Timeout Of Watchdog Timer - Mitsubishi Electric MELSEC iQ-R C R12CCPU-V User Manual

Timeout of watchdog timer

When the watchdog timer times out, an error indicating that the monitoring time set in the watchdog timer setting has been
exceeded (watchdog timer error) occurs. If a user watchdog timer error occurs, the BUS RUN LED turns OFF and the ERROR
LED starts flashing. If a system watchdog timer error occurs, the READY LED turns OFF.
System watchdog timer
In case of failure of a C Controller module hardware and interrupt program execution, timeout will occur as the system
processing has been suspended for a long time.
User watchdog timer
If a user program cannot complete processing within the time specified by using the C Controller module dedicated function
(CCPU_StartWDT), and also cannot reset by using the C Controller module dedicated function (CCPU_ResetWDT), a
timeout will occur.
Precautions
When using the following functions, a user watchdog timer error occurs easily since the CPU utilization by a system task with
high priority increases.
• Shell command
• Connection with CW Workbench and Wind River Workbench
• Mounting and unmounting an SD memory card
• Unmounting the USB Mass Storage Class-compliant device
• File access
• Ethernet communication
• NFS server communication
4 BASIC FUNCTIONS
4.1 Program Monitoring (WDT) Function
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