The Research Of Intrinsic Safety Combustible Gas Detector

With the rapid increase of combustible gas applied range, the leakage of combustible gas is more often. If combustible gas is not detected immediately and accumulates to the blast limit, it can lead to fire and blast. It can endanger the property and human life. So it is necessary to develop a new type of combustible gas detector.According to the design requirements, cost and other factors, we choose the KC-1 catalytic combustion gas sensor to measure the concentration of combustible gas. We choose ATmega128 as the core part of combustible gas alarm instrument. It is used to get, process and display the signal.This paper discusses the combustible gas detector instrument hardware circuit and software program design in detail, introduces the design of the DC power supply, the safety barrier and the preamplifier. And to ensure that the circuits are safe, we check the every node in the circuits. This paper also introduces the core chip, interface with external circuit and central flow chart. The hardware circuit mainly includes malfunction self-diagnosing circuit, MCU interface circuit, sound alarm circuit, light control circuit and display circuit. The applied software are composed by main program flow, initial subprogram flow, malfunction self-diagnosing subprogram flow, concentration disposal subprogram flow, alarm subprogram flow and so on.This combustible gas detector can detect the concentration of combustible gas, and displays the value of concentration on the instrument. When combustible gas reaches alarm threshold value, the instrument sends out sound and light alarm. The combustible gas detector instrument has got past the test and got a satisfying result. It has a high practical value.