Echelon LonWorks Twisted Pair Control Module - Manual (Page 30)

22 Network Cabling and Connection
is supported per segment, so at least one of the terminations must be the
RC-type.
TP/XF-78, TP/XF-78F, and TP/XF-1250
The following sections describe the wire characteristics and cabling terminations
for TP/XF-78, and TP/XF-1250 channels. In addition, the device distribution rule
for TP/XF-1250 network segments is described.
Wire Characteristics
The Neuron 3150 TP/XF-78, TP/XF-78F, and TP/XF-1250 control modules are
designed for distributed control applications using low-cost, Level IV twisted pair
wire. The TP/XF-1250 Control Module can also use AWG 24 (0.511 mm)
ANSI/TIA/EIA-568-B.2-2001 Category 5 or Category 6 twisted-pair wire. The
characteristics of the wire used to implement a network affects the overall system
performance with respect to total distance, stub length, and total number of
nodes supported on a single channel.
The TP/XF-78 and TP/XF-78F control modules have been qualified using the
following cable types:
• Primary bus: Level IV, AWG 22 (0.65 mm)
• Stubs (where permitted): Level IV, AWG 24 (0.511 mm) cable or Level
IV, AWG 22 cable
The TP/XF-1250 Control Module has been qualified using the following cable
types:
• Primary bus: Level IV, AWG 22 (0.65 mm); or AWG 24 (0.511 mm)
ANSI/TIA/EIA-568-B.2-2001 Category 5 or Category 6 twisted-pair cable
• Stubs (where permitted): Level IV, AWG 24 (0.511 mm) cable; Level IV,
AWG 22 cable; or AWG 24 (0.511 mm) ANSI/TIA/EIA-568-B.2-2001
Category 5 or Category 6 twisted-pair cable
For all of the control modules, under no circumstances should smaller gauge
Level IV cable be substituted for Level IV, AWG 22 (0.65 mm) twisted pair cable
for the bus, or should Category IV cable be used in place of Level IV cable.
Echelon periodically qualifies new cables for twisted pair transceivers, and it is
advisable to check with Echelon from time to time to determine if new cables are
available for use with the control modules.
The characteristics and suppliers of Level IV cable are described in the Junction
Box and Wiring Guidelines for Twisted Pair LonWorks Networks engineering
bulletin (005-0023-01).
Device Distribution Rule for TP/XF-1250 Segments
Because of the transmission characteristics of the TP/XF-1250 channel,
communication failures can result from reflections of the TP/XF-1250 module’s
1.25 Mbps transmitted signal under conditions of concentrated device loading.
These communication failures are eliminated when devices are used in a
distributed configuration. For this reason, it is essential to follow a simple
topology rule when using TP/XF-1250 control modules, TPT/XF-1250