What is the first step in troubleshooting a multistep PLC controlled machine that has stopped?

The first step in troubleshooting a multistep PLC controlled machine that has stopped is to verify power and pressure indicators. This step is crucial because ensuring that the machine has power and that the pneumatic system is functioning properly is fundamental to diagnosing any issues. Without power, the PLC cannot operate, and without adequate pressure in the pneumatic system, the machine will not perform any tasks.

By verifying these indicators, you establish a baseline condition of the machine's functioning. If power and pressure are both present and at acceptable levels, you can proceed to other troubleshooting steps, such as checking input indicators or inspecting for physical damages. If either power or pressure is inadequate, it indicates where the problem may lie, allowing for a more focused approach to resolving the issue.

This first step effectively rules out major operational failures and directs the troubleshooting process toward more specific areas of concern within the machine's systems.