Delta ASDA-A3 Series User Manual page 321

Motion Control
Synchronous Capture axis
In rotary shear applications, the system needs to automatically compensate the mechanical or
material differences in order to ensure the cutting spot is correct. Delta servo drive provides 2
types of compensation functions, synchronous Capture axis and E-Cam phase alignment. The
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introduction of the synchronous Capture axis is as follows. After the external sensor detects the
alignment mark, it sends the digital input signal (DI7) to the slave servo axis through the
hardware wiring. The servo drive compensates the position error according to the deviation
between the set pulse number and the pulse number actually received, and then corrects the
cutting or packing positions until it is within the set zone. You can use the synchronous Capture
axis for compensation if deformation and slippage occur in either the cutter or film of the
packing machine. Reasons that may cause inaccurate cutting are as follows:
Loss of pulse: unstable pulse output from the master axis or the slave axis is unable to
1.
properly receive pulses from the master axis due to noise or other factors.
Errors accumulated over long periods of time: significant calculation error due to the
2.
number of pulses accumulated over long periods of time.
Material slippage: relative slippage between material and roller causing inaccurate cutting
3.
length.
Nature of the material: different tension between materials wound onto the inner circle and
4.
outer circle.
Tension mechanism causing material deformation: material deformed due to tension
5.
mechanism of the machine causing inaccurate cutting length.
Alignment mark position: printing or other factors may cause inconsistent spacing between
6.
marks.
 Compensation mechanism of synchronous Capture axis
The servo drive uses the deviation between the pulse number within two marks set in P5.078
and the actual received pulses within two marks as the basis for correction. Next, the servo
drive calculates the pulse number of the synchronous Capture axis and regards it as the source
for the master axis. The deviation is saved in P5.079. You can directly write the deviation into
this parameter to shift the cutting or packaging spot. You can also shift the cutting or packaging
spot by writing the shift compensation deviation in P1.016, so that the cutting or packing spot
shifting amount is value of P5.079 plus P1.016. During synchronous Capture axis operation, the
deviation in P5.079 remains within a small range. If the deviation increases constantly, it may be
caused by mechanism deviation, signal interference or inappropriate parameter settings. In this
case, set the correction rate and correction rate filter with P5.080 and P1.015. The larger the
correction rate, the faster the synchronous deviation is corrected to 0, but the speed changes
more drastically. In contrast, the smaller the correction rate, the slower the synchronous
deviation is corrected to 0, and the speed changes more moderately. The compensation
mechanism is shown in Figure 7.3.7.15.
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ASDA-A3