Programmable Logic Controller Implementation Research Articles

The Role of PLC in Automation, Industry and Education Purpose: A Review

Programmable logic controller (PLC) plays a significant role in every era, either it is in field of automation, industry or educational purposes. As the demand for automation grows exponentially, control systems need to be easy to program, flexible, reliable, and cost-effective. This article provides an overview of PLC implementation in automation, industry, and education. This article reviews an investigation into the role of PLC in automation, industrial, and educational goals. PLC has its own limitations, but research shows that it has more benefits than limitations. After survey it will see that the PLC can be used in any application, either it is simple or complex control systems. The analysis conducted and focuses on the concept, operation, advantages and practical applications of PLC, as well as comparison with other control systems.

Implementation of FATEK PLC Based Three Floor Elevator System

The implementation of a low-cost FATEK PLC-based three-floor lift system is described in this study. Elevator systems are critical for vertical mobility in buildings, and their control methods have been revolutionized by the use of programmable logic controllers (PLCs). To control the motion of the lift, we use a DC geared motor. In this example, push buttons are used to direct the elevator to the desired floor. In this scenario, ladder diagram programming was utilized. Because the PLC is easy to programme.

Boundary-Based Predictive Controller and Its Application to Control of Dissolved Oxygen Concentration in Activated Sludge Bioreactor

This article presents the concept of boundary-based predictive controller (BBPC) as an effective tool to control industrial processes with <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on-</small> - <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> actuator, for which the control goal is defined to keep the process output within the desired range. An example use of BBPC is shown in application to control of dissolved oxygen (DO) concentration in the laboratory activated sludge setup with biological reactor. It is suggested how to identify dynamical parameters of the proposed DO concentration model and how to provide adaptability required to ensure desired control performance in the presence of significant changes of process load disturbance. Practical implementation in programmable logic controller in the form of a general purpose library function block is also presented. Experimental comparison with conventional <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> – <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> controller shows robustness and superiority of the proposed BBPC.

Implementation of PLC Based Automated CNG Tank for Chuter Assembly Line

Abstract: The purpose of this study is to discuss Programmable Logic Controller (PLC). PLC is a type of digital computer that automates electromechanical activities like controlling machinery or manufacturing lines, among others. PLC’s are employed in numerous equipment and industries. The primary purpose of implementing a PLC is to eliminate concerns with relay irregularity and logic control. HMI (Human Machine Interface) is used in conjunction with a PLC to control and monitor the performance of industrial devices The aim of this project is to illustrate the usage of PLC in automated CNG tank for chuter assembly line and the utilization of its high capabilities and efficiency to process input and output signals from several sensors. With the help of software validation and hardware implementation used for demonstrating the ease of operation with the control system.

Design and Implementation of PLC based Smart Coffee Maker

Automation is preferred in every production and service field to reduce human intervention to achieve high efficiency, reliability and less human effort. In this paper the design of a smart coffee maker is implemented using a Programmable Logic Controller (PLC). The proposed coffee machine includes eight different modes that offer hot drinks ranging from black coffee to white tea depending on the user’s input. Because of its durability and ease of installation and maintenance, the proposed Smart Coffee Maker system includes a PLC controller. Furthermore, the PLC monitors the input on a regular basis, and the actuators utilized in the project, such as the conveyor belt, various valves, and the lamp, are controlled based on the input and custom program downloaded in the PLC to achieve the automation of the coffee making process. Toggle switches are used to select the appropriate mode, while limit switches are used to assure the operation sequence by functioning as a control signal/input to turn the conveyor belt motor ON/OFF. The smart coffee maker technology has been tested in the laboratory and has shown to be effective.

Design and Implementation of Programmable Logic Controller Based Automatic Transfer Switch

A PLC-based automatic transfer switch (ATS) may improve production in the industry efficiency and also the household power connection. It's an electrical switch that may be used to change the load when the main power is failing to supply electricity. Manually controlled transfer switches exist. In this scenario, a switch must be thrown by an operator to take manual control of the system. Some, on the other hand, are activated automatically when the main power source fails. When a major source of electricity is no longer functioning, power from a new or used generator can be either manually or automatically transferred when utilize a transfer switch for transferring control to the on-side application. Using a programmable logic controller (PLC), we describe the implementation and design of an automatic transfer switch (ATS). The primary function of a transfer switch is to divert electricity from the main grid to a standby power supply. Single-phase and three-phase circuit breakers, Siemens Logo PLC, relays, and indicator lights are used in this system. This portable and economic system would be helpful to every domestic, industrial, factory, and academic institution.

