User Manual

Functions

9.1 Monitoring Functions

SIMATIC IPC427C

Operating Instructions, 04/2009, A5E02414743-01

9.1.3 Watchdog (WD)

Function

If the user program does not respond to the watchdog within the predetermined monitoring

time, the watchdog monitors the program process and informs the user about various

reactions.

After POWER ON of the device 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.

Watchdog reactions

If the watchdog is not triggered again within the set time, the following reactions will be

triggered:

Reaction Option

Switch watchdog LED to red None

Trigger a PC reset Configurable

Enabling the DiagBase or DiagMonitor software None

Note

If the desired device reset is not performed, go the Advanced menu of the BIOS Setup and

set the SafeCard functions to Enabled. Contact Customer Support for a detailed description

of the Watchdog functions.

WD monitoring times

The monitoring times are defined as follows:

Normal mode: 94 ms, 210 ms, 340 ms, 460 ms, 590 ms, 710 ms, 840 ms and 960 ms.

Macro mode: 2s, 4s, 6s, 8s, 16s, 32s, 48s and 64s.

Note

The watchdog is retriggered if the monitoring time is changed at the active watchdog (that is

while the watchdog is running)!