Rockwell Automation FactoryTalk Scheduler Users Guide - Manual (Page 52)

F ACTORY T ALK S CHEDULER U SER ’ S G UIDE
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S TEP 4: L OAD O PERATION B-20
S TEP 5: L OAD O PERATION C-20
The first step in the simulation-based sequencer is to load all operations that can begin at
the current time. In this example, Operation 10 for Job A (A-10) can be loaded on
Resource 1, and Operation 10 for Job B (B-10) can be loaded on Resource 2. Next, the
simulated time is advanced to the ending time of Operation A-10, and Operation C-10 is
then loaded on Resource 1. Next, simulated time is advanced to the end of Operation
B-10, and Operation A-20 is loaded on Resource 2. Next, simulated time is advanced to
the end of Operation C-10, and Operation B-20 is loaded on Resource 1. Next, simulated
time is advanced to the end of Operation B-20. Since no further operations remain to be
loaded on Resource 1, simulated time is advanced to the end of Operation A-20 where the
final operation, C-20, is loaded on Resource 2.
In contrast to the algorithmic sequencer, the simulation-based sequencer only moves time
forward. It only advances time forward once all operations that are to be loaded at that
time have been loaded. Hence, the simulation-based sequencer temporarily stops time and
examines the entire job set, advancing to the next event time once all operations have been
loaded. The algorithmic sequencer, on the other hand, is constantly moving back and forth
in time as it loads all operations for each job. It starts at the current time and goes forward
in time loading all operations for this first job. It then returns to the current time and again
moves forward in time to load all operations for the second job. It continues in this
fashion, moving forward and backward in time, until all jobs are fully loaded on the
planning board. Hence, the algorithmic sequencer fixes a job and works across time,
advancing to the next job once all operations have been loaded.
Time
Resource 1
Resource 2
5 10 15
B-10
A-10 C10
A-20
B-20
Time
Resource 1
Resource 2
5 10 15
B-10
A-10 C10
A-20
B-20
C-20