If the step is not executed despite the output of the PLC being set, what should be checked first?

In situations where a step is not executed despite the output of the PLC being set, it is crucial to first check the signals between the output module and the actuator. This step is essential because even if the PLC has given the correct output command, the actuator needs to receive that signal to operate correctly. A fault in the connections, such as a broken wire, incorrect wiring, or a malfunctioning output module could prevent the actuator from receiving the signal and executing the desired action.

By ensuring that all signals are correctly transmitted from the output module to the actuator, one can confirm that the hardware connections are functional and that the actuator is capable of performing its intended action. If any issues are present in this pathway, they must be addressed before considering other troubleshooting areas. It is a logical first step since the output has been confirmed to be set, indicating that the problem likely lies in the communication or connection to the actuator itself.