EXCEL 50 INSTALLATION INSTRUCTIONS
25
EN1B-0101
L
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Network Interface
Excel 50 Controllers may be equipped with an application
module (see Table 15) containing an FTT-10A Free Topology
Twisted Pair Transceiver which allows communication with
other device on a L
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network. FTT-10A transceivers
communicate at 78 Kbaud and provide transformer isolation
so that the bus wiring does not have a polarity; that is, it is
not important which of the two bus terminals are connected
to each wire of the twisted pair.
LEDs
C-BUS TxD, YEL
POWER, GRN
C-BUS RxD, YEL
LON SERVICE, RED
RESERVED
00
00
01
24
C-BUS
SH
IE
L
D
C + C -
4 5 6
LON
BUS
NO
T
US
E
D
A1 A2
1 2 3
LON SERVICE BUTTON
C-BUS
TERMINATION
SWITCH
Fig. 45. LonWorks network connection.
FTT devices can be wired in daisy chain, star, loop or any
combination thereof as long as the maximum wire length re-
quirements given below are met. The recommended con-
figuration is a daisy chain with two bus terminations. This
layout allows for maximum bus length, and its simple struc-
ture presents the least number of possible problems, par-
ticularly when adding on to an existing bus.
NOTE:
A doubly-terminated bus may have stubs of up to
10 ft (3 m) from the bus to each node.
Table 20. Doubly-terminated bus specifications.
Cable Type
Max. bus length
Belden 85102
2,700 m (8,900 ft)
Belden 8471
2,700 m (8,900 ft)
Level IV, 22 AWG
1,400 m (4,600 ft)
JY (St) Y 2x2x0.8
900 m (3,000 ft)
TIA568A Categ. 5 24AWG, twisted pair
900 m (3,000 ft)
NOTES:
The cable types listed above are as recommended by
Echelon in their FTT-10A User Guide. The cable re-
commended by Honeywell is the level IV, 22 AWG, solid
core, nonshielded cable. Belden part numbers are
9H2201504 (plenum) and 9D220150 (non-plenum).
The FTT specification includes two components that must be
met for proper system operation. The distance from each
transceiver to all other transceivers and to the termination
must not exceed the
maximum node-to-node distance
. If
multiple paths exists, the
maximum total wire length
is the
total amount of wire used.
Table 21. Free topology (singly-terminated)
specifications.
Cable type
Maximum node-
to-node distance
Maximum total
wire length
Belden 85102
1,650 ft (500 m)
1,650 ft (500 m)
Belden 8471
1,300 ft (400 m)
1,650 ft (500 m)
Level IV, 22AWG
1,300 ft (400 m)
1,650 ft (500 m)
JY (St) Y 2x2x0.8
1,050 ft (320 m)
1,650 ft (500 m)
TIA568A Category 5
24AWG, twisted pair
825 ft (250 m)
1,500 ft (450 m)
IMPORTANT
Do not use different wire types or gauges on the
same L
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network segment. The step change
in line impedance characteristics would cause
unpredictable reflections on the network.
NOTE:
In the event that the limit on the total wire length is
exceeded, then FTT physical layer repeaters
(FTT 10A) can be added to interconnect segments
and increase the overall length by an amount equal
to the original specification for that cable type and
bus type for each repeater used. For example,
adding repeaters for a doubly-terminated bus using
JY (St) Y 2x2x0.8 cable increases the maximum
length 3,000 ft (900 m) for each repeater.
L
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Bus Termination
One or two Termination Modules, part no. 209541B, are re-
quired for a L
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Bus with FTT devices on it, de-
pending upon the configuration. The maximum lengths des-
cribed in the previous section must be adhered to for either a
daisy chain or free topology L
ON
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network layout. See
Fig. 46 and Fig. 47 for connection details for the 2095401B
Termination Module.
Fig. 46. Termination Module connections for doubly-
terminated FTT network.
Fig. 47. Termination Module connections for a singly-
terminated FTT network.
(optional)
