Siemens SINUMERIK 828D

B2: Acceleration
4.2 Functions
Basic Functions
226 Function Manual, 09/2011, 6FC5397-0BP40-2BA0
4.2.7 Path acceleration for real-time events (channel-specific)
4.2.7.1 General Information
General Information
So that no compromise has to be made between machining-optimized acceleration on the one hand and time-
optimized acceleration in connection with the following real-time events on the other:
• NC-STOP / NC-START
• Changing the feedrate override
• Changing the velocity default for "safely reduced velocity" within the context of the "Safety Integrated" function
for the real-time events mentioned, the path acceleration can be specified using a channel-specific system
variable:
$AC_PATHACC =
path acceleration
Real-time event acceleration will only be active for the duration of the change in velocity in respect of one of the
real-time events specified above.
Limiting
If the specified path acceleration exceeds the capabilities of the machine axes that are of relevance for the path,
a limit will be imposed on the path acceleration within the control so that the resulting axial acceleration (a
res
) is
restricted to less than 2x the parameterized maximum axial value (a
max
).
a
res
= 2 * a
max,
with a
max
= MD32300 $MA_MAX_AX_ACCEL
Effectiveness
Note
Real-time-event path acceleration is enabled, irrespective of the radial acceleration.
Effective Real-time event acceleration is only enabled in AUTOMATIC and MDA operating
modes in conjunction with the following real-time events:
• NC-STOP / NC-START
• Override changes
• Changing the velocity default for "safely reduced velocity" within the context of the
"Safety Integrated" function
Not effective Path acceleration for real-time events is ineffective for changes in path velocity that are
attributable to path planning during preprocessing for the channel, such as contour
curvatures, corners, kinematic transformation limitations, etc.
Real-time-event path acceleration is ineffective if the programmed value is smaller
than the path acceleration calculated during preprocessing for the path section
concerned.