Hardware connection for NIDAQ 4-20mA output signal to 1-Channel 4-20mA Current Loop Receiver 16-Bit ADS1115 I2C Mini Module


I have a device that outputs a 4-20mA signal from a NIDAQ via two ports, NIDAQ-0 and NIDAQ-1. NIDAQ-0 is the positive and NIDAQ-1 is the negative. I connect the current loop receiver to an Arduino Uno directly using 5V, GND, A4(SDA) and A5 (SCL). As I understand, 4mA is supposed to give 6430 on the Arduino, and 0mA should give 0. I get a reading of about 78 when nothing is connected.

For the following, I set the NIDAQ to output 4mA.
When I connect a multimeter across the NIDAQ ports, with the COM port at NIDAQ-1, I am able to read the 4-20mA current.

However, when I try to connect the IN port on the current loop receiver to NIDAQ-0 (+ve) and GND to NIDAQ-1 (-ve), with the multimeter in series, I get no current on the multimeter, and the Arduino reads a 78.

If I switch the connection, so the IN port on the current loop receiver is to NIDAQ-1 (-ve) and GND to NIDAQ-1 (+ve), with the multimeter in series, I get 1mA on the multimeter and about 1600 on the Arduino.

Am I using the wrong module or making the wrong connection?


Is there any way you can provide a photo of your wiring setup or even better a wiring diagram?

This is the set up with multimeter that shows the NIDAQ is giving the right output.

The following are the two connections diagrams with the current loop and the readouts on Arduino and multimeter are indicated on the diagrams itself.

@TravisE_NCD_Technica I hope these drawings give sufficient information. Are you able to advise on the connection? Thank you.

Do your 4-20mA output sensors provide a line voltage? 4-20mA sensors either provide a signal voltage or not, this determines if the receiver needs to provide line voltage or not(there are different versions of the product for both instances).

We sell several 4-20mA input monitoring devices. Can you specify which specifically you are using?