Essay Example on PLCs: Digital Control for Flexible & Reliable Manufacturing

Introduction

A Programmable Logic Controller (PLC) refers to an industrial digital computer adapted for the control for technical processes within the manufacturing sector. It is a digital approach in the technological processes requiring higher reliability, ease of programming, and diagnosis of fault processes (Alphonsus & Abdullah, 2016). The PLCs emerged in the automobile industry for the provision of flexible and easily programmable controllers to replace hard-wired relay logic systems. Ever since the PLCs were developed for higher-reliability automation controllers to match harsh environments, one of the broad areas where the PLC application is frequent is the manufacturing sector. Over the past decades, the PCLs form a critical role in the manufacturing industry because it eases the overall production process. The first PLCs were introduced in the early-1960s and were climatic intolerant; hence were very hard to program (Alphonsus & Abdullah, 2016). The current PLCs are powerful and are capable of operating in both environments, with backup power supplies, stable software operating system, and flexible inputs and outputs to ensure an interrupted control of its processes. The paper seeks to examine technological trends in the manufacturing industry, how the PLCs are incorporated in the automotive manufacturing industries and its implications in the current processing sector.

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Technology Trends in Manufacturing

Manufacturing technology has evolved tremendously for the past few decades towards the current automated and software-driven industries. The introduction of advanced technologies in the manufacturing sector has changed the phases of manufacturing into a more manageable way. These technologies have significantly cut costs of production, facilitated speed, increased precision, improved efficiency, and flexibility for the manufacturing companies. Some of the trends in the manufacturing sector begin with the introduction of 3D Printing technology. The 3D Printing technology forced the ancient engineers to think very divergently when thinking about product development. After a few years, nanotechnology emerged, which involves the manipulation of matter on atomic and molecular scales, thus eliciting super-precision manufacturing. Soon after the introduction of nanotechnology, the Internet of Things (IoT) emerged. The IoT is a manufacturing technology allowing electronic devices linked to each other based on the pre-existing internet structure. Later, another sophisticated cloud computing technique arose. Cloud computing refers to the practice of using a network of internet-linked remote services on various locations to manage, store, and process a piece of information. The introduction of cloud computing gave way for the presentation of massive data and predictive maintenance technology in the manufacturing sector. The recent technological advancement allows manufacturing industries to gather, process, and vast information in real-time. According to the introduction of big data, and predictive maintenance technology led to the introduction of PLCs currently used by most of the manufacturing companies (Bellmunt et al., 2006). The PLCs are used in civil applications and manufacturing industries to monitor and manage the production process and establish systems.

Major Components of the PLCs

PLCs have significant advantages over the ancient relay systems based on substantial considerations. A single PLC could run multiple machines, ease troubleshooting, incorporate efficient space, and relatively simple visual observation. Similarly, the PLCs have low costs provided by their relatively low prices and ease of implementation before being implemented in the field (Jack, 2010). The PLCs have four major components that ensure it operates smoothly and delivers quality outputs. The input/output Modules were responding to analog systems; the input converts signals to logics that could be used by the CPU while the output converts control signals to digital values to be used by various output devices. The power supply is obliged to provide power to operate the PLC activities. The Central Processing Unit (CPU) stores and run the software of the PLC programs (Jack, 2010). Moreover, the co-processor Modules expand the functionality and capability of the PLC system. However, the PLC is also composed of the software to give instructions to the CPU and the co-processor modules, and the peripheral device inputs data and monitor the overall operation of the equipment.

How the PLCs are used in Automotive Manufacturing

Programmable Logic Controllers were innovated in the 1960s and have played a vital role in the automotive manufacturing operations. According to automotive manufacturing, the PLCs refer to hardware devices such as the computers monitoring the inputs and outputs and establish logic-based decisions for automated processes (Bellmunt et al., 2006). The technology existed many years ago but has since been a critical component of the manufacturing sector. There are many ways within the manufacturing industry that PLCs are applicable. Among them are the wind turbine operation, the smart factory, cement manufacturing, glass manufacturing, virtual modeling, and many others.

