Signal acquisition circuit of aviation pneumatic fire alarm sensor

Abstract

The invention discloses a signal acquisition circuit of an aviation pneumatic fire alarm sensor. The signal acquisition circuit comprises three redundancy channels with dissimilar redundancies; the first redundancy channel and the second redundancy channel are respectively compared through a positive phase comparator and a negative phase comparator, and the first characteristic pressure value and the second characteristic pressure value are respectively compared with preset voltage thresholds of at least two comparators so as to distinguish at least three states of a signal loop formed by an alarm diaphragm capsule and a fault diaphragm capsule; the third redundancy channel adopts an analog quantity voltage acquisition mode, acquires and processes differential signals of the first characteristic pressure value and the second characteristic pressure value, and distinguishes at least three states of a signal loop formed by the alarm diaphragm capsule and the fault diaphragm capsule through calculated resistance value. According to the technical scheme of the invention, the problem that an existing single-path resistance acquisition channel is designed for small aircrafts with a small number of engine fire alarm sensors and is not suitable for fire alarm signal acquisition of medium and large aircrafts is solved.

Description

technical field [0001] The invention relates to but not limited to the technical field of signal acquisition of aviation pneumatic fire alarm sensors, in particular to a signal acquisition circuit of aviation pneumatic fire alarm sensors. Background technique [0002] At present, airborne fire alarm sensors are widely used in aviation, which mainly use the principle of nitrogen expansion when heated. When the temperature in the detection area changes, the pressure of the gas chamber inside the pneumatic fire alarm sensor changes, and the resistance value of the sensor’s alarm bellows Both the impedance value of the membrane box and the faulty capsule change. Through the measurement of the impedance value, various working conditions such as normal, fire, and fault (faults include sensor short circuit, open circuit, and pollution) can be distinguished. [0003] The traditional single-channel resistance acquisition channel acquisition method is suitable for small aircraft with ...

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Problems solved by technology

[0004] Purpose of the present invention: In order to solve the problems in the background technology, the present invention proposes a signal acquisition circuit of an aviation pneumatic fire alarm sensor, to solve the problem that the existing single resistance acquisition channel is designed for small aircraft with a small number of engine fire alarm sensors Yes, it is not applicable to the collection of fire alarm signals of medium and large aircraft

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