Siemens SINUMERIK 840D sl Function Manual page 427

● $AA_QEC_ACCEL_1/_2/_3
● $AA_QEC_TIME_1
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
"Acceleration limit values for the characteristic areas 1/2/3"
The acceleration characteristic is divided into three areas. In each area there is a different
quantization of the acceleration steps. In the low acceleration range, an especially high
resolution is required for the characteristic in order to reproduce the widely varying
compensation values there. For this reason, the input signals are quantized more finely,
the smaller the acceleration is.
Recommended values for
– $AA_QEC_ACCEL_1: 20 mm/s
– $AA_QEC_ACCEL_2: 600 mm/s
– $AA_QEC_ACCEL_3: 1000 mm/s
The value of the parameter $AA_QEC_ACCEL_3 must be entered as appropriate to the
requirements; i.e. the neural network only works and learns optimally in this range. If a
higher acceleration is detected than the parameterized working area, the injection
amplitude that was determined during the defined maximum acceleration of the working
range is used. At high accelerations, this injection value is relatively constant.
The recommended values must only be changed if the compensation is insufficient in
these acceleration ranges. For further information, please refer to Section "Further
optimization and intervention options".
"Time constant for the neural QEC (decay time)"
With this, the decay time of the compensation setpoint pulse is set if adaptation of the
decay time is not used.
The optimum decay time must be ascertained manually using the circularity test at a
working point in the mid acceleration range. The procedure is described in detail in
connection with conventional friction compensation (Section "Commissioning of
conventional friction compensation") (analogous to machine data
MD32540 $FRICT_COMP_TIME (friction compensation time constant)).
With the recommended value (15 ms), it is possible to achieve good results.
Range of values: ≥ 0; recommended value: 0.015s
If the decay time adaptation is active, then $AA_QEC_TIME_1 determines the filter time
constant in the center of the operating range (i.e. with 0.5 * $AA_QEC_ACCEL_3).
Neural quadrant error compensation
(= 2% of $AA_QEC_ACCEL_3)
2
(= 60% of $AA_QEC_ACCEL_3)
2
(maximum acceleration of working range)
2
Compensations (K3)
427