Technical Manual
FT420
– Iss 2.4
15
2.1.3 System Expansion Limitations
The expansion limits listed below must not be exceeded.
Only these additional boards can be added to the standard FT420 small enclosure:
•
2 x display boards
•
1 x expansion board (if necessary, another expansion board can be fitted on top of the first
board).
To add additional optional modules, or a higher power rated OWS, a medium or large enclosure may
be required.
Table 4 Expansion Limitation
Expansion / display board Type
Maximum Qty in CIE
Maximum individual functions
8 Zones Expansion Board
2
16 Additional zones (termination)
4 Supervised Voltage Outputs Expansion Board
6
24 Supervised output (24V
DC
or
100V RMS speaker circuit)
8 Clean Contact Relay Outputs Expansion Board
3
24 Relays
8 Non-Supervised Voltage Output
1
Only one board can be used
Maximum
number of Control Expansion Boards
7
4 Zones Display Board
4
16 additional zones (display)
4 Zone Display Board for
1
Only one board can be used
OWS Main Display Board
1
Only one board can be used
8 OWS Tone Selection Display Board
1
Only one board, 8 tone selections
8 PA Zone Control Display Board
3
24 PA Zone control buttons
Total number of expansion display boards on
each display board expansion bus
5
Maximum
number of Expansion Display Boards
10
Fan Control Expansion Board
Space limitation /
impact only
2 Fan terminations
Fan Control Display Board
Space limitation /
impact only
2 Fan status and control
2.1.4 Control Expansion Bus
As per Table 4, each FT420 system can be fitted with up to seven Control Expansion Boards that can
be daisy-chain connected to the Main Control Board. Every Expansion Control Board has two bus
connections; in and out and a Bus Address Selection Circuit. IDC 20-way ribbon cables are used for
the bus interconnections.
The bus address selection is based on an 8-Bit DIP switch.
Only one DIP switch bank (one bit) can
be turned ON at any time.
The address bit setting of all the expansion boards shall be different from
each other. Refer to Table 15 on page 27.
There are two bus connectors on each expansion board. One connector connects the incoming bus
and the other outgoing connects to the next expansion board. Expansion boards must be connected
with the output bus of the “previous” board connected to the input bus of the “next” board.
