How can I used a GPIB multimeter to measure multiple test points?

[Brad22]

I wish to connect my Tektronix TDS 360 Oscope and a HP 34401A Multimeter to multiple test points on a bed of nails. Both are GPIB controlled. Is there some kind of GPIB or serial controlled switching device?

[Brian_Vibert]

There are several options out there. We like to use a Agilent 34970A, which as a built in multimeter. You can get the multiplexer card to switch between different points. I think you can get it without the DMM and switch your own instruments using it. This is, of course, just one of many options out there.

Brian

[pavanb]

Hello,

You could daisy chain the instruments and control each one with a single GPIB controller just by referencing them. You could have a maximum of 14 device, a total cable length of 20m, no distance more than 4m between two devices, and an average separation of 4m between devices with 2/3 devices on the bus powered on.

Hope this helps.

[Brad22]

Thank you for your answer. I have my DMM and Oscope daisy chained together. I just don't know how to switch from test point to test point. Say I want to check for 5VDC at TP2, -5VDC at TP3, and then AC noise on TP3, and so on.

Brad

[Dennis_Knutson]

As Brian responded, you'll need to purchase some switching equipment. There are numerous manufacturers of GPIB, serial, PXI, VXI, ISA bus, etc. Like Brian, I use the HP34970. For your application, a matrix switch might be useful where you connect rows to the two instruments and columns to the test points. The actual switch you use will depend on how many test points you have and signal bandwidth. The trade magazines Test & Measurement World (http://www.tmworld.com/) and Evaluation Engineering (http://evaluationengineering.com/) both have buyer's guides that list a lot of the switching manufacturers.