Johnson Controls MS-IOM3723 Installation Manual page 7

Communications bus and supply power
wiring guidelines
Table 4 provides information about the functions,
ratings, and requirements for the expansion module's
communication bus and supply power terminals; it
additionally provides guidelines for wire sizes, cable types,
and cable lengths when wiring the expansion module
communication buses and supply power.
Communications bus and supply power terminal blocks, ratings, and requirements
Table 4: Communications bus and supply power terminal blocks, functions, ratings, requirements, and cables
Terminal block/Port
Terminal labels Function, electrical ratings/Requirements
label
+
-
COM
FC Bus
or
SHLD
SA Bus
or
SA PWR
SA/FC BUS
(Port)
HOT
24~
COM
Note: See Table 3 to determine wire size and cable
lengths for cables.
Note: The SA Bus and FC Bus wiring
recommendations in this table are for MS/TP bus
at 38,400 baud. For more information, refer to
the MS/TP Communications Bus Technical Bulletin
(LIT-12011034).
FC or SA Bus Communications
Signal Reference (Common) for FC or SA Bus
communications
SHLD on FC Bus: Isolated terminal (optional
shield drain connection)
SA PWR on SA Bus: 15 VDC power lead
connection
Note: The SA PWR terminal on an IOM
expansion module does not supply 15
VDC. The SA bus supervisor supplies 15
VDC to devices on the SA bus requiring
power.
RJ-12 6-Position Modular Connector provides:
FC or SA Bus Communications
FC or SA Bus Signal Reference and 15 VDC
Common
Commissioning Converter or ZFR /ZFR Pro
Wireless Router
(Maximum total current draw for SA Bus is 100
mA.)
24 VAC Power Supply - Hot
Supplies 20–30 VAC (Nominal 24 VAC)
24 VAC Power Supply - Common
In addition to the guidelines in Table 4, observe the
following guidelines when wiring an SA or FC bus and the
24 VAC supply power:
• Run all low-voltage wiring and cables separate from
high-voltage wiring.
• All SA and FC bus cables, regardless of wire size, should
be twisted, insulated, stranded copper wire.
• Shielded cable is strongly recommended for all SA and
FC bus cables.
• Refer to the MS/TP Communications Bus Technical
Bulletin (LIT-12011034) for detailed information
regarding wire size and cable length requirements for
the SA and FC buses.
Recommended cable type
FC Bus: 0.6 mm (22 AWG) stranded, 3-wire
twisted, shielded cable recommended.
SA Bus: 0.6 mm (22 AWG) stranded, 4-
wire (2 twisted-pairs), shielded cable
recommended.
Wireless Commissioning Converter
retractable cable or 24 AWG 3-pair CAT 3
Cable <30.5 m (100 ft)
0.8 mm to 1.0 mm
(18 AWG) 2-wire
Termination details
A set of Johnson Controls termination diagrams provides
details for wiring inputs and outputs to the controllers.
See the following table in this section for the applicable
termination diagram.
IOM3723 Input/Output Module Installation Guide
Note: On the SA Bus, the + and - wire
are one twisted pair, and the COM
and SA PWR are the second twisted
pair of wires.
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