| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the occurrence of lamination shift in an electrochemical gas sensor. <P>SOLUTION: This carbon monoxide gas measuring instrument includes the electrochemical gas sensor 1, producing the electric current corresponding to the concentration of target gas between a detection electrode 31 and a counter electrode 32; a current/voltage conversion circuit 40 for converting the current flowing through the electrochemical gas sensor 1 to voltage; a power supply 33 supplying a charge current into charge the electrochemical gas sensor 1; the resistor R1 provided between the supply passage of the charge current into the electrochemical gas sensor 1 from the power supply 33 and the input terminal of the current/voltage conversion circuit 40 and set to a resistance value wherein the inflow current from the power supply 33 changes, corresponding to a charge in the resistance value of the series internal resistance component possessed by the equivalent circuit at the start time of charge of the electrochemical gas sensor 1; and a self-diagnosing means 10a for calculating the resistance value of an internal resistor, on the basis of the output voltage from the current/voltage conversion circuit 40 at the start time of charge of the electrochemical gas sensor 1 and the resistance value of the resistor R1 and detecting the lamination shift of the electrochemical gas sensor 1, on the basis of the resistance value of the internal resistor. <P>COPYRIGHT: (C)2011,JPO&INPIT |
