Good morning,

I want to connect a PT100 sensor (2 wires: red and white) to a LOGO 8 without using the AM2 RTD.

I've checked the forum about connecting a 2 wired PT100 to AM2 RTD, and it seemed to me that the red wire is connected to U1+, whereas the white wire is connected both to U1- and IC1.

Does this mean I need to connect the red wire to +24 V, and the white wire both to 0 V and, for example, AI7 (I7)? Or is it impossible to connect the PT100 to LOGO without the AM2 RTD expansion?

I attached an example of my program: I can't get Q1 to switch between 0 and 1, it seems the sensor doesn't work with the configuration I described previously.

Thanks in advance.

Here is show connection with RTD module

You can't connect PT100 sensor without RTD or PT100 module

Also see this instruction LINK there show how connect PT100 and program block's in your picture maybe not choose in analog amplifier - PT100 sensor and second function block you need use same AI not SF001