Watchdog Timer
This is a countdown counter that runs independently of the main software and resets the controller if it is not fed regularly. The GS740-3P has an independent watchdog of approximately 2 seconds. The purpose is to make sure that, in a situation where the software has hung, the system returns to a defined start rather than freezing in an undefined position.
The working principle is simple. The main program loop clears the counter on every pass. If the program hangs somewhere and cannot feed the counter, the countdown reaches its end and a reset is produced at hardware level. The controller restarts, reads the calibration memory and returns to normal operation.
On the user side this looks like a very short interruption: the channel goes for a moment to a position close to idle and then returns to the command. This behaviour is not a fault on its own, but if it repeats often it is telling you something. The most common real cause is not the software but the supply; a voltage collapse during cranking, a loose chassis connection or a supply cable of insufficient cross-section can reset the controller.
For this reason, if the system drops to idle by itself, first measure the voltage at the supply terminals while the engine is running, and check the chassis point and the seating of the sockets.
Context in which this term is used: Electronic speed and throttle control on diesel engines