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FPGA-Based Programmable Logic Controller
Published in Hafiz Md. Hasan Babu, VLSI Circuits and Embedded Systems, 2023
As shown in Fig. 22.1, a PLC consists of input modules, a processor, and output modules. An input accepts a wide range of digital or analog signals from various field devices (sensors) and converts them to a logic signal that the processor may use. Based on program instructions in memory, the processor takes judgments and executes control instructions. The processor's control instructions are converted into a digital or analog signal that can be utilized to control a variety of field devices by output modules (actuators). The desired instructions are entered using a programming device. As a result, PLCs can be complicated, and they're typically constructed on 486 and Pentium processors with a large number of analog and digital I/Os. Occasionally, an application may require the usage of a PLC with very restricted capabilities, but the pricing does not fit the budget. Thus, PLCs are more cost-effective, smaller, and easier to operate than PC-based systems for tiny, stand-alone control of a single process. PLCs, which can handle from 15 to 128 I/O points, are commonly used by control engineers.
Programmable-logic controllers and operation
Published in Raymond F. Gardner, Introduction to Plant Automation and Controls, 2020
There are several different languages that may be used to program a PLC, from BASIC, C, PASCAL, C++, Java, etc. However, since industrial PLC control schemes produce similar functions as the traditional logic used in the electrical ladder diagrams, the most common industrial PLC programming language is ladder-logic. Some PLCs use combinations of ladder-diagram programming with a more sophisticated language. An example might be that when an action occurs, one of the PLCs responses may be to supply a message on a computer screen through a user-defined function generated by the higher-level language. In addition, more complex functions, such as proportional-plus-integral-plus-derivative control (PID) may be available within the PLC software. During operation, the user may be given the ability to tune the system for good response by modifying variables in the program.
Batch and Continuous Process Control
Published in Brian Roffel, Patrick Chin, Computer Control in the Process Industries, 2017
A major breakthrough came in the early 1980s when computer manufacturers developed batch control systems for mini- and microcomputer systems. Until recently, there were a number of differences between a PLC and a computer system: A PLC has a simple operating system, and only limited security checking is done. To bring the security checking of both hardware and software functions within a PLC at the level of a computer would at least require hardware modifications and major (expensive) software modifications.A PLC has a simple and specific application language in the form of a ladder diagram or Boolean algebra. This implies a limited instruction set.The operating system of a PLC is not accessible to a user. Higher level programming languages cannot be used.
Shop floor to cloud connect for live monitoring the production data of CNC machines
Published in International Journal of Computer Integrated Manufacturing, 2020
Prathima B A, Sudha P N, Suresh P M
Programmable Logic Controller (PLC) is an industrial digital computer used for many different types of process control applications. They are fast and designed for the rugged industrial environment. The PLC consists of CPU, Memory, Input/Output, Power supply unit and communication interfaces. Programs are written on the computer and downloaded into the PLC using its communication interface. These loaded programs are stored in the non-volatile memory of the PLC. In the proposed work, ABB’s AC500-eCo PM554-ETH CPU is used for data computations. The ABB automation builder development tool and CodeSys automation software is used for software development. The software is developed using the Ladder Diagram programming Language. This application software so developed is downloaded into the PC using MODBUS TCP/IP network protocol.
Design of a smart control system for the management of sustainable energy supplies in remote areas: A case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Ahmed KASAPBAŞI, Hüseyin CANBOLAT
PLC program package is software for solving the controlling system problems using an automation tool. This programming package is basic for running a PLC. The program consists of the operating system and the user program. The operating system is fixed and unchangeable, but the user program is alterable. The PLC programs package uses different programming languages such as Ladder (LAD), Statement List (STL), Instructions Lists (ILs), Function Block Diagram (FBD), and Sequential functions charts (SFC) language. In this study, the PLC is programmed utilizing a Ladder language. The user interface of a PLC simulator enables the operator to run and test the programs offline without the need to use additional hardware (Bolton 2006; Xiong et al. 2021).
Project Time Deployment: a new lean tool for losses analysis in Engineer-to-Order production environments
Published in International Journal of Production Research, 2022
Massimo Bertolini, Marcello Braglia, Leonardo Marrazzini, Mattia Neroni
The system is equipped with a Programmable Logic Controller (PLC), an industrial digital computer, which is customary in robotic devices as in any activity that requires reliability, fault processing, and programming. The PLC broadcasts the commands to engines in real time and is networked with a Supervisory Control and Data Acquisition (SCADA) system. The SCADA is a control system equipped with a Human Machine Interface (HMI) which allows a high level of control of operations and an efficient monitoring of the system’s state, using a user-friendly interface. Thanks to the system’s architecture, once the system has received a set of operations, it is fully automated and can handle goods without an operator.