Design and Implementation of Programmable Logic Controller Based Automatic Transfer Switch

A PLC-based automatic transfer switch (ATS) may improve production in the industry efficiency and also the household power connection. It's an electrical switch that may be used to change the load when the main power is failing to supply electricity. Manually controlled transfer switches exist. In this scenario, a switch must be thrown by an operator to take manual control of the system. Some, on the other hand, are activated automatically when the main power source fails. When a major source of electricity is no longer functioning, power from a new or used generator can be either manually or automatically transferred when utilize a transfer switch for transferring control to the on- side application. Using a programmable logic controller (PLC), we describe the implementation and design of an automatic transfer switch (ATS). The primary function of a transfer switch is to divert electricity from the main grid to a standby power supply. Single-phase and three-phase circuit breakers, Siemens Logo PLC, relays, and indicator lights are used in this system. This portable and economic system would be helpful to every domestic, industrial, factory, and academic institution.

Petri Net-Based Semi-Compiled Code Generation for Programmable Logic Controllers

Industrial discrete event dynamic systems (DEDSs) are commonly modeled by means of Petri nets (PNs). PNs have the capability to model behaviors such as concurrency, synchronization, and resource sharing, compared to a step transition function chart or GRAphe Fonctionnel de Commande Etape Transition (GRAFCET) which is a particular case of a PN. However, there is not an effective systematic way to implement a PN in a programmable logic controller (PLC), and so the implementation of such a controller outside a PLC in some external software that will communicate with the PLC is very common. There have been some attempts to implement PNs within a PLC, but they are dependent on how the logic of places and transitions is programmed for each application. This work proposes a novel application-independent and platform-independent PN implementation methodology. This methodology is a systematic way to implement a PN controller within industrial PLCs. A great portion of the code will be validated automatically prior to PLC implementation. Net structure and marking evolution will be checked on the basis of PN model structural analysis, and only net interpretation will be manually coded and error-prone. Thus, this methodology represents a systematic and semi-compiled PN implementation method. A use case supported by a digital twin (DT) is shown where the automated solution required by a manufacturing system is carried out and executed in two different devices for portability testing, and the scan cycle periods are compared for both approaches.

Adaptive predictive controller for energy-efficient batch heating process

This paper presents the concept of adaptive predictive controller (APC) designed to improve energy efficiency of heating liquid content in batch process vessel with heating jacket. In practice, such processes are controlled by conventional on–off controllers that ensure fast heatup but it fails to prevent from significant overheating resulting in undesired energy lost and potential content damage. Suggested concept is based on simplified heating model used for prediction of maximal temperature of the vessel content. It ensures time-optimal heatup without overheating and adaptability ensuring robustness to uncertainty on heating dynamics and content rheology. Practical implementation in Programmable Logic Controller (PLC) in the form of a general purpose library function blocks is also presented. It is validated by virtual commissioning based on realistic distributed parameter model of batch heating process with additive measurement noise. Results show robustness and superiority of APC and its ability for significant improvement in heating energy efficiency.

Practical PLC-Based Implementation of Adaptive Dynamic Matrix Controller for Energy-Efficient Control of Heat Sources

For the efficient control of industrial heat sources, adaptation to significant changes in operating conditions and in heat demand variations are the critical issues. This article presents the concept of the adaptive dynamic matrix controller dedicated to control of heat sources operated as a part of heat distribution systems. The adaptation is based on interpolation of the process nonlinearities. The implementation in programmable logic controller in the form of a general purpose function block is presented and practical issues of the minimization of the memory load and computational complexity are addressed. The suggested concept is experimentally validated by both virtual and real commissioning in the industrial conditions. The aspect of energy efficiency of the heat source control systems is also discussed and for assessment of the energy supply performance, the energy error index is proposed. In terms of this index, the results show superiority of the suggested controller over the conventional approaches.

