In a continuous-cycle program, what do the start and stop pushbuttons control?

In a continuous-cycle program, the start and stop pushbuttons are used to control an internal coil. This internal coil functions as a memory bit or flag that tracks the status of the cycle operation—specifically, whether the system should be running or stopped.

When the start pushbutton is pressed, it energizes the internal coil, enabling the sequence of operations to begin and allowing the program to execute its defined routine. Pressing the stop pushbutton de-energizes this internal coil, effectively halting the continuous cycle and stopping the operations. This mechanism allows for simple toggling of the operational state based purely on user interaction with the pushbuttons.

This understanding of internal coils is fundamental in programmable logic controller (PLC) programming, as they represent the on/off state of processes within the control program, allowing for straightforward control logic and operations.