Distributed Control Systems (DCS) have been successfully utilized to help control manufacturing and production processes since the late 1970s. The primary function of these DCS systems has been the automatic feedback control of the various process loops across the plants and the human interfacing with plant operators guiding the production from control rooms. Although these systems have proven to be very successful at improving the efficiency of industrial operations as compared with earlier control technologies, the state-of-the-art has not grown significantly since their inception. Most plants still operate exactly as they did 40 years ago.
Considerable research and development has been invested in expanding the functionality of DCS's in the areas of advanced controls and advanced manufacturing execution software. Numerous industrial plants have started to employ advanced controls in critical or high-value process operations, with some venturing into the use of advanced application software packages, each typically designed to address a specific issue or challenge within the industrial operations. Entrepreneurial software companies typically developed the software at this level of operation, essentially between the automation and business levels, often referred to as the manufacturing execution software (MES).
Although some industrial operations implemented advanced control and advanced MES software, the vast majority of processes are still controlled by simple automatic feedback control. The efficiency and effectiveness of most plants is a function of the installed feedback control systems. As a result, many industrial managers have expressed concerns that, in spite of the huge investments made in automation systems and software, plants do not appear to be operating better than they had been 30 years ago. In some cases, the plants actually appear to be operating less efficiently, possibly due to the reduced and inexperienced work forces and aging equipment.10/25/2010
Variable Frequency Drives (VFDs) with diode rectifier front end are typically equipped with a resistorcontactor arrangement to limit the inrush current into the dc bus capacitors, thereby providing a means for soft charging the dc bus capacitors. Because of the mechanical nature of the magnetic contactor typically used in VFDs, there exists a concern for fatigue. In addition, during a brown out condition, typically the contactor remains closed and when the voltage recovers, the ensuing transient is often large enough to possibly cause unfavorable influence to surrounding components in the VFD. Many researchers and application engineers have thought about this issue and many are actively seeking non-mechanical solutions in a cost effective manner.
In this paper, a new topology to soft charge the dc bus capacitor is proposed. Other techniques that have been evaluated are also introduced. The relative advantages and disadvantages are discussed. Experimental tests to show the feasibility of the proposed idea is also provided.05/17/2010
Diode rectifier with large DC bus capacitors, used in the front ends of Variable Frequency Drives (VFDs), draw discontinuous current from the power system resulting in current distortion and hence voltage distortion. Typically, the power system can handle current distortion without showing signs of voltage distortion. However, when the majority of the load on a distribution feeder is made up of VFDs, current distortion becomes an important issue. Multi-pulse techniques to reduce input harmonics are popular because they do not interfere with the existing power system either from higher conducted EMI when active techniques are used or from possible resonance, when capacitor based filters are employed.
In this paper, a new 18-pulse topology is proposed that has two six-pulse rectifiers powered via a phase-shifting isolation transformer, while the third six-pulse rectifier is fed directly from the AC source via a matching-impedance. This idea relies on harmonic current cancellation strategy rather than the flux cancellation method and results in lower overall harmonics. It is also seen to be smaller in size and weight, and lower in cost compared to an isolation transformer. Experimental results are given to validate the concept.05/17/2010
The date of January 1, 2005 sits vividly in the minds of manufacturers within the industrial control panel field. That's because that's the day when the National Fire Protection Association's (NFPA) National Electrical Code (NEC) 2005 Article 409 officially went into effect. The code required that short circuit current rating be clearly marked on the industrial control panels in order to be inspected and approved. The markings made it easier to verify proper over-current protection against hazards such as fires and shocks on components or equipment, whether it be for initial installation or relocation. It was the beginning of an era when things would become a little more complicated, but for all the right reasons of ensuring more safety within the industrial world.
The main vision of the NFPA is to reduce or limit the burden of fire and other hazards on the quality of life by providing and advocating scientifically based consensus codes and standards, research, training and education. These codes and standards were established to minimize the possibility of and effects of fire and other risks. Due to misinterpretations, inconsistencies and advancements in technology over the years, they have had to update their codes with consistency in order to comply with existing standards.
