Discrete systems for railway electrodynamic centralization installations

Research in bidirectional data flow analysis seems to have come to a halt due to an impression that the case for bidirectional data flow analysis has been considerably weakened by a plethora of investigations based on decomposability of known bidirectional placement algorithms into a sequence of purely unidirectional components. This paper shows that the approach of decomposability is not general enough in that it derives its power from the simplifying graph transformation of edge-splitting and the favourable nature of flows in partial redundancy elimination (PRE). This follows from the fact that in the absence of edge-splitting, PRE cannot be performed using a sequence of cascaded unidirectional flows. Further, edge-splitting inherently converts data flows involved in PRE into unidirectional flows. In our opinion, this obviates the need of an alternative formulation. We also show that edge-splitting cannot convert data flows involved in "truly" bidirectional data flow problems into unidirectional flows. Thus not every bidirectional data flow problem can be converted into unidirectional flows. Besides, we argue that the premise that bidirectional analysis is more complex than unidirectional analysis, is invalid. We also mention some issues in bidirectional data flow analysis which need to be investigated.

In this article, a speed control of DC motor is designed and illustrated using fuzzy logic-based programmable logic controller (PLC). The DC motor is an attractive part of electrical equipment in many industrial applications requiring variable speed and load specifications due to its ease of controllability. The designed system is consisted of three main parts including programmable logic controller, pulse width modulation (PWM) bipolar drive and DC motor. In the control section, PLC is used as real time controller and fuzzy logic algorithm is designed based on nonlinear model of DC motor, and its parameters are optimized in MATLAB software. Then, it is implemented using rslogix5000 PLC and programming language ladder for speed control. Finally, with favorable results, the efficiency of the controller is successfully proved under different load conditions. The obtained results demonstrate the efficiency of the PLC intelligent controller in enhancing the accuracy and speed control of DC motor.

With the rapid advancement of science and technology, the role of technology in industry is also increasing, particularly through automation that simplifies and enhances work process efficiency. To support this development, education plays a crucial role in enhancing students' competencies. One relevant subject in industrial technology is Programmable Logic Controller (PLC). In PLC education, trainer tools are used to help students understand industrial control concepts. At Politeknik Manufaktur Bandung, particularly in the Mechatronics and Automation Engineering Technology programs, the use of PLC trainers is still limited to basic input-output features. Survey results show that most students only understand Ethernet communication protocol and have never connected more than one PLC in a single system, resulting in a limited understanding of inter-PLC communication. This research aims to develop a trainer that teaches various PLC communication protocols, including Controller Link, DeviceNet, Serial RS-232C, and Ethernet, with inter-PLC and HMI communication implementation. The system uses three PLCs, where an Omron CP1H PLC as the master uses Controller Link to communicate with another Omron CP1H PLC as a slave, DeviceNet for remote slave devices, Serial RS-232C to communicate with an Omron CJ2M PLC as a slave, and Ethernet connected to Human Machine Interfaces (HMI) Omron NB7W and Kinco GL070E for PLC data monitoring. Based on the assessment results, the overall trainer tool evaluated received an effectiveness score of 95.1% from 6 aspects of the assessment. This trainer is expected to enhance students’ understanding of PLC communication protocols and their applications in integrated systems.

The major obstacles to teaching Programmable Logic Controller (PLC) is a variety of PLCs and the rapid pace of technological development with new models and innovations. Moreover, costs incurred in the setting up of comprehensive and modern PLC laboratory facilities, and in the required periodic updating of teaching material and equipment are, as a result, very high. After investigated the conception and features of PLC and embedded system, the development of the embedded PLC for teaching machatronics students is proposed in this paper with the seamless combination of the LabVIEW software and the ARM Microcontroller with the LabVIEW embedded module. The flexibility of the proposed PLC makes it relatively easy and less costly to teach the basic principle of different kinds of PLCs due to their variety and rapid change. The implementation of the embedded PLC is discussed and evaluated. The results of evaluation shows that embedded PLC can be taught in an uncomplicated manner.

