How to monitor an actuator’s feedback line from a micro controller?

the AG-020-B electric actuator is controlled from a microcontroller. Terminal 1 is connected to the DC PSU GND, Terminal 2 is connected to the +24VDC via a high side Power MOSFET(TPS22810) as shown below. This is for power saving.



Low side MOSFET (AUIPS1021) Q5A and Q5B are used to control the opening/closing of the valve via terminal 3 and 4. The microcontroller I/O lines Valve_Ctrl_1a and Valve_Ctrl_1b provide a 3.3V signal.



- Comments are welcome regarding the power and switching circuitry.

- Any suggestion on how to monitor the feedback lines on terminal 8 and 10 from a microcontroller. A lamp is not suitable as the system will be enclosed in a box. The issue is that the voltage and current are too high to connect directly to the microcontroller. I've come up with a relay as a possible solution but I would rather use discrete devices.

Hi Mark-I suggest using optocouplers like the Lite-On LTV-8141 or LTV-8241. The difference between the two is that the 8141 contains one device and the 8241 contains two. These couplers will work on AC or DC input. I see the valve works on either AC or DC.Here's how to connect it: You'll need to limit the current into the LEDs' on the input side of the coupler.  Assuming that you're using an LTV-8141, connect a 1K ohm 1-watt resistor in series with pin 1 (one side of the LEDs), and connect the other side of the resistor to pin 8  (or 10) of the actuator.  Connect pin 2 (the other side of the LEDs) to +24 volts.  That's it for the input side.  For the output side tie the emitter of the transistor (pin 3 of an LTV-8141) to ground, and the collector (pin 4) through a 1K ohm 1/4 watt resistor to the + side of the logic DC supply voltage. Also tie the collector to the input of your microcontroller. If possible, locate the optocoupler close to the microcontroller instead of close to the actuator.Let me know how this works out. Please feel free to ask questions if I have not make this clear.-Rick