Therefore, the focus of this paper will look at the changes that occurred due to Article 409, the impacts that it had, who was affected by the code and how to comply with the code. Precautions like this article had been enforced in the past, but they were too vague, so people found ways to get around them.
The biggest change that took place within the article was the new requirements adopted for industrial machinery electrical panels, industrial control panels, some HVAC equipment, meter disconnect switches and various motor controllers. For the purpose of this paper, we will be concentrating on industrial control panels which are specified as assemblies rated for 600V or less and intended for general use. All in all, it states that the above products must feature a safe design and be clearly marked with specific information concerning Short Circuit Current Rating (SCCR) in efforts of aiding with the designing, building, installation and inspection of the control panels. This way, the above users can both reference and apply all the needed requirements for all new products and installations as well as for modifying existing ones.05/17/2010
This technical white paper will discuss Yokogawa's CENTUM VP DCS (Distributed Control System) product, hereafter referred to as "CENTUM VP", and the extent of its compliance with Part 11 of Title 21 of the Code of Federal Regulations, (21 CFR Part 11), the Electronic Records / Electronic Signatures Rule.
CENTUM VP Batch Management is the optional Batch control function for CENTUM VP, which provides recipe management and process management functionality based upon the ISA-88 Batch Control System standard. This whitepaper addresses the use of CENTUM VP and the Batch Management function.
A detailed analysis of Part 11 was performed, the results of which are listed in the Detailed Part 11 Compliance section (section 5) of this document, which supports the compliance of the CENTUM VP system to Part 11.
CENTUM VP is a comprehensive software package containing configurable functions that support Part 11 compliance (audit trails, electronic signatures and electronic records). The system capitalizes on its Part 11 compliance attributes in the marketing strategy of supplying FDA regulated industries with state of the art automation capabilities.
User training and education as well as the development and utilization of policies and procedures are key components of Part 11 compliance which must be established by the user.04/15/2010
Delivering increased precision and enabling advanced regulatory control strategies for continuous process control.
Process control in the most generic sense involves continuously controlling an operation or sequence of operations that changes the state of matter; specifically, this includes changing the state of energy, chemical composition, and/or physical dimension of a substance.
As complex programs need to interface with various aspects of a comprehensive production system, Logic Developer Process Edition function blocks from GE Intelligent Platforms add precision and ease of use to reduce the learning curve for engineers, enable higher operational efficiency, and lower development costs.
This white paper helps engineers and programmers explore the power provided by Logic Developer Process Edition function blocks that allow changes in the state of matter to be controlled to generate beneficial outputs that enhance life (e.g., fuel in, electricity out), and illustrates how businesses can use these function blocks to realize advanced regulatory control strategies. It also explains the differences between Logic Developer Process Edition and GE's Proficy Machine Edition PLC Logic Developer programming software, which is optimal for leveraging an integrated development environment for discrete, motion, and multi-target control applications.04/07/2010
Ensuring your PAC-based control system is an integrated, robust and flexible information producer helps improve business performance, lower costs and uncover unique opportunities for competitiveness.
All companies seek ways to make their businesses grow for the long-term. Ask any manufacturer today what he/she needs in an increasingly challenging economy. It's likely to include cutting costs, improving yield, increasing functionality and becoming more competitive in the global marketplace.
Manufacturing convergence helps companies meet these business drivers - globalization, innovation, productivity and sustainability - by more closely aligning manufacturing technologies and production system operations with the rest of the enterprise. This convergence is enabled throughout the manufacturing environment with the technologies of convergence - control, power, information and communication.03/24/2010
Today's control system engineers face competing design demands: increase embedded system performance and functionality, without sacrificing quality or breaking the budget. It is difficult to meet these challenges using traditional design and verification approaches.
Without simulation it is impossible to verify a control design until late in the development process when hardware prototypes become available. This is not an insurmountable problem for simpler designs with predictable system behavior, because there are fewer sources of error in simpler control algorithms--and those errors can often be resolved by tuning the controller on the hardware prototype.
