Mitsubishi Electric MELSEC iQ-R Series - Resetting the Watchdog Timer

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7 APPLICATION INSTRUCTIONS
7.3 Program Execution Control Instructions
Resetting the watchdog timer
WDT(P)
These instructions reset the watchdog timer.
■Execution condition
Processing details
• These instructions reset the watchdog timer in a program.
• These instructions are used when the scan time exceeds the value set for the watchdog timer depending on the condition.
If the scan time exceeds the value set for the watchdog timer every scan, change the watchdog timer value in parameter
using the engineering tool.
• The time values required for t1 from step 0 to the WDT(P) instruction and t2 from the WDT(P) instruction to the END
(FEND) instruction must not exceed the value set for the watchdog timer.
• The instruction can be used twice or more in a single scan, but it takes time to turn off the output when an error occurs.
• Executing the instruction does not clear the scan time value stored in the special register. For this reason, the scan time
value in the special register may be greater than the value set for the watchdog timer in parameter.
Operation error
There is no operation error.
Ladder ST
ENO:=WDT(EN);
ENO:=WDTP(EN);
FBD/LD
Instruction Execution condition
WDT
WDTP
RnCPU
RnENCPU
RnSFCPU RnSFCPURnPCPURnPCPU
(Standard) (Safety)
(Redundant) (Process)
EN ENO
WDT
END (FEND)
t1 t2
0 step