Opensuse Linux and the Prologix GPIB to USB converter

This page describes how to control the Prologix GPIB-USB converter on an Opensuse 10.3 linux system using Labview 8.2.
Everything described below is done as root; once it works you should give normal users read and write access to /dev/ttyUSB0 and continue to work from your normal account.

• Plug in the USB cable with the converter.
• Check if the right modules get loaded:
  $ lsmod | grep ftdi
  ftdi_sio    37128     0 
  usbserial  35252    1  ftdi_sio
  usbcore    123756  6  ftdi_sio,usbserial,nikal,ehci_hcd,uhci_hcd

  The device should show up on the USB:
  $ lsusb:
  Bus 001 Device 004: ID 0403:6001 Future Technology Devices International, Ltd 8-bit FIFO

  and a new device node should be created:
  $ ls -l /dev/ttyUSB0
  crw-rw---- 1 root uucp 188, 0 Dec 4 15:39 /dev/ttyUSB0

• You can check if the converter works correctly by using the program kermit (package ckermit):
  $ kermit
  C-Kermit 8.0.211, 10 Apr 2004, for Linux
  Copyright (C) 1985, 2004,
  Trustees of Columbia University in the City of New York.
  Type ? or HELP for help.
  (/root/) C-Kermit>set line /dev/ttyUSB0
  (/root/) C-Kermit>set terminal echo on
  (/root/) C-Kermit>connect
  Connecting to /dev/ttyUSB0, speed 9600
  Escape character: Ctrl-\ (ASCII 28, FS): enabled
  Type the escape character followed by C to get back,
  or followed by ? to see other options.
  ----------------------------------------------------
  ++ver (enter)
  Prologix GPIB-USB Controller version 5.0
  

• Make sure you have the necessary packages installed (your version numbers will probably be higher than mine due to security updates).
  $ rpm -qa | grep kernel
  kernel-default-2.6.22.13-0.3
  kernel-source-2.6.22.13-0.3
  linux-kernel-headers-2.6.22-19
  kernel-syms-2.6.22.13-0.3
• do:
  $ cd /usr/src/linux
  $ make cloneconfig
  $ make modules_prepare
  $ make modules
  (the last step is according to the NI-Visa documentation not mandatory, it avoids some warning messages)

• Download the newest NI-VISA for linux (at the time of writing version 4.2) from the National Instruments website.
• Run the INSTALL script from /usr/src/linux
• check for error messages, especially in the NI-KAL post installation script.
• create/edit /etc/profile.local with:
  VXIPNPPATH=/usr/local/vxipnp
  export VXIPNPPATH
  export LD_LIBRARY_PATH=/usr/local/vxipnp/linux/bin:$LD_LIBRARY_PATH
• reboot

Figure 1

Figure 2

• run visaconf from the command line
press the add static button
select Local Serial Port as the new interface
set the binding: /dev/ttyUSB0
set an alias like prologix
change the interface number to 5 (or another non used number)
The other settings like Baudrate, parity, stop bits and flow control can remain unchanged; they are irrelevant.
After pressing OK the main window should look like Figure 1.
if you now plug in the device and press edit on the ASRL5::INSTR, the Resource editor (Figure 2) window should show the state of the device as ready.
• Start NIvisaic
  if ASRL5::INSTR shows up you are ready to use the device under labview.

  However there seems to be a bug in the NI software which only shows up if your computer has no generic serial port like some laptops:
  $ NIvisaic
  An error message pops up:
  unable to find resources using expression "?*"
  Return status code 0xBFFF0011
  Status name: VI_Error_RSRC_NFOUND



Figure 3

Workaround: create a hardlink:
$ rm /dev/ttyS0
$ ln /dev/ttyUSB0 /dev/ttyS0
$ ls -l /dev/ttyS0
crw-rw---- 2 root uucp 188, 0 Dec   7 10:17 /dev/ttyS4

Now NIvisaic looks like Figure 3; both entries will work under labview.

3) Communicate with the converter using Labview 8.2

Figure 4

• find in the examples the Basic Serial Read and Write.vi (Figure 4)
• set the VISA Ressource name to ASRL5::INSTR
• open the Visa Configure Serial Port SubVI and set the button Enable Termination Char to off.(Figure 5)

Figure 5

4) Related ressources

• NI site on troubleshooting the serial communication under linux
• Controlling a Third-Party USB Serial Interface in Linux Using NI-VISA
• corresponding thread in the NI instrument control forum

---

[ Matthias Schröter, Home ]

Page maintained by Sibylle Nägle
Last modified: 22 Dec 2007