FX-PCV terminal functions, ratings, requirements, and wiring
guidelines
Input and Output wiring guidelines
Table 4 provides information about the functions, ratings, and requirements for the FX-PCV input
and output terminals, and Table 5 provides guidelines for wire sizes and cable lengths.
In addition to the wiring guidelines in Table 4, observe these guidelines when wiring FX-PCV inputs
and outputs:
• Run all low-voltage wiring and cables separate from high-voltage wiring.
• All input and output cables, regardless of wire size or number of wires, should consist of twisted,
insulated, and stranded copper wires.
• Shielded cable is not required for input or output cables.
• Shielded is recommended for input and output cables that are exposed to high electromagnetic
or radio frequency noise.
• Cable runs of less than 30 m (100 ft) typically do not require an offset in the input/output
software setup. Cable runs over 30 m (100 ft) may require an offset in the input/output software
setup.
Maximum cable length versus load current
Use Figure 12 to estimate the maximum cable length relative to the wire size and the load current
(in mA) when wiring inputs and outputs.
N2/FC and SA bus and supply power wiring guidelines
Table 6 provides information about terminal block functions, ratings, and requirements.
Table 6 also provides wire size, cable type, and cable length guidelines for wiring the FX-PCV
communication buses and supply power.
In addition to the guidelines in Table 6, observe these guidelines when wiring the SA and N2/FC
Buses and supply power:
• Run all low-voltage wiring and cables separate from high-voltage wiring.
• All N2/FC and SA Bus cables, regardless of wire size, should be twisted, insulated, stranded
copper wire.
• Shielded cable is strongly recommended for all N2/FC and SA Bus cables.
• Refer to the
N2 Communications Bus Technical Bulletin (LIT-636018)
for detailed information
regarding wire size and cable length requirements for the N2/FC and SA buses.
Termination diagrams
A set of Johnson Controls
®
termination diagrams provides details for wiring inputs and outputs
to the FX-PCV18 Series controllers. See the figures in this section for the applicable termination
diagrams.
FX-PCV1826/1832 Programmable VAV Box Controller Installation Instructions
10
