2-wire and 3-wire instrumentation drawing

[kpitsmpl]

I am not sure in what forum to best ask this question.

I have 3 gas monitoring devices requiring 3-wire wiring scheme. As this is my first time doing this I am not sure what is the difference between a 2-wire scheme and 3-wire scheme. Does anyone know of any good online resources that shows a typical wiring diagram of this?

Thanks all.

 

[danw2]

You really should find the manufacturer's wiring diagram, and not use a generic wiring diagram.

For generic 3 wire sensor/transmitters:

1) DC power (typically 24Vdc, but not always)

2) Signal output +

3) common power supply return (-) and signal ground (-)

Dan