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2. ITEMS MONITORED BY THE RAS FEATURE
2.5 Watchdog Timer Monitoring
This equipment has a built-in watchdog timer and can monitor the operation of the OS and a
user program.
• Automatic retriggering feature
The watchdog timer monitoring process in the RAS software automatically retriggers the
timer and monitors the operation of the OS.
• User program operational state monitoring
A user can monitor the operational state of a user program by using dedicated library
functions.
In addition, you can select either one of the following actions to be taken when a timer
timeout occurs.
(1) The system is reset.
(2) The timeout code is displayed on the status display digital LEDs.
(3) A memory dump is generated.
For information about (1), see "5.1.3 System reset due to timeout detection". For
information about (2), see "4.4.2 Codes to be displayed". For information about (3), see
"5.1.4 Memory dump due to timeout detection".
Note that you can configure the watchdog timer settings and the action on timeout in the RAS
Setup window. For information about how to use the RAS Setup window, see "3.1.3 Using
the RAS Setup window".
2.5.1 Automatic retriggering feature for a watchdog timer
The automatic retriggering feature can detects the situation that the watchdog timer
monitoring process in the real-time priority class cannot run for a certain period of time (the
situation that the watchdog timer expires) as an OS hung-up.
To use this feature, in the RAS Setup window, select Automatic retrigger under
Watchdog timer setting.
When an OS hung-up occurs, the processes on the OS may not run as
scheduled, and the processing of the equipment may be delayed. As a result, the
facility that uses this equipment may be affected. You must resolve the root
cause of the OS hung-up as soon as possible.
NOTE
In this feature, OS hung-up is defined as a state that a process in the real-time priority
class cannot run for a certain period of time.
NOTICE
2-4
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