Implementation of Programmable Logic Controller in multi machine operations with product sorting and packaging based on colour detection

Automation is widely used in various industries to increase the speed, accuracy and effectiveness of production and reduce the risk of hazards. In general, the manufacturing industry has a product packaging and sorting process based on size, weight, shape, height and color. Currently, the sorting process in the industry is still mostly done manually which causes human error problems, so the development of industrial automation that is low cost, easy to maintain, efficient, user friendly and more accurate needs to be done. Programmable Logic Controller (PLC) is one of the most widely used for automation equipment in the industry and can be programmed to control machine operations. In this paper, the Mitsubishi Melsec PLC with ladder diagram programming using GX work2 has been developed to control multi-machine operation by product sorting and packaging based on product color. Multi-machine operation consists of three DC motors used for conveyors, two single solenoids, proximity sensors, inductive sensors and limit switches. The proximity sensors are used to detect the products based on color. The system is equipped with an emergency button and alarm system to facilitate the implementation of troubleshooting. To facilitate communication with operators and user-friendly systems, the human machine interface (HMI) is used as an interface for system monitoring and controlling. HMI uses Pro-face from Schneider which is programmed using GP-Pro EX4.0. The ladder diagram has been implemented in the PLC and tested on hardware to simulate the system. Based on test results, MELSEC PLC can communicate with HMI and control multi-operation machines with product sorting and packaging. The machine can separate and package metal products by colour and the packaging system can be monitored and controlled remotely automatically with HMI.

PLC implementation of a real-time embedded MPC algorithm based on linear input/output models

How to efficiently implement Model Predictive Control (MPC) in embedded systems is a topic that is attracting a lot of research recently, due to its impact in practical applications. Implementing MPC in industrial Programmable Logic Controllers (PLCs) is of particular interest due to their widespread prevalence in the industry in comparison with other embedded systems, such as FPGAs or microcontrollers. In this paper, we present a PLC implementation of real-time embedded MPC for multivariable systems described by linear time-invariant input/output models subject to upper and lower bounds on input and output variables. The MPC algorithm uses a recently developed primal active-set method for bounded-variable least-squares problems. We highlight and address some crucial challenges that arise in implementing the MPC algorithm in a PLC. Possible extensions of the proposed methods are presented along with hardware-in-the-loop simulation results of controlling a nonlinear multivariable system using a real industrial PLC.

DESIGN AND IMPLEMENTATION OF DEADLOCK CONTROL FOR AUTOMATED MANUFACTURING SYSTEMS

Petri nets are robust mathematical tools for the modelling, handling, and control of deadlock problems in automated manufacturing systems (AMSs). Several methods have been proposed to prevent deadlocks in AMSs. However, it is important to convert the controlled system represented by Petri nets into the program of a programmable logic controller (PLC) for the implementation of automation tasks. This study proposes a methodology based on Petri nets for deadlock prevention, and generates PLC codes for an AMS. In the suggested methodology, a Petri net model of an uncontrolled system is built, and the controlled Petri net model is developed using a deadlock-prevention method. The controlled Petri net model is then transformed into an automation-controlled Petri net model, which is further converted into a controlled token-passing logic model. The controlled token- passing logic model is utilised to generate the ladder diagrams for the AMS under consideration. The proposed methodology was tested using a real-world AMS at King Saud University labs. It provides an effective method for PLC implementation from a controlled system model represented by Petri nets.

PLC Implementation of Piecewise Affine PI Controller Applied to Industrial Systems with Constraints

In this paper, the design of a piecewise affine proportional integral (PWA-PI) controller algorithm based on invariant set and multiparametric programming for constrained systems is proposed. We implemented the algorithm in a programmable logic controller (PLC) to control an industrial constrained level plant and analyze its behavior. Structured text routines were programmed and validated while controlling two systems with PLC. The results show that the constraints on the error, integral of the error, system output and control action are respected because PWA-PI controllers are tuned from the solution of an optimization problem. The evaluated performance indexes (such as mean square error, Goodhart, overshoot and settling time) show that PWA-PI can be adjusted for better performance than proportional integral (PI) controller tuned by Ziegler–Nichols (Z–N) rules. In the analyzed cases, a settling time of 108 s was obtained, whereas PI controller with Z–N rules presented a 179 s settling time. All of the analyzed performance indexes that we used to evaluate both controllers show PWA-PI as a better controller for constrained systems.

PLC Implementation of Symbolic, Modular Supervisory Controllers

The Supervisory Control Theory was introduced in 1987 by Ramadge and Wonham (1987), and industrial applications are still scarce. This paper outlines an automatic code generation framework to construct the control logic for a programmable logic controller (PLC) from a symbolic, modular supervisor. The modeling and supervisor generation is performed with Supremica (Malik et al. (2017)), and the supervisor is implemented with the IEC 61131-3 programming language Structured Text. This framework is used to teach model-based approaches and SCT to mechanical engineering students.

