In a previous lesson we explained the purpose of the watchdog timer. In this lesson, we will expand that lesson a little further and demonstrate the function of the watchdog timer. We are going to modify a previous program that contains a properly executed jump instruction such that it creates a condition called an infinite loop. An infinite loop condition causes the watchdog timer to time out, which in turn causes the PLC to go into Stop mode. We explain how a properly executed jump instruction should be written to avoid this condition.