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Break-glass detectors are suitable for fixing on standard window glass. The break-galss detector requires 12 V dc regulated supply, which is provided by the control panel. All devices powered in such a manner are generally called auxiliary devices and all the detections units which follow in this section fall into that category. The 12v power terminal to which they are connected is often reffered to as the auxillary.
Structure and working
The break-glass detectors is capable of detecting any kind of glass break in the frequency which lies in the region of 150 khz. Since break-glass detectors are secured in position by adhesive and do not generate external energy, any number of detectors may be fitted on the same window pane without any risk of interaction.
Break-glass detectors use a fail safe feature, having normally closed construction, with the output connected into an anti-tamper 24-hour guard loop provided by the control panel. Since the loop is permanently active, an audible response will be made by the panel even if the detector goes into alarm with the control panel in the off condition. Thus, a latching LED indicator can identify the detector which has actuated the alarm condition.
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