Compliance and performance analysis of an IEC 61131-3 structured text engine within a distributed control system
Nuutinen, Lauri (2025)
2025
Automaatiotekniikan DI-ohjelma - Master's Programme in Automation Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2025-08-12
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202508098155
https://urn.fi/URN:NBN:fi:tuni-202508098155
Tiivistelmä
The market for distributed control systems is on the rise. With the increasing market, providers of distributed control systems have an opportunity to enhance the offerings of their systems. Providing customers with standardised programming tools is a competitive advantage for a provider of distributed control systems. Structured text is a widely known programming language defined in the IEC 61131-3. This thesis analyses the state of a structured text programming tool of a distributed control system.
The goal of this thesis is to analyse the IEC 61131-3 compliance and comparative performance of a function block executing structured text code, Iecst. The results of the analyses aim to identify weaknesses in the current implementation of Iecst and to guide the future development of Iecst.
To analyse the IEC 61131-3 compliance of Iecst, first, the functionality of an IEC 61131-3 compliant system is reviewed through literature. Next, the functionality of Iecst is tested with a combination of automated and manual test cases to assess compliance. For the comparative performance analysis, a benchmark is designed based on previous performance testing of similar tools. The benchmark contains tests on different types of structured text statements and a complete program. The performance tests are conducted with Iecst and its main competitors.
During the functionality testing of Iecst, multiple compliance issues were found. The issues were documented, and their severities were estimated. For the critical functionality issues, preliminary solutions were presented. Additionally, the results of Iecst’s performance testing show slower execution speeds than those of the competing blocks. The results suggest that Iecst struggles, especially when the program length increases. Four possible approaches for improving the performance of Iecst are presented.
The goal of this thesis is to analyse the IEC 61131-3 compliance and comparative performance of a function block executing structured text code, Iecst. The results of the analyses aim to identify weaknesses in the current implementation of Iecst and to guide the future development of Iecst.
To analyse the IEC 61131-3 compliance of Iecst, first, the functionality of an IEC 61131-3 compliant system is reviewed through literature. Next, the functionality of Iecst is tested with a combination of automated and manual test cases to assess compliance. For the comparative performance analysis, a benchmark is designed based on previous performance testing of similar tools. The benchmark contains tests on different types of structured text statements and a complete program. The performance tests are conducted with Iecst and its main competitors.
During the functionality testing of Iecst, multiple compliance issues were found. The issues were documented, and their severities were estimated. For the critical functionality issues, preliminary solutions were presented. Additionally, the results of Iecst’s performance testing show slower execution speeds than those of the competing blocks. The results suggest that Iecst struggles, especially when the program length increases. Four possible approaches for improving the performance of Iecst are presented.