What is the internal shunt resistor value in the compact RIO 9219 when measuring current?

[mz]

Usually a shunt resistor is 250 ohms.  Does the 9219 card use a internal 250 ohm resistor or is it another value?  If I measure it with a ohm meter, it appears to be a high value (several K ohm) is this correct?

[aNIta B]

Hi mz,

         I believe this value is 5Ohms, based on this page of the 9219.  If you look at the 125mV voltage specification in the table, it corresponds with the 25mA current, equally 5 Ohms.  Let me know if you need further information!

[mz]

aNItaB

Thanks for you input.  I just get some strange readings here with my circuit and I would like to know for sure what the resistance is.  I don't know why NI does not show the resistance value of 'Rsh' in the 9219 manual.  Knowing the loop resistance is important in some cases.

Mike

[aNIta B]

The shunt resistor shown in the manual may actually be a resistor network.  However, the total input impedence is 40 Ohms.