Method and apparatus for inspecting a danger alarm system

摘要

A method and apparatus for inspecting a danger alarm system, such as a fire alarm system, having a plurality of discrete alarm units which are connected to a central station having a means for cyclically sampling and connecting the alarm units to a like plurality of evaluators permits the alarm units to be connected individually or in groups to an inspection display without suppressing the display of an actual alarm signal which may be received during the inspection. A first report of an alarm unit to be inspected is evaluated as an inspection report and an actual alarm report from the same alarm unit arriving after the inspection report is evaluated and displayed as an alarm report. Given alarm units which emit multi-level or analog signals, the alarm unit signals are evaluated in the central station with two threshold circuits, the evaluator at the central station being switched during an inspection to a less sensitive state and the inspection signals being evaluated by a lower threshold stage and a true alarm signal which may occur during an inspection being evaluated as such by an upper threshold stage.