How many 4-20 mA loops can be in each channel?

[jmgrove]

I'm still getting accustomed to 4-20 mA loops, and our setup is several sensors (multiple pressure, one flow, and oxygen) wired into an NI 9923 terminal block that is then inserted into the NI 9208 current input module. My two questions are 1) If I'm running a two-wire 4-20 mA loop into the module, should it be run with the negative wire inserted into one of the Vsup terminals and the positive inserted into an analog input terminals? 2) Since it has 16 channels, am I limited to 16 different devices or is it possible to share terminals?

Thank you for the help! The pin diagrams aren't the easiest to follow for a novice.

[Benjamin.S · Accepted solution]

Hello,

1)The getting started guide gives insight in to how to connect to the pins.

http://www.ni.com/pdf/manuals/375170c.pdf

2) If you split your current input to two terminals, the effect current to each input would be cut in half. If you had something like a switch mechanic you could use multiple terminals using the same input.

Best,

Ben

[jmgrove]

Thank you for the response!

I guess I wasn't clear about my second question. By "sharing a terminal", I was asking whether it is possible to use a ferrule to join multiple sensors for a single analog input terminal. I'm imagining a case where I would want more than 15 sensors pulling analog readings into the NI system.

Is this possible?