Wind Turbine Operation

The PLCs are capable of improving the performance of wind turbines through the installation of non-OEM PLCs. Most of the wind turbines utilize mechanical type anemometers and wind vanes to measure conditions of wind, and data are sent to wind controllers. Previously, the manufacturing industries were using the Original Equipment Manufacturer to monitor and control the wind turbine systems. However, the industries revealed that the OEM was leading to higher costs of maintenance and adverse turbine performance power. The physical inspection of the overall control system showed that most of the sensors in wind conditions were failing to lead to poor accuracy. The wind turbine also suffered adversely during the winter season due to the freezing climate causing the anemometer to lock up shutting down the turbines. Also, the wind vane sensors were inaccurate in higher turbulence due to the higher turbulent rotor wash. There was a need for the wind turbines to operate safely as wind information is important in recording the turbulence and protect turbines. Later, the mechanical sensors of the wind measurements were replaced with a single ultrasonic sensor that incorporated the PLC.

The incorporation of the PLCs in the wind turbine sensors played a significant role in converting the signals from the ultrasonic sensors and effectively controlled the wind turbines. Previously, there was no particular system to convert the signals from wind turbine sensors in a form that the turbine controllers would utilize. Currently, the PLC could convert the signals effectively into an essential form the wind turbine controllers would utilize. The manufacturing industries, therefore, installed a Modbus adapter, which allows inputs from ultrasonic sensors and sends it to the PLCs via the adapter. In this case, the PLC acted as an emulator for the turbines to emulate the digital logic sensor signal as required by each turbine controller (Jack, 2010). Also, some algorithms were created to provide nonlinear corrections to the wind turbine sensors' dynamics. Consequently, information from the PLCs are transmitted to a control center, where engineers perform statistical analysis, program the PLCs and turbine controllers, and evaluate information to predict misinterpretations or problems before they develop. The results are increased meteorological accuracy, few operational downtimes, and reduced turbine-drive-train fatigue with improved turbine efficiency.

Cement Manufacturing

PLC plays an important role in the cement manufacturing process. In the cement production line, equipment such as the crushing machine, rotary kiln, packaging machine, and grinding machine is used. The overall process involves the mixing of various raw materials and several compounds in a kiln. The production of quality cement is mandatory during the process of mixing, and accurate data in the mixing process is required. A technique for providing accurate data of variables used along with the best quality of raw materials is required. The accuracy is accomplished through the incorporation of the PLC put together with the distributed control system. A distributed control system is composed of the PLC in its user mode, and configuration software is incorporated in the cement industry's manufacturing process and management procedures. In particular, the PLC controls ball milling, shaft kiln, and coal kiln. The PLC program ensures proper mixing procedures within the kiln by determining the best outputs to result in the essential quality of cement.

Glass Production

The use of PLC in the Glass Industry began in the early 1980s, and it is being assembled in bits. It is significant to recognize that PLC is used in almost all parts of the glass manufacturing sectors. In the glass industry, it is used to control rations, equipment for cold forging, and the process of flat glass. With the innovations taking shapes in all manufacturing sectors, PLC enhances the productivity demand, PLC control mode with intelligence devices are currently in use in the glass industry. Concerning the production of float glass, the PLC plays a vital role in the control of tasks since the control system in the glass industry is more complicated (Jack, 2010). In this case, the PLC is comprised of analog processing to incorporate a large amount of data. Accordingly, the glass industry has incorporated the Bus Technology, which constructs the control mode of both the PLC and Distributed Control System (DCS). Bus Technology refers to distributed control networks mostly used in industrial automation. In this case, the DCS specifically deals with data recording, analog controlling, and PLC majorly deals with digital quantity and position control.

Appropriately, the above control system is advantageous for the glass industry on both DCS and PLC since they fully play to enhance the reliability and flexibility of the system of control. On the other hand, the production of toughened glass requires the control system to adopt other control modes. In this case, the PLC plays as the lower computer constituting the DCS with the industrial computer. Accordingly, the control mode offers overall play to the function of both the PLC and the industrial computer, where the PLC is solely responsible for the position control and the digital quantity control and the industrial computer otherwise, deals with information acquisition and display. In this case, the control mode and the human-computer interaction technology are effectively employed to improve the function of the control system in the glass industry (Prabhaker, 2001). Generally, the PLC is incorporated in the glass industry in both analog information recording and the digital quality and position control.

Smart Factory

A smart Factory refers to a potentially digitalized and highly linked production facility, which relies majorly on smart manufacturing. One of the current significant technologies within smart manufacturing is the Industrial Internet of Things (IIoT). The technological innovation enhances the advancement in smart manufacturing since the smart factory revolution. The Smart Factory technology is built upon the transformation from the ancient automation to the most current, linked, and flexible system. IIoT is the most critical element in the creation of the Smart Factory. The factory incorporates devices such as the camera and sensors throughout the manufacturing facility to check on the status, collect information, analyze it, and utilize insights for operational optimization (Ghosh et al., 2017). The P...