In an emergency you may wish your fire alarm system to perform a number of automated tasks – this could include grounding a lift or closing doors. To do this you will require fire alarm relays, devices which allow the automation of certain functions.
What is a relay?
A relay is a simple electromechanical switch. While we use normal switches to close or open a circuit manually, a relay is also a switch that connects or disconnects two circuits. But instead of a manual operation, a relay uses an electrical signal to control an electromagnet, which in turn connects or disconnects another circuit.
What are relays used for in fire alarm systems?
Relays are often used on fire systems for;
- Releasing door holders.
- Plant shut-down.
- Sprinklers.
- AOV.
- Linking Panels.
- Access Control.
- Signalling ARC.
How are relays used in fire alarm systems?
Relays can be used to control voltage feeding a particular supply and either apply or drop voltage in the event of a fire activation.
Relays can be used to signal to monitored inputs, these inputs would monitor a nominal EOL resistance and in the event of a fire alarm activation would switch to pick up the trigger value resistance.
Relays can also be used to signal a simple NO/NC contact.
