On 11 nov, 20:30, Jean Dubois <jeandubois...@gmail.com> wrote: > On 9 nov, 22:14, w...@mac.com wrote: > > > > > On Nov 9, 2012, at 3:43 PM, Jean Dubois <jeandubois...@gmail.com> wrote: > > > > The error may be obvious but finding this file and how to install it > > > is not unfortunately. > > > It seems I have to install it from the National Instruments site but > > > Debian Linux doesn't seem to be supported... > > > and I doubt whether just copying this file will be sufficient to make > > > PyVisa work. > > > I wonder whether there might be another way to communicate via USB > > > with a Keithley programmable power supply using Python. > > > > best regards, > > > Jean > > > > -- > > >http://mail.python.org/mailman/listinfo/python-list > > > I've been using pyserial quite successfully to control a USB-to-serial > > converter. > > > That is, controlling a couple of RS232 serial devices via the USB port > > through a KeySpan USB-to-Serial converter. > > > Pyserial seems to make communication through the USB port quite > > transparent, at least on my OS-X system. > > > -Bill > > Well, in fact I do have some working scripts using pyserial to control > an older (and more expensive) Keithley sourcemeter in combination with > a USB-to-serial converter. > But the trouble started when buying a cheaper and newer Keithley model > which does not have rs232 but only USB. I noticed they have put an > extra layer above USB called USBTMC > which complicates things further. I followed the instructions > athttp://www.home.agilent.com/upload/cmc_upload/All/usbtmc.htm?&cc=BE&l...outline > and compiled and loaded the usbtmc-driver but I still can't > communicate with the Keithley, hence I started looking for an > alternative using PyVisa...and now I'm stuck > > jean
I finally got it working without PyVisa as follows: #!/usr/bin/python #sample program for Keithley 2200 USB #first compile and load module usbtmc import os usbkeith = open('/dev/usbtmc1','r+') #next commando is very important #without it you can fetch data but not SET data usbkeith.write("SYST:REM" + "\n") usbkeith.write("*IDN?\n") identification=usbkeith.readline() print 'Found: ',identification usbkeith.write("SOUR:CURR 0.2A\n") usbkeith.write("SOUR:OUTP:STAT ON\n") usbkeith.write("MEAS:VOLT?\n") measurement=usbkeith.readline() print 'Measured voltage: ',measurement regards, jean -- http://mail.python.org/mailman/listinfo/python-list