Programming Guide

20 VAV-SVP01A-EN
VAV Start Up/Check Out Procedure
Wiring requirements
The recommended Comm5 communication-link wiring is 22 AWG, Level 4, twisted-pair wire. See
Ta ble 5, p . 2 0 "Specifications for Level 4-compliant cables". The wire can be either shielded or
unshielded. However, unshielded wire is recommended for most installations.
The maximum wire length for Comm5 communication links is 4,500 ft (1,400 m). Comm5
communication-link wiring must be installed in a daisy-chain configuration (Figure 4, p. 21 and
Figure 5, p. 22).
Table 5. Cable specifications
Specification Value
dc resistance
(Maximum resistance of a single copper conductor regardless of whether or not it is solid or stranded and regardless
of whether or not it is metal coated.)
18.0 Ω/1,000 ft 20°C
dc resistance unbalance (maximum) 5%
Mutual capacitance of a pair (maximum) 17 pF/foot
Pair-to-ground unbalance (maximum) 1,000 pF/foot/1,000 ft
Characteristic impedence
772 kHz 102 Ω
± 15%
1.0 MHz 100 Ω
± 15%
4.0 MHz 100 Ω
± 15%
8.0 MHz 100 Ω
± 15%
10.0 MHz 100 Ω
± 15%
16.0 MHz 100 Ω
± 15%
20.0 MHz 100 Ω
± 15%
Attenuation (maximum dB/1,000 ft at 20°C)
772 kHz 4.5 dB/1,000 ft at 20°C
1.0 MHz 5.5 dB/1,000 ft at 20°C
4.0 MHz 11.0 dB/1,000 ft at 20°C
8.0 MHz 15.0 dB/1,000 ft at 20°C
10.0 MHz 17.0 dB/1,000 ft at 20°C
Worst-pair near-end crosstalk (minimum)
(Values shown are for information only. The minimum NEXT coupling loss for any pair combination at
room temperature is to be greater than the value determined using the formula NEXT (F
MHz
)>NEXT
(0.772)-15
log10
(F
MHz
/0.72) for all frequencies in the range of 0.772 MHz-20 MHz for a length of 1,000
ft.)
772 kHz 58 dB
1.0 MHz 56 dB
4.0 MHz 47 dB
8.0 MHz 42 dB
10.0 MHz 41 dB
16.0 MHz 38 dB
20.0 MHz 36 dB
dc resistance unbalance (maximum) 5%