Determining acceleration/deceleration (G08/G09/G900/G901)

Notice

The acceleration definition operations on only effective in connection with slope types STEP, TRAPEZ and SIN2. The definition operation has no effect with slope type HSC.

Syntax:
G08	Acceleration at block start	modal, initial state
G09	Deceleration at block end	non-modal, effect dependent on G901/G900
G901	Deceleration after block end; can be cancelled by G09 blockwise		modal
G900	Deceleration towards block end independent of G09 modal active		modal

If two consecutive NC blocks are programmed at different feedrates, a "soft" adaptation occurs at the block limit. As specified by G08, an acceleration takes place only at block start. G09 specifies that a deceleration to the feedrate of the next block should already occur at the end of the current block.

G08 and G09 are the default settings at program start. The G901 function defines the default setting for deceleration only after block end. The inverse G function G900 is a change-back function and is equivalent to the channel default setting.

Attention

During transition from G00 to G01, G02 or G03, G09 is always active, i.e. deceleration at block end down to the velocity of the following block.

If the path velocity limit is already achieved while G901 is active, the velocity of the following block is reached at block end, i.e. then G901 is not effective.