1 AIT Asian Institute of Technology

Knowledge-oriented object-based simulation of programmable logic controllers

AuthorTarongoy, Francis Noel J.
Call NumberAIT Thesis no.IE-94-08
Subject(s)Programmable controllers

NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology
PublisherAsian Institute of Technology
Series StatementThesis ; no. IE-94-08
AbstractIn order to cope up with the increasing efficiency and flexibility requirements imposed on the industrial control systems, programmable logic controllers (PLCs) have been widely and extensively used in industries. These programmable devices are programmed frequently for the controlled components/equipments to perform various tasks. However, the development of PLC control program takes much time and requires good knowledge and understanding of PLC operation and functioning. Furthermore, the verification and testing of the PLC program is usually done on-line which increases the equipment down-time and even presents danger both to the personnel and machines involved due to some logic errors in the program. This thesis work is aimed at developing a PLC simulator specifically for training and program verification purposes in the personal computer (PC). The two most commonly used PLC programming methods, the ladder diagram and the mnemonic code, are simulated. The development of the PLC simulation system uses object-orientation in all its stages of development. The analysis starts with the identification of various components involved in the simulation based from the PLC requirements specification; then, the interaction among these components is established along with their essential attributes and functions. As the analysis merges to design, more attributes and functions are added to each object for actual computer implementation. Inheritance hierarchy is further established which serves as the basis for coding the classes in the Borland C++ programming environment. Strategies for checking the connection of the constructed ladder diagram and the syntax of the components used as well as run-time simulation strategies for both programming methods are also developed and implemented. The PLC simulation software developed has been successfully tested and found helpful in understanding the underlying concepts and principles of operation of PLCs. The software enables the users to develop their PLC control programs either in ladder diagram or in mnemonic codes, checks the connection and syntax of the constructed PLC program, and displays its operation on the graphical interface screen. Thus, the software can be used as an excellent tool for acquiring theoretical and practical knowledge about PLC programming and operation even in PC.
Year1994
Corresponding Series Added EntryAsian Institute of Technology. Thesis ; no. IE-94-08
TypeThesis
SchoolSchool of Engineering and Technology (SET)
DepartmentDepartment of Industrial Systems Engineering (DISE)
Academic Program/FoSIndustrial Engineering (IE)
Chairperson(s)Batanov, Dentcho N.
Examination Committee(s)Qi, Yulu ;Bohez, Erik L.J.
Scholarship Donor(s)ADB - Japan;
DegreeThesis (M.Eng.) - Asian Institute of Technology, 1994


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