Yaskawa MotionWorks+ Windows Software User Manual
Page 224
Appendix C MW+ Camming 101
MotionWorks+™
218
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When the next product arrives, the position is recorded with the latch function. The
latch value was 5.6. Since the machine cycle is 5.5, it is expected that the next latch
will arrive at 5.5. If it comes later, the product has stretched. NOTE: For simplicity,
we are using user units in this discussion. In MW+, use the
mPosition_Latch_External_Counts, which is the unmodularized encoder latch in
counts.
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Here is the EXCEL formula for column D:
=IF ( ABS ( MOD ( C6 - C5 , $A$1 ) ) < $A$2 , MOD( C6 - C5 , $A$1 ) * -1 , $A$1-MOD ( C6 -
C5 , $A$1 ) )
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Here are the equivalent formulas to determine the adjustment in MW+:
IF (Abs(CurrentLatch – PreviousLatch) % mMachineCycle_External_Main) < MaxShift THEN Rel-
ativeShift = (CurrentLatch – PreviousLatch) % mMachineCycle_External_Counts) * -1
ELSE
RelativeShift = sMachineCycle_External - (CurrentLatch – PreviousLatch % sMachineCycle-
External))
END
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The following is the equivalent block structure in MW+. The following is a diagram
of a complete program thread that handles adjustments. Blocks are included to control
the timing of the correction, to assure that it takes place when a cut is not occurring.
Another thread is dedicated to capturing the registration (not shown.)