4-20ma Current receiver (PR55-5A) wiring and misc questions

I have a PR55-5A, and a mega modem to measure water level. My water level transducer requires 24v, and has 2 wires (red and black). I’m planning on powering my PR55-5A, and my transducer using 2x 12v batteries in a remote location without power available.
The NCD website says to connect my external power to the sensor in the following way:

Here are my questions:
1 - The M12 pigtail from NCD has a blue and brown wire coming out of it. My transducer sensor from china has a red and black wire. Which connection goes where?
2 - Is it possible to power the PR55-5A using 24v? I could swear I read 6-36v DC on the website before purchasing, but on the back of the device itself it says 4-12v DC. If I can’t power it using 24v, I’ll need to use a DC Buck converter to bring it down to 12v.
3 - If I have to buy a DC Buck converter, what what is the maximum amperage the PR55-5A will draw? I’m assuming a 1amp converter is plenty?
4 - When connecting the PR55-5A to an external power supply, should I remove the AA batteries?
5 - Is there anything I need to change when switching to external batteries with a barrel connector from internal batteries? I saw some old models required changing jumpers.
Here is a photo of the wires I’m working with.


  1. wiring can be found in manual
  2. Yes, you can power using 24V. We recommend 12V( less stress on the internal power supply).
  3. max power draw will be 12V/100mA.
    4/5. no need to remove batteries. Use to onboard switch to select external power