Siemens SINUMERIK 840D sl Function Manual page 485

Functionality
The current closed-loop control gain for clearance control is produced by the active
characteristic specified via machine data:
• MD62510 $MC_CLC_SENSOR_VOLTAGE_TABLE1 (coordinate voltage of interpolation
points sensor characteristic 1)
• MD62511 $MC_CLC_SENSOR_VELO_TABLE1 (coordinate velocity of interpolation
points sensor characteristic 1)
or
• MD62512 $MC_CLC_SENSOR_VOLTAGE_TABLE2 (coordinate voltage of interpolation
points sensor characteristic 2)
• MD62513 $MC_CLC_SENSOR_VELO_TABLE2 (coordinate velocity of interpolation
points sensor characteristic 2)
CLC_GAIN can be used to multiply the closed-loop control gain of the characteristic by a
programmable factor.
Increasing the gain (CLC_GAIN > 1.0) may lead to oscillation in the controlled axes!
Instant of activation
The modified closed-loop control gain is effective in the part program block in which
CLC_GAIN has been programmed or, if this block does not contain any executable
instructions, in the next part program block with executable instructions.
Response to characteristic changeover
The programmed factor remains active even when the gain characteristic is changed over
with CLC_SEL, i.e. it is immediately applied to the newly selected characteristic.
Response to CLC_GAIN=0.0
If the closed-loop control gain for clearance control is deactivated with CLC_GAIN=0.0, the
CLC position offset present at the time of deactivation is retained and is not changed. This
can be used for example when laser-cutting sheet steel to "skip over" sections of sheet that
are not to be machined without foundering.
If the tool orientation is changed when 3D clearance control is active and the closed-loop
control gain has been deactivated (CLC_GAIN=0.0), the CLC offset vector is rotated
simultaneously. This generally induces an offset in the CLC operating point on the workpiece
surface (see following diagram).
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
CAUTION
TE1: Clearance control
11.6 Programming
485