I'm trying to get my HP 3437A working properly over GPIB, and I'm having trouble. (Keep in mind that this is my first GPIB use, and this is a very early GPIB instrument.)
I'm not 100% sure I'm reading the manuals correctly, both for the 3437A and for the National Instruments GPIB-232CV-A that I am using.
I have the 3437A configured to address 7, not talk-only. The 232CVA is also configured to address 7*, controller mode. On the RS-232 side, timeout termination (this means that GPIB switches from talk to listen about 300ms after the last byte transmitted), 9600 baud, no parity, 1 stop bit, 8 bits per char, no XON/XOFF (uses RTS/CTS instead).
*No, this doesn't mean they both think they have address 7. In controller mode, the 232CVA can only talk to one device; this is the address of that device.
It seems to work properly at first. I can transmit commands, and the instrument responds, and it transmits data back to me. However, after some time (about a minute), I stop receiving data. The 3437A still responds to outgoing commands, but I do not receive any more data until I power-cycle the 232CVA.
Also, I'm not really sure what causes the 3437A to transmit. Sometimes, it seems to give me one reading when I release the bus, and other times, it seems to just spit out a stream.
My first thought was that I wasn't fetching the data often enough, and a buffer filled up somewhere and it barfed. But the manual says that data GPIB->serial is not buffered at all, it's just pushed straight to serial, so the only buffer to fill up is on my PC, and it does not have any issues. All buffers are empty and there is no error reported. (Also, it doesn't know when the 232CVA is power cycled.)
So... problem with the GPIB-232 adapter? Me misreading a manual? Does anybody with some GPIB experience see what my problem is?