Reinhard Hametner

The adaptation of test-driven software processes to industrial automation engineering

Software components provide an increasing part of added value in automation systems and become more complex to construct and test. Test-driven development (TDD) of software systems has been successfully used for agile development of business software systems. Test cases guide the system implementation and can be executed automatically after software changes (continuous integration & build strategy). However, TDD processes need to be adapted to control automation systems engineering, where real-world systems are challenging to model and to test automatically. In this paper we introduce an adapted TDD process from the business software engineering domain to industrial automation engineering. We identify a set of UML models that enable the systematic derivation of test cases. Based on an initial empirical study we evaluate the adapted TDD process based on an industrial use case to identify strength and limitation of this approach. Major results of the study were that UML models enabled effective test case derivation in the study context.

Test case generation approach for industrial automation systems

The need for increasing flexibility of industrial automation system products leads to the trend to shift functional behavior from hardware solutions to software components. This trend causes an increasing complexity of software components and the need for comprehensive and automated testing approaches to ensure a requested quality level. Nevertheless, a key task in software testing is to identify appropriate test cases typically requiring high effort for test case generation and rework effort for adapting test cases in case of requirements changes. Semi-automated derivation of test cases based on models, like UML, can support test case generation. In this paper we introduce an automated test case generation approach for industrial automation applications which are specified by UML state chart diagrams. In addition we present a prototype application of the presented approach for a sorting machine. Major results showed that state charts (a) can support efficient test case generation and (b) enable automated code generation of test cases and code for the industrial automation domain.

Automation component aspects for efficient unit testing

Automation systems software must provide sufficient diagnosis information for testing to enable early defect detection and quality measurement. However, in many automation systems the aspects of automation, testing, and diagnosis are intertwined in the code. This makes the code harder to read, modify, and test. In this paper we introduce the design of a test-driven automation (TDA) component with separate aspects for automation, diagnosis, and testing to improve testability and test efficiency. We illustrate with a prototype, how automation component aspects allow flexible configuration of a “system under test” for test automation. Major result of the pilot application is that the TDA concept was found usable and useful to improve testing efficiency.

Agile testing concepts based on keyword-driven testing for industrial automation systems

In the field of industrial automation systems software becomes an important factor because engineers tend to move the realization of functional requirements from hardware to software components. The main reason for this is that software components allow increasing product flexibility. As a consequence software complexity increases rapidly and requires systematic, automation-supported and agile testing approaches. Thus, systematic and agile testing are key challenges in industrial control software development to ensure and improve systems quality. Further different implementation standards, i.e., IEC 61131-3 and IEC 61499, arise additional challenges in constructing and testing industrial automation systems software. This paper presents an agile and keyword-driven test approach with focus on testing implementations based on both important industrial standards and illustrates the applicability of the purposed approach in a sample implementation, i.e., a High Speed Pick and Place unit. Main results show the applicability of keyword-driven testing based on a defined subset of keywords (common for IEC 61131-3 and IEC 61499) and thus enable agile and automation-supported testing more effective and efficient.

Automation component architecture for the efficient development of industrial automation systems

The increasing complexity of automation applications needs a new framework architecture to develop automation control systems. This paper shows a workflow for engineering and maintenance applications in the automation control system domain. A new component architecture is specified which supports component-oriented design, reusability, and encapsulation of functional parts. The common component includes an automation sub-component, diagnosis sub-component, an optional condition monitoring sub-component, and a test sub-component for an efficient development process.

A framework for automated testing of automation systems

Increasing complexity of software components in automation systems require systematic and frequent testing approaches. Test-First Development (TFD) - an established approach in business IT software development - promises to support test automation in automation systems development. Nevertheless, linking test case generation, execution, and reporting requires a sound framework to support testing processes more efficiently. In this paper we present a framework for automating test processes based on UML models and TFD. Applying this framework in prototype applications in industry environment identified the framework as promising candidate to improve automation systems development and product quality.

Automated Test Case Generation for Industrial Control Applications

The need for increasing flexibility of industrial automation system products leads to the trend of shifting functional behavior from hardware solutions to software components. This trend causes an increasing complexity of software components and the need for comprehensive and automated testing approaches to ensure a required (high) quality level. Nevertheless, key tasks in software testing include identifying appropriate test cases that typically require a high effort for (a) test case generation/construction and (b) test case modification in case of requirements changes. Semi-automated derivation of test cases based on models, like UML, can support test case generation. In this paper we introduce an automated test case generation approach for industrial automation applications where the test cases are specified by UML state chart diagrams. In addition we present a prototype application of the presented approach for a sorting machine. Major results showed that state charts (a) support efficient test case generation and (b) enable automated generation of test cases and code for industrial automation systems.

Utilizing IEC 61499 in an MDA control application development approach

Traditional control application engineering techniques tend to mix logical functionality with hardware access methods. This greatly impedes reusability. Through separation of the logical control application domain and the specific hardware domain the MDA (Model-Driven Architecture) proposes a solution to this problem. In the domain of embedded systems development this approach brought a great advantage in reducing the complexity of the development process. In this paper we investigate if and how IEC 61499 can be utilized as a DSL (Domain Specific Language) for control application development in the domain of industrial automation systems. We will show the potentials of our work by developing a sample control application using the suggested methods.

Selecting UML models for test-driven development along the automation systems engineering process

Test-driven development (TDD) — an established approach in business IT software development — enables test case generation based on models early in the development process. Applying TDD and models in automation systems engineering (ASE) can increase testing effectiveness and efficiency. A key question is which models are suitable for ASE application. UML models support software and systems engineering development in (a) systematically capturing requirements, (b) describing the static system architecture, and (c) specifying dynamic systems behavior. In this paper we discuss selection criteria for UML model selection in ASE and evaluate strengths and limitations of selected models.

A unit-test framework for event-driven control components modeled in IEC 61499

To cope with the need for flexibility of industrial applications, and other customer related requirements, functional control behavior is shifted from hardware to software. This leads to higher software complexity. Therefore, testing of industrial software is a key technique to ensure overall system quality. Based on an analysis of testing approaches in software engineering and requirements in industrial automation system design with IEC 61499 function blocks a new unit testing process is proposed. The implementation of a platform independent test framework for IEC 61499 function blocks shows the applicability of the proposed testing process with representative examples. The presented solution is the first test framework based on the test first development approach to increase the software quality for industrial automation systems.