Abstract: A power supply for providing excitation to notification appliance circuits (NACs) in fire alarm applications meets revised national and international requirements for both NAC drive and auxiliary load drive tasks with a single circuit configuration. The requirements stipulate ability to tolerate inrush when activating strobe lights and horns of ten times the nominal output, while limiting short-circuit drive in AUX mode to eight amperes after five seconds. The novel power supply improves on the requirements, first by continuously testing for overcurrent NAC status and signaling faults in real time, and second by shutting off AUX drive in event of a short and retrying periodically without a requirement for manual reset. Thus testing for wiring errors is rendered safer and nondestructive, and correction of a wiring error can be quicker.

Abstract: There is provided an alarm system for detecting and warning of the presence of alarm and trouble conditions in a plurality of zones. The system comprises a loop controller having supply lines extending to the plurality of zones and a module connected to the supply lines within each zones. The module includes means for detecting whether communication between the module and the loop controller has been disrupted. If an alarm condition occurs in a particular zone, the module initiates communication of the alarm condition to the loop controller. During normal operation, when communication with the loop controller has not been disrupted, the module has shared operations with the loop controller to determine whether an alarm condition exists. When communication with said loop controller has been disrupted, temporarily or otherwise, the module continues to operate independently of the loop controller and determines whether an alarm condition exists.

Abstract: There is provided an alarm system for detecting and warning of the presence of alarm and trouble conditions in a plurality of zones. The system comprises a loop controller having supply lines extending to the plurality of zones and a module connected to the supply lines within each zones. If an alarm condition occurs in a particular zone, the module initiates communication of the alarm condition to the loop controller. The system also includes means for variably controlling a specific personality of the module, such as a microcontroller, so that the module functions selectively in a variety of specific ways. The means for variably controlling includes means for selectively storing configuration data, such as an EEPROM, in the module to define the specific personality.

Abstract: A ground fault detection scheme uniquely incorporated within a distributed intelligence, fire alarm and detection system, such that detection is achieved with location identification. The modules (and transponders) of the system collaborate with the loop controller in performing ground fault operations to determine precise existing ground conditions at the module locations.