| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a slave capable of continuously operating an alarm means for specifying output equipment whose short circuit is occurred even at turning off a power source for the output equipment. SOLUTION: This device is provided with an output circuit 16 for turning ON/OFF an OUT terminal 16" and an internal circuit including an MPU 13 for controlling the operation of an output circuit (transistor 16') according to a control instruction from a PLC. The internal circuit and an output circuit are constituted to receive power supply from power feedlines in different systems, and the transistor outputs a short-circuit detection signal to the MPU at detecting the short-circuit. At receiving the short-circuit detection signal, the MPU turns ON a short-circuit buffer, and turns ON a relevant status LED 20. The MPU obtains the operating state of an I/O power source 19 through a photo-coupler 15c, and holes the short-circuit buffer in the ON state even when the power source is turned off. Therefore, the status LED can be lighted even when the power source is turned off.</p> |
