Watchdog (Wd); Fan Monitoring - Siemens SIMATIC Rack PC 840 V2 Operating Instructions Manual

Functions

9.3 Watchdog (WD)

9.3 Watchdog (WD)
9.3
Function
The watchdog monitors the program execution and reports a program crash to the user by
means of various reactions.
After POWER ON of the PC, or after a HW RESET (cold restart), the watchdog is in idle
state, i.e. a reaction of the WD will not be triggered and the Watchdog LED is switched off.
The Watchdog LED is lit green when the watchdog is enabled (by executing the driver or the
SOM program).
WD reactions
If the WD is not triggered again within the set time (by driver or SOM program), the following
reactions are initiated:
Response
The Watchdog LED switches from green to red
Trigger a PC reset
SOM or DiagMonitor- software is activated
WD monitoring times TWD
The TWD are adjustable in increments of one second in a range from 3 to 255 seconds.
Note
If the watchdog time is changed after the watchdog was enabled (i.e., while the watchdog is
running), the watchdog is retriggered!
9.4

Fan monitoring

9.4
The function monitors operation of the front and processor fans. When a fan fails, the
following reactions are triggered:
Response
The Temp LED switches to red
The Fan LED switches to red
SOM or DiagMonitor- software is activated
The temperature error is retained until the cause of the fan failure has been rectified and the
error is reset in one of the following ways:
• Acknowledgement of the error message by the SOM program.
• Restart of the device.
The flashing Temp LED indicates that the device is being operated at its limits. Please check
whether the permissible ambient temperature has been exceeded, or whether the filter is
soiled.
9-2
Option
None
Configurable
None
Option
None
None
None
Operating Instructions, Edition 05/2006, A5E00248055-04
SIMATIC Rack PC 840 V2