visa read buffer empty after rqs

[Wensu]

Hello,
I have problems when trying to communicate with IEEE 488 measurement equipment (such as HP 3478A, Keithley 175).
There are plug and play drivers, but they only work if GPIB card is installed on the local computer.  My multimeter is connected via gpib to a remote computer, so using the gpib commands directly will not work.
I am trying to convert the driver for the HP 3478A multimeter such that it will work using VISA.
The problem is that when the buffer is read after the Service Request event occurs (wait for rqs.vi), the read buffer is empty.

I have attached the VI in question along with the ni-spy capture.

Please help me figure out what I am doing wrong.

Thanks,
Victor

[LuI]

Victor,

I'd suggest running the driver on the machine where the GPIB controller rersides. This can be done by opening an application reference (AppRef) to this machine and opening a VI reference (VIRef) to that AppRef.  With that VIRef, either call the driver using the Call_by_reference node or set the required controls, invoke the VI and read the reqired indicators These functionality is provided by the invoke node. Both methods have their pros and cons, check the examples.

I do not have used these techniques on a different machine, but have used this to start and stop daemons, completely independent and invisibel background processes. So I konow it works.
Greetings from Germany!<br>-- <br>Uwe