This is the Optional Stop M-command of G-code known as M01. This command will cause the machine to stop, or hold only if another programmable condition is met. Typically this command can be programmed to stop unless interaction from the operator has occurred. For example, the machine could be made to stop unless the operator has already pressed a button or activated a switch. Useful with repetitive machine tasks that require operator interaction.
It is important to check with the manufacturer or your CNC control software, or CNC machine to understand how M01 can work and be programmed. Typically this command will be treated the same as a M00 command by default and work will only resume by pressing Cycle Start.
Standard Format: M01
There are no additional parameters required for M01 execution.
In this example, the M01 command will be executed stopping the machine until Cycle Start is pressed.
... M01 ...