Rockwell Automation FactoryTalk Scheduler Users Guide - Manual (Page 59)

5 • S CHEDULING C ONCEPTS
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Maximum Facility Capacity category ignore the job due date and are focused on
generating a schedule that is efficient in terms of increasing the effective capacity of the
facility. The rules in this category include Least Setup Time, Campaign Sequence Up,
Campaign Sequence Down, Campaign Sequence Cycle, and Least Setup With Campaign.
In addition, each of these rules has an associated Timed rule.
All rules in this category focus on maximizing the facility capacity by reducing chang-
eover cost within the facility. This changeover cost can be in the form of a sequence-
dependent setup time that is required between each pair of operations, or in the form of
maintenance that is required if we fail to follow certain prescribed operating policies (e.g.,
moving from wide to small widths on a roller). In either case, we are striving to eliminate
any unnecessary, unproductive time in the facility.
In cases where we must look at the changeover cost in terms of a sequence-dependent
setup time between successive operations for an entire sequence of operations, we can use
the campaign rules. For example, in mixing paint, we typically want to move progres-
sively from light colors to dark colors in a predefined sequence. This is done to avoid the
expense of fully cleaning the mixing tank when going from a dark to a light color. In some
of these cases, we have a pre-specified sequence that we want to follow. For example, we
may want to process orders in the color sequence A, B, C, D, and E, referred to as a cam-
paign sequence. If we have just processed color A, we would first look for other orders
that also have color A. If none are currently available, we would look for orders with color
B, followed by color C, etc.
The campaign rules provide this capability. These rules allow us to specify a campaign
value (e.g., paint color, curing temperature, etc.) that is associated with each order/
operation and dynamically build campaigns that automatically either increase, decrease,
or cycle this value up and down. The dynamic campaign rules all work in conjunction
with the campaign sequence resource selection rules that select the appropriate resource
whose change in campaign value is the smallest.
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In the case of an increasing campaign strategy, the Campaign Sequence Up rule
selects the operation that has a campaign value that is greater than or equal to the
campaign value of the last selected operation. For example, if we are building an
increasing campaign on part size, the rule selects an operation that has the same or
next highest size. If none of the waiting operations have the same or larger value, the
rule starts a new campaign by selecting the operation with the smallest campaign
value.
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The Campaign Sequence Down rule is similar, but selects operations whose
campaign value is the same or smaller than the campaign value of the last selected
operation.
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The Campaign Sequence Cycle rule alternates back and forth between an increasing
campaign and a decreasing campaign. If the campaign is increasing, it will continue to