Detector with variable sample rate

• US 6,222,456 B1
• Filed: 10/01/1998
• Issued: 04/24/2001
• Est. Priority Date: 10/01/1998
• Status: Expired due to Term

• Current Assignee: Pittway Corporation (Honeywell International Inc.)
• Original Assignee: Pittway Corporation (Honeywell International Inc.)
• Inventors: Tice, Lee D.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): LA, ANH V
• Application Number:
  US09/164,498
• Time in Patent Office: 936 Days
• Field of Search: 340/628, 340/629, 340/630, 340/632, 340/578, 340/584, 340/589, 250/574, 250/575, 356/436, 356/437, 356/438, 356/439
• US Class Current: 340/630
• CPC Class Codes: G08B 17/107 for detecting light-scattering due to smoke
• CPC Class Codes: G08B 29/26 by updating and storing reference thresholds

Abstract

A detector includes a sensor of an ambient condition. Outputs from the sensor are sampled at a predetermined rate when the outputs do not represent an alarm condition. The outputs are analyzed using pattern recognition techniques to determine if a predetermined profile, which precedes the presence of an alarm condition, is present. In the event that the profile is detected, the sample rate is increased along with associated sample value processing. The detector includes a programmable processor coupled to the sensor. The processor includes pattern recognition instructions for detecting the presence of the predetermined profile. The processor also includes instructions for altering the sampling rate in response to the detected presence of the profile. A second sensor can be incorporated to provide sample rate altering signals.

Claims

1. An electrical unit comprising:

a sensor for generating an output;

a control element coupled to the sensor wherein the element includes circuitry for sampling the output of the sensor at a first rate thereby producing a sampled output, decision circuitry for determining if the sampled output exhibits a predetermined, non-threshold based, profile, and circuitry which in response thereto, increases the sampling rate to a second, higher, rate.

2. A unit as in claim 1 wherein the control element comprises a programmed processor with instructions for increasing the sampling rate from the first rate to the second rate in response to the presence of the profile in the output.

3. A unit as in claim 2 wherein the decision circuitry comprises additional instructions for recognizing the presence of the profile.

4. A unit as in claim 2 wherein the decision circuitry includes instructions which determine that the profile is present in response to sampled values exhibiting an increasing amplitude.

5. A unit as in claim 2 wherein the sensor comprises an ambient condition sensor and the decision circuitry includes instructions which determine that the profile is present in response to a gradient of sampled amplitude values of the output exceeding a selected first value.

6. A unit as in claim 2 wherein the decision circuitry includes a storage unit wherein information defining a predetermined profile is stored therein, and wherein instructions are stored therein for increasing the sampling rate to the second rate in response to the sampled output from the sensor corresponding to the prestored information.

7. A unit as in claim 1 wherein the decision circuitry includes pattern recognition circuitry for determining that the profile is present in the output.

8. A unit as in claim 5 wherein the sensor comprises a photoelectric smoke sensor.

9. A unit as in claim 1 which includes at least a second, different sensor which generates a second output and including interface circuitry coupled to the decision circuitry wherein the profile determination is based, at least in part, on the second output.

10. A unit as in claim 9 wherein the decision circuitry includes circuitry for adjusting the sampling rate of the first output in response to a profile based, at least in part, on the second output and for adjusting a sampling rate of the second output in response to a profile based, at least in part, on the first output.

11. A unit as in claim 10 wherein the sensors are responsive to the presence of ambient conditions indicative of the presence of fire.

12. A unit as in claim 11 wherein the first sensor includes a smoke sensor.

13. A unit as in claim 10 wherein the first sensor includes a smoke sensor and the second sensor includes a sensor selected from a class which includes a gas sensor, a humidity sensor, a thermal sensor, a dust sensor and a velocity sensor.

14. A unit as in claim 10 wherein the decision circuitry comprises a programmable processor and a plurality of associated decision-related instructions coupled thereto, and, wherein the sampling rate adjusting circuitry comprises rate modifying instructions coupled to the processor.

