Powering I/O Circuits - AutomationDirect C0-USER-M Manual

Powering I/O Circuits

In most applications, it will be necessary to power the input devices from one power source,
and to power output loads from another source. Loads often require high-energy AC power,
while input sensors use low-energy DC. If a machine operator is likely to come in close
proximity to input wiring, then for safety reasons, high-energy output circuits would be
isolated.
For the DC input/output circuits, you can use the same power source as the PLC module
(and I/O modules). However, you lose the isolation between the logic circuits and the input/
output circuits. For AC input/output circuits, you don't need to worry about sharing the
24VDC.
Power Supply
24VDC
0VDC
Isolation Boundary
To keep the isolation between the logic circuits and the input/output circuits, we recommend
using another power supply for the DC input and output circuits.
Power Supply
24VDC
0VDC
Isolation Boundary
24VDC
Power
Supply
0VDC
CLICK PLC Hardware User Manual, 5th Edition, Rev. F – C0-USER-M
PLC Unit Input Module
Logic Circuit
Input Output
Circuit Circuit Circuit
Load
PLC Unit Input Module
Logic Circuit
Input Output
Circuit Circuit
Load
Chapter 3: Installation and Wiring
Output Module
Logic Logic
Circuit Circuit
Input Output
Circuit
Load
Output Module
Logic Logic
Circuit Circuit
Input Output
Circuit Circuit
Load
Lose
Isolation
Keep
Isolation
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