No, the controller is part of the emergency circuit, it helps the stop the motors that are moving. The controller will monitor the emergency stop circuit input and if it sees that the emergency stop has been activated it will bring all motors to a safe condition as quickly as possible. Sometimes it is even a good idea to fit a timer that allows the controller enough time to stop the motors before turning the power off. Linear motors in particular may not stop gracefully without power. This means that if the power is tuned off the axis may not stop causing injury to an operator or until it hits the end of the axis causing possible damage to the machine.