Bartosz Trybus

Architecture of FPGA Embedded Multiprocessor Programmable Controller

This paper presents the design and implementation of a multiprocessor programmable controller in field-programmable gate array (FPGA). The novelty of the proposed solution is that it combines two approaches used so far in the domain of FPGA implementations of control algorithms, i.e., program based and hardware coded, and applies multiple processors in a single FPGA chip. The controller is programmed according to the IEC 61131-3 standard and runs control tasks in parallel. Performance tests of the prototype show that it is able to execute control programs significantly faster than industrial programmable logic controllers.

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.

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.

Data Acquisition Server for Mini Distributed Control System

The paper describes PACQ, a distributed control mini system. WWW and data acquisition functionality of PACQ server is presented from the user perspective together with a discussion on security issues. The communication between the server and control modules is modelled with hierarchical timed coloured Petri net. Programmability of the control modules using CPDev environment and their system software is also characterized.

Hierarchical Petri Net for the CPDev Virtual Machine with Communications

Hierarchical Coloured Petri nets are used to model interaction of CPDev virtual machine with communication subsystem of a small distributed control and measurement system. The machine executes control programs and implements communications. Both vertical and horizontal communication are modelled, as shown by the example of the distributed system with new SMC programmable controller. The model can be used to analyse correlation between the machine cycle time and communication load and to determine optimal parameters of the system.

Analysis of Challenge-Response Authentication in a Networked Control System

Analysis of authentication time in challenge-response protocol has been presented here. The protocol has been used in a prototype Networked Control System (NCS) with multiple Plant Control Units (PCU) and Supervisory Control Unit (SCU). The units are programmed in IEC 61131-3 compliant CPDev (Control Program Developer) environment. Global variable manager is used to share common data across the network. The paper presents theoretical estimation of the handshake time during authentication between SCU and PCU. Experiments have been carried out to compare the estimations with a real application.

CPDev engineering environment for control programming

Programming a control example by CPDev tool using LD, FBD, and SFC graphical languages of IEC 61131-3 standard is presented. Another example demonstrates the use of data structures and arrays of function blocks in ST textual language. The two parts indicate that CPDev provides now essential functionalities specified in the standard. Remarks how the tool relates to established engineering environments such as CoDeSys, STEP 7, Control Builder F, and ISaGRAF are also given.