A Framework for Modular PLC Programming Based on Object Oriented Design

Sammanfattning

This thesis investigates the development of an object-oriented modular framework for PLC systems, intended for use at Etteplan, an international engineering consultancy. The thesis was motivated by recurring challenges in PLC projects, including unclear program flows, low code reusability, and limited scalability. These issues justify the need for a standardized framework grounded in the IEC 61131-3 standard, fourth edition. Using design science research as the overarching methodology, the thesis combines a literature review and source code review with semi-structured interviews with practicing automation engineers. The result is a platform-independent framework design based on modular architecture and object-oriented constructs, accompanied by development guidelines. The framework template was partially implemented in Beckhoff’s development platform TwinCAT 3. The framework aims to improve code reuse, maintainability, and knowledge transfer within Etteplan’s projects.