| 摘要 |
<p>A method of and apparatus for monitoring for incipient hyper-sensitivity of any detector station in an alarm system comprising a plurality of detector stations in a spur loop-ring between an alarm unit and an end-of-line unit. The detector stations are each provided with means for triggering an alarm, and with self-monitoring means for detecting any excessive increase in sensitivity due to contamination of a detector, which means initiate a fault indication, thus enabling remedial action to be taken before a false alarm is given.</p> |
