I have one of these outside:
Manual here:

I would like to connect it into Idratek using its 12v power supply from one of the nodes (and connecting the sensor into the DFP-H02. Power is easy but I am strugling to find the way for the sensor. There is an A (the other I would assume is the minus but I believe there is power as the specs talk about current ( A' Open collector -ve switching - 25mA max. Alarm period 400ms).
Can anyone help me on that? What do I have to do to protect cortex and run the sensor into the module?