In order to read I/O for a project what must you do first?

• A. Turn on the main switch on the workstation
• B. Open RSLogix and select I/O
• C. Power-cycle the workstation
• D. Wait for the program to initialize

Answer: (A)

To read live I/O you must have power to the hardware. Turning on the main switch supplies the PLC and its I/O modules with power, enabling sensors to be read and outputs to be driven. Without power, there’s nothing active to read, so the software has nothing to display or monitor. Opening the programming software alone doesn’t energize the hardware, so it won’t let you read real I/O until power is on. The other steps—power cycling or waiting for initialization—are actions you might take later if issues arise, but they aren’t the required first step to access I/O. Energize the system by turning on the main switch, then you can connect with the software to read I/O.