Siemens SINUMERIK 840D sl Programming Manual page 140

Feed control
7.7 Programmable acceleration override (ACC) (option)
Example
Program code
N50 ACC[X]=80
N60 ACC[SPI(1)]=50
Further information
Acceleration override programmed with ACC
The acceleration override programmed with ACC[...] is always taken into consideration on
output as in system variable $AA_ACC. Readout in the parts program and in synchronized
actions takes place at different times in the NC processing run.
In the part program
The value written in the part program is then only taken into consideration in system variable
$AA_ACC as written in the part program if ACC has not been changed in the meantime by a
synchronized action.
In synchronized actions
The following thus applies: The value written to a synchronized action is then only considered
in system variable $AA_ACC as written to the synchronized action if ACC has not been
changed in the meantime by a part program.
The preset acceleration can also be changed via synchronized actions (see Function Manual,
Synchronized Actions).
Example:
Program code
...
N100 EVERY $A_IN[1] DO POS[X]=50 FA[X]=2000 ACC[X]=140
The current acceleration value can be called with system variable $AA_ACC[<axis>].
Machine data can be used to define whether the last ACC value set should apply on RESET/
part program end or whether 100% should apply.
140
Comment
; The axis slide in the X direction should only be
traversed with 80% acceleration.
; Spindle 1 should only accelerate or brake with 50% of
the acceleration capacity.
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals