Acquisition every 0.5s [Linux-GPIB]:Sometimes fails to read data from Keithley 2000 multimeter

[Gilles 248]

Hi,

I've written a C porgram on Linux which polls every 0.5s the DCF77 clock, then reads data from a Keithley 2000 multimeter, filters the data and finally writes every 10s the filtered data to a file.

I have the following problem:
Sometimes it fails to read the data from the multimeter, the acquisition will occur for example 1s later.
The data are read with the simple ibwrt/ibrd commands. Timeout is set to 1s and I have tried to set the multimeter to UNListen, UNTalk (at address 1) but it doesn't seem to work...
Well, in fact I don't know if I should send the UNListen, UNtalk commands.

Could it be that the PC is too slow ?

It runs on COMPAQ Pen
tium 166 MHz / GPIB card ISA bus / RedHat 6.2 with updated Kernel 2.2.19 and the nigpib 0.6 linux drivers.

Any help would be grealy be appreciated.

Cheers,

Gilles Celli

[egamez]

HI!,
why don't you try with the nigpib-488.2 routines, whith those you don't have to take care about setting the UNtalk or UNlisten signals.

When your program fails, does it give you "garbage" or nothing?, because if gives you "garbage" , it could be because the buffer where the data is read it's too small.

You can try with "ibic" first, to check the above point. I don't think that your PC is slow, for this task.

Regards.

Enrique Gámez