Programmable logic controller (PLC) is a reliable platform for regulatory control in industrial environment. Capability of PLC as an automation solution platform is getting enhanced over the years. Advancements in PLC capability open up possibility of deploying advanced control and optimization solutions on PLC. Optimization solver is primary building block of the advanced automation solutions; feasibility of deploying open source optimization solvers on PLC is uncertain because of platform related constraints. This work evaluates feasibility of deploying open source optimization solvers on PLC and highlights deployment challenges for PLC platform. Optimization complexity is varied using widely used generalized test functions to assess limitations of PLC platform. A realistic case study of parallel compressor train load allocation optimization is presented to validate the analysis findings and discuss a practical application of optimization on PLC platform.

A Programmable Logic Controller (PLC) is a standard industrial control device that provides a simple, yet robust, method of controlling manufacturing and dynamic processes. As a result of their low cost, adaptability, and reliability, PLCs are by far the most common control mechanism used by manufacturing businesses of all sizes for environment control, food processing, motion control, and automated test equipment. Yet even though PLCs are heavily used by industry, their use in teaching control theory concepts is uncommon for mechanical engineering programs. Traditional control systems engineering courses focus on the theory and mathematics of continuous-based control systems and rarely involve the use of PLCs, which provide an excellent platform to teach feedback control. Only a few programs have included a specific focus on non-continuous (on/off) control commonly used in industrial environments. In addition, learning ladder logic, a programming language for PLCs, can be difficult and seem unnecessary for those with a traditional programming background, such as C++. Recognizing the appropriate ways of how and when to use PLCs is a key factor in applying control theory effectively in an industrial or even a research environment This paper reviews the literature devoted to control systems education. It shows how academia is using PLCs in education and how it can complement the traditional focus on continuous-based control. A key objective of this paper is to review the PLC use in mechanical engineering education, which traditionally takes place in a control systems engineering course. This paper will also address a proposal by the authors that implementing PLCs into a control systems course for mechanical engineering students can enable a natural integration of continuous and non-continuous control theory.

A Programmable Logic Controller (PLC) is a very common industrial control system device used to control output devices based on data received (and processed) from input devices. Given the central role that PLCs play in deployed industrial control systems, it has been a preferred target of ICS attackers. A quick search in the ICS-CERT repository reveals that out of a total of 589 advisories, more than 80 target PLCs. Stuxnet attack, considered the most famous reported incident on ICS, targeted mainly PLCs. Most of the PLC reported incidents are rooted in the fact that the PLC being accessed in an unauthorized way. In this paper, we investigate the PLC access control problem. We discuss several access control models but we focus mainly on the commonly adopted password-based access control. We show how such passwordbased mechanism can be compromised in a realistic scenario as well as the list the attacks that can be derived as a consequence. This paper details a set of vulnerabilities targeting recent versions of PLCs (2016) which have not been reported in the literature.

To overcome the shortcomings of external PLC (Programmable Logic Controller) and soft PLC being widely employed in switch control of CNC machine tool, an embedded PLC system was developed by integrating AVR single chip ATMEGA169, PC bus technique and dual port RAM. Both hardware circuit and software of the PLC system were designed and implemented. The software of Industrial PC was developed by using ladder-diagram IDE (Integrated Design Environment) based on the platform of Borland C++ Builder. In this environment, it can fulfill edit, compilation and communication function of ladder-diagram file. It also can monitor and diagnose PLC running status. This developed embedded PLC system has the characteristics of compact structure, high communication and reliability. It can effectively satisfy real-time control requirements of CNC machine tool.

The characteristics and applications of the system for welding machines based on SCM , based on PLC control system and PC-based industrial control system was introduced. It has certain significance to the design of welding machine control system.

