| 摘要 |
PURPOSE:To obtain a device having a high reliability with regard to safety by detecting a characteristic deterioration (life) of a gas sensor itself, informing that the gas sensor has reached its life, and detecting a fact that a heater of the gas sensor has been disconnected. CONSTITUTION:A semiconductor type gas sensor 100 has a reducing gas detecting use gas sensing part 200 and a heating heater 300 of the gas sensing part 200. In some optional period, a heater control part 400 is driven, a temperature of the gas sensing part 200 is made to fall from that of the time of a stationary operation, and a variation of an output signal of a signal detecting part 700 of the gas sensor 100 is measured by a counter 727. When this measured value exceeds some value, a life display/alarm of the gas sensor 100 is executed. Also, when a gas leak signal is continued for a prescribed time, a gas leak display/alarm is executed, and when a heater disconnection has been detected, a heater disconnection display/alarm is executed. The heater control part 400 drives the heater 300 by a constant-current source, and when a current has come not to flow to the heater, a heater disconnection display is executed.
|
