Input and output wiring guidelines
The following table provides information and guidelines
about the functions, ratings, and requirements for
the SNC input and output terminals and references to
guidelines for determining proper wire sizes and cable
lengths.
In addition to the wiring guidelines in the following table,
observe these guidelines when wiring inputs and outputs:
• Run all low-voltage wiring and cables separate from
high-voltage wiring.
• Ensure all input and output cables, regardless of wire
size or number of wires, consist of stranded, insulated,
and twisted copper wires.
• Shielded cable is recommended but not required for
input or output cables.
• Shielded cable is recommended for input and output
cables that are exposed to high electromagnetic or
radio frequency noise.
• Inputs/outputs with cables less than 30 m (100 ft)
typically 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.
Terminal wiring and cable length guidelines
Table 6: Terminal wiring
Terminal block label
Terminal labels
Function, ratings, and
requirements
Determine wire size and
maximum cable length
+15 V
15 VDC Power Source for active
(3-wire) input devices connected
to the Universal UI-# terminals.
Provides 100 mA total current.
Same as Universal inputs UI-#
Note:
Use a 3-wire cable
for devices that source
power from the +15 V
terminal.
Analog Input - Voltage Mode
(0–10 VDC)
10 VDC maximum input voltage
Internal 110k Ohms Pulldown.
See Guideline A in Table 7.
Analog Input - Current Mode
(4–20 mA)
Internal 100 Ohms load
impedance.
See Guideline B in Table 7.
Analog Input - Resistive Mode
Internal 12 V, 15k Ohms pull up.
Qualified Sensors: 0–2k
potentiometer, RTD (1k Nickel
[Johnson Controls sensor], 1k
Platinum, and A99B Silicon
Temperature Sensor) NTC Sensor
(10k Type L, 10k JCI Type II,
2.252k Type II).
See Guideline A in Table 7.
UI-#
Binary Input - Dry Contact
Maintained Mode
1 second minimum pulse width
Internal 12 V, 15k Ohms pull up.
See Guideline A in Table 7.
UNIVERSAL
(Inputs)
UI-C#
Universal Input Common
for all
Universal input terminals
Note:
All Universal UI-C#
terminals share a common,
which is isolated from all
other commons.
Same as (Universal) UI-#.
F4-SNC Installation Guide
8
