09.95
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9–58

SINUMERIK 840C (IA)
9.5.4.2 Further optimization and intervention options
Checking methods
1st method: Circularity test
2nd method: Display of characteristic – in this display, the compensation amplitude is output
as a % of the maximum speed as a function of the set memory partitioning.
3rd method: Record the learning process for a difficult acceleration (derived from the
SERVICE quadrant error compensation display) with SERVO trace. The following
SERVO trace parameterization is recommended:
Measuring times, trigger conditions:
Trace 2, 3, 4 with start trigger Trace 1, measuring time 200 ms, triggering
time–50 ms
Trace 1: Edge signal threshold for positive passage through zero, edge signal
threshold for negative passage through zero at threshold = 0.
Trace signals:
Trace 1: Partial setpoint FIPO output (for triggering only)
Trace 2: Following error
Trace 3: Learning criterion QEC
Trace 4: Quadrant error
Examination of Trace 2 and 3:
SIf the bump can be seen in following error and not in learning criterion QEC,
the measuring time in the area examined must be increased.
SIf the bump can be clearly seen in learning criterion QEC and a later fault is
also included, the measuring time must be reduced.
SIf vibrations are contained in the following error at the time of the passage
through zero, they must be eliminated by trying other control settings. A very
high position setpoint smoothing can only be considered a solution during the
automatic learning stage. Conditions can also be improved by reducing the
measuring time.
Table: Possible errors and how they can be eliminated
Error: Recognized by: Remedial action:
Compensation not adequate Circularity test Increase the learning rate or
increase number of learning
passes
Overcompensation in the lower
and middle range SCircularity test
SDisplay of the characteristic:
Overshooting in this range
Increase measuring time in this
range (MD 1372*, MD 1376*)
Over compensation in the upper
range SCircularity test
SDisplay of the characteristic:
Overshooting in this range
SCheck with SERVO Trace
Check the following error and
learning criteria QEC with
SERVO Trace or DAC output and
adapt the measuring time in this
range on the basis of that
information (MD 1380*)
Large fluctuations in
compensation: sometimes
overcompensation, sometimes
undercompensation
SCircularity test
SDisplay of the characteristic:
Large fluctuations
Decrease learning rate, restart
learning process (with fewer
learning passes)
9 Drive Servo Start-Up Application (as from SW 3)
9.5.4 Neural quadrant error compensation (QEC – SW 4)