I'm not entirely clear what it is you want to do. Do you want one front panel to control all the generators in the same way all at once? Or are you just wondering how you can specify which instrument each instrument driver VI should talk to?
If it's the latter, you just call Initialize multiple times with a different "Instr Descriptor" for each pulse generator. Each resulting VISA session corresponds to a different instrument. If you want the former, then you have to do things yourself; there's no built-in way to get VISA calls to do things to multiple devices. Basically, you'll wrap every one of your instrument driver VIs with a wrapper that takes an array of VISA sessions and loops through executing the instrument driver calls on each VISA session. Note that there will be a latency; the instruments will not be sent the same commands exactly at once. (That is a much more complicated problem to solve.) Anyway, perhaps these help you, or maybe you can clarify what it is you want to do. Brian
