SA/FC Bus and Supply Power
Wiring Guidelines
Table 5 provides information about the functions, ratings,
and requirements for the communication bus and supply
power terminals; and guidelines for wire sizes, cable
types, and cable lengths when wiring the controller's
communication buses and supply power.
In addition to the guidelines in Table 5, observe these
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 FX-PC Series Controllers MS/TP
Communications Bus Technical Bulletin
(LIT-12011670)or MS/TP Communications Bus for
BCM System Technical Bulletin (LIT-12011908) for
detailed information regarding wire size and cable
length requirements for the SA and FC buses.
Table 5: Communications Bus and Supply Power Terminal Blocks, Functions, Ratings, Requirements, and Cables
Recommended Cable Type
1
Function, Electrical Ratings/RequirementsTerminal
Labels
Terminal
Block/Port Label
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.
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.
FC or SA Bus Communications+
-
FC BUS
2
or
SA BUS
2
Signal Reference (Common) for FC or SA Bus
communications
COM
SHLD on FC Bus: Isolated terminal (optional shield drain
connection
SAP WR on SA Bus: 15 VDC power lead connection
Note: The SA PWR terminal on an FX-PCX controller does
not supply 15 VDC. The SA bus supervisor supplies 15
VDC to devices on the SA bus requiring power.
SHLD
or
SAPWR
Bluetooth® Commissioning Converter
retractable cable or 24 AWG 3-pair CAT 3
Cable <30.5 m (100 ft)
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 FX-ZFR1811 Wireless Router
(Maximum total current draw for SA bus is 240 mA.)
SA/FC BUS
2
(Port)
0.8 mm to 1.5 mm
2
(18 AWG) 2-wire
24 VAC Power Supply - Hot
Supplies 20-30 VAC (Nominal 24 VAC)
HOT24~
24 VAC Power Supply - Common
(Isolated from all other Common terminals on controller.)
COM
1
See Table 4 to determine wire size and cable lengths for cables.
2 The SA Bus and FC Bus wiring recommendations in this table are for MS/TP bus communications at 38,400 baud. For more
information, refer to the FX-PC Series Controllers MS/TP Communications Bus Technical Bulletin (LIT-12011670) or MS/TP
Communications Bus for BCM System Technical Bulletin (LIT-12011908).
16FX-PCX47 Expansion Input/Output Module Installation Instructions