Johnson Controls M4-XPM Installation Manual page 5

Figure 7: SA bus terminal block wiring
Note:
The PWR/SHD terminal does not supply 15 VDC. The
PWR/SHD terminal is isolated and can be used to
connect (daisy chain) the 15 VDC power leads on the
SA bus or the cable shields on the FC bus.
The SA bus supervisor (CGE, CGM, CVE, CVM, FAC,
FEC, or VMA Controllers) supplies 15 VDC to the
devices on the SA bus that require power.
SA/FC bus port
The SA/FC bus port on the front of the expansion module
is an RJ-12, 6-position modular jack that provides a
connection for devices on the SA bus or a ZFR183x Pro
Wireless Router depending on which bus the expansion
module is operating on.
The SA/FC bus port is connected internally to the SA/
FC bus terminal block. See
supply power wiring guidelines
about communication bus port functions, ratings and
requirements. The SA/FC bus port pin assignment is
shown in Physical features.
Figure 8: Pin number assignments for sensor, SA bus
and FC bus ports on expansion modules
Supply power terminal block
The 24 VAC supply power terminal block is a gray,
removable, 2-pin terminal block that fits into a board-
mounted pin header on the top right of the controller.
Communications bus and
for more information
Wire the 24 VAC supply power wires from the transformer
to the HOT and COM terminals on the terminal plug as
shown in Figure 9. For more information about the Supply
Power Terminal Block, see Table 5.
Figure 9: 24 VAC supply power terminal block wiring
Table 2: Supply power terminal block wiring
Description
1 Supply power terminal block
2 Supply power terminal header
3 Wires from Johnson Controls 24 VAC, class 2 power
transformer
4 24 VAC (Orange wire)
5 COM (Brown wire)
Note: The supply power wire colors may be different
on transformers from other manufacturers. Refer to
the transformer manufacturer's instructions and the
project installation drawings for wiring details.
Important: Connect 24 VAC supply power to the
expansion module and all other network devices
so that transformer phasing is uniform across the
network devices. Powering network devices with
uniform 24 VAC supply power phasing reduces
noise, interference, and ground loop problems. The
expansion module does not require an earth ground
connection.
Important: Power wires must be less than 30
meters between expansion module and transformer.
Inputs/outputs with cables less than 30 m (100 ft)
typically do not require an offset in the software
setup. Cable runs over 30 m (100 ft) may require an
offset in the input/output software setup.
Terminal wiring guidelines, functions,
ratings, and requirements
This section provides further guidelines on input and
output wiring, maximum cable length versus load current,
and SA Bus and supply power wiring.
For information about removing a terminal block from the
expansion module, see Removing a terminal
M4-XPM Expansion Modules Installation Guide
block.
5