I use a bunch of GPIB-120A isolators. They are great for breaking ground loops and reducing CPU noise from a computer when making sensitive low temperature measurements. AFAIK the GPIB-120A has been discontinued by NI. We attempted to use the new GPIB-120B but it is a complete piece of crud and was discusses as a complete fail on these boards awhile ago. I got my hands on the last 5 GPIB-120A models that NI had. One of my units has a problem and we shipped it back to NI for repair. They offered a refurb or ***new***(???) unit of the same model.
Is there a replacement for the GPIB 120A that does not inject an unbeliveable amount of noise into a measurement system? Has NI recognized this failure and/or started up the production of the 120A again? Any alternative hardware to achieve ground isolation and noise reduction without adding high frequency noise to the system.
See http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/GPIB-120B-causes-noises/td-p/878437 if there are any questions about how useless the GPiB-120B. I can also give a short rundown on the poor design choices with the GPIB-120B.