Relay is a dry contact relay to control a power supply remotely. The relay’s dry contacts are electrically isolated to the power supply circuit of the device. Relay can be used in both low-voltage and domestic power grids. The device features two types of protection: voltage and temperature.
Only a qualified electrician or installer should install Relay.
The relay can control the power supply of electrical appliances connected to the circuit via the Ajax apps, automation scenarios, via relay function button, or by pressing Button.
Relay is connected to the Ajax security system via the Jeweller radio protocol. The communication range is up to 1,000 meters in an open space. The device works only with Ajax radio signal range extenders and hubs.
- Antenna.
- Power supply terminal block.
- Terminal block to connect appliances.
- Function button.
- LED indicator.
- PS IN terminals — “+” and “-” connection terminals of a 7–24 V⎓ power supply.
- Relay terminals — output potential-free terminals of Relay contacts to connect appliances.
Operating principle
Relay is a dry contact relay to control a power supply remotely. The relay is installed in the electrical circuit gap to control the power supply of devices connected to this circuit. Relay is controlled via the device function button (by pressing and holding it for 2 seconds), the Ajax app, Button, and automation scenarios.
Relay is powered by a 7–24 V⎓ power supply. Recommended power supply voltages: 12 V⎓ and 24 V⎓.
Relay features potential-free (dry) contacts. Dry contacts are electrically isolated to the relay’s power supply. Thus, this device can be used in low-voltage and household networks, for example, to simulate a button, a toggle switch, or to control water shut-off valves, electromagnetic locks, irrigation systems, gates, barriers, and other systems.
Relay commutes one single pole of the electrical circuit. The relay can operate in bistable or pulse mode. In pulse mode, you can set its duration: from 0.5 to 255 seconds. The operating mode is selected by users or PRO with admin rights in the Ajax apps.
A user or a PRO with admin rights can select the normal state of the relay contacts:
- Normally closed — the relay stops supplying power when activated and resumes when deactivated.
- Normally open — the relay supplies power when activated and stops when deactivated.
Relay measures supply voltage. This data, along with other operating parameters of the relay, is available in the device States. Relay states update frequency depends on the Jeweller or Jeweller/Fibra settings. The default value is 36 seconds.
Relay maximum resistive load is 5 A at 36 V⎓ and 13 A at 230 V~.
Automation scenarios
Ajax’s scenarios offer a new level of security. With them, the security system not only notifies about threats, but also actively resists them.
Scenario types with Relay and examples of usage:
- By alarm. Lighting is switched on when an opening detector activates the alarm.
- By security mode change. The electric lock is automatically blocked when the object is armed.
- By schedule. The irrigation system in the yard is switched on according to the schedule at the specified time. Lighting and TV are switched on when the owners are away, so the house doesn’t seem empty.
- By pressing Button. Switching on night lighting by pressing the smart button.
- By temperature. The heating is turned on when the temperature in the room is lower than 20°C.
- By humidity. The humidifier is switched on when the humidity level drops below 40%.
- By CO₂ concentration. Supply ventilation is turned on when the carbon dioxide concentration level exceeds 1000 ppm.
Scenarios by the Button pressing are created in the Button settings, scenarios by the humidity and CO₂ concentration levels are created in the LifeQuality settings.
Control via the app
In Ajax apps, you can switch on and off electrical appliances connected to an electrical circuit controlled by Relay.
Click the toggle in the Relay field in the Devices 
menu: the state of the relay contacts will change to the opposite, and the connected electrical device will switch off or on. This way, a security system user can remotely control the power supply, for example, for lighting or an electric lock.
When Relay is in pulse mode, the toggle will change from on/off to pulse.
Protection types
Relay has two types of protection that operate independently: voltage and temperature.
Voltage protection: is activated if the relay supply voltage exceeds the range of 6.5–36.5 V⎓. Protects Relay from voltage surges.
Temperature protection: is activated if the relay heats up to temperatures above 65°C. Protects relay from overheating.
When voltage or temperature protection is activated, the power supply through Relay is stopped. Power supply resumes automatically when voltage or temperature parameter returns to normal.
Jeweller communication protocol
Relay uses the Jeweller radio protocol to transmit alarms and events. This wireless protocol provides fast and reliable two-way communication between the hub and connected devices.
Jeweller supports block encryption with a floating key and authentication of devices at each communication session to prevent sabotage and device spoofing. The protocol involves regular polling of devices by the hub at intervals of 12 to 300 seconds (set in the Ajax app) to monitor communication with all devices and display their statuses in the Ajax apps.
Sending events to the monitoring station
The Ajax security system can transmit alarms and events to the PRO Desktop monitoring app as well as the central monitoring station (CMS) via SurGard (Contact ID), SIA DC-09 (ADM-CID), ADEMCO 685, and other proprietary protocols.
With PRO Desktop, the CMS operator receives all Relay events. In other cases, a monitoring station receives only notification about connection loss between Relay and the hub (or range extender).
The addressability of Ajax devices allows sending not only events but also the type of the device, its assigned name, and room to PRO Desktop/CMS (the list of transmitted parameters may vary depending on the type of the CMS and the protocol selected for communication with the CMS).
The device ID and zone number can be found in the Relay States in the Ajax app.
Selecting the installation spot
A 39 × 33 × 18 mm device is connected to the circuit gap. Relay dimensions allow installing the device into the deep junction box, inside the electrical appliance enclosure, or in the distribution board. A flexible external antenna ensures stable communication. To install Relay on a DIN rail, we recommend using a DIN Holder.
Relay should be installed in a place with a stable Jeweller signal strength of 2–3 bars. To roughly calculate the signal strength at the place of installation, use a radio communication range calculator. Use a radio signal range extender if the signal strength is less than 2 bars at the intended installation location.
If you install Relay outdoors, place the device in a sealed box. This will protect against the condensation, which can damage Relay.
Do not place Relay:
- In rooms where the humidity and temperature indicators do not correspond to the operating parameters. This may damage the device or cause it to malfunction.
- Near sources of radio interference: for example, at a distance of less than 1 meter from a router. This can lead to a loss of connection between Relay and the hub (or range extender).
- In places with low or unstable signal strength. This can lead to a loss of connection between the relay and the hub (or range extender).
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