Step Transition Watchdog Timer Replacement Method - Mitsubishi Electric MELSEC-Q Series Programming Manual

Step Transition Watchdog Timer Replacement Method

Operation of step transition watchdog timer
The step watchdog timer measures the ON time of the special relay for step transition watchdog timer start (SM90 to SM99),
and when it exceeds the time set to the special register for step transition watchdog timer setting (SD90 to SD99), the
corresponding annunciator (F) set to any of (SD90 to SD99) is turned ON. The following figure shows a step transition
watchdog timer program.
Step transition watchdog timer replacement method
When performing the same operation as that of the step transition watchdog timer, create the following program at the
operation output.
A
APPENDICES
181
Appendix 2 Restrictions on Basic Model QCPU, Universal Model QCPU, and LCPU and Alternative Methods