Quick guide to how to set up a Stanford Research Systems (SRS) DS345 synthesized function generator.
1) Ensure you're not going to shock anything (i.e. having the computer and device on two different grounds), then plug in the GPIB-USB-HS cable to device.
2) On the front panel of the DS345 set gpib to on (address default should be 19).
3) Open NI's Measurement and Automation Explorer, and ensure the device shows up.
4) Open NIvisaic.exe and send a query "*IDN?\n". You should get the device info back.
5) Using NIvisaic, write "FUNC\s1\n" this should change the function type generated to Square Wave type.
6) Use Labviews VISA library. For still unknown reasons, I could not get the normal GPIB library to control the DS345 over GPIB-USB-HS. This means the entire driver library for the DS345 didn't work for me. This means you'll have to do some more work learning the DS345's communication protocol (see http://www.thinksrs.com/downloads/PDFs/Manuals/DS345m.pdf). But I only needed to change 2 things on the DS345 so that fit my needs.