| 摘要 |
<p>PURPOSE:To make it possible to monitor the operation and stop of a plant without using any complicated, high-priced answer-back circuit. CONSTITUTION:This device is used in a controller for controlling and monitoring the operation of a plant. In a digital output device 3, a control current used as ON, OFF control signals for controlling the plant in response to ON, OFF control commands from a CPU2 of the controller is output to a drive device 4 of the plant through a cable; and detecting means 3b is provided for detecting whether the control current used as ON, OFF control signals is flowing to the cable.</p> |
