Siemens SINUMERIK 802C base line Technical Manual page 80

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Backlash compensation
Overview
Function
Activation
Leadscrew error compensation (LEC)
Overview
Function
Activation
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4-42
In practice, this value can be optimized. To this aim, the thread is first tested
with compensating chuck and the calculated values. Then the values should be
modified sensitively such that the difference path in the compensating chuck
approximates to zero.
Now, the POSCTRL_GAIN values displayed on the service display for axis and
spindle should be identical.
Notice
If MD 32900 DYN_MATCH_ENABLE has been set to "1" for the drilling axis, it
should also be set to "1" for all interpolating axes. This increases the traversing
accuracy along the contour. However, the entries for these axes in MD 32910
DYN_MATCH_TIME [n] must be left at the value "0".
The falsification of axis travel due to mechanical backlash can be compensated
(cf. Technical Manual "Description of Functions").
The axis-specific actual value is corrected by the backlash compensation value
(MD32450 BACKLASH) with each change of the traversing direction.
The backlash compensation is active in all operating modes only after
referencing.
The compensation values are determined by means of the measured error
curve and entered in the control system using special system variables during
start–up. The compensation tables (cf. Technical Manual "Description of
Functions") must be created in the form of NC programs.
The leadscrew error compensation (LEC) changes the axis–specific actual
position by the associated compensation value.
If the compensation values are too high, an alarm message can be output (e.g.
contour monitoring, speed setpoint limitation).
The LEC is only activated in all operating modes if the following requirements
are met:
The number of compensation intermediate points must be defined. They are
only active after Power ON (MD: MM_ENC_MAX_POINTS).
Caution
Changing the MD: MM_CEC_MAX_POINTS[t] or MM_ENC_COMP_MAX _POINTS
automatically reorganizes the NC user memory when the control system is
booting. All user data stored in the user memory (e.g. drive and MMC machine
data, tool offsets, part programs, compensation tables etc.) are deleted.
SINUMERIK 802C base line
Start-Up