Siemens SINUMERIK 808D ADVANCED Parameter Manual page 207

The following values are recommended:
3:
5:
5:
5:
A value that is too low this may lead to additional velocity limitations if a
sufficient number of blocks cannot be made available for interpolation.
MD28530 $MC_MM_PATH_VELO_SEGMENTS additionally increases the memory requirement of
dyn. Look Ahead. Values higher than 5 are only practical in exceptional cases.
3 ... 5
Recommended setting.
28533 MM_LOOKAH_FFORM_UNITS
- Memory for extended LookAhead
-
808d-me42 -
808d-me62 -
808d-te42 -
808d-te62 -
808d-mte40 -
808d-mte60 -
Description:
The machine data is used to configure the work memory for extended LookAhead.
The MD scales the value defined internally through MD28060 $MC_MM_IPO_BUFFER_SIZE,
MD28520 $MC_MM_MAX_AXISPOLY_PER_BLOCK, MD28530 $MC_MM_PATH_VELO_SEGMENTS, MD28535
$MC_MM_FEED_PROFILE_SEGMENTS, MD28540 $MC_MM_ARCLENGTH_SEGMENTS).
Its practical size depends on the part program, the block lengths, the axis dynamics,
and an active kinematic transformation.
The MD should only be set for those channels in which free-form surfaces are also
machined.
0
> 0 : extended LookAhead is active if switched on by MD20443 $MC_LOOKAH_FFORM.
The guide value for free-form surface applications is: 18..20
28540 MM_ARCLENGTH_SEGMENTS
- Number of memory elements for arc length function representation DWORD
-
808d-me42 -
808d-me62 -
808d-te42 -
808d-te62 -
808d-mte40 -
808d-mte60 -
Description:
Number of memory elements available for the arc length function for parameterizing
polynomials.
If this machine data is equal to zero, a fixed interval division is used to represent
the arc length function. In this case, the calculated function is only tangent-
continuous. This can lead to discontinuities in the axis accelerations.
If the function G643 or G644 is used for smoothing and/or COMPCAD, this MD should be
assigned a value of at least 10. In this case, the calculated function also has a
constant curvature which results in a smoother progression of the path velocity, as
well as the axis velocities and accelerations.
Parameter Manual
Parameter Manual, 08/2015, 6FC5397-8EP40-0BA1
for G643 and G644, if only geometry axes are traversed
for G643 and G644, if geometry and rotary axes are traversed
for COMPCAD
for dyn. transformation
:
0, 0, 0, 0, 0, 0, 0, 0...
18
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
: default LookAhead is active.
0, 0, 0, 0, 0, 0, 0, 0...
5
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
0, 0, 0, 0, 0, 0, 0, 0...
3.3 Channel-specific machine data
C02
DWORD
0 100000
0 100000
0 100000
0 100000
0 100000
0 100000
C02
0 100
0 100
0 100
0 100
0 100
0 100
Machine data
-
PowerOn
0/0 S
1/1 M
0/0 S
0/0 S
0/0 S
0/0 S
B1
PowerOn
0/0 S
1/1 M
0/0 S
0/0 S
0/0 S
0/0 S
207