Marcin Jamro

CPDev Engineering Environment for Modeling, Implementation, Testing, and Visualization of Control Software

The paper presents the CPDev engineering environment, which is a comprehensive set of integrated tools for programming PLCs, PACs, and DCSs, according to the IEC 61131-3 standard. The environment supports various parts of the project development, including modeling (using SysML diagrams), implementation (with IEC 61131-3 textual, graphical, and mixed languages), testing (by textual, table, and performance tests), simulation (in off-line mode), debugging (with tracing variable values and breakpoints), hardware resources configuration, execution (either on the virtual machine or FPGA-based hardware machine), as well as visualization. The CPDev project is designed in a way supporting portability. Therefore, prepared control programs can be run on any supported target platform, such as AVR, ARM, and x86. The environment has a few applications, both industrial and laboratory.

IEC 61131-3 programmable human machine interfaces for control devices

HMI graphical panels become more and more common in control devices such as industrial PLC controllers. The authors propose a multiplatform solution incorporating HMI development tools and runtime environment which takes into account specifics of such devices, including limited resources. HMI visualization is oriented to graphic objects and can be programmed in languages defined in IEC 61131-3 standard together with control algorithms. An architecture of the mechanism, as well as details of development and runtime components are presented.

An approach to SysML modeling of IEC 61131-3 control software

Designing, developing, and maintaining control software is often a complex and difficult task, especially in larger projects. The paper presents a concept of applying the Model-Driven Development approach with SysML modeling to the IEC 61131-3 development process. Four types of diagrams are used to model different aspects of the system: Requirements Diagram, Package Diagram, Block Definition Diagram, and State Machine Diagram. The models represent POUs and their requirements, resources, and tasks. Some POUs can be modeled as state machines as well. The SysML diagrams can be used to generate code templates for the implementation in IEC 61131-3 languages, such as ST or FBD. The paper also describes an extension to the CPDev engineering environment, which integrates the proposed SysML modeling with programming and execution of IEC 61131-3 software. The example of an engine and pump control system is presented to show various stages of the proposed approach.

Testing Procedure for IEC 61131-3 Control Software

Abstract Control software often performs complex tasks in industry. Its proper operation is crucial for safety as well as efficient management of system resources and processes. However, testing of such a kind of software is usually less organized than in traditional business IT applications. In this paper, procedures and tools for control software testing are proposed. The modeling stage of project development involves SysML as a specification language for Program Organization Units and POU-oriented tests. Corresponding implementation is created in the languages defined in the IEC 61131-3 standard and can be verified using two testing methods, namely table and unit tests. The first option is an easy way of checking whether a function block, a function, or a program produces correct values of outputs for particular values of inputs. More advanced unit tests are specified in a dedicated test definition language, called CPTest+. The proposed procedure is described using the Pulse-Width-Modulator (PWM) example, which is common in the on-off PID control. The presented test tools have been introduced into the CPDev programming environment.

Testing communication tasks in distributed control systems with SysML and Timed Colored Petri Nets model

HighlightsThere is a lack of appropriate methodologies and tools applicable to small- and medium-sized DCSs, especially for analysis and testing of communication tasks during early development stages. The paper proposes a flexible and efficient approach that fills this gap.Communication tasks and their parameters are specified in the SysML modeling language.The diagrams are used to automatically generate a model of communication subsystem in the Timed Coloured Petri Nets (TCPNs) formalism.Simulation of the TCPN model allows to estimate performance of a target system implementation and to predict its behavior in various cases. Nowadays, Distributed Control Systems (DCSs) are commonly used and supersede stand-alone controllers in many industrial applications. Efficient communication is crucial for their proper operation. Unfortunately, there is a lack of appropriate methodologies and tools applicable to small- and medium-sized DCSs, especially for analysis and testing of communication tasks during early development stages. The paper proposes a flexible and efficient approach that fills this gap. It consists of the following steps. At the beginning, communication tasks and their parameters are specified using graphical diagrams from Systems Modeling Language (SysML). Then, the diagrams are used to automatically generate a model of communication subsystem in the Timed Colored Petri Nets (TCPNs) formalism. Finally, simulation of the TCPN model allows to estimate performance of a target system implementation and to predict its behavior in various cases. Thus, potential bottlenecks might be identified earlier and easier, as well as eliminated even before creation of a hardware prototype. The proposed approach has been introduced into the Control Program Developer (CPDev) engineering environment, which allows to program industrial controllers. Appropriate software tools, namely the editor for SysML communication model, the TCPN library with simulation engine, and the testing framework have been prepared.

