• 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 8 to estimate the maximum cable length relative to the wire size and the load current (in
mA) when wiring inputs and outputs.
SA bus and supply power wiring guidelines
Table 5 provides information about terminal block functions, ratings, and requirements.
Table 5 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 5, observe these guidelines when wiring the SA Buses and
supply power:
• Run
all
low-voltage wiring and cables separate from high-voltage wiring.
• All SA Bus cables, regardless of wire size, should be twisted, insulated, stranded copper wire.
• Shielded cable is strongly recommended for all SA Bus cables.
• Refer to the
FX-PC Series Controllers Communications Bus Technical Bulletin (LIT-12011670)
for
detailed information regarding wire size and cable length requirements for the SA Buses.
Termination diagrams
A set of Johnson Controls termination diagrams provides details for wiring inputs and outputs to
the controllers. See the figures in this section for the applicable termination diagrams.
Table 2: Termination details
Type of field
device
Type of
Input/
Output
Termination diagrams
Voltage Input -
External Source
UI
Voltage Input -
Internal Source
UI
11
FX-PCV1615/1626/1628/1630 Programmable VAV Box Controllers Installation Instructions
