M48 - M53 (Feed-Speed Override Control)
M48 Enable feed and speed override, set back to last user feed override value.
M49 Disable feed and speed override and set to 100%
M50 P... Set feed Override to a given P value, if the P value is less than zero feed override is disabled and the value remains as is.
M51 P... Set speed Override to given P value, if the P value is less than zero speed override is switched off.
M52 P...Enable feed Override by analog input. M52 P0 disables feed override by analog input. P1 is optional.
M53 P... Enable feed Hold input. M53 P0 disable feed Hold input. P1 is optional.
To enable the speed and feed override switches, program M48. To disable both switches, program M49.