Python USBTMC Readme

Python USBTMC provides a pure Python USBTMC driver for controlling instruments over USB.

Extract and run

  # python setup.py install

If you cannot access your device without running your script as root, then you may need to create a udev rule to properly set the permissions of the device. First, connect your device and run lsusb. Find the vendor and product IDs. Then, create a file /etc/udev/rules.d/usbtmc.rules with the following content:

  # USBTMC instruments
  
  # Agilent MSO7104
  SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="0957", ATTRS{idProduct}=="1755", GROUP="usbtmc", MODE="0660"

substituting the correct idVendor and idProduct from lsusb. You will also need to create the usbtmc group and add yourself to it or substitute another group of your choosing. It seems that udev does not allow 0666 rules, usually overriding the mode to 0664, so you will need to be a member of the associated group to use the device.

If you want to put the kernel usbtmc device in the same group, add the following content to the usbtmc.rules file as well. This is optional as Python USBTMC bypasses and disconnects the kernel usbtmc driver and the device will actually disappear from /dev when Python USBTMC connects.

  # Devices
  KERNEL=="usbtmc/*",       MODE="0660", GROUP="usbtmc"
  KERNEL=="usbtmc[0-9]*",   MODE="0660", GROUP="usbtmc"

Connecting to Agilent MSO7104A via USBTMC:

import usbtmc
instr =  usbtmc.Instrument(2391, 5973)
print(instr.ask("*IDN?"))
# returns 'AGILENT TECHNOLOGIES,MSO7104A,MY********,06.16.0001'