I am trying to do this measuring using LabVIEW SignalExpress as software in a PCB which has conectors that fit with SHC68-68
Module cable pcb
PXIe 1078 (PXIe 6361) ----- SHC68-68-EPM ------ PCB
however I am not obtaining the real voltages.... I made the acquisition via signal express and later I made a measuring with an multimeter and the results are different values.....
Doing another test like that I am obtaining the real voltages
Module cable module
PXIe 1078 (PXIe 6361) ----- SHC68-68-EPM ------ SCB 68 ---------- external power source
why I am not obtaining the real voltages in case one? is it a question of callibration? set up? or maybe it is not possible to do a direct measuring?
I really will appreciate any advice or comment about this problem.
You should post your question to the SignalExpress board. Not many people here use it but offhand, I'd say you have a configuration problem. You have not provided any details on actual connections or task setup (i.e. differential, RSE, etc.). Provide that when you repost.
It sounds more like a wiring or grounding issue. The SCB 68 is a shielded connector block, so there might be a chance that the PCB either has a ground loop or has some connection errors. Is there a chance you could provide me with a connection schematic or the PCB´s schematic?