| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely perform an abnormality diagnosis in the event of abnormality of a gas concentration measuring apparatus 1 comprising a cell composed of a solid electrolyte and a pair of electrodes and a heater 70 retaining the temperature of the cell at an active temperature. <P>SOLUTION: In an activated state of a sensor device 10, when voltage on the connection points between the sensor device 10 and a sensor control circuit 50 becomes a preset abnormal value, the sensor control circuit 50 is electrically cut off from each connection point. Then, the delivery of power to the heater 70 is ceased to lower the temperature of each cell below the active temperature, thereby increasing the internal resistance of each cell. Thereafter, the sensor control circuit 50 supplies to the sensor device 10 a current in a degree not damaging the sensor device 10, to detect voltage on each connection point at that time. By comparing the detected voltages on the respective connection points, a content and location of abnormality occurring is identified of the sensor device 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
