I have a 4-20mA pressure transducer that sends a signal 300-500' to a recording interface hooked up to a PC computer through a com port.
It is run in 4wire #18 shielded com cable.
When I isolate it from the the recorder my Fluke reads 4mA. When I hook up to the recorder the amps jump to 7 to 9 mA. The shield is bonded at the transducer end only. I can't figure out where the current is coming from.
The recorder works fine on all 5 channels with 3 other transducers from 3 other machines. When I hook up this one to any channel, the current increases.
