In Reply to: 4-20mA wiring diagram posted by Hugh on 03/24/00 at 1:37 PM:
Please take a look at http://www.measure.com/how2measure.html for some really comprehensive info on 4-20 mA current loops.
If we say for the sake of argument, that you had a 100 ohm resistor carrying the 4-20 mA, and that the voltage drop across that resistor were 0.4V to 2.0V, I would define the "sourcing" wire as being that wire at which the positive end of the resistor's voltage appears and the "sinking" wire as being that wire at which the negative end of the resistor's voltage appears.
That being said, my sense of it is that your meter's + input should go to that wire which is sourcing your current and your meter's - input should go to the wire which is sinking current. However, take a look at that site.
John Dunn - President