Multiple input/output Programmable Logic Controller (PLC) module for educational purposes is fabricated because of current PLC Kit that was unable to enhance learners theoretical understanding and hands-on skill especially for programming, wiring, design of circuit and problem solving. The available PLC Kit comes with a casing which learners struggling in comprehend the theoretical knowledge, cabling connection between input components, PLC modules and output components respectively. Newly designed PLC modules are developed and fabricated with additional input and output devices, cost effective and user friendly. Moreover, this module come with multiple Input/Output (I/O) devices such as push buttons (normally open), DC motor (24V), DC relay (24V), DC solenoid piston cylinder (24V) and DC light (24V) and able to interfacing with different kinds of PLC controller produced by Matsushita, Omron, Siemens and etc. Through conducted surveyed, it is found that on average of 93.20% agreed that newly developed Multiple I/O PLC module is user friendly, safe and attractive to be used while 95.70% participants agreed that there are enhancements in theoretical understanding and hands-on skill aspect in their learning process.

Developing a hybrid programmable logic controller platform for a flexible manufacturing system

Programmable Logic Controllers (PLCs) are widely used for control and automation of machines and processes, so the quality of PLC software has a direct impact on production efficiency. This paper describes a PLC program for a food production line that was completely rewritten using a different software architecture and framework. The PLC hardware and the production line equipment were not changed, so this project provides an opportunity to quantify the impact of different PLC software architecture on production efficiency. The average number of cases of products produced per production hour during the first ten months with the new program was 6.1% higher than the average during the previous ten months with the old program. PLC software, unlike most other software, is often used by the end-user for troubleshooting. In this case, a relatively simple architecture and framework that favors the end-user significantly improved production efficiency over a more sophisticated architecture and framework that favors the software developer. Suggestions for further research on software architecture and framework are given.

This paper proposes a machine vision module for PLCs (Programmable Logic Controllers). PLC is the industrial controller most widely used in factory automation system. However most of the machine vision systems are based on PC (Personal Computer). The machine vision system embedded in PLC is required to reduce the cost and improve the convenience of implementation. In this paper, we newly propose a machine vision module based on PLC. The image processing libraries are implemented and integrated with the PLC programming tool. In order to interface the libraries with ladder programming, the ladder instruction set was also designed for each vision library. By use of the developed system, PLC users can implement vision systems easily by ladder programming. The developed system was applied to sample inspection system to verify the performance. The experimental results show that the proposed system can reduce the cost of installing as well as increase the ease-of-implementation.

Honeypots are a common tool to set intrusion alarms and to study attacks against computer systems. In order to be convincing, honeypots attempt to resemble actual systems that are in active use. Recently, researchers have begun to develop honeypots for programmable logic controllers (PLCs). The tools of which we are aware have limited functionality compared to genuine devices. Particularly, they do not support running actual PLC programs. In order to improve upon the interactive capabilities of PLC honeypots we set out to develop a simulator for Siemens S7-300 series PLCs. Our current prototype XPOT supports PLC program compilation and interpretation, the proprietary S7comm protocol and SNMP. While the supported feature set is not yet comprehensive, it is possible to program it using standard IDEs such as Siemens' TIA portal. Additionally, we emulate the characteristics of the network stack of our reference PLC in order to resist OS fingerprinting attempts using tools such as Nmap. Initial experiments with students whom we trained in PLC programming indicate that XPOT may resist cursory inspection but still fails against knowledgeable and suspicious adversaries. We conclude that high-interactive PLC honeypots need to support a fairly complete feature set of the genuine, simulated PLC.

This article explores the widespread application and importance of the Programmable Logic Controller (PLC) in industry. PLC, as an industrial controller designed specifically for industrial environments, occupies an important position in the field of industrial automation control due to its advantages of being less susceptible to interference, high reliability, easy programming, fast installation, and small size. With the rapid development of PLC technology, great progress has been made in the development of technology, hardware, and software, resulting in increasingly powerful functionalities and significantly enhanced system development and compatibility. This paper mainly analyzes the design ideas and applications of PLC in life and industry in detail, aiming to research PLC and find more scenes in industry fields in which PLC can participate. PLC has a wide range of applications and significant importance in industry. The continuous progress and innovation of its technology will bring more opportunities and challenges to the field of industrial automation control. In the future, with the deepening development of advanced manufacturing models such as Industry 4.0 and intelligent manufacturing, PLC technology is expected to play a greater role in more fields and promote industrial automation to a higher level.