The 24 VAC supply power terminal block is a gray, removable, 3-terminal plug that fits into a board-mounted jack on the top right of the controller.
Wire the 24 VAC supply power wires from the transformer to the HOT and COM
terminals on the terminal plug as shown in Figure 1.
Do not use the middle terminal on the supply power
Figure 1. 24 VAC supply power terminal block wiring
Note: The supply power wire colors may be different on transformers from other manufacturers. Refer to the transformer manufacturer’s instructions and the project installation drawings for wiring details.
Important: Connect 24 VAC supply power to
controller and all other network devices so that transformer
phasing is uniform across the network devices. Powering network
devices with uniform 24 VAC supply power phasing reduces noise,
interference, and ground loop problems. The field
controller does not require an earth ground connection.