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How to manage access control system (ACS) using Ajax Relay


⚠️ Relay installation is done by a qualified electrician only! Regardless of the type of electrical circuit in which the device is placed.


Relay can be used to block magnetic card-mediated access to the premises when the security system is armed. And also in the manual mode by controlling the power supply to the magnetic reader of the access control system (ACS).

👆🏻 The relays are used to open and close electrical circuits and can be used to control the power supply to electrical appliances. Ajax Relay — wireless low-tension dry contact relay. It is controlled remotely via the Ajax application. It can react on the “night mode”, as well as to arming and disarming of the security system.

How does ACS work

When a key card is brought close to the magnetic reader, the signal is transmitted to the ACS controller, which sends a pulse or breaks the power supply circuit of the lock. The latter is followed by the door opening for the time specified in the access control settings.

Schematic diagram of connecting the Relay to a magnetic reader

👆🏻 In order to connect according to the schematic diagram, you must have an external 12/24 V power source!

  1. Connect the power supply to the power terminals of the relay.
  2. Connect the “+” terminal of the power supply to one of the relay contact terminals, and the “+” terminal of the magnetic reader to the other contact terminal of the relay.
  3. Connect the “–” terminal of the magnetic reader to the “–” terminal of the power source.

This connection scheme enables the Relay to control the power supply to the magnetic reader.

⚠️ Take care in advance of the feasibility of disconnecting the ACS in the case of emergency!

Magnetic Reader Power Management

Relay Setup

  1. Go to the Devices tab.
  2. Enter the Relay menu, go to Settings (⚙️) and select Bistable operation mode, and also set Initial state of contact terminals: Normally closed.

Manual control of the ACS

Click the switch in the Relay line — the state of the relay contact terminals will become the opposite.

When the Relay contact terminals are closed, the power is supplied to the reader and the door can be opened with a key card. When the contact terminals are opened, the reader is left without power and the door remains closed.

Automatic control of the reader power supply (when the state of the security system changes)

In the relay settings, select the response to arming / disarming as in the screenshot:

Upon disarming of the system

  • The Relay closes and supplies current to the magnetic reader — the magnetic reader is turned on, the door opens only when the key card is presented.

Upon arming of the system

  • The Relay contact terminals are in the open state stopping the power supply to the reader — the door is closed and not unlocked by applying the key card to the magnetic access control system reader until the system is disarmed or until it is manually turned on.

In order to open/close the lock when the night mode is used, enable the React to night mode option.

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