Fitting Fixture and Services

Fittings, Fixtures And Services 3(1+2)

Lesson 07 : Safety fittings-locking system and remote control

Burglary protection

Burglar Alarm System
A burglar alarm control panel is a wall-mounted unit where the detection devices and wiring of the alarm are ultimately connected and managed. These include devices such as bells, sirens, door contacts, motion detectors, smoke detectors, etc. The simplest type of burglar alarm control consists of a single relay. In this type, the sensor circuit (called the loop in industrial terminology) holds the relay energized. Since the path for the loop goes through a set of contacts which are normally open (when the relay is restored they are open, when the relay is energized they are closed), when the loop opens. A second set of contacts on the relay, are normally closed (when the relay is restored they are closed, when the relay is energized they are open) is used to operate the enunciator, usually a bell. These controls and a closely related dual-relay design are still widely used in stand-alone applications, powered by lead-acid batteries.The most common security sensors are used to indicate the opening of a door or window or detect motion via passive infrared (PIR). Some systems serve a single purpose of burglar or fire protection. Combination systems provide both fire and intrusion protection.