How to monitor an actuator's feedback line from a microcontroller?
It should be: terminal 1 &amp; 2 connected to PSU , no need to be controlled by MCU.
The terminals 3 &amp; 4 are switshed to terminal 1 as depicted using your low side switch (of course the device is connected to DC PSU). Once the valve opens/closes you can turn off the signal. The voltage IMO is the same as supply voltage.