Johnson Controls FX-PCV1656, Installation Instructions Manual, Page: 7 / 13

Table 3: Communication Bus and Supply Power Terminal Blocks, Functions, Ratings, Requirements, and
Cables
Recommended Cable Type
1 Function, Electrical
Ratings/Requirements Terminal
Labels Terminal Block/Port Label
0.6 mm (22 AWG) stranded, 3-wire
twisted, shielded cable
recommended FC Bus Communications +
-
FC BUS
2
Signal Reference (Common) for bus
communications COM
Isolated terminal (optional shield drain
connection) SHLD
0.6 mm (22 AWG) stranded, 4-wire
(2 twisted-pairs), shielded cable
recommended SA Bus Communications +
-
SA BUS
2
SA Bus Signal Reference and 15
VDC Common COM
Note: The + and - wires are one
twisted pair, and the COM
and SA PWR wires are the
second twisted pair.
15 VDC Supply Power for Devices on
the SA Bus SA PWR
24 AWG 3-pair CAT 3 Cable
<30.5 m (100 ft) RJ-12 6-Position Modular Port
provides FC Bus Communications
FC Bus provides 15 VDC Power for:
FC BUS
• Wireless Bluetooth ®
Commissioning Converter
• Wireless ZigBee ® Field Bus
Router
0.8 mm to 1.5 mm
2
(20 to 18 AWG) 2-wire
24 VAC Power Supply - Hot
Supplies 20–30 VAC (Nominal
24 VAC)
HOT 24~
24 VAC Power Supply Common
(isolated from all other Common
terminals on controller)
COM
1 See Table 2 to determine wire size and cable lengths for cables other than the recommended cables.
2 The SA Bus and FC Bus wiring recommendations in this table are for MS/TP Bus communications at 38.4k baud. For more
information, refer to the
FX-PC Series Controllers MS/TP Communications Bus Technical Bulletin (LIT-12011670) .
7 FX-PCV1656 Programmable VAV Box VAV Controllers Installation Instructions