| 摘要 |
A CO concentration monitoring device operating under the control of a processor periodically checks the CO sensor to insure its ongoing integrity and to issue a distinctive audio signal to a user if sensor integrity has become suspect. The periodic integrity check procedure places a predetermined DC voltage across the sensor. Then, the voltage source is removed leaving the sensor charged as a capacitor such that reading the voltage remaining across the sensor, reading the temperature of the sensor and comparing a temperature adjusted representation of the voltage appearing across the sensor to at least one predetermined representation of a voltage representing a threshold at which sensor integrity becomes suspect. If this condition is determined, a sensor condition alert signal responsive is issued to drive a horn in a distinctive audio sequence (e.g., three 10 millisecond duration pulses spaced at about 500 millisecond intervals). In an optional feature, a manually actuable switch serves to selectively inhibit drive to the horn for a predetermined period if the sensor integrity condition has been determined to be marginal, but not yet failing.
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