Today's multidomain designs combine mechanical, electrical, hydraulic, control, and embedded software components. For these systems, it is no longer practical to delay verification until late in the development process. As system complexity grows, the potential for errors and suboptimal designs increase. These problems are easiest to address when they are identified early in the development process. When design problems are discovered late, they are often expensive to correct and require time-consuming hardware fixes. In some cases the hardware simply cannot be changed late in the development process, resulting in a product that fails to meet its original specifications.
Traditional verification methods are also inadequate for testing all corner cases in a design. For some control applications, it is impractical or unsafe to test the full operating envelope of the system on hardware.03/02/2010
Carbon-dioxide capture and storage (CCS) offers the potential for major reductions in carbon dioxide emissions of fossil fuel-based power generation in the fairly short term, and oxyfuel combustion is one of the identified CCS technology options. Foster Wheeler (FW) is working on reduction of carbon dioxide with its integrated Flexi-Burn dual-oxidant PC and CFB technology.
The proven high efficiency circulating fluidized-bed (CFB) technology offers a solution for carbon dioxide reduction both in re-powering and in greenfield power plants. CFB technology has the advantages of a more uniform furnace heat flux, excellent fuel flexibility and offers the opportunity to further reduce carbon dioxide emissions by co-firing coal with bio-fuels.
Development and design of an integrated Flexi-Burn dual-oxidant CFB boiler and balance of plant system was conducted in both air mode and oxyfuel mode. Through proper configuration and design, the same boiler can be switched from air mode to oxyfuel mode. The dual-oxidant CFB system incorporates features to maximize plant efficiency and power output when operating in the oxy-firing mode through firing more fuel in the same boiler.
Existing boiler design tools are being modified to incorporate the features of oxy-combustion, so that various design options can be evaluated. The 460 MWe supercritical CFB power plant (currently under construction by FW) has been used as the basis for an integrated Flexi-Burn dual-oxidant CFB study.09/23/2009
Process Analytics and Intelligencesometimes called Manufacturing Intelligencehas transformed the way companies produce goods, understand their manufacturing processes, and ensure a quality product in ways we could not have foreseen ten years ago.
Real-time Analytics have replaced the legacy concept of running reports. Reports that represent a static picture of a process at a fixed point in time are great tools for compliance audits and long term warranty analysis. However, they may not accurately represent the "as-is" state of a process. Reports showing large amounts of data can be difficult to interpret. There are often limitations in how the report data can be drilleddown and viewed.
With today's large volumes of data, there's a wealth of information that can be gained about the process. But how can this data be captured, managed and retrieved in a way that presents the information in an up-to-theminute easy to understand format? Real-time Analytics provides the techniques and solutions that address this problem. Instead of users having to interpret the data, it's presented in a graphical form enabling them to easily drill down to explore the data in real-time.
This white paper discusses how Process Analytics is implemented and utilized. Ways of managing and distributing Process Analytics to the organization are presented.08/20/2009
Thirty years ago, specifying an enclosure involved three steps: ordering the appropriately sized gray box, installing sensitive electronic equipment and hoping the enclosure would withstand its surroundings.08/07/2009
The plant operator has an extremely valuable and important responsibility: being the force and energy managing a capital enterprise easily worth hundreds of millions of dollars to produce or impact a daily revenue stream of millions, give or take. We ask him to be ever mindful of what the plant might be doing. We ask him to be capable of finding every little problem before it grows into a big one. We ask him to shoulder the burden of everything that goes wrong during his watch, all without any recognition when nothing does, and precious little (if not actual blame) when it goes wrong and he manages to manage. Within his area of responsibility and authority he must be able to view every control loop, most sensors, most pieces of equipment, and much of the supporting utilities, and then adjust as appropriate.
