Using A Watchdog Timer For Monitoring A User Program; Figure 2-2 Example Of A Flow Chart Of Monitoring The Operational State Of A User; Program - Hitachi HF-W7500 65 Feature Manual

2.7.2 Using a watchdog timer for monitoring a user program

In order to use a watchdog timer for monitoring the operational state of a user program,
you can use a configuration, for example, where the user program periodically retriggers
the watchdog timer (that is, resets the timeout counter of the watchdog timer to the initial
value) and another program checks whether timeout occurs for the watchdog timer. The
flow chart for this configuration is shown below.
Figure 2-2 Example of a Flow Chart of Monitoring the Operational State of a User Program
Monitored program
Process a user-defined
routine
Trigger
the watchdog timer
Retrigger
HF-W
Watchdog
timer
2. ITEMS MONITORED BY THE RAS FEATURE
Monitoring program
Check whether
timeout occurs for
the watchdog timer
Get the value of the
timeout counter
2-9