(Conventional Fire Alarm Control Panel
- Monitoring and alarm for each zone (zone). Each zone includes some or all input devices (detectors, fire alarm buttons) in an area or a floor of a building.
– It is not possible to know exactly which device triggered the fire alarm or malfunctioned in the Zone. Because many devices are installed in the same area, when a fault occurs, the center can only generalize and display the problem area, but not the exact location of each detector. each fault location. This limits the processing and monitoring capabilities of the system. The fire alarm panel has one or more channels (zones). Some fire alarms allow expansion of zone capacity while others do not, which limits usefulness when a facility wants to expand its fire alarm system. Each zone circuit uses 2 or 4 wire cores, so the number of signal wires connected to the fire alarm center is a lot. This makes wiring complicated and expensive for multi-zone fire alarm systems.
– Fire alarm center type usually uses 1 or more electrical circuits connected to initiating devices (detectors, push buttons) in parallel wiring, each of these circuits is called a signal circuit.
– The signal circuit is connected to a mixture of initiating devices in the same protection area. The normal, abnormal or alarm condition of the displayed area is visible on the annunciator of the fire alarm panel. The display face can be LED or LCD.
– On the display surface is usually written the name of the protected area (zone). It is for this reason that we are used to incorrectly calling the signal circuit of the fire alarm center the zone.
– To control the signal line, a device (usually a resistor) is installed at the end of the signal line, parallel to the furthest device on the signal line, this device is often called a line end device or is the end-of-line resistor. This type of wiring is called Class B type.
– Normally on the signal circuit, there will be an electric current passing through the end device of the line back to the fire alarm center. If the line is broken, the current will be reduced and the center will signal the fault of that circuit
– In order for the monitoring function to be effective, devices on the signal line must not be wired in a branching fashion.
– Some fire alarm panels allow connection of signal lines in a loop (Class A) without the use of resistors at the end of the line. This method is very effective in monitoring and maintaining system operation in the event of a wire break, but often when choosing Class A wiring, the zone capacity of the cabinet is halved.
– The fire alarm panel has one or more alarm circuits (outputs). Sound or light alarm devices are installed in parallel on the alarm circuit. The alarm circuit can be programmed to alarm according to one or a group of signal circuits (zones) or general alarms.
– Some hubs allow the installation of end-of-line equipment for Class B alarm control or Class A looping.
(Addressable Fire Alarm Control Panel
– Addressable fire alarm system has superior features than conventional fire alarm system, with large information capacity, flexible control ability.
– Monitoring, fire alarm and control by each device (address). Addressable devices can be detectors, fire alarm buttons, horns, lights and modules to communicate with conventional and peripheral devices.
+ The capacity of the addressable fire alarm center is determined by the number of SLC circuits (Signaling Line Circuits) and the number of addressable devices that can be installed on each SLC circuit. The SLC circuit provides power, communication and monitoring of all devices connected to it. Each SLC circuit can accommodate several dozen to several hundred addressable devices, depending on the manufacturer. Each SLC loop circuit can contain many types of addressable devices. Devices are usually (non-addressable) connected to the loop via addressing modules. Each addressable device on the SLC loop has a unique address when installed. Monitoring is done from the control center by polling the devices in the SLC loop.
+ The fire alarm situation is displayed by point (address), allowing to quickly find the fire. Many systems support flexible I/O programming to connect input devices to outputs.
– Addressable fire alarm panels use one or more SLC (Signaling Line Circuits) signaling circuits, commonly known as loops. Depending on the protocol used, the SLC circuit can monitor or control hundreds of devices.
– Some protocols allow the installation of a mixture of probes and I/O modules on the same SLC circuit, while some protocols only allow a maximum of 50% of the detector/transducer capacity and 50% for the I/O module.
– The fire alarm center monitors the devices on the SLC circuit in a poll manner, each time polling a few or more devices depending on the manufacturer. Large fire alarm systems can use multiple SLC circuits.
– Each device installed on the SLC circuit has its own address, so the fire alarm panel knows the status of each individual device connected to it.
– Different from conventional fire alarm panels, addressable fire alarm centers allow the connection of both the initiating device (input) and the control device (output) in common on the same SLC loop signal circuit.
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