Date of Award

Spring 5-31-1996

Document Type


Degree Name

Master of Science in Manufacturing Systems Engineering - (M.S.)


Industrial and Manufacturing Engineering

First Advisor

MengChu Zhou

Second Advisor

Reggie J. Caudill

Third Advisor

Xiuli Chao


In the 1960's and earlier discrete event systems (DES) were controlled by hardwired electromechanical relay systems. In 1969 an electronic programmable logic controller (PLC) was introduced. PLC's have been programmed utilizing relay ladder logic (RLL). RLL is a graphical programming language with software "devices" used to emulate electromechanical devices. RLL programs, however, often become large and difficult to understand because its graphical representation of physical switching devices obscures the discrete event dynamics inherent in the process to be controlled. Petri nets are a methodology for modeling discrete event systems (DES). Using a Petri net based controller, a control strategy could be developed that captures the discrete event dynamics of the process. This should result in a control strategy that is much easier to understand, troubleshoot, modify and evaluate.

Included in

Manufacturing Commons