Siemens SINUMERIK 840D sl Function Manual page 438

K3: Compensation
5.6 Friction compensation (quadrant error compensation)
● Since a characteristic is learned and stored for every direction of acceleration, double the
● The number of learning passes must be raised because only every second passage
● If the characteristic resolution is the same, commissioning takes longer.
Figure 5-25
Changing the characteristic ranges
The acceleration characteristic is divided into three ranges. In the low acceleration range, an
especially high resolution is required for the characteristic in order to reproduce the widely
varying compensation values there. Therefore, the lower the acceleration rate, the finer the
quantization of the input quantity (see diagram below).
In the high acceleration range, there are only small changes in the compensation values so
that a small resolution is perfectly sufficient.
The percentage settings recommended in Section "Parameterization of neural QEC" for
$AA_QEC_ACCEL_1 (2% of $AA_QEC_ACCEL_3) and for $AA_QEC_ACCEL_2 (60% of
$AA_QEC_ACCEL_3) are based on empirical values measured on machines with a
maximum acceleration rate (= operating range) of up to approx. 1 m/s
If the working range is significantly reduced, then the limit values for a
somewhat higher as a percentage of a
the range of approx. 5% of the maximum acceleration. Useful boundaries for
$AA_QEC_ACCEL_2 are approx. the values 40% to 75% of the maximum acceleration.
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memory space is required in the non-volatile user memory. The machine data below must
be adjusted accordingly.
MD38010 $MA_MM_QEC_MAX_POINTS
(number of values for quadrant-error compensation with neural network)
occurs at the same location.
Example of directional friction compensation (circularity test)
. However, $AA_QEC_ACCEL_1 must not exceed
3
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
.
2
and a must be set
1 2
Extended Functions