I need to make a zero speed sensor controller i.e. using proximity sensor to judge rotation of a shaft or motor, and cause a trip when rotation is slower or zero. It s outputs connected to a relay which is NO. When motor is started it outputs high signal to close the relay, after a delay of 2 sec, it checks if the speed is ok or within range it will keep the output high keeping relay contacts close. When speed/rotation is less then it outputs no signal, opening the relay contacts causing the motor to stop or trip.