EP 0052220 B1 19860723 - METHOD AND DEVICE FOR MEASURING THE RESISTANCE IN A SIGNALLING LINE
Title (en)
METHOD AND DEVICE FOR MEASURING THE RESISTANCE IN A SIGNALLING LINE
Publication
Application
Priority
DE 3043357 A 19801117
Abstract (en)
[origin: EP0052220A2] 1. A method of measuring the resistance in a signalling line of a hazard alarm system, the individual signalling lines (M, L) of which commence from a central control unit (Z) and are each provided with series-connected alarms (M1 to Mn) having a variable resistance value, where a voltage source (UV) is connected to the signalling line (ML) via a series resistor (RV) and a capacitor (C) is charged by a constant current in dependence upon the resistance value (RX) of the signalling line (ML), characterised in that the capacitor (C) is charged by a separate constant current source independent of the current in the signalling line and its charging time (T), which is proportional to the resistance value (RX), is measured in digital form by means of a counting device and a clock pulse generator (TG), the capacitor being discharged before measurement commences.
IPC 1-7
IPC 8 full level
G08B 25/00 (2006.01); G08B 25/01 (2006.01)
CPC (source: EP)
G08B 25/018 (2013.01)
Designated contracting state (EPC)
AT BE CH FR GB IT LI NL SE
DOCDB simple family (publication)
EP 0052220 A2 19820526; EP 0052220 A3 19820929; EP 0052220 B1 19860723; AT E20982 T1 19860815; DE 3043357 A1 19820603; DE 3043357 C2 19850117
DOCDB simple family (application)
EP 81108038 A 19811007; AT 81108038 T 19811007; DE 3043357 A 19801117