SCADA Online Product Quality Control

Controlling the quality of the product during the manufacturing phase is the process of analysis, control, management of factors and variables that affect the quality of the final product. Integrating the computer in the industrial manufacturing control will ensure the quality of the product, as well as to provide the necessary data for the production process progress, the ingredients ratio used in each production batch and statistical data of the changes that may occur in the composition of the product. Traditional methods to control the quality of the product are inadequate and inappropriate; they need to be changed to keep pace with the huge development in the field of industrial automation, control systems, industrial quality and computer technology used in various industries as well as clear development in the field of industrial sensors. This study falls into three-research area: integration of SPC and EPC, SCADA batch processes monitoring and control, and concrete batching plant. The objectives of this study are (a) To design a SCADA system for batch process monitoring and quality management, (b) To establish an integrated SPC/EPC methodology for a batch process, and (c) to illustrate the proposed approach with an application of the analysis and monitoring of an industrial concrete batching plant. The concrete batching plant has different batch processing subsystems, but the aggregate batching process has the greatest impact on product quality, unfortunately, this industrial process is poorly automated, in most plants in Gaza strip. The traditional control or even the manual control is still common which leads to uneven mixtures and inconsistent product quality subject to several disturbances. A complete PLC system is designed for full-automated concrete plant, with new aggregate weighing and batching algorithm implemented for adaptive flow rate and feeding speed control. Through this study ,the implemented algorithm and SCADA system , process engineers at the industrial plants are now able to use a valuable decision making tool when the production process is affected by certain disruptions, with obvious consequences on product quality, productivity and competitiveness

Limited Lookahead Supervisory Control with Buffering in Discrete Event Systems

The Supervisory Control Theory (SCT) of Discrete Event Systems (DES) provides systematic approaches for designing control command sequences for plants that can be modeled as DES. The design is done "offline" (before supervisor becomes operational) and is based on the plant and design specification DES models. These models are typically large, resulting in DES supervisors that require large computer memory - often unavailable in embedded mobile systems such as space vehicles. An alternative is to use the Limited Lookahead Policies (LLP) in which only models of individual plant components and specifications are stored (which take far less memory). The supervisory control command sequences are then calculated "online" during plant operation. In this way, "online" memory requirement can be reduced at the expense of higher "online" computational operations. In this thesis, the implementation issues of LLP supervisors are studied. The design of LLP supervisors is based on assumptions some of which may not hold in practice. Notably it is assumed that after every event, the supervisory control command can be calculated and applied before the next event occurs. This assumption usually does not hold. To address this issue, a novel technique is proposed in which supervisory control commands are calculated in advance (and online) for a predefined window of events in the future and buffered. When the window starts, the commands would be ready after each event. This eliminates the delay due to online calculations and reduces the delay in responding to new events to levels close to those of standard supervisors (designed "offline"). In an effort to assess the proposed methodology and better understand the implementation issues of SCT, a two degree-of-freedom solar tracker with two servo motors is selected as the plant. Previously, a standard supervisor had been designed for this solar tracker to guide the tracker and perform a sweep to find a sufficiently bright direction to charge the battery and other parts of the system (from its Photo Voltaic cell). The design of the standard supervisor and its software implementation is improved and polished in this thesis. Next the LLP with buffering is implemented. Several experimental results confirm that the plant under the supervision of LLP supervisor with buffering can match the behavior of the plant under the supervision of standard supervisor

Discrete Event Simulations

Considered by many authors as a technique for modelling stochastic, dynamic and discretely evolving systems, this technique has gained widespread acceptance among the practitioners who want to represent and improve complex systems. Since DES is a technique applied in incredibly different areas, this book reflects many different points of view about DES, thus, all authors describe how it is understood and applied within their context of work, providing an extensive understanding of what DES is. It can be said that the name of the book itself reflects the plurality that these points of view represent. The book embraces a number of topics covering theory, methods and applications to a wide range of sectors and problem areas that have been categorised into five groups. As well as the previously explained variety of points of view concerning DES, there is one additional thing to remark about this book: its richness when talking about actual data or actual data based analysis. When most academic areas are lacking application cases, roughly the half part of the chapters included in this book deal with actual problems or at least are based on actual data. Thus, the editor firmly believes that this book will be interesting for both beginners and practitioners in the area of DES