Describe the purpose of the M30 code, and its impact on the CNC control system after program completion.

The purpose of the M30 code in a CNC program is to signal the end of the program and reset the CNC control system to its initial state, preparing it for the next operation. M30, which stands for "Program End and Reset," is typically the last command in a CNC program. Its impact on the CNC control system after program completion includes rewinding the program to the beginning. The control system automatically resets the program counter to the first line of the program, so it's ready to be run again. It also resets certain machine functions. M30 typically resets functions like coolant, spindle rotation, and feedrate override to their default settings. This ensures that the machine starts in a known state for the next program. It also transfers control back to the operator. After executing the M30 code, the control system returns to its normal operating mode, allowing the operator to load a new program, set up a new workpiece, or perform other tasks. It might also trigger a machine stop. Depending on the machine configuration, M30 may also cause the machine to stop all axis movements. Essentially, it signifies that the machining operation is complete, and the machine is ready for the next task. It is important to use M30 at the end of every CNC program to ensure consistent and predictable machine behavior.