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2.3.3 24VDC Power Supply Wiring
The main printed circuit card on the chassis
is supplied with 24V DC from the power
supply.
In addition, the operating status of the power
supply is communicated to the main
electronics via a serial link.
The two cables are fitted as standard and
plug onto the main printed circuit card.
Refer to diagrams opposite.
+V DC POWER
0V DC POWER
BATTERY +
BATTERY –
COMMS LEAD
DC POWER LEAD
To remove the chassis assembly, disconnect
the two cable plugs from the chassis card
itself. There is no need to remove the wiring
from the power supply.
Note: If wired correctly, the DC Supply plug is
reversible without presenting a danger of
polarity reversal.
OBSERVE POLARITY OF CONNECTIONS!
SUPPL
Y
PSU
Comms
ZONE
- 2 -
ZO N E
- 3 -
S
N
D
R
-
1
-
S
N
D
R
-
2
-
S
-
SERIAL COMMS DC POWER
2.3.4 External Wiring
General Notes
Install cables suitable for the application and
degree of fire protection required.
All input and output circuits are SELV type.
To maintain electrical integrity of the SELV
wiring on the output lines all SELV wiring
should be segregated from the LV mains wiring
and be wired using cable with insulation
suitable for the application.
NB: Minimum / Maximum cable size for all
connections is limited to 0.35mm² / 2.5mm² (22-
14AWG).
Any specific recommendations are detailed
below for each type of circuit.
Refer to the Recommended Wiring Routing
section for details of cable routing within the
enclosure.
All electrical wiring installation work should be
carried out in accordance with the code of
practice applicable in the country of installation.
To minimise the effects of EMC interference all
data wiring circuits should be wired with a
twisted pair of conductors with a cross sectional
area suitable for the loading conditions.
In areas where cabling may come into contact
with high frequency interference, such as
portable radio transceivers etc. the output
wiring cable should be of a twisted pair
construction within an overall screen. The
screen should be terminated to one of the
dedicated earth studs available in the panel.
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