It don't look like any one reads any thing that's posted and start dumping out Idea's
First this is a loop you power this on the high side with power able to output more then 20mA at 24 volts the transmitter reads say a temp of 10 C and that means it needs to lower the low side to 5mA then the receiver which is a 250 ohm resistor Is read and show 5 mA the uC then tells you the reading is how these work.