How a Relay Works and Using Them in a Security System

[@paulhawkins9187]

So when the coil energizes ( eg. pull the fire alarm initiation ) , does that cause the circuit to open, releasing the door maglock?

[@ADIGlobalDistribution]

Hi, that depends on if you have used the Normally Open terminals or the Normally Closed terminals. You should be able to uses your multimeter to check, Apply power and see which terminals are closed or short. Of course you also have a Mag lock that may be Fail secure or Fail safe so again removing power may lock the door or the opposite.
Hope that helps