METHOD FOR MONITORING OF CONDITION AND INTEGRITY OF LOOP CIRCUIT Russian patent published in 2009 - IPC G08B17/00 

FIELD: physics, alarm.

SUBSTANCE: method may be used in systems of fire and fire-security alarm, and is intended for monitoring of fire and security loop circuit condition, and also for monitoring of loop circuit integrity. To monitor condition of fire alarm boxes with the help of stated method, level of basic DC voltage is supplied to loop circuit with connected fire alarm boxes, which is used to generate multi-level information signal that varies its level in case of actuation of each fire alarm box connected into loop circuit, and which makes it possible to further discriminate the level that corresponds to actuation of single fire alarm box from the level in actuation of two and more fire alarm fire boxes and intended for multidigit analog-digital conversion, to which total voltage of loop circuit is exposed. In order to monitor integrity of the loop circuit itself, stated method provides for connection of active terminal device in the end of loop circuit, which, during arrival of basic DC voltage, generates signal of integrity in the form of sequence of periodically repeating single control pulses, period of which is identified bases on condition of maximum economy of electric energy in the loop circuit from one side and condition of permissible time of truthful definition of loop circuit integrity from the other side, and their duration is selected as shorter that maximum duration of pulses at the inlet of receiving-control instrument, not taken into account as alarm condition, on the one side, and on the other side higher than period of loop circuit voltage measurement by receiving-control device.

EFFECT: suggested method is more efficient by energy expenditures for process of monitoring.

10 dwg