GPIB device works with old PC but write error with faster CPU?

[sheng peng]

I have some GPIB devices(HP 8753C, Gigatronics 8542, newport ESP7000) and NI PCI-GPIB card, they all work fine with my 1.4GHz XEON CPU and Labview 6.0 and IEEE488.2 V1.6. But after I move to a P4 2.6GHz CPU and LabView 7 and IEEE488.2 V2.1, they don't work (same LabView code). I look into it and found "write error" if I read right after write. I have to put a delay between write and read. Anyone can tell me why?

[JoshuaP]

Hey Sheng,

I would suggest opening up the properties for your GPIB card in MAX and go to the Advanced Tab. Then try to increase your bus timing and the poll time. It is also a good idea to set your cable length to a number that more accurately represents your cable length.

If this doesn't work try running NI-SPY to see if you can see what the problem is. You might have to add a little wait in the LabVIEW code to allow your instrument to catch up as a last resort.

I hope this helps out.

JoshuaP
National Instruments