Different ground problem (pseudo ground)

[StupidDum]

I wish to build a current loop receiver using instrumentation amplifier. This amplifer will convert the current passing through a sense resistor, and convert it to voltage.

I use 5V and 0V as supplies to the amplifier, and leave the differential inputs floating. In this case, the potential at inputs might be floating at higher or lower than the common-mode range, and cause error. A simple solution is to use +12, and -12v supplies, which can tolete higher CMR.

I came across a term "pseudo ground" in a loop receiver IC. So.. what is PSEUDO GROUND?

 

[Russlk]

Pseudo ground usually has a DC offset from "real" ground. It could be the output of an op amp or just a long wire from some remote ground.