| 摘要 |
<p>A low power local alarm indicating system for interconnectable detectors enables a viewer to, after the fact, determine which detector or detectors had previously gone into a local alarm. An alarm latch (22-ia) such as a bistable multivibrator circuit, is set each time the respective detector goes into a local alarm. Subsequently, if the detector's test switch (30-i) is activated, a local alarm visual indicator is provided. In a disclosed embodiment, the indication is provided by the blinking of a light emitting diode (28-i) on the detector, for a predetermined interval. Where multiple detectors are interconnected, each detector that goes into alarm not only sets its local alarm latch (22-ia) and emits a local alarm, it also generates an interconnect alarm signal to the remaining interconnected detectors. The interconnected detectors go into alarm at least for as long as the interconnect signal is present. If any detector in interconnect alarm receives sufficient local input to go into a local alarm, the respective smoke latch (24-i) will be set even in the presence of an interconnect input. <IMAGE></p> |
