The Magnetic Door Lock

How to Use the Magnetic Lock in an Access Control System

Controlling the Mag-Lock
Controlling the Mag-Lock

The magnetic door lock is a unique lock requiring special handling to ensure safety. Since the mag lock holds the door shut and prevents both egress and ingress, additional devices must be present to allow people to exit.

This article describes how to use the magnetic lock in your access control system.

Wiring the Magnetic Lock

The locking mechanism of the magnetic lock is an electromagnet and an armature plate to secure the door.  The electromagnet is attached to the door frame while the armature plate is attached to the door. 

The door access controller or reader-controller provides an electric current that passes through the electromagnetic. The current goes through a winding that causes a magnetic attraction to the armature plate holding the door closed. The magnetic strength can provide over 1500 lbs. of holding force. Locks with higher magnetic force can secure an outer door, while lower force locks can be used to secure inner doors.

The electromagnet is wired to the door controller. The diagram below shows an example of lock wiring, but additional wiring is required to ensure safe egress.

Access Control with Mag Lock
Access Control Using a Mag-Lock

Installing the Mag Lock

Magnetic Lock
Magnetic Lock

The magnetic lock is mechanically easy to install since it consists of two parts. The “plate” attaches to the door, and the mag lock mechanism attaches to the frame.

The plate and electromagnet must be aligned so that when the door closes, the two parts of the lock come together precisely. Any offset will reduce the holding power of the lock.

Wiring the Electric Lock for Safe Exit

Additional components and wiring are required to ensure that a person can exit the area, especially in an emergency. The local municipalities and fire marshals define the exit devices needed.

The REX Button Opens the Door

The Request to Exit Button (REX) is always required to make it easy for anyone to exit a controlled area. The button is connected to the controller or wired to the power line of the mag lock.

Motion Detector Automatically Opens the Door Lock

In addition to the REX button, the motion detector provides an additional exit method. This is a hands-free method of exiting. It also provides an extra safety feature that activates even if the person can’t see the button. This is a required addition in some municipalities.

Push-Bars Release the Mag-Lock

Push-bars (or Crash-Bars) can also be used to release the mag lock. These pressure-sensitive bars are mounted to the door and wired so that the electric switch removes current to the mag lock and allows the door to open.

Wiring the Mag Lock for Fire Alarm Control

Many municipalities and safety officers require that all the doors be opened if a fire alarm occurs. There are several ways to ensure that the door opens in a fire.

Using a Relay to Control Power to Electric Lock

In this example, the fire alarm box opens a relay controlling all the power. The 12 VDC power to the lock originates from a central power supply.

Power control using relay fire alarm box
Power Control to the Electric Lock

Connecting the Fire Alarm Using a Power Over Ethernet Adapter

Instead of a central relay, this power control method uses a special electronic box designed for IP door readers.

Door Access and Fire Control with Altronix-PoE
Door Access and Fire Control Using Altronix-PoE

It uses the Altronix Entrada2DMK adapter kit. The kit includes two adapters; one is placed near the fire alarm box and the other near the IP door reader and electric lock.

The device-side adapter provides power to the IP door reader and the electric lock. When a fire alarm signal is detected, the door is unlocked. This system is very flexible, so you can select a normally open or normally closed trigger from the fire alarm box.  A dedicated network cable is required between the transmitter and receiver adapters. A number of receivers can be daisy-chained to one of the receivers connected to the transmitter.

Controlling Access Readers Using a Power Supply Controller

Power to all the locks can be controlled through a power control box. The Altronix Power Controller AL125UL is an example of this type of power control. Other controllers include UPS battery backup.

Door Access and Fire Control with Altronix-Power
Door Access and Fire Control with Altronix-Power

The power controller includes relays that control the power that is supplied to all the locks. When the fire alarm unit provides a signal indicating an alarm condition, the power to all the electric locks is removed. When power is lost, all the magnetic locks open..

Door Access Magnetic Door Lock Control Summary

The magnetic door lock is one way of locking the door in an access control system. Special circuits are required to ensure that the door can be opened in an emergency. Various wiring solutions, such as the REX button, push-bars, motion detectors, and fire control signals, provide quick egress.

Don’t hesitate to contact us at 800-431-1658 in the USA or 914-944-3425 everywhere else to learn more about access control, or use our contact form.