Evaluation of a UML-Based Versus an IEC 61131-3-Based Software Engineering Approach for Teaching PLC Programming

Abstract

A field experiment investigated the evaluation, teaching, and application of two different approaches to automatic control in programmable logic controllers, in particular comparing the Unified Modeling Language (UML) to the classic procedural paradigm (IEC 61131-3). A total of 85 apprentices from a vocational school for production engineering with a specialization in mechatronics took part in the training and the experiment. This paper details the results of the training using both approaches, and the correlations found between the modeling and/or programming performance and cognitive abilities, interest, workload, expertise, and school grades. In general, the results show that students can be trained to carry out authentic programming tasks within one and a half days, even for beginners in programming. The data distinguish the two approaches. Function Block Diagram programming (IEC 61131-3) can be best predicted by the grade in mathematics, programming experience, and cognitive demand. For performance in UML class diagram and state chart modeling, the grade in mathematics plays an even more prominent role; this explains the greater variance in modeling performance in the UML group than in the 61131/Function Block Diagram group. With respect to other findings, the paper concludes that special problem-solving skills and skills for abstract thinking should be taught when teaching UML-based modeling approaches.

Usability Experiments to Evaluate UML/SysML-Based Model Driven Software Engineering Notations for Logic Control in Manufacturing Automation

“…classes or function blocks) should be measured differently than the correctness of low level behavioral model elements (e.g. correct steps or transitions from one state to another one [63]) due to the different degree of difficulty and ease of change in case of an error. Because IEC 61131-3 FBD is a language without nodes and edges Schalles approach is not feasible.…”

“…• OO modeling and FBD programming show different relations to variables like cognitive abilities, experience, workload, and knowledge the students' performance in the plcUML/CD + SC groups seems to be less related to previous knowledge and cognitive abilities than students' performance in the 61131/FBD groups [63].…”

“…Because in industry very often skilled workers are conducting maintenance tasks and even easy design modifications 1st and 2nd year apprentices from a vocational school in Munich (89 subjects) act as subjects. Selected results of this experiment are reported already in [63].…”

“…grades in mathematics, German, automation, and mechatronics as well as cognitive capabilities, motivation levels, challenge, and workload (single instruments are described in [63]). As performance variable the programming/modeling achievement was evaluated.…”

“…This difference is slightly not significant (ANOVA, F(1, 81) = 3.60, p = 0.06), cf. [63]. On the basis of the unexpected results further analysis of models, modeling process and the relation between model and results as well as subjective results have been conducted.…”