What command is used to reset a CNC program?

The command utilized to reset a CNC program is indeed M30. This command serves a dual purpose; it not only indicates the end of the program but also allows the CNC machine to reset the program to the beginning, preparing for a potential restart. When M30 is executed, the machine will stop executing the current program and reset the program counter, ensuring that upon the next cycle, the CNC will start from the beginning of the program rather than picking up from where it left off. This function is crucial for ensuring accurate repeatability in operations, making it a foundational command in CNC programming.

In contrast, the other commands listed do not serve the purpose of resetting a CNC program. M00 is typically used to halt the program temporarily but does not reset it. M10 and M20 do not have standard definitions related to resetting programs or indicating the program end in common CNC practices, and their behaviors can vary between different machines and setups, thus making them less relevant for the task of resetting a CNC program.