摘要 |
READ-ONLY SEQUENCE CONTROLLER A read-only sequence controller has a main circuit and a sub-circuit operated by a command signal from the main circuit at a predetermined cycle time. The cycle time of the main circuit is longer than the sub-circuit in order to control the sub-circuit. A sensor is provided on an outlet of a machine for detecting a discharge of a work at every cycle end and producing a discharge signal which is fed to the sub-circuit. In normal operation, the sub-circuit is re-started in response to the discharge signal and the command signal from the main circuit. When abnormality occurs, the sensor does not produce the discharge signal. In response to absence of the discharge signal and to the command signal, a stop control circuit produces stop signals to stop the main circuit and the sub-circuit.
|