Pb with controler of NI PXI-GPIB

[cyril.V]

I drive my NI PXI-GPIB device thanks to Labview 8. Reads and Writes work well with many instruments.

I have a problem with one instrument : sometimes an error appears with a Read instruction. This error doesn't appear at each reading.

When I drive this instrument with another GPIB device, I have no problem.

So the problem seems to come from the Ni PXI-GPIB controler. Are there any solution ?

NI spy view :

ibrd(GPIB0, "", 1 (0x1))        0xc164       iberr: 6             ibcntl: 0(0x0)

Thanks

Cyril Vaille

[ChristopheS.]

Hi,

Have you make test in MAX with a simple query like *.idn?

Have you an error message, or error code ?

Regards,

[cyril.V]

Almost writes and reads works well. The are only about 1 Read per 10 that returns an error.

It's an old instrument and perhaps the NI PXI-GPIB controler is too fast.

Cyril Vaille

[ChristopheS.]

Yes it's one possibility a old instrument with low speed can have difficult to comunicate with a high speed board.

You can increase the time out of the read, or add a wait function.

Regards

[cyril.V]

I ever wait beetween 2 reads (500 ms) and the Time out is fixed to 1000 ms.

The error appears before the time out, so it's come from the NI contoler of the GPIB.

I have no problem when I use another GPIB device to drive the instrument.

[ChristopheS.]

What is the error code ?

have you try with another GPIB cable ?

Are the instrument IEE 488.1 or IEE 488.2 compliant ?

Regards,

[cyril.V]

 the instrument is 488.1 (so I use the 488.1 VIs), the error code (ni spy) is given in my first message. The cable is good (I drove the instrument with another GPIB device but the same cable).

Thanks for your help.

[ChristopheS.]

iberr == Error 6 is a timeout error.  It means that the command did not go through in the time allotted for it to execute.  This usually means either that there is a problem with the communications link (cable is disconnected, instrument is not ready to receive the command, instrument is not powered on, etc.) or that the command needs more time to execute.

Try to use the function ibtmo for set a timeout.

(there is a post on the web http://forums.ni.com/ni/board/message?board.id=140&message.id=13349&requireLogin=False, with the same problem.)

Regards,