EP 0044725 A2 19820127 - Improvements relating to security alarm systems.
Title (en)
Improvements relating to security alarm systems.
Title (de)
Sicherheitsalarmsysteme.
Title (fr)
Systèmes d'alarme de sécurité.
Publication
Application
Priority
GB 8023674 A 19800719
Abstract (en)
An alarm system uses piezo-electric crystals (2) which when vibrated produce an electrical signal that is used to generate an alarm. Each crystal is in a sensor unit (1) with a latch circuit (13) and an indicator (15), and the threshold at which the alarm triggers latch-on and activates the indicator is adjustable. The latched-on alarm signal in normal use is passed by cable to a remote control module (21), where the actual alarm can be raised. For setting up, the sensor is provided with a periodic power supply from the control module and the alarms (24, 29) are disabled, so that during power-on periods an operator can adjust the sensor threshold without disturbance at the control module. If latching occurs at the wrong level, the subsequent momentary power-off restores the sensor to its primed state, enabling re-adjustment. As well as being responsive to sensor vibration above a set level, an alarm is raised if the cable circuit is broken or short circuited.
IPC 1-7
IPC 8 full level
G08B 13/12 (2006.01); G08B 13/16 (2006.01)
CPC (source: EP)
G08B 13/126 (2013.01); G08B 13/1654 (2013.01)
Designated contracting state (EPC)
BE CH DE FR GB IT NL SE
DOCDB simple family (publication)
EP 0044725 A2 19820127; EP 0044725 A3 19820203; EP 0044725 B1 19860102; DE 3173358 D1 19860213
DOCDB simple family (application)
EP 81303291 A 19810717; DE 3173358 T 19810717