Johnson Controls SNC Series User Manual

Table 7: Cable length guidelines for recommended wire sizes
Guideline Wire size/gauge and type Maximum cable length and
type
Assumptions
1.0 mm (18 AWG) stranded copper 457 m (1,500 ft) twisted wire
0.8 mm (20 AWG) stranded copper 297 m (975 ft) twisted wire
0.6 mm (22 AWG) stranded copper 183 m (600 ft) twisted wire
A
0.5 mm (24 AWG) stranded copper 107 m (350 ft) twisted wire
100 mV maximum voltage drop
Depending on the cable length
and the connected input or
output device, you may have
to define an offset in the setup
software for the input or output
point.
1.0 mm (18 AWG) stranded copper 229 m (750 ft) twisted wire
0.8 mm (20 AWG) stranded copper 137 m (450 ft) twisted wire
0.6 mm (22 AWG) stranded copper 91 m (300 ft) twisted wire
B
0.5 mm (24 AWG) stranded copper 61 m (200 ft) twisted wire
100 mV maximum voltage drop
Depending on the cable length
and the connected input or
output device, you may have
to define an offset in the setup
software for the input or output
point.
C See Figure 10 to select wire size/gauge. Use
stranded copper wire.
See Figure 10 to determine cable
length. Use twisted wire cable.
N/A
Maximum cable length versus load current
In most cases inputs/outputs with cables less than 30 m (100 ft) 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. Use Figure 10 to estimate the maximum
cable length relative to the wire size and the load current (in mA) when wiring inputs and outputs.
Figure 10: Maximum wire length by current and wire size
Communications Bus and supply terminal blocks, functions, ratings, requirements,
and cables
Table 8: Communications Bus and supply terminal blocks, functions, ratings, requirements, and cables
Terminal block/
port label
Terminal
labels
Function, electrical ratings/requirements Recommended cable type
- (03)
+ (04)
FC Bus Communications
COM (02) Signal Reference (Common) for bus communications
FC BUS
SHLD (01) Isolated terminal (optional shield drain connection)
0.6 mm (22 AWG) stranded, 3-
wire twisted, shielded cable
recommended
FC BUS
(port)
FC Bus RJ12 6-Position Modular Connector provides:
• FC Bus Communications
• FC Bus Signal References and 15 VDC Common
• 15 VDC Power for Wireless Commissioning
• Converter or ZFR1811 Wireless Router
Wireless Commissioning Converter
retractable cable or 24 AWG 3-pair
CAT 3 Cable <30.5 m (100 ft)
F4-SNC Installation Guide12

Johnson Controls SNC Series Specifications

General

Brand	Johnson Controls
Model	SNC Series
Category	Controller
Language	English