Siemens SINUMERIK 840D sl Function Manual page 415

Learning motion
The axis traversing motions that must be executed to learn a specific response are
generated by an NC program. Each learning motion of the sample learning cycle comprises
a group of NC blocks with parabolic movements (ensuring that the axis traverses at the most
constant possible setpoint speed after the zero crossing; see diagram below) in which the
axes oscillate at constant acceleration in each program section. The acceleration is
decreased from group to group. In the diagram below, NC blocks 2 to 3, 5 to 6 and 8 to 9
each form a group; the transitional movements to lower acceleration rates are programmed
in blocks 1, 4, 7 and 10.
Note
So that the learning parameters act as preset, the feedrate override switch must be set to
100% during the learning phase.
Figure 5-30
Assignment of system variables
Before a learning cycle is called, all QEC system variables must be set to the values
required for the learning process. The values recommended in the reference NC program
must be checked and changed if necessary (see Section "Parameterization of neural QEC").
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Note
The circularity test is an integral component of HMI Advanced. The commissioning tool
must be used with HMI Embedded.
Typical traverse motion of an axis when learning the QEC characteristic
Compensations (K3)
5.7 Neural quadrant error compensation
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