Fire detection system and method using multiple sensors
First Claim
Patent Images
1. A detector comprising:
- at least three different ambient condition sensors, one of the sensors is a primary condition sensor, the others are secondary condition sensors, all of the sensors produce respective condition indicating outputs;
control circuitry which defines a time variable alarm threshold for the primary condition sensor, the control circuitry is responsive to outputs from the two secondary sensors to form a cross-correlated threshold adjusting indicium, the control circuitry including further circuitry to adjust the time variable alarm threshold in accordance with the indicium; and
alarm determination circuitry responsive to the adjusted time variable threshold.
1 Assignment
0 Petitions
Accused Products
Abstract
Outputs from a plurality of different ambient condition sensors are cross correlated so as to adjust a threshold value for a different, primary, sensor. Cross-correlation processing can be carried out locally in a detector or remotely. To minimize false alarming, the alarm determination can be skipped if the output from the primary sensor does not exhibit at least a predetermined variation from an average value thereof.
67 Citations
26 Claims
-
1. A detector comprising:
-
at least three different ambient condition sensors, one of the sensors is a primary condition sensor, the others are secondary condition sensors, all of the sensors produce respective condition indicating outputs; control circuitry which defines a time variable alarm threshold for the primary condition sensor, the control circuitry is responsive to outputs from the two secondary sensors to form a cross-correlated threshold adjusting indicium, the control circuitry including further circuitry to adjust the time variable alarm threshold in accordance with the indicium; and alarm determination circuitry responsive to the adjusted time variable threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A system comprising:
-
first software recorded on a computer readable medium for responding to received first and second signals, each indicative of a respective ambient condition, to form a cross correlated threshold adjusting indicium; second software for carrying out a predetermined function, responsive to the indicium, for adjusting a threshold associated with a third sensor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A fire alarm system comprising:
-
at least three sensors, the sensors each generating signals indicative of a respective environmental condition being monitored, where one of the sensors is selected to be a first sensor generating a first sensor signal and the remaining at least second and third sensors generating at least second and third sensor signals respectively; and circuitry where the at least second and third sensor signals are combined to form an adjustment function, the adjustment function is used by the circuitry to alter a threshold value, where the first sensor signal is compared to the altered threshold value and an alarm condition is indicated if the first sensor signal crosses the altered threshold value. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
-
Specification