HOT-LINE CONNECTING/DISCONNECTING DEVICE FOR I/O UNIT OF PROGRAMMABLE CONTROLLER

摘要

PURPOSE:To replace only an I/O unit having its fuse blown with a normal one without stopping the actions of other normal I/O units by switching a programmable controller to a hot-line connection/disconnection mode via a mode switching means and attaining the attachment/detachment of the abnormal I/O unit. CONSTITUTION:A mode switching means 7 switches the operation mode of a programmable controller to a hot-line connection/disconnection mode. A control unit 1 works as usual even after the programmable controller is switched to the hot-line connection/disconnection mode. Thus the input/output processes are carried out to the normal I/O units 2a-2n. However an I/O input/output inhibiting means inhibits the input/output process to the I/O unit whose blown state of fuse is stored in a memory means 8. Thus this abnormal I/O unit can be attached or detached during the hot-line connection/disconnection mode. Then the abnormal I/O unit is replaced with another normal one.