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What is the end of line resistor used for in fire alarm circuits?
Wiki User
∙ 11y ago
An End of Line resistor is used to create a small constant load in a protective zone or loop.
The control panel monitors the current in the loop to detect if the wires have been cut open, or shorted, both of which would be either a "trouble" or "alarm" indication.
Wiki User
∙ 11y ago
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Why you use ELR?
An ELR is terminology used in fire alarm systems. It stands for End of Line Resistor. It is used as a load on individual fire alarm circuits. This load draws a small current that is monitored by the alarm panel. What the panel is monitoring for is open circuits in break glass and bell circuits. If the current is non existent then it means that one of the fire circuits is opened, out of service and non operational. In the alarm panel a relay is de-energized and a trouble alarm is activated to bring attention to the problem. Once the problem is repaired the current again flows through the ELR and the trouble relay resets.
What height to install a fire alarm strobe light?
140cm.from floor line
What does EOL mean in fire alarm systems?
It means 'End Of Line'. In a fire alarm system (usually conventional systems use this technique) a resistor is placed at the very end of the fire alarm circuit at the last device. This device could be a Manual Call point, Sounder, Bell Smoke/Heat detector, strobe etc. This then enables the panel to monitor the circuit. For example, if the resistor is moved or disconnected, then it will show up as a fault on the panel, giving indication the something has gone wrong in the system and that it needs to be fixed. Not all EOL's are resistors though. They can also be capacitors or diodes from what we know.
What all is found in a fire alarm circuit?
There are many possible types of sensors and circuits for fire alarms. If you mean alarm SENSOR circuit, there are often two types to a smoke sensor: a power circuit and a sensor trip circuit. The power circuit supplies power to the sensor for its internal electronics and the sensor trip circuit is a separate pair of wires to the dry contacts that open or close to signal an unusual smoke or heat condition. Various supervisory means are used to determine whether the sensor is properly connected and operating (i.e., no open circuit or short circuit), such as an "end-of-line" (EOL) resistor, or a modulated, query-response or polling signal. At the alarm-panel end, each circuit would have its own connection for a zoned system: one pair for the power and the other pair for the trip circuit. Other types of circuits include heat detectors, manual pull stations, sprinkler flow switches, supervisory tamper switches, and other types of inputs. Output circuits could include lights, sirens, bells, door-closing signals, HVAC control signals (on or off), elevator return commands, remote signalling to monitoring centers, etc. Many residential fire alarm circuits now include one or more wires to connect the otherwise independent smoke alarms so that any one of them will trigger all the others, for better sound penetration of the alarm annunciation.
Symbol for resistor?
-------------[_________]-------------- and put a line on the top of the box
What are the disadvantages of ammeter?
The inconvenience of an ammeter is that it needs to be placed in the line in which you want to measure the current; for production circuits, this is often inconvenient or impossible, so usually the current in a circuit is derived by measuring the voltage drop across a resistor.
Difine what is fixed tapped resistor?
This is usually a resistance wire wound resistor that has a physical connection on the body of the resistor called a tap. It about the same as tapping a water line to attached a hose line to your icemaker.
What is the purpose of a bite alarm?
A bite alarm is used in fishing. It makes a sound when a fish tags the fishing line to alert the fisherman. The bite alarm is on the fishing line in a way that makes a sound when the line moves.
What is the nominal zone circuit voltage in an Addressable Fire Alarm System?
When we discuss fire panels and "nominal" voltage on a circuit we must first determine what type of circuit. Addressable panels can have varied circuits that all perform different funtions. The two most common are Notification Appliance Circuits (NAC), and Signaling Line Circuits (SLC). "Nominal" should be replaced by different terms. "Monitoring voltage", and "Active Voltage" to be substituted for NAC circuits, and "intializing voltage" and "polling voltage" for SLC circuits. Monitoring voltage for NAC circuits vary, however it commonly either between 2-4vdc, or -24vdc. Once a NAC circuit is activated "active voltage" it is almost always 24vdc. "Intializing voltage" on a SLC circuit is caused when a circuit is first plugged into its associated board and the voltage "spikes" to 24vdc then settles at its "polling voltage" at either 24vdc or between 12-18vdc.
What is the difference between 'Class A' fire alarm vs 'Class B' fire alarm wiring?
In class A wiring, 2 wires start from alarm control panel terminal, run through fire sensors / detectors and the same 2 wires run back into the alarm control panel and get connected as 2 more wires thus there would be 4 wires at the panel totally. This would help the control panel monitor all the sensors / detectors even if a loop wire breaks in the middle. In Class B wiring, the control panel is just connected to 2 wires. These 2 wires run through fire sensors / detectors and terminate at end of line resistor. Thus if any wire breaks in between the sensors that are connected to control panel end of wire would only be monitored. The broken wire side of sensors won't be monitored
What products does Notifier by Honeywell make?
The Notifier by Honeywell line of products consists in general of fire detection systems. Notifier makes fire alarms, control panels, gas detection systems, and integrated notification, management, and alarm systems.
The span of transmission line between towers takes the form of?
a resistor
