linux-gpib with asyn

["Wilkins, Stuart" <swilkins@bnl.gov>]

Hi!

I have been using linux-gpib and asyn (and StreamDevice) for communication with Keithley Electrometers. I have one comment on the documentation and one bug which I would like to see if anyone else has seen.

Firstly, according to the asyn documentation the following command at the iocsh sets up the board.

GpibBoardDriverConfig(portName,autoConnect,BoardIndex,timeout,priority)

From this documentation, it looks like you assign the GPIB board with the integer "board index", however after about 2 hrs of trying to get this working, I delved into the souce code for this driver. In fact, this is not the behavior in the code, the port driver tries to open the gpib card with the same name as the portName as defined in /etc/gpib.conf. I think (although in places the code is fairly cryptic) it is only if you open a certain gpib address that it uses board index, but I cannot find the config to give the primary and secondary address at the iocsh. It might be a good idea to update this in the asyn documentation (or at least clarify it!)

Having got past this stage, I noticed that some of my communications are being garbled, with replies returning where the first character is NULL [chr$(0)] instead of the correct character. Has anyone seen this behavior. I am not sure if it is due to the linux-gpib driver, asyn or the Keithley. I plan to put another device on the bus to see if it is just this combination. Is anyone out there using this combination?

Best wishes,

Stuart