| 摘要 |
The present invention relates to an alarm condition detector such as a dangerous concentration detector of noxious gases in a medium. The invention finds applications in the field of measurment chains coupled to at least one sensor and particularly in the field of security against noxious gases. The invention is particularly characterized in that the detector includes, in addition of the sensor (1), a means (7) for producing at least during the operation of the detector, and also at predetermined moments, a reference value (Vref) representative of the intrinsic condition of the detector, a means (8) for producing at predetermined instants a threshold value (Vthreshold) according to the relationship: Vthreshold = f(Vref, tv), a function both of said reference value (Vref) updated at that instant and of an alarm level (tv), a calculation means (6) for calculating an alarm condition receiving as input the measuring signal (Vmes) and said threshold value (Vthreshold) and producing, as output, said alarm signal.
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