The Q-Series PLC supports the facility to FORCE I/O but it is not always clear how to find out what has been forced or how to track forces. This document details the use of a feature called “Forced Input Output Registration/Cancellation”.
One common problem with forcing PLC inputs (Xs) and Outputs (Ys), is knowing what has been forced. The “Forced Input Output Registration/Cancellation” feature not only gives control of I/O forcing, but also provides a visual indication and tracking method. This feature specifically enables both inputs and outputs to be forced both ON and OFF. In the example below, X0 has been forced ON and Y11 has been forced OFF.
This screen is an up-to-date record of the current forced status up to 32 I/O. In addition to this screen the MODE LED on the PLC will be flashing to indicate that 1 or more forces are present.
Individual forced items can be returned to normal operation with the Cancel It button and/or all forced I/O can be cancelled with the Clear All button. If forces are left active on the PLC, the MODE LED will continue to flash.
In GX Developer the Forced Input Output Registration/Cancellation feature can be found under the Debug section of the Online menu. In GX IEC Developer the Forced Input Output Registration/Cancellation feature can be found under the Debug menu.
For further information, please refer to the GX IEC and GX Developer manuals.