I am not familiar with your particular machine, so I don't know whether you have had to do any PLC programming for these M codes, but in general when an M code is issued a FIN(ish) signal has to be sent back to the CNC side somehow, in the case of M code functions that do not need to have confirmation, such as coolant on, for example, the FIN signal is returned in the ladder without physical input confirmation.
For others such as tool change for e.g., then an input is usually assigned for a external FIN signal input, this particular input is used by all confirming M codes.
Hope this helps a bit.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.