2.3
ALARM RELAY
NOTE: The alarm relay is a 3 contact changeover arrangement that is
isolated (volt-free). This relay is normally energised, and switches off when
the alarm is triggered, or in the case of power failure. It may be used to
trigger an external bell, warning lamp, or digital communicator (telephone
dialler).
If an external device is used connect the alarm as appropriate, according to
the diagram in the next section.
2.4
POWER CONNECTIONS AND WIRING DIAGRAM
NOTE: This device should be properly earthed. Flexible wires simplify
connection to the terminals. All connections should be secure and adequately
tightened. It is good practice to keep mains cables away from sensor cables
and other low voltage signal cables.
Connect the supply to the unit, as per diagram below, using the appropriate
input voltage according to the application.
Alarm
Relay
L E N + -
Connect as appropriate
to application
Mains
Input
220 - 240V AC
DC
Input
20 - 28V DC
Sensors
CH1 CH2
SWITCH OPEN = DOOR OPEN
SWITCH CLOSED = DOOR CLOSED
D
o
o
r
max
5A
PC
2.5
BATTERY
The battery supplied is a 9V PP3 nickel metal hydride rechargeable battery
and is attached to the lid of the terminal compartment, but not plugged in.
This should be plugged in after installation. This battery is not essential for
the system operation, but is used in the case of power failure, thereby
continuing to log the two input temperatures for 6 - 7 hours, and maintaining
the system clock.
If the power cut takes longer and the battery is discharged, the clock must be
set when the power supply is re-established. The system parameters remain
intact.
It is recommended that the battery is changed every 12 months, in order to
maintain good power failure operation. When replacing, ensure that the type
of battery used is as specified - only a rechargeable PP3 battery should be
used directly, as the battery is charged from the unit.
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