Figure 17: UI dry contact input
Callout Description
1 Field device
2 22 AWG copper stranded twisted wire up to
100 m (328 ft) in length
3 Controller
4 UI terminal
5 COM terminal
Dry contact6
Normally open or normally closed as
required
Power supply terminal wiring
Connect the 24 VAC supply power wires from the
transformer to the HOT and COM power terminals as
shown in Figure 18.
Note: The supply power wire colors may differ on
transformers from other manufacturers. Refer to
the transformer manufacturer’s instructions and the
project installation drawings for wiring details.
Important: To reduce noise, interference, and
ground loop problems, connect a 24 VAC supply
power to the controller and to all other network
devices so that transformer phasing is uniform
across network devices. The controller does not
require an earth ground connection. However, when
you need to ground the secondary of the 24 VAC
transformer, make only one ground connection
near the transformer. For more information, see the
following figure.
Figure 18: Transformer grounding
CAUTION
To avoid property damage, check all wiring
connections before you apply power to the system.
If you wire this terminal incorrectly, a short circuit
can occur across the 24 VAC power supply on the
controller. A short circuit can cause a tripped circuit
breaker or a blown fuse. If you use a transformer
with a built-in fuse, you may need to replace the
transformer.
Input and output terminal wiring
considerations
• Run all low-voltage wiring and cables separate from
high-voltage wiring.
• For all input and output cables, use twisted, insulated,
and stranded copper wires.
• Use shielded cables for input and output cables
that are exposed to high electromagnetic or radio
frequency noise.
• Cable runs over 30 m or 100 ft require an offset in the
input and output software setup.
RS-485 bus terminals
Wire the RS-485 terminals in a daisy-chain configuration.
Use a stranded three-wire twisted and shielded cable
as shown in Figure 19. The three different wires are the
positive bus, the negative bus, and the COM.
You can use the RS-485 positive and negative wires as
sensor actuator (SA) bus +ve and SA bus -ve.
Figure 19: RS-485 wiring
FW-14 Quick Start Guide 7
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