Siemens SINUMERIK 840D sl Function Manual page 124

F2: Multi-axis transformations
2.12 Online tool length offset
The following machine data and setting data are available for configuring online tool length
compensation:
Machine data / setting data
MD21190 $MC_TOFF_MODE
MD21194 $MC_TOFF_VELO (speed online tool
offset)
MD21194 $MC_TOFF_ACCEL (acceleration on‐
line tool offset)
SD42970 $SC_TOFF_LIMIT (upper limit of off‐
set value $AA_TOFF)
With the acceleration margin, 20% is reserved for the overlaid movement of online tool length
offset, which can be changed via the following machine data:
MD20610 $MC_ADD_MOVE_ACCEL_RESERVE(acceleration margin for overlaid
movements)
Activation
The TOFFON instruction can be used to activate online tool length offset from the part program
for at least one tool direction, if the option is available. During activation an offset value can
be specified for the relevant direction of compensation and this is immediately traversed.
Example: TOFFON(Z, 25).
Repeated programming of the instruction TOFFON( ) with an offset causes the new offset to
be applied. The offset value is added to variables $AA_TOFF[ ] as an absolute value.
Note
For further information about programming plus programming examples, please see:
Reference:
Programming Manual, Job Planning; Transformations
As long as online tool length offset is active, the VDI signal on the NCK → PLC interface in the
following interface signal is set to 1:
DB21, ... DBX318.2 (TOFF active)
While a correction movement is active, the VDI → signal in the following interface signal is set
to 1:
DB21, ... DBX318.3 (TOFF movement active)
Reset
Compensation values can be reset with the TOFFOF( ) command. This instruction triggers a
preprocessing stop.
Accumulated tool length compensations are cleared and incorporated in the basic coordinate
system. The run-in is synchronized with the current position in main run. Since no axes can
be traversed here, the values of $AA_IM[ ] do not change. Only the values of the variables
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Meaning for online tool length offset
The contents of $AA_TOFF[ ] are traversed as an
absolute value or integrated
Speed of online tool length offset
Acceleration of online tool length offset
Upper limit of tool length offset value
Function Manual, 01/2015, 6FC5397-2BP40-5BA2
Special functions