I an in the process of replacing a 34401a with a 34410a in an ATE system. The 34401a was controlled via RS232, but the 34410a doesn't offer that option, so the PC is running the VISA interface software and I am talking to the meter over a TCP/IP network. It's pretty much going but for one thing:
With RS232 comms it was relatively easy to tailor the response timeout to the command, so I had a timeout of a second or so for most commands, but a 20-second timeout for the "*TST?" (self-test) command, as this takes much longer before it issues a response.
Can I do this with the VISA interface? The command timeout seems to be set to 2000 mS but I can't find anywhere this might be set or changed. Anyway I would like to set it under program control - if I set it to 20 seconds for every command it will take that long before I can detect that the meter isn't going to respond to any command, so I would prefer to set it to 20 seconds, issue the *TST? command, wait for the response, and then set it back to 1 second.
Another solution would be if it were possible to "poll" the interface to determine if any output (i.e. a command response) from the meter was waiting. The only commands I an using are WriteString and ReadString - there may be other lower-level ones.
I'm programming in Delphi, with code based on the C examples.