Can someone please explain to me in simple terms, the best practice with multiple 4/20ma pressure/flow transducers on multiple different 24VDC power supplies, All wire back to a non isolated 5069 IF8 card. Do you have to use isolators or not. The common terminals "-" on the IF8 are all tied together internally. If all your power supply "-"'s land on these terminals, and your power supplies "-" weren't connected to earth ground, you wouldn't have any ground loops, and all your power supplies would be at the same "-" reference correct??? Just trying not to smoke a $1000 analog input card.