Abstract: A burner control system includes an input interface 10 for receiving burner status inputs. These are passed to address bus 14 and used to access addresses within EPROM 18. Data at the accessed addresses are output on bus 20 to control the burner via output interface 23 with related relays. Oscillator 16 and counter 17 sequence the selected address areas of the EPROM via bus 15 and a start up sequence, for example, can thus be effected. Incorrect status of the inputs from input block 10, flame detector 12 or the internal system checks in blocks 28 or 29 to bus 14 will cause the EPROM to be addressed at locations which contain data in a form that will cause shutdown or lockout via relay 25. Parity check block 22 also actuates lockout if errors are detected. System status can be provided by display 19.

Abstract: A fail-safe supervisory circuit for a microprocessor-controlled fuel burner has a diode pump circuit (C4, C5, D7, D8) triggered by a resettable monostable (R7, T2, R8, C3) responsive to an encoded signal from the microprocessor, to act as a watch-dog timer. A triggered bistable (D1, T1, R2, IC8) provides a RESET signal on power-on or manually. A direct connection from this bistable to the monostable enables the timer circuit until the microprocessor program commences.