on 1st read of device: ibrd ERR TIMO CMPL EABO

[Ezra]

I am using the Visual C++ 32 bit language interface for GPIB to communicate with a HP8920 & HP8922 Cellular test systems on the same GPIB connection.

My problem is that whenver I start my application, the first read to the HP8922 (After first doing CGPIBDevice.Open and CGPIBDevice.Write) always gives me the following GpibError:
ibrd Error ibsta=&Hc100
iberr = 6 EABO
ibcntl = 0

All I am trying to do is write the *IDN? command to the device and read it back. After I get the error message, if I try again it will work fine. The error only happens the very first time I attempt to read from the HP8922. If I start the application and try and read from the HP8920, I dont get that error. An
y ideas what my problem might be and how to fix it?

Thanks so much,
Ezra

[Alan_L]

Ezra,

I recommend that you try communicating with your instruments through Measurement And Automation Explorer. Clicking "query" with the default "*IDN?" string should, of course, cause the device to respond with its identification information. If this works every time, then there is most likely a small flaw in the logic of your program. Perhaps the first time you run the program you are not sending the proper termination character? Also, always be sure to include a brief delay between any GPIB writes and reads as instruments need some time to respond. Finally, if you're using LabVIEW 7.0, you could try using the Instrument I/O Assistant to query the HP devices. It's definitely a useful feature that especially simplifies parsing of instrument responses.


Thanks!

Alan
Applications Engineer
National Instruments