Siemens SINUMERIK 840D sl Function Manual page 123

MD21190 $MC_TOFF_MODE (operation of tool offset)
The following machine data can be used to set whether the content of the synchronization
variable $AA_TOFF[ ] is to be approached as an absolute value or whether an integrating
behavior is to take place.
MD21190 $MC_TOFF_MODE
The integrating behavior of $AA_TOFF[ ] allows 3D remote control. The integrated value is
available via the system variable $AA_TOFF_VAL[ ].
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
online tool offset)
SD42970 $SC_TOFF_LIMIT (upper limit of
offset 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 parts
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:
References: /PGA/Chapter "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)
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
F2: Multi-axis transformations
1.12 Online tool length offset
Meaning for online tool length compensation
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
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