7
INM F890 Rev 1
5 .2 Power A and Power B
Power A supplies Power Module A and Power B supplies Power Module B. Each module
provides DC power to all eight segments - see Figure 4. DC supply connections are
as follows:
Power A
Power B
Pin No.
Connection
Pin No.
Connection
1
+ve
3
+ve
2
-ve
4
-ve
Cable lengths on the Power connectors should not exceed 30m nor be routed outside
the building.
5 .2 .1 Redundancy
For
redundant operation,
F801 or F802 modules must be fitted in Power Module A
and Power Module B locations. For
non-redundant operation
fit an F801 or F802 in
the Power Module A location and apply power to Power A terminals. The F800-BLK
would then be placed on the Power Module B connector to allow the alarm circuit to
function. Power must be connected to Power B terminals if live replacement of Power
Module A is necessary since Power B terminals feed the Power Module B connector.
5 .2 .2 Terminator
A single terminator is provided automatically on each segment whether one or two
Power Modules are used.
5 .3 Alarm Connection
In an alarm condition a normally closed, galvanically-isolated relay contact in each F801
or F802 goes to an open-circuit condition. These relays are connected in series on the
F890-CA carrier and are presented at terminals as follows:
Alarm
Pin No.
Connection
91
+ve
92
-ve
In non-redundant applications using a single Power Module, the alarm connections
on the carrier will be open-circuit, indicating a permanent alarm condition unless the
F800-BLK module is fitted in place of the missing Power Module.
If multiple F890 units are used, a common alarm circuit can be achieved by ‘daisy-
chaining’ the alarm circuits (see Figure 6).
