Which method is commonly employed to troubleshoot a malfunctioning PLC system?

Troubleshooting a malfunctioning PLC system typically involves checking the status of inputs and outputs, as well as examining the program logic. This method allows a technician to diagnose issues by verifying that the PLC is receiving the correct signals and has the expected outputs based on the underlying logic programmed into the system. By systematically testing the inputs and outputs, one can identify whether the issue lies with the hardware, such as sensors and actuators, or with the software, including the logic used to control the PLC.

This approach is not only efficient but also targeted, as it focuses on understanding the relationship between the system's physical components and its programming. Identifying discrepancies in the expected behavior of inputs and outputs can help pinpoint the source of the malfunction, making it a vital step in effective troubleshooting.

In contrast, modifying the power source may not address the underlying issue unless power supply problems are suspected. Replacing all internal components is often unnecessary and can lead to increased downtime and cost. Switching the PLC model would not resolve existing issues and may introduce compatibility concerns or further complications in troubleshooting, making it an impractical choice in most scenarios.