Abstract: A control system for an assembly tool includes sensors which monitor the status of the tool at each step of operation and a controller receives signals from the sensors to ensure proper status in any given step. The tool includes a collar transfer device which receives a fastener collar from a remote collar sending unit and transfers the collar to a collar-swaging assembly which moves the collar to a cooperating fastener pin and swages the collar onto the pin. The sensors of the system monitor the position of the collar transfer device, the presence or absence of a collar in the collar transfer device, the position of the swaging assembly, the presence or absence of a collar in the swaging assembly, and the presence or absence of a fastener pin of proper length in a position to be engaged by the collar.