Report on Programmable Logic Controller (PLC)

Introduction of Programmable Logic Controller (PLC)

By automating the work in industries, the quality and productivity is improved and errors and wastage is reduced. For this industrial automation, software and computers are used. A digital industrial computer control system known as Programmable Logic Controller (PLC) is also used for the purpose of industrial automation and its objectives include; increasing in efficiency, collection of data of better quality, increased efficiency, improvement in metrics, and improvements in processes.

Background of Programmable Logic Controller (PLC)

A set of technologies that use control systems and devices such as robots and software for the purpose of enabling industrial processes and machinery, without any human efforts in it is called industrial automation. The use of industrial automation, mitigates the possibility of any human efforts in it, it also reduces costs, saves time, and aids in achievement of high performances. A PLC is a kind of a digital computer; it is used for the control purposes of manufacturing processes. It has also been ruggedized.

Objective selection of Programmable Logic Controller (PLC)

The PLC gives many advantages as compared to its previous versions. It has the ability to tolerate the environment better than other computers. It was also compact and required less maintenance then relay systems. It was an easily extensible version. It ranged from digital and analog I/O, extended temperature ranges, immunity to electrical noises and resistance to vibration and impact. It requires the programming device that is used for the developing and later downloading the created program into the memory of the controller.

Programming of Programmable Logic Controller (PLC)

The programs of PLC are written typically in special software on a personal computer. The program is stored in a PLC either in non-volatile flash memory or battery-backed –up RAM. The programme is transferred from a personal computer to the PLC through a board of programming which is responsible for writing a program into a removable chip such as EPROM in some programmable controllers. For backup and restoration the software can be uploaded by the PLC program. For debugging and trouble- shooting the PLC software, the software provides functions.  The PLC systems in majority adhere to the IEC 61131-3 of control systems programming standard. There are a variety of ways to programme PLC, from the relay-derived logic to programming languages such as specially adapted dialects of BASIC and C. A very high-level programming language, designed to programme PLC based on state transition diagrams is another method that is called state logic. To all the manufacturers the basic concepts of PLC programming are common to all manufacturers. Different models may not be compatible even within the same product line of a single manufacturer.

Simulation of Programmable Logic Controller (PLC)

For the purpose of adequately understanding the operation of PLC, a considerable time must be spent in programming, for testing and debugging the programs of PLC. The systems of PLC are inherently expensive, the cost of down-time is also too high. Loss of productivity and dangerous conditions can occur if a PLC is programmed the wrong way. The time can be saved in automated control applications in PLC simulations software such as PLCLogix.

Functionality of Programmable Logic Controller (PLC)

PLC  are intentionally made for more tolerant or severe conditions and also offer extensive input/output for establishing the PLC to sensor and actuators, that’s the main difference of PLC from most of the other computing devices. Simple digital elements such as limit switches, analog variables from process sponsors, and more complicated data such as that from positioning or machine vision systems can be included in PLC. Elements such as sirens, indicator lamps, pneumatic or hydraulic cylinders or electronic motors are outputs of PLC. In a simple PLC an input/output arrangement may be build, or there may be an I/O module that is attached to a fieldbus or computer network that will plug into the PLC.

System scale of Programmable Logic Controller (PLC)

For input and output, a small PLC will have a fixed number of connections built in. If the base model has insufficient I/O expansions are available. Modules with different functions are placed in modular PLC called chassis. For the specific application the processor and selection of I/O modules are customized. It may have thousands of inputs and outputs and several racks may be administered by a single processor. For mounting the I/O points directly to the machine, options are available.

Conclusion of Programmable Logic Controller (PLC)

Automatic methods are improving productivity and quality by reducing the errors and wastage ratio. These programs are often controlled by computer software in the digital industrial computer control system that is often known as programmable logic controller (PLC). The method improves the production rate and reduce human errors. The prime concern of the present work is the ways to maintain the system that range from digital and analog. The program use debugging and functions.  PLC programming result in high cost of downtime, less dangerous conditions, loss of productivity, and control applications of PLC simulations. In a nutshell, PLC programming and simulation induce impact on process in many ways.  

References of Programmable Logic Controller (PLC)

Erickson, K. T. (n.d.). Programmable logic controllers. IEEE potentials, 15(1), 14-17. 1 (15), pp. 14-17.

Reis, R. A. (2002). Programmable logic controllers: principles and applications. 4.