Figure 10: Maximum wire length for low-voltage (<30 V) Inputs and Outputs by current and wire size
Communications bus and supply power wiring guidelines
Table 7 provides information about terminal
block functions, ratings, and requirements for the
communication bus and supply power terminals. The
table also provides wire size, cable type, and cable length
guidelines for wiring the communication buses and
supply power.
Important:
Refer to the
N2 Modernization Guide for
Legacy N2 Controllers (LIT-12012005)
for guidelines
when you use this device on an N2 bus.
In addition to the guidelines in Table 7, observe these
guidelines when wiring the FC Bus, SA Bus, or the 24 VAC
supply power:
• Run
all
low-voltage wiring and cables separate from
high-voltage wiring.
• All FC and SA Bus cables, regardless of wire size, must
be twisted, insulated, stranded copper wire.
• Shielded cable is strongly recommended for all FC and
SA Bus cables.
Communications bus and supply power terminal blocks, ratings, and requirements
Table 7: Communication bus and supply power terminal blocks, functions, ratings, requirements, and cables
Terminal block/Port label
Terminal labels
Function, electrical ratings/
Requirements
Recommended cable type
Ethernet (Ports) (CVE models) ETH-1 and ETH-2
Connect to BACnet/IP Network
Ethernet ports; 10/100 Mbps; 8-pin
RJ-45 connector
+
-
FC Bus Communications
COM
Signal Reference (Common) for bus
communications
FC BUS (CVM models)
1
SHD
Isolated terminal
0.6 mm (22 AWG) stranded, 3-wire
twisted, shielded cable recommended
FC BUS (Port) (CVM models)
FC BUS
RJ-12 6-Position Modular Port provides
FC Bus Communications.
FC Bus provides 15 VDC Power for:
•
MAP Gateway
•
Wireless ZigBee Field Bus Router
24 AWG 3-pair CAT 3 Cable <30.5m
(100 ft)
M4-CV Series VAV Box Controllers Installation Guide
10