How do I poll a hp438a (powermeter) in VB so that I know when the measurement cycle is complete?

[expediter]

I am using a hp438a powermeter to measure RF gain from a device. My program is using 488.2 commands (ibwrt, ibrd, etc.) What command can I use to detect when the powermeter measurement cycle is complete (data ready)? The instruments on the bus are an hp8350b (ID 19), and an hp438a (ID 13). I have tried the command ibrsp without success.

Thanks,
Ken

[Randy Solomonson]

Hello-

It is necessary to use the GPIB commands (ibwrt, ibrd, etc) to send message strings to these devices. Usually the manual for the instrument will give the string necessary to send. However, there is an Instrument Driver available for the 438a that will have a set of LabVIEW VIs or CVI functions that send and receive the necessary message strings. These instrument drivers are available at ni.com/idnet.

Randy Solomonson
Applications Engineer
National Instruments