RSE measument of current? With resistor?

[Vr6Fidelity]

Can this be done? Im currently maxing out my 32 channel USB 6218 card.

Generally i run a 4-20ma current loop thru the resistor and measure the differential voltage drop across it.

Is there any way to do this with one wire? (rse)

I was thinking but the other end of the resistor to AI-gnd or sense but i know thats a really bad idea due to having voltage and current flowing thru my ground path.

Ideas?  

Message Edited by Vr6Fidelity on 04-18-2007 10:00 AM

[AnalogKid2DigitalMan]

Hi Vr6:

If you are skilled in electronics, you could possibly use a differential input op-amp, possibly with an isolated front end.

Just a thought.

-AK2DM

[johnsold]

Generally current loop systems are not referenced to ground unless you are absolutely sure your resistor is connected where the loop returns to the grounded side of the power supply.

If you use a differential amplifier across the resistor, the output of the amplifier can be a single ended signal that you could measure with a single channel of your DAQ device. You could also amplify the signal to provide the maximum possible resolution.

Lynn