15. A unit as in claim 4 wherein the rate modifying instructions both increase and decrease the sampling rates of the outputs.

16. A unit as in claim 15 wherein the first sensor comprises an optical-type smoke sensor and the second sensor comprises an ion-type smoke sensor.

17. A unit as in claim 1 which includes circuitry for processing the sampled output to thereby produce a processed output wherein the processing is alterable in response to increasing the sampling rate.

18. A unit as in claim 17 wherein the processing comprises filtering the sampled output and wherein the filtering is altered in response to increasing the sampling rate.

19. A unit as in claim 18 wherein the filtering is decreased in response to increasing the sampling rate.

20. In a condition monitoring system having at least one sensor, a method comprising;

sampling of data from a sensor;

establishing a rate of sampling the data;

processing the sampled data using at least one of algorithms and other logical means to form processed values; and

prior to an alarm condition being determined, changing the rate of sampling of the data in response to the processed values exhibiting a selected profile.

21. A method, as in claim 20, where the sampling rate is increased if the processed values are increasing.

22. A method as in claim 20 where the sampling rate is increased if the processed values are exceeding a predetermined minimum value less than the alarm threshold.

23. A method, as in claim 20 where the sampling rate is increased if a plurality of the processed values exceed a predetermined threshold.

24. A method, as in claim 22, where the sampling rate is decreased if the processed values are less than a predetermined threshold.

25. A method, as in claim 21 wherein the sampling rate is increased if the profile of the processed values is similar to or matches a profile representative of a selected condition.

26. A method as in claim 21 wherein the sampling rate is decreased if the profile of the processed values is not similar to or is not matching a profile representative of a selected condition.

27. In an abnormal condition monitoring system such as a fire alarm system, a method comprising;

sampling of data from a sensor;

establishing a rate of sampling the data;

processing the sampling of the data using at least one of algorithms and other logical means; and

prior to an alarm condition being determined, changing the rate of sampling of the data dependent upon a profile of the sampled data from the sensor.

28. A method as in claim 27 wherein the rate of sampling data is increased if the profile of the data from the sensor corresponds to the presence of a predetermined condition.

29. A method, as in claim 27, wherein the rate of sampling data is decreased if the profile of the data from a sensor does not correspond to the presence of a predetermined condition.

30. A method as in claim 27 wherein the rate of sampling data is increased if a gradient of the data from a sensor exceeds a preset value.

31. A method as in claim 27 wherein the rate of sampling data is decreased if the gradient of the data from a sensor does not exceed a preset value.

32. A method as in claim 27 wherein the rate of sampling data is increased if the profile of the data from a sensor is similar to or matches a profile representative of an abnormal condition.

33. A method as in claim 27 wherein the rate of sampling data is decreased if the profile of the data from a sensor is not similar to or does not match a profile representative of an abnormal condition.

34. A fire detector comprising:

a housing;

a fire sensor carried by the housing;

a sampling circuit coupled to the sensor;

sample rate establishing circuitry coupled to the sampling circuit;

processing circuitry coupled to the sampling circuit and to the establishing circuitry wherein the processing circuitry receives sampled values, indicative of outputs from the fire sensor, and wherein the processing circuitry provides at least one rate of change input to the rate establishing circuitry thereby causing that circuitry to establish a first quiescent rate and a second higher rate, in response to a predetermined profile which is independent of any fire threshold value.

35. A detector as in claim 34 wherein the processing circuitry includes pattern recognition circuitry for establishing the presence of the predetermined profile in a selected plurality of sampled values.

36. A detector as in claim 34 which includes a second, different sensor coupled to the processing circuitry for supplying profile related signals thereto.

37. A detector as in claim 36 wherein the processing circuitry includes pattern recognition circuitry for establishing the presence of the predetermined profile in the signals received from the second sensor.

38. A detector as in claim 34 wherein the processing circuitry includes a filter for filtering the sampled values to first and second different to degrees and circuitry for switching from one degree of filtering to another when the sample rate is altered.

39. A detector as in claim 38 which includes a second sensor which generates a profile establishing signal which is coupled to the processing circuitry.