scale cal point: i.e., cal point + offset <= default max cal point.
 

Offline garrettm

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Re: Automated DP832 Calibration
« Reply #74 on: July 18, 2020, 06:40:29 am »
Thinking about this some more, I believe a uniform offset isn't really needed. We probably only need to shift the lower couple of points.

Find offset:
  If readback of min cal point is < 0, step up using absolute value of initial readback, then smallest increment as needed until a readback >= 0 is reached. Store this value as the offset.

Apply offset:
  For each cal point, test readback value. If < 0, add offset to default cal point, else use default cal point.

This assumes that the calibration process is linear near zero, otherwise we should probably choose the offset such that some minimum positive value is achieved for the lower cal points, say 10mV for ch1 DAC-V. Of course the ADC and DAC don't need to use the same adjustment process and may likely need to be different.
« Last Edit: July 18, 2020, 05:40:43 pm by garrettm »
 


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