Abstract: A communication and data interpreting system for detecting and converting and combining multiple analog signals from flame detectors into a single analog signal and RS 485 for transmission. This system also uses an analog clamping circuit to generate the analog signal from flame rod sensors and a load resistor and a high voltage generator for generating the signal in an UV sensing tube. The input signals are then multiplexed and sent to a microcomputer. The microcomputer uses a diode and a solid state relay circuit to generate a compatible signal output to a burner control.

Abstract: A flame detection system utilizing microcomputer control of a unique self-checking signal interruption system for checking the status of the sensing tube by employing solid state switches and a balance beam shutter. The microcomputer uses a diode and a solid state relay circuit to generate a compatible signal output to a burner control.

Abstract: A control system for a multiple burner furnace has a programmable processor interfaced to hardware input and output circuitry associated with the furnace. The programmed processor provides a number of operating modules including a polling module, a startup module, a run module, and an alarm module. The processor and the associated hardware are interlocked in such a fashion that safe operation of the furnace is assured. For example, watchdog timers driven from the processor are interlocked with flame sensing hardware to control the main fuel valve and prevent fuel from flowing to the furnace in the event of either hardware or software malfunction. The safety features are equivalent to or better than a hardwired dedicated control system, while providing additional program-related flexibility and functionality.