Method and apparatus for inspecting a danger alarm system
First Claim
1. A method for inspecting a plurality of alarm units in a danger alarm system having a central station connectible to each of said alarm units and each of said alarm units emitting an alarm signal during normal operation upon the occurrence of a danger condition in an area monitored by said alarm unit and emitting an inspection signal of shorter duration than said alarm signal during an inspection signal of said system, said central station having an alarm display means and an inspection display means, comprising the steps of:
- cyclically connecting said alarm units to a signal evaluation means at said central station;
evaluating and displaying at said inspection display means a first report received by said central station from an alarm unit being inspected after connection to said signal evaluation means;
automatically resetting said alarm unit being inspected after a selected time delay to normal operation after said first report has been received;
storing said inspection report to indicate said alarm unit has been inspected; and
maintaining a path from an alarm unit being inspected to said alarm display means during said inspection such that an alarm signal received at said central station during said inspection is not suppressed and is evaluated by said central station, and is displayed by said alarm display means if danger conditions exist after said time delay.
1 Assignment
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Accused Products
Abstract
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.
24 Citations
15 Claims
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1. A method for inspecting a plurality of alarm units in a danger alarm system having a central station connectible to each of said alarm units and each of said alarm units emitting an alarm signal during normal operation upon the occurrence of a danger condition in an area monitored by said alarm unit and emitting an inspection signal of shorter duration than said alarm signal during an inspection signal of said system, said central station having an alarm display means and an inspection display means, comprising the steps of:
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cyclically connecting said alarm units to a signal evaluation means at said central station; evaluating and displaying at said inspection display means a first report received by said central station from an alarm unit being inspected after connection to said signal evaluation means; automatically resetting said alarm unit being inspected after a selected time delay to normal operation after said first report has been received; storing said inspection report to indicate said alarm unit has been inspected; and maintaining a path from an alarm unit being inspected to said alarm display means during said inspection such that an alarm signal received at said central station during said inspection is not suppressed and is evaluated by said central station, and is displayed by said alarm display means if danger conditions exist after said time delay. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for inspecting a danger alarm system having a plurality of alarm units respectively connected in series in a plurality of alarm lines, a central station, and a multiplexer means for cyclically connecting said alarm lines to said central station, said alarm units emitting an alarm signal upon the occurrence of danger conditions in an area monitored by said alarm unit, and emitting an inspection signal of shorter duration and said alarm signal during an inspection of said system, said apparatus being disposed at said central station and comprising:
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an alarm display means; an inspection display means; and an evaluator means interconnected between said multiplexer and said alarm display means and said inspection display means for directing signals received from said alarm units during an inspection to said inspection display means, said evaluator means having a path during said inspection from said alarm unit being inspected to said alarm display means such that no suppression of alarm signals received from said alarm units during said inspection occurs. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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Specification