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2-5 Wiring CPUs and Expansion I/O Units
Power Supply Use a commercially available 24-VDC, 100 to 120-VAC, or 200 to 240-VAC
power supply (depending on your model) for the CPU. When an Expansion
I/O Unit(s) or an I/O Link Unit is used, the power supply must also be con-
nected to each of these Units. Where possible, use independent power
sources for the inputs, the output loads, and the CPU. All of the CPUs and
Expansion I/O Units may be connected to the same power source. If a CPU
and an Expansion I/O Unit are connected to separate power supplies, then
the CPU (as well as the Programming Console, etc.) will not operate unless
power is turned on to the Expansion I/O Unit.
Wiring The following diagram illustrates the proper wiring for CPUs and Expansion
I/O Units with the suffix “-A.” These models use a power supply of 100 to 240
VAC, with an operating voltage range of 85 to 264 VAC. The internal
noise-reduction system in these Units is sufficient for general power line
noise, but ground noise can be greatly reduced by using a 1:1 insulating
transformer. Ground only the primary side of the transformer. To prevent volt-
age drop, use wires 2 mm
2
or less in cross sectional area, twisting them as
shown in the diagram. When power is turned on, the incoming current will be
approximately 10 A.
Breaker
Insulating
transformer
1:1
M3.5 screws
Wiring CPUs and Expansion I/O Units Section 2-5
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