Comm5 Physical Link Repeater; When Is The Link Repeater Required; Link Repeater Guidelines; Link Repeater Connections - Trane Tracer MP581 Hardware Installation

Chapter 7 Wiring Comm5 links
44

Comm5 physical link repeater

A Comm5 link repeater regenerates the signal on a Comm5 link. The con-
figurations on either side of the repeater should be daisy chain. Both link
segments require proper termination (see Figure 24).

When is the link repeater required?

A link repeater is required when:
• The total wire length is greater than the maximum wire run length of
4,500 ft (1400 m).
• More than 60 devices are connected to a link. This total does not
include the BCU, the link repeater, and the temporary use of a service
tool on the same link.
More than eight zone sensor communication stubs (maximum 50 ft)
•
are required on a Comm5 link (see "Comm5 zone sensor comm jack"
on page 46).

Link repeater guidelines

Follow these guidelines when using link repeaters:
Only one link repeater can be used on a link.
•
The use of a repeater doubles the maximum allowable wire length.
•
For example, when a repeater is used with a daisy chain configura-
tion, the total wire length can be 9,000 ft (3,800 m) (with half the wire
length on either side of the repeater).
• The link repeater is limited to 60 devices on either side of the link.
The link repeater requires an earth ground. The installer should be
•
aware of this before making any power connections.

Link repeater connections

The recommended shield connections are shown in Figure 25. Use these
connections for instances where shielded communication wire is used. For
an example of using a repeater to create an extended daisy chain configu-
ration see Figure 26 on page 45.
Follow these guidelines when using a repeater:
Read the Comm5 repeater installation, 3270 3285 information that
•
comes with the link repeater.
For information about terminating daisy chain configurations, see
•
"Termination resistance placement for Comm5 links" on page 42.
Shield-drain wires entering the repeater should be connected to a ter-
•
minal marked with a capacitor symbol. The entering shield-drain
wire must be connected to earth ground at the system panel.
Shield-drain wires leaving the repeater should be connected to the
•
repeater terminal marked with an earth ground symbol.
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