Mes trouvailles du jour : 1 March 2016

USB connected digital multimeter and graph plotting (UNI-T UT61E and sigrok)

Ever wanted to have nice plot (U/I curve, whatever) simply plotted?

I got 2 UNI-T UT61E with USB cable (50€ each)

With sigrok you can easily get data from many device with a single command:

sigrok-cli –driver=uni-t-ut61e:conn=BUS.DEVICE -O analog  –continuous

Where BUS and DEVICE is replaced with the output of lsusb

lsusb
Bus 002 Device 002: ID 8087:8001 Intel Corp.
Bus 003 Device 086: ID 1a86:e008 QinHeng Electronics HID-based serial adapater
Bus 003 Device 087: ID 1a86:e008 QinHeng Electronics HID-based serial adapater

In my case, as I’ve 2 devices, so 2 different commands are used:

sigrok-cli –driver=uni-t-ut61e:conn=3.86 -O analog  –continuous

sigrok-cli –driver=uni-t-ut61e:conn=3.87 -O analog  –continuous

 

But what about logging in the same file the two ouputs simultaneously?

Here comes the magical function: paste and joined pipe:

paste <(sigrok-cli –driver=uni-t-ut61e:conn=3.86 -O analog  –continuous) <(sigrok-cli –driver=uni-t-ut61e:conn=3.87 -O analog  –continuous) > measure.csv

 

I’ll let you deal with the uber simple csv processing with octave or libreoffice calc (mV, mA range condition, etc…), as this blog entry is mainly used as a personal notepad.

 

Note: if you have trouble connected with sigrok, with an error. You may need to disable the power feature, with the script pointed by blog.philippklaus.de

#!/bin/bash
# see http://www.erste.de/UT61/index.html
for dat in /sys/bus/usb/devices/*; do 
  if test -e $dat/manufacturer && grep -q "WCH.CN" $dat/manufacturer; then
    echo "Suspending ${dat}."
    echo auto > ${dat}/power/control
    echo 0 > ${dat}/power/autosuspend 
  fi      
done

Mes trouvailles du jour : 8 February 2016