Hi,
How to communicate with several instruments depends on programming language you are using. I found an example an CVI (C), which I'll attach.
You can look through the GPIb support site to see if you can find other examples and information:
http://www.ni.com/support/gpibsupp.htm
There really isn't much difference between communicating with 1 instrument or with several instruments. If you are using C, you just need to open one unit descriptor per device and uses those unit descriptors to reference the devices. If you're using LabVIEW, you just differentiate between devices using the address in the bus.
Some functions simplify the operation with multiple devices, refer to the NI-488.2 user manual and reference manual for more info:
http://dig
ital.ni.com/manuals.nsf/webAdvsearch/2E52C6C7B8872A5B86256B600076601E?OpenDocument&vid=niwc&node=132100_US
http://digital.ni.com/manuals.nsf/webAdvsearch/7F9CFDD677DFE7A48625672B006C4ADB?OpenDocument
DiegoF.
