azor32:
Having some trouble working out how the microswitch signals the controller when to stop sending 24 volts to the motor.
That sounds like the mechanism used in a screen wiper motor to make it park at the right position.
In a screen wiper when you turn on the wiper-switch it provides power to the motor in parallel with the microswitch - effectively overriding the OFF position of the microswitch so the motor moves. Then, if you turn off the wiper-switch when the wipers are not at the park position the microswitch keeps supplying power until the park position is reached.
If that has any relevance then you need to tell us what role you want the Arduino to play.
...R