Programmable Logic Controller for Embedded Implementation of Input-Constrained Systems

Programmable logic controllers (PLCs) have the benefit of being able to withstand a variety of environments while maintaining high reliability compared to computers and other controllers. Traditionally, PLCs have been used for simple ON-OFF control schemes or for proportional-integral-derivative (PID) control. However, recent developments in technology have allowed even low-cost PLCs to implement more advanced and efficient algorithms. This paper investigates a PLC implementation of the specialized Projected Gauss-Seidel (PGS) algorithm. The PGS algorithm is able to quickly and efficiently solve both symmetric and asymmetric mathematical programming problems. The algorithm can be further utilized to solve more complicated problems such as model predictive control (MPC). The focus of this paper is to solve a general constrained optimization problem on a PLC and to expand the capability to solve a MPC example. The DirectLogic Do-More PLC is exploited both for computational efficiency and for memory utilization.

A Method for PLC Implementation of Supervisory Control of Discrete Event Systems

This paper faces the problem of coordinating equipment operation in a flexible manufacturing system consisting of several subsystems including robots, assembling machines, CNC lathes, and mills. There are two main problems in such a system. The first is controlling each individual subsystem considering its own sensors, actuators, and specialized controller to perform a certain sequence of activities. Due to their expertise and/or application of formal methods, programmable logic controller (PLC) practitioners and equipment manufacturers develop efficient and safe solutions to address this problem. The second problem is coordinating the concurrent operation of these subsystems with the goal of producing what is requested as efficiently as possible and guaranteeing the integrity and safety of the system. Supervisory control theory (SCT) is particularly suited to this problem. This paper presents a method that allows a designer to systematically convert SCT’s results into a PLC application program. The resulting program conforms to IEC 61131-3 and preserves the natural modularity of the system to be controlled and control specifications. An extension of this method allows a designer to reuse existing PLC hardware and application programs designed for the control of equipment by easily integrating with the code corresponding to the SCT solution. A major portion of this code may even be automatically generated, reducing development time and minimizing editing errors.

PLC Implementation of a Nonlinear Model Predictive Controller

This paper describes the implementation of an efficient model predictive control (MPC) approach on a standard programmable logic controller (PLC). PLCs are commonly used in industrial automation but are typically limited in view of computational performance and memory. The MPC scheme in this contribution is well suited for nonlinear input constrained systems with sampling times in the millisecond range and can also be applied to tracking control problems. Experimental results for a laboratory crane demonstrate the real-time applicability of the PLC implementation.

An improved hybrid approach for the PLC-based implementation of reduced RW supervisors

A successful application of a hybrid (mixed Petri net/automaton) approach for the real-time supervisory control of an experimental manufacturing system was reported recently. The hybrid approach includes a Ramadge--Wonham (RW) supervisor in the form of an automaton. The reduced RW supervisor offers fewer states for the programmable logic controller (PLC) implementation of the hybrid controller with less memory requirements, but due to a problem called the avalanche effect, the PLC implementation of the hybrid controller with the reduced RW supervisor was not possible. This paper proposes a method to both detect and eliminate the avalanche effect problem for a RW supervisor in the form of an automaton, which enables the PLC implementation of the hybrid controller with the reduced RW supervisor. In addition, this paper improves the recently proposed hybrid approach by including the reduced RW supervisor and the avalanche effect detection and elimination method. The applicability of the improved hybrid approach is demonstrated by the PLC-based real-time control of an experimental manufacturing system.

Study on LD-VHDL conversion for FPGA-based PLC implementation

Programmable logic controllers (PLCs) have been widely used in manufacturing systems for many years. PLC performance is highly constrained by speed of the microprocessor and real-time firmware of the PLC. To enhance conventional PLC performance and flexibility, this paper proposes a new PLC design based on field programmable gate array (FPGA) with parallel execution mechanism and reconfigurable hardware structure. Since ladder diagrams (LD) are the most popular programming language of PLCs, the essential approach of this research is to convert LD programs to equivalent and very high speed integrated circuit hardware description language programs (VHDL), which are the major programming language for FPGA design. This conversion process requires two steps. The first step is to convert the LD program to a VHDL program, in which the LD sequence is controlled by a state machine process. The second step is to optimize the state machine process with concurrent sensitive signals to assure that independent operations in the LD program can be executed in parallel in FPGA. Considering the diversity of LD instructions from different PLC providers, a universal converter with an extended Boolean equation as a bridge is introduced to implement the conversion of LD programs to VHDL. In the second step, the condensed simultaneity graph theory (CSG) is applied to optimize the converted VHDL program with concurrent sensitive signals, which is explained by a practical example.