Rigol DP832 power supply as automated Curve Tracer - Page 1
Forum section: electronics / testgear

author: RoGeorge
author_rank: Super Contributor
timestamp: October 13, 2021, 08:18:33 pm
content: Made a Python script to control the DP832 for curve tracing.The advantage of a DP800 power supply is that:- DP832 and other DP800 series power supplies can be controlled remotely- can set votlages and currents with mV and mA resolution (and accuracy, too, if calibrated)- has 2-3 output channels, like it would be 2-3 different power supplies in one instrument- has automated switching from CV to CC mode- has adjustable over voltage and over current protection for each channel output- can measure its own voltage, current and power for each channelThat will be enough to automate voltage/current setting and reading in order to trace some I-V plots using nothing but a program and some alligator clip wires to connect the component under test.For now I only used it for MOSFET curve tracing:- connect the GS of the MOSFET to channel 1 (CH1) of the DP832, and the DS to CH2- open the control script and set the desired parameters, for example the Vgs max, Id max, etc.- run the curve tracer script and the result should look like this on the screen (also saved on disk):The control script 'dp832_curve_tracer_v0.ipynb' attached was made in Jupyter Lab using Python, PyVISA, Numpy and Matplotlib, all FOSS, should work on any OS but I've tested it with Linux only, on a Kubuntu 20.04 LTS.The upper cell has most of the configurable parameters of the curve tracer.

author: Smokey
author_rank: Super Contributor
timestamp: February 21, 2023, 12:42:21 am
content: Linking in this other thread, which is pretty relevant:https://www.eevblog.com/forum/testgear/rigol-dp832-remote-command-update-rate/

author: jomosoft
author_rank: Contributor
timestamp: March 16, 2025, 05:08:15 pm
content: I tried this but get a strange dip in the curves. Happened on different types of mosfets.

author: RoGeorge
author_rank: Super Contributor
timestamp: March 16, 2025, 06:53:58 pm
content: That's strange.Is the power supply measuring correctly?Try with just a resistor instead of the DS of the MOSFET, and the plot should look like a straight (tilted) line. If it's not a line, increase the time for the the Vds step, and double check the output voltage and current with a DMM. The programmed voltage (sent from the PC) has to be the same as measured with the DMM, and has to be the same with the voltage indicated on the DP832 display.You can also check manually, without any program. If the voltage/current is not the same between these three:- what you set- the DMM reads- and the DP832 displayyou may need to calibrate your DP832.There is an automated procedure, with a helping program to calibrate DP800, but it's cumbersome. In theory, calibration should be possible manually, but in practice it is not possible.Note that, for each channel, DP832 has many calibration values to adjust, and these values are to be calibrated in tens of points for each channel:- output voltage (has to met the voltage you set from the knob or from PC)- output current- read voltage (what you see on the display, or read by the PC)- read currentYou'll need a calibration script and a good DMM. Usually the calibration is OK from factory, so let's hope you won't need to do that. Maybe the unusual plots are because of some other reason.

author: jomosoft
author_rank: Contributor
timestamp: March 16, 2025, 08:05:01 pm
content: I've done a manual cycle with a DMM between the drain and noticed the same dip in current. Gone check some things tomorrow, let you know if I find something.

author: Grandchuck
author_rank: Super Contributor
timestamp: March 16, 2025, 08:13:04 pm
content: Try a resistor in the gate lead ... 2.2 k or so.

author: jomosoft
author_rank: Contributor
timestamp: March 16, 2025, 08:38:43 pm
content: Yes will do...

author: jomosoft
author_rank: Contributor
timestamp: March 20, 2025, 05:20:57 pm
content: Took Another mosfet, changed some parameters and add a 2k2 resistor in the gate. Looks a lot better now !