Communication Performance Tests in Distributed Control Systems

The paper presents a concept and implementation of Communication Performance Tests (CPT) for small distributed control systems. Requirements for the communication performance are specified using SysML notation. Test cases included in the specification are translated into a dedicated test definition language CPTest+. System implementation is then verified by executing the tests generated from the specification and analyzing results of test runs. The procedure is supported by specialized tools integrated with IEC 61131-3 development environment, including SysML model editor and CPTest testing environment.

Development and Execution of POU-Oriented Performance Tests for IEC 61131-3 Control Software

Due to performing complex and crucial tasks in industry, the control software should be created in a way ensuring possibly the highest quality. It can be increased by modeling, standardized implementation, and precise testing. The latter should verify not only functional requirements, but also nonfunctional, such as performance. In the paper, a concept of agile POU-oriented performance testing is proposed, which is dedicated to the IEC 61131-3 standard. The approach allows to measure and analyze execution times of particular Program Organization Units. The concept supports multiple target platforms and allows to take performance into account during early development stages, as well as to perform regression testing. The proposed process consists of a few stages, namely modeling (using SysML diagrams), implementation (in a dedicated test definition language), and execution (by a dedicated testing framework). The approach has been introduced into the CPDev engineering environment for programming industrial controllers.

Measuring, Monitoring, and Analysis of Communication Transactions Performance in Distributed Control System

Nowadays, distributed control systems often consist of complex software executed on many components connected together. Due to performing crucial tasks in industry, it is important to ensure that communication between devices in distributed control systems works as expected and does not reach nor is dangerously close to the given boundary value. The paper presents a concept of Extended Communication Performance Tests, together with their development and execution. What is more, a way of measuring, monitoring, and analysis of communication in a small distributed control system is proposed. A structure of system, communication tasks, and performance requirements are modeled on three kinds of SysML diagrams, namely Block Definition, Internal Block, and Requirement Diagram. Test cases are automatically generated in the CPTest+ test definition language. A set of dedicated tools allows engineers to monitor communication time parameters in the on-line mode, check constraints, and prepare performance analysis. The concept has been integrated with the CPDev engineering environment designed for programming industrial controllers, as well as small and medium-sized distributed control systems.

POU-Oriented Unit Testing of IEC 61131-3 Control Software

Software testing is an important part of project development. Depending on system type and size, it is performed variously. Unit testing is one of the available approaches that is used to ensure that behavior of small software parts is consistent with requirements. It allows to improve software quality and decrease overall costs. Despite the fact that such an approach is commonly judged as a vital concept, it is not usual in control software. In this paper, the comprehensive approach to test the IEC 61131-3 software using unit tests is presented. It supports to create tests in two ways-either in textual and graphical IEC 61131-3 languages or in the CPTest+ dedicated test definition language. The latter is equipped with many advanced features, such as test fixtures and inclusions, parameterized and analog signal extensions, mock objects, as well as a few kinds of suites. The overall solution runs on the developer and testing station; hence, it does not have significant impact on performance of the control program and tests are more reliable and repeatable. To explain the concept, the simple running example is presented in this paper. The described solution has been introduced in the CPDev engineering environment for programming controllers.

SysML modeling of POU-oriented unit tests for IEC 61131-3 control software

Control software performs an important role in various areas in industry. It might be responsible for executing the tasks, where even a small mistake could cause serious damages, loses or could be dangerous for operators. Thus, it is necessary to ensure that the control software quality is as high as possible. There are some approaches to increase it, such as using modeling, standardized implementation, and precise testing. In this paper, the process of modeling unit tests is presented. Such tests are dedicated to Program Organization Units from solutions created according to the IEC 61131-3 standard. The proposed approach allows to model requirements with tests that verify them, a complete test behavior, as well as test suites. For this purpose, three kinds of diagrams from the SysML language are used, namely Requirement, Activity, and Block Definition Diagrams. The model is used to automatically generate templates of tests, the complete tests implementation in the CPTest+ test definition language, as well as a configuration of test suites. The proposed concept has been introduced into the CPDev engineering environment that allows to program controllers.