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Monitoring and signalling system

  • US 4,284,849 A
  • Filed: 11/14/1979
  • Issued: 08/18/1981
  • Est. Priority Date: 11/14/1979
  • Status: Expired due to Term
First Claim
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1. In a monitoring and signalling system, apparatus comprising:

  • sensor means arranged to monitor the occurrence of an associated activity and operative in response to monitoring the occurrence of the activity to produce a signal indicative of the occurrence of the activity;

    sensor activity recording means for recording sensor activity data representing a count of the number of times the sensor means has monitored its associated activity and produced signals, said data having a first value when the sensor means has not monitored its associated activity and has not produced signals and a different value when the sensor means has monitored its associated activity and produced signals;

    processing means operative when signals are produced by the sensor means to receive and process said signals and in response to processing each signal to change the value of the sensor activity data in the sensor activity recording means to record the occurrence of the activity monitored by the sensor means, whereby the sensor activity recording means maintains a continuing tally of the number of times the sensor means has monitored its associated activity and produced signals;

    timing means operative on a regular basis to cause the existing sensor activity data recorded by the sensor activity recording means to be read out therefrom; and

    sensor data processing means arranged to receive and process sensor activity data read out from the sensor activity recording means and operative whenever the sensor activity data has its first value indicating that the sensor means has not monitored its associated activity and produced signals since the last readout of sensor activity data from the sensor activity recording means to produce an output condition indicative of this fact.

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