Microprocessor controlled vehicle system - is monitored using control pulse whose first absence causes restart and second emergency action

A monitoring device for program controlled devices, esp. microprocessor controlled vehicle systems, involves detecting a control pulse during each program cycle. It differentiates between faults arising during a program cycle, deciding whether they result from temporary faults or system failure. This enables use of a reliable criterion for operating an emergency switch. If no control pulse is detectd a new program cycle is initiated. A time element drives a coincidence circuit connected to the device so taht the coincidence circuit is switched when no further pulse is detected during the timer rest period.