EP 0121521 B1 19880518 - SELF-CONTROLLED AND SELF PROTECTED ALARM DEVICE
Title (en)
SELF-CONTROLLED AND SELF PROTECTED ALARM DEVICE
Publication
Application
Priority
FR 8216842 A 19821006
Abstract (en)
[origin: FR2534396A1] The invention relates to an electronic self-controlled alarm device. Set off conditions of the alarm are periodically established by varying alternatively into plus and into minus the resistance of the detection loop wherein are arranged detectors comprising a resistance in series with contacts. A self protection capacitive loop controls a square signal generator which produces: a) short pulses having the frequency f (self-protection), b) rectangular signals having the frequency 2f (self-control), verified at the terminals of the time delayed alarm relay. The cut-off or the shorting of a detector or of the detection loop sets off the alarm. The absence of self protection pulses or an incorrect frequency of the self-control signals sets off a fault warning device. The invention applies to alarm, surveyance, control, measurement apparatus and installations used for the protection against burglary and fire, in the industry, for the medical surveyance, etc.
IPC 1-7
IPC 8 full level
G08B 13/22 (2006.01); G08B 29/04 (2006.01)
CPC (source: EP)
G08B 13/22 (2013.01); G08B 29/04 (2013.01); G08B 29/046 (2013.01)
Designated contracting state (EPC)
AT BE CH DE GB LI LU NL SE
DOCDB simple family (publication)
FR 2534396 A1 19840413; FR 2534396 B1 19860516; DE 3376702 D1 19880623; EP 0121521 A1 19841017; EP 0121521 B1 19880518; WO 8401456 A1 19840412
DOCDB simple family (application)
FR 8216842 A 19821006; DE 3376702 T 19830929; EP 83902995 A 19830929; FR 8300194 W 19830929