4-20ma MCP3428 Loop Power Supply

I have a loop with 3 MCP3428 4 channel 4-20ma receiver boards used to read 12 pressure transducers. Currently testing with one and four sensors. I constructed the electrical system in the diagram to power the boards, the sensors, and the Arduino off a DC 12 power supply but when I perform a test with the sensors feeding them 24 volts, I get ADC values below what 4ma would be. A quick check with a multimeter shows the sensors are outputting .2ma to 1ma. I figure this is a power issue as I tested the sensors with another Digi sensor reading device and they were outputting the expected values. I have the MCP3428 setup in 16-bit resolution, with the gain set to 2 and set to continues mode with a half second delay between reads. Can anyone tell me what I did wrong with powering the sensors? Also will my design in the diagram experience any voltage drop from running all 12 sensors? Sorry for any stupid mistakes and questions, new to this field and this product. all advice is much appreciated!

AWT-DC-Diagram.pdf (34.9 KB)

I will recommend starting with one sensor. You can checkout the wiring diagram on the product page under drawing sections.

Make sure your 12V power supply is big enough to support sensor and the board.


I’ve done most of my testing with one sensor, first with a 24v .5amp ac to dc as the power supply for the sensor and had the same issue following the wiring diagram provided on the product page. Now I’m testing the setup that’s in the diagram with one sensor and still have an issue and the ADC values are the exact same as before with the ac to dc power supply. The diagram is modeled off of the drawing provided on the product page which just shows that power ground goes to MCP3428 sensor in ground, power positive goes to sensor supply and sensor output goes to MCP3428 sensor in positive. The battery I’m using in the 12v dc test is a new car battery.

Thank you for the support, hope that clears up my setup for testing.

try a separate power supplies.
one for board
one for sensor

If you conenc a meter in series, do you get any current values?

Just tested different power supplies, got an ADC at 16 bit of 2530 and .25 ma from the multimeter inline between the sensor and the MCP3428

what kind of sensor is it?
can you share the datasheet?

Submersible 0-10 PSI pressure transducer 4-20ma

is the sensor submersed or its in air ?

if its in Air it wont work because the Air pressure is 14.69PSI.

The sensor is submerged. This is a PSIG sensor meaning it accounts for atmospheric pressure in its readings using a vent tube in the wire. I have it in a test tank, it should yield a result of 3.6 feet and has when using the digi connect sensor to perform the read, that expected result is confirmed.