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Home >> BMW >> 2003 >> 745Li >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> Intelligent Safety Integration System - Overview >> Intelligent Safety Integration System (ISIS) >> System Overview >> Safety Information Module (SIM) >> Watchdog Function

Watchdog Function

The Intelligent Distributor allows the SIM to deactivate the power supply for individual satellites. This possibility is used to implement a watchdog function. The relevant status telegram is used to monitor the satellites. If any of the following faults is detected by the bus master (SIM), the satellite is deactivated:

Depending on the type of fault, up to two attempts are made to switch on again after 100 ms. If the power on reset in the satellite module does not rectify the fault, the satellite remains off until the next wake-up of the bus system.

Fig 1: Watchdog Function Circuit Diagram
G03391520Courtesy of BMW OF NORTH AMERICA, INC.