Honeywell CVL4022ASVAV1 Engineering Manual page 17

Bus Communication Wiring
The maximum LONWORKS® Bus network length is 4,600 ft.
(1,400 m). For LONWORKS® Bus network lengths greater
than the above, see "LONWORKS® Bus Wiring Guidelines,"
form no. 74-2865. The theoretical limit for each LONWORKS®
Bus segment is 60 controllers. Up to 120 controllers can be
configured when the Q7751A,B Router (configured as a
repeater) is used, and the bus must be either singly or doubly
terminated. Each network segment can have a maximum of
one repeater. Actual installations may have a lower limit,
depending on the devices connected.
Honeywell provided cable types for LONWORKS® Bus
communications wiring are Level IV 22 AWG (0.34 sq mm)
plenum or non-plenum rated unshielded, twisted pair,
stranded conductor wire.
• For non-plenum areas, U.S. part AK3798 (single-pair
stranded) can be used.
• In plenum areas, U.S. part AK3797 (single-pair stranded)
or U.S. part AK3799 (two-pair stranded) can be used.
Contact Echelon Corp. Technical Support for the
recommended vendors of Echelon approved cables.
Communications wiring can be run in a conduit, if needed,
with non-switched 24 Vac or sensor wiring.
Pull the cable to each controller on the LONWORKS® Bus
and connect to the controller's communication terminals 7 and
8. (See Table 8 on page 14 and Table 9 on page 15 and Fig.
18 on page 19 for location of terminals 7 and 8.)
NOTE: Connection for operator access to the LONWORKS®
Bus is provided by plugging the Serial LONTALK® Adapter
(SLTA) connector into the LONWORKS® Bus jack (see Fig. 18
on page 19).
IMPORTANT:
Notes on communications wiring:
• All field wiring must conform to local codes and ordinances
(or as specified on installation drawings).
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
BROWN
ORANGE
PART NO. 209541B
TERMINATION
MODULE
Fig. 16. Termination Modules (LONWORKS® daisy chain connections)
• Do not bundle device output wires with sensor, digital input
or communications LONWORKS® Bus wires.
• Do not use different wire types or gauges on the same
LONWORKS Bus segment. The step change in line
impedance characteristics causes unpredictable reflections
on the LONWORKS® Bus.
• In noisy (high EMI) environments, avoid wire runs parallel
to noisy power cables, motor control centers, or lines
containing lighting dimmer switches. Keep at least 3 in. (76
mm) of separation between noisy lines and the
LONWORKS® Bus cable.
The theoretical limit for each LONWORKS® Bus segment is
60 controllers. Up to 120 controllers can be configured when a
repeater is used, and the bus must be either singly or doubly
terminated. Actual installations may have a lower limit
depending on the devices connected.
• The singly terminated bus must have one 209541B Excel
10 FTT Termination Module for T tap or Star configurations.
• The doubly terminated bus must have two 209541B Excel
10 FTT Termination Modules, one at each end of the daisy
chain (Bus style) wiring run. Note that the Q7751A,B router
(configured as a repeater) has onboard terminating
networks that can be jumper selected on each segment.
• Make sure that neither of the LONWORKS® Bus wires are
grounded.
NOTE: If a 209541B Termination Module is required at the
controller, connect two of the three termination module wires
to the LONWORKS® Bus terminals 7 and 8, which are
labeled Net-1 and Net-2, on the controller. Selecting the
appropriate two wires depends on the LONWORKS® Bus
network topology. Refer to the "LONWORKS® Bus Wiring
Guidelines," form 74-2865, and the "Excel 10 FTT Termination
Module Installation Instructions," form 95-7554. For example,
on a doubly terminated daisy-chained bus topology, where
controllers are on either end of an LONWORKS® Bus wire
run, mount the termination module on the appropriate
terminals, as shown in Fig. 16.
1 1 1 1 1 1 1 2 2 2 2 2 1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4 3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
1 2 3 4 5 6 7 8 9 0 1 2
PART NO. 209541B
BROWN
TERMINATION
MODULE
17
1 1
ORANGE
M33711
31-00083—02