Combustible gas detection system
AssigneeThe Bendix Corporation
InventorJoe K. Winner
Life of this patent
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Abstract
A combustible gas detection system in which remotely located combustible gas sensors of the analog type are monitored by a central controller. The sensor analog data is converted to digital data and transmitted to the controller. The controller tests the integrity and validity of data received from the sensor, identifies the nature of any faults therein and vocally signals the cause of such faults. The controller computes the concentration of combustible gas at the sensor and automatically determines sensor calibration constants from received sensor data.
Claims7
A combustible gas detection system comprising, a sensor module located at a site to be monitored for combustible gas, said sensor module including,
- a combustible gas sensor providing an analog signal related to the concentration of combustible gas to which it is exposed;
- means for converting said analog signal to a digital signal representing the numerical value of said analog signal, and
- means for transmitting said digital signal as a digital word having a predetermined serial data format;
- and
- a controller remotely located from said sensor module, said controller including,
- means for receiving said digital word transmitted by said sensor module;
- means for testing the time duration of said received digital word to determine whether said time duration acceptably conforms to the time duration of said predetermined serial data format;
- means providing the difference in value between two said digital words successively received;
- means for testing said difference against a fixed value representing the maximum acceptable change between two said successive words;
- means operable upon failure of said received words to meet said time duration test or said value difference test for providing a failure warning identifying data fault as the cause of failure;
- computing means including a memory wherein calibration constants are stored, said calibration constants having been determined by exposure of said combustible gas sensor to gases of known concentrations of combustibles;
- means applying said received word to said computing means for calculation from said received word and said stored calibration constants of the concentration of combustible gas present at said sensor module;
- means for testing said calculated concentration against a predetermined range of probable values for such concentrations obtainable from a normal combustible gas sensor;
- means operable when said calculated concentration is outside said predetermined range of probable values for providing a failure warning identifying said combustible gas sensor as the cause of failure;
- means for comparing said calculated concentration with a predetermined alarm set point;
- means providing an alarm signal whenever said calculated concentration exceeds said alarm set point;
- and
- means for displaying said calculated concentration of combustible gas.
Dependencies are inferred from the claim text.