METHOD AND DEVICE FOR MONITORING DETECTOR LINE OF FIRE DETECTION SYSTEM FOR FAULTS

• US 20070268646A1
• Filed: 05/11/2007
• Published: 11/22/2007
• Est. Priority Date: 05/11/2006
• Status: Abandoned Application

• Current Assignee: Siemens Building Technologies Fire & Security Products GmbH & Company OHG
• Original Assignee: Siemens AG
• Inventors: SCHERMANN, Harald
• Application Number:
  US11/747,672
• Publication Number:
  US 20070268646A1
• Time in Patent Office: Days
• US Class Current: 361/118
• CPC Class Codes: G08B 29/06 Monitoring of the line circuits, e.g. signalling of line faults
• CPC Class Codes: G08B 29/123 of line circuits

Abstract

A limit indicator technology based detector line of a fire detection system has a line current applied to it during operation and has a final element formed by a TVS diode. At least one of the line current and the line voltage are monitored. Faults of the detector line are detected by a brief increase and a brief reduction in the line current.

Claims

1. A method for monitoring a limit indicator technology based detector line of a fire detection system for faults, comprising:

applying a line current to the detector line during operation, the detector line having a final element formed by a TVS diode;

monitoring at least one of the line current and a line voltage; and

briefly increasing and briefly decreasing the line current, enabling detection of faults by said monitoring.

2. The method as claimed in claim 1, wherein one of the faults detected by decreasing the line current is a creeping short-circuit.

3. The method as claimed in claim 2, wherein said briefly decreasing the line current is repeated periodically.

4. The method as claimed in claim 3, further comprising averaging measured values, obtained during a period of said monitoring of the at least one of the line current and the line voltage.

5. The method as claimed in claim 2, further comprising averaging measured values, obtained during a period of said monitoring of the at least one of the line current and the line voltage.

6. The method as claimed in claim 1, further comprising averaging measured values, obtained during a period of said monitoring of the at least one of the line current and the line voltage.

7. A device for monitoring a limit indicator technology based detector line of a fire detection system, comprising:

detectors connected to the detector line, the detector line having a TVS diode as a final element;

a control center applying a line current to the detector line; and

means for monitoring at least one of a line current and a line voltage while the line current is increased briefly and reduced briefly enabling detection of faults.

8. The device as claimed in claim 7, wherein said means briefly reduces the line current periodically.

9. The device as claimed in claim 8, wherein said means comprises a microcontroller controlling the monitoring for the faults.

10. The device as claimed in claim 9,

wherein said means further comprises an analog/digital converter, coupled to or integrated in said microcontroller, converting measured values of the at least one of the line current and the line voltage.

11. The device as claimed in claim 10, wherein said microcontroller averages a plurality of the measured values of the at least one of the line current and the line voltage.