Johnson Controls IOM3711 Installation Manual page 9

Note: The required wire sizes and lengths for high-
voltage (>30 V) Relay Outputs are determined by the
load connected to the relay, and local, national, or
regional electrical codes.
Maximum cable length versus load
current
Use Figure 8 to estimate the maximum cable length
relative to the wire size and the load current (in mA) when
wiring inputs and outputs.
Note: Figure 8 applies to low-voltage (<30 V) inputs
and outputs only. The required wire size and length
for high-voltage (>30 V) Relay Outputs is determined
by the load connected to the relay and local electrical
codes.
Max wire length by current and wire size
graphic
Figure 8: Maximum wire length for low-voltage (<30
V) Inputs and Outputs by current and wire Size
Table 4: Communications bus and supply power terminal blocks, functions, ratings, requirements, and cables
Terminal block/Port Terminal
label labels
+
-
COM
FCBUS
or
SHLD
SABUS
or
SAPWR
SA/FC BUS
(Port)
Function, electrical ratings/Requirements
FC or SA Bus Communications
Signal Reference (Common) for FC or SA Bus
communications
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 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 ZFR181x/ZFR 182x Wireless
Router
(Maximum total current draw for SA Bus is 240 mA.)
SA/FC bus and supply power wiring
guidelines
Table 4 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 expansion
module's communication buses and supply power.
In addition to the guidelines in Table 4, 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 MS/TP Communications Bus Technical
Bulletin (LIT-12011034) for detailed information
regarding wire size and cable length requirements for
the SA and FC buses.
IOM3711 Input/Output Module Installation Guide
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.
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.
Wireless Commissioning Converter
retractable cable or 24 AWG 3-pair
CAT 3 Cable <30.5 m (100 ft)
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