The SR2 has an two on-board 12V Alarm relays, operating in parallel, which can be connected to a buzzer or beacon and one, mains, Power Failure relay.

•Their functions and connections, via JP2, are outlined below:

Pin

Connection

Description

1

Relay 1 N/O

The first alarm relay is normally open and closes, with a nominal 12V appearing on Pin 1, in the event of any Channel Alarm from the assigned Sensor Groups(s) in EMS.

•This relay is suitable for driving Alarm Beacons.

•It is fused via F1.

2

Relay 1 GND

3

Relay 2 Common

This is a changeover relay responding to alarms in the software and has volt free fail-safe operation.

•When no alarms exist, pins 3 and 5 are connected.
The relay coil is energised at power on, so that the normally closed connection is open and the normally open connection is closed, connecting pins 3 and 5.

•When an alarm exists, pins 3 and 4 are connected.
In the event of any Channel Alarm in the assigned Sensor Groups(s) in EMS or an SR2 power failure (both mains and backup battery down), power is removed from the relay coil, connecting pins 3 and 4.

4

Relay 2 NC

5

Relay 2 NO

6

Relay 3 Common

This is a changeover relay indicating the mains power state of the SR2.

•The Power Fail relay coil is energised at power on, assuming power is present.

➢The normally closed connection is open and the normally open connection is closed; pins 6 and 8 are connected.

•In the event of mains power fail, power is removed from the coil and pins 6 and 7 are connected.

7

Relay 3 NC

8

Relay 3 NO

 

•DIP Switch 3 sets which alarms will open the relays:

ON

Network Fail Alarm:

The relays will respond to all Channel Alarms from Sensors in the assigned Sensor Groups(s) or a network communications failure (no network communications for 60 minutes).

➢When the network communications are restored, the relay will be reset.

OFF

(default)

Normal Operation:

The relays will respond to all Channel Alarms from Sensors in the assigned Sensor Groups(s).