Rockwell Automation FactoryTalk Scheduler Users Guide - Manual (Page 100)

F ACTORY T ALK S CHEDULER U SER ’ S G UIDE
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developed is a “2 by 5 Pool 4,” which is what we need. If we attach this time pattern to our
Labor resource, we can check our results using the Sequence > Simulate option. The
comparison reveals that the number of late orders is now four. Using the backward
method followed by the forward by release date option provides an increase in the number
of late orders (eight) with all orders scheduled. Increasing the labor pool to five results in
five late orders for Backward By Due Date and Forward By Release Date. The simulation
yields four late orders.
Analysis summary
Throughout our analysis of schedule options, we have assumed that the primary objective
was to reduce the number of late orders. We started with 20 late orders for our baseline
case and reduced this number to four. In most scheduling environments, it is necessary to
consider multiple performance measures when evaluating the quality of a schedule. For
example, although we were able to reduce the number of late orders significantly, some of
our methods reduced the number of late orders but caused the average late value of our
late orders to be rather large.
So let’s consider one additional performance measure for the schedules we evaluated: the
largest difference between the due date and completion date for our latest end item (latest
end order). Although this additional performance measure is not included in the Baseline
Comparison, it can be obtained from the Schedule Analyzer. A summary of our eight
main cases is given next.
Case 1: Forward By Release Date
Case 2: Forward By Due Date
Case 3: Simulation (default rules)
Case 4: Simulation (new rules)
Case 5: Backward By Due Date & Forward By Release Date
Case 6: Simulation (new rules Labor Pool 4)
Case 7: Backward By Due Date & Forward By Release Date (Labor Pool 5)
Case 8: Simulation (new rules Labor Pool 5)
1 2 3 4 5 6 7 8
Late 20 21 9 11 8 4 5 4
Early 0 0 0 0 0 0 0 0
On Time 13 12 24 22 25 29 28 29
Avg. Late 1:16:01 1:16:07 2:04:28 1:19:58 7:06:53 2:21:05 2:08:30 2:20:56
Latest End Order 3:18:03 2:33:55 4:13:54 3:15:58 10:14:21 3:13:13 3:15:05 3:12:49