G93, G94: Feed Rate Mode

G93 – feedrate setting mode in inverse time. In this mode, the F parameter means that the movement must be completed in 1/F minutes. For example, if parameter F is 2, the movement should be completed in half a minute.

When the feedrate inverse time setting mode is active, parameter F must be present on each line containing the movements G1, G2, G3. This mode does not affect fast movements of G0.

G94 –  feedrate setting mode in units per minute. In this mode, the F parameter means that a certain number of inches per minute, millimeters per minute or degrees per minute must be traversed, depending on which units of measurement are used and which axes are moved.