Siemens PC 670 用户手册
Hardware Information
Release 04/02
7-8
Panel PC 670 Computing Unit, Equipment Manual
7.4.4
Watchdog (WD)
Function
The watchdog monitors the execution of a program. The purpose of the WD is to
report a program crashing to the user by means of different reactions.
report a program crashing to the user by means of different reactions.
After switching on the computing unit or after a HW-RESET (cold start) the
watchdog remains in standby, i.e. no WD reaction is activated and the RUN-LED
remains switched off. If the watchdog is activated (by driver or SOM program) the
Run LED is green.
watchdog remains in standby, i.e. no WD reaction is activated and the RUN-LED
remains switched off. If the watchdog is activated (by driver or SOM program) the
Run LED is green.
WD-Reaktionen
If the WD is not retriggered within the set time (by driver or SOM program), the
following reactions are triggered:
following reactions are triggered:
Reaction
Options
RUN LED switches from green to red
Always
Acknowledge WD
Always
Initiate reset on the computing unit
Adjustable
IRQ an die Rechnereinheit absetzen
Adjustable
SOM application is displayed
Adjustable
The reactions you want to have triggered can be set by drivers or the SOM
program.
program.
WD monitoring times TWD
The monitoring times can be adjusted in increments of one second over the range
from 3 to 255 seconds.
from 3 to 255 seconds.
Note
If the watchdog time is modified after the watchdog has been activated – in other
words, while the watchdog is running – the watchdog will be retriggered as a
result!
words, while the watchdog is running – the watchdog will be retriggered as a
result!