Programming Guide

VAV-SVP01A-EN 21

VAV Start Up/Check Out Procedure

Note: Use 105 Ω, 1%, 1/4 W for 22 AWG, Level 4.

Comm5 Link Repeater

A Comm5 link repeater regenerates the signal on a Comm5 link. The configurations on either side

of the repeater should be daisy chain. Both link segments require proper termination (Figure 5,

p. 22).

Link repeater requirements.

A link repeater is required when:

• The total wire length is greater than the maximum wire run length of 4,500 ft (1,400 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

Link repeater connections.

The recommended shield connections are shown in Figure 6, p. 22. Use these connections for

instances where shielded communication wire is used. For an example of using a repeater to create

an extended daisy chain configuration, see Figure 5, p. 22.

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" onFigure 4, p. 21.

• Connect shield-drain wires entering the repeater to a terminal marked with a capacitor symbol.

The entering shield-drain wire must be connected to earth ground at the system panel.

• Connect shield-drain wires leaving the repeater to the repeater terminal marked with an earth

ground symbol.

Figure 4. Daisy chain configuration

Termination Resistor