Rockwell Automation FactoryTalk Scheduler Users Guide - Manual (Page 99)

7 • S CHEDULE A NALYSIS
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Now, use the Sequence > Forward > By Release Date menu option to schedule the
remaining orders.
Reviewing the comparison indicates that we have reduced our number of late orders by 12
compared to our base case.
A closer inspection of our comparison shows that we have increased the lateness of our
late jobs significantly. If determining the better schedule is your responsibility, you may
have to take a closer look at the details of the late orders, which you can do easily by using
the Schedule Analyzer. For now, let’s continue our analysis.
Bottleneck scheduling
FactoryTalk Scheduler bottleneck scheduling is based on the concepts of the theory of
constraints. It attempts to develop a schedule that emphasizes the use of the declared
bottleneck resources. If you select the Database > View menu option, followed by the
Database > Open > Resources menu option, you will be able to see that none of our
resources have been checked as a bottleneck resource. Before we can use this method, we
first need to determine if we have any resources that are truly bottlenecks.
One method for identifying bottlenecks is to examine the queue in front of each resource
over time. We can easily do this by opening the Charts window and looking at the waiting
time plots for each resource. With one exception, there is very little work waiting. The
exception is the Assembly and Pack Area 1 resource and the Machiner, which has as much
as 56 hours and 30 hours of work, respectively, waiting for the resource. Although this
would tend to indicate that this is a bottleneck, which could be set as such, it would have
very little impact on the resulting schedule. There are two reasons for this. The first reason
is that the only orders that use the Assembly and Pack areas are the end product items,
which have only one operation. Thus, the bottleneck concepts do not apply. In addition,
there are two Assembly and Pack areas and the second area is not used. This is because
the constraint or bottleneck is not the Assembly and Pack areas but is the availability of
labor. Each operation at these areas requires two labor resources, and we have a labor pool
of three. Thus, the second area will never be used.
Since the bottleneck concepts do not apply to additional resources, we need to consider a
different approach. One possible alternative is to consider the impact of increasing our
labor pool capacity to four. We’ll do this next.
Adding pooled resources
The number of labor resources (an Adjustable Pooled resource) is defined by the time
pattern attached to that resource. In order for us to change this value, we need to define a
new time pattern with a capacity of four and attach it to our Labor resource. In Appendix
D, we show how to use the time pattern editors. Included in the time patterns already