Reading 4-20mA pressure transducer, 3 wire system

[Abdoul78]

Hello

I'm using NI USB-6221 to measure 4-20 mA signal from a pressure transducer, Swagelok, S-type, PDF attached

I need to connect a shunt resistor but not sure how to connect it, and what is the best resistor value to use.

Regards;

[Jason_D]

Abdoul78,

Depends on what range you want your results to come in on if you want the range to be 0-10V.  Since V=I*R thus 10=.02*R means that R=500 I would reccommend  500 ohm (or less) resistor so that when you measure 20mA (your high range) you will get at MAX 10V.  You will simply place this resistor in between the current leads and measure the voltage across that resistor.