  This work deals with the production planning problem in Discrete Event
Systems, using the Supervisory Control Theory to delimit the search universe
and developing two heuristics based on the maximization of the parallelism to
find sequences that minimize makespan. The role of the Supervisory Control
Theory is to provide the set of all safe production sequences, given by the
closed loop behavior. Although the use of heuristics does not provide
necessarily the absolute optimal solution in general, we present a case study
where it happens for all batch sizes. The efficiency in terms of computation
time is also illustrated by the case study.