The failure to maintain situational awareness has been present in almost every disaster event that was not the result of spontaneous complete surprise. Start with the assumption that no one wants an accident. That no one would chose disaster over success. But accidents and disasters happen. We now know to a high degree of certainty that they happen because those in charge of ensuring that they do not happen, aren't aware that they are happening. They fail to know the situation. They are unaware of what is really going on, what is likely to happen, or what isn't happening that they think is. As explained in my book Alarm Management for Process Control, the solution is facilitated by effective operator interface design. Let's follow the path of interface design that can lead to better situation awareness.07/08/2009
Since 1997, the Chilean-based operations of Methanex, the worlds largest producer and marketer of methanol, have been using the PI System from OSIsoft to improve product quality. With the success of using real-time data to improve operations, the company has recently begun to implement OSIsofts PI System as a strategic initiative to more fully integrate and distribute operations information throughout the company for better competitive advantages.05/15/2009
Like many companies, Janssen Pharmaceutical was implementing SAP as their Enterprise Resource Planning (ERP) system. In order to integrate manufacturing data from the plant floor into SAP, Janssen simultaneously installed the OSIsoft PI System. For the first time, financial people, who had never been able to link to the production floor, were now costing in real time. People in Operations, Engineering, Quality Assurance (QA), Environmental and Security were able to obtain multiple views from one data source, resulting in better operational visibility, process improvement and collaboration. The use of the PI System has led to better decisions and ongoing improvements such as: reduced cycle times, superior batch quality and releases, thorough incident investigations, decreased process variability, real-time costing, and better alarm management and security monitoring.
Now, with the implementation of OSIsofts RtReports product, Janssen can provide QA with a tool that streamlines the validation process for faster and more accurate compliance monitoring and reporting. The reams of paper with sign-offs and manual inputs from production to QA have been replaced with a few targeted reports that include batch trends. Production is able to reduce cycle time with configurable, real-time batch performance reporting. Of significant importance to Janssens business evolution is that RtReports has become a major part of Janssens progression towards electronic batch records.04/24/2009
The purpose of this paper is to trace the history of the development of process control, advanced process control and related applied engineering technologies, and to discuss the reasons why the industry has encountered difficulties. This paper also presents some recommendations to improve the likelihood of successful APC project implementation, and make some predictions about the future direction of the technology.03/26/2009
Integrators frequently use OPC technology to connect one Industrial Automation system (PLC, DCS, SCADA, HVAC, etc) with another so data can be shared between the two systems. Because OPC technology is based on the Client/Server architecture, the challenge is that two OPC Servers cannot communicate with each other directly. A variety of vendors provide an intermediate software solution, generically called an OPC Bridge, to facilitate this sort of communication. This whitepaper discusses the concept of the OPC Bridge, the solution architecture, required software components, and various features to help Integrators differentiate between different OPC Bridge products.01/26/2009
Why is Lack of Interoperability in Wireless a Concern in Industrial Applications?
While the available potential for wireless deployment in factory automation is high, the adoption of wireless is plagued by various concerns surrounding the wireless technology, one of which is lack of interoperability. In the recent past, interoperability was not as major concern as it is currently. People predominantly used to build their own systems or purchased them from a single supplier. Increasing plant automation has spurred the demand for wireless devices and systems for numerous applications like monitoring, alarm and telemetry with a large number of suppliers offering these systems or solutions. They are often customized on proprietary protocols but not based on a common standard or architecture. As a result, these devices offered from multiple suppliers are not often compatible with one another. So even though the options have increased, the end users have become more concerned about the compatibility of the devices.10/08/2008
The ISA100.11a D2 draft is a major step forward over D1. The D2 document is the first draft that attempts to be a full specification of the network and application protocols for process monitoring and control devices. However, it is incomplete.
The editors have done a substantial amount of work in generating the newest version of the specification. A large number of comments were reviewed, accepted, accepted in principal or otherwise incorporated into the document. In addition, new technical material was developed to fill in the technical omissions that existed in the old document. As a result, the D2 draft requires a thorough review.
In reviewing the document the first goal is to determine if the technical details meet the overall goals stablished for the standard. This paper considers the primary goal of a standard: the interoperability and interchangeability of products (Section 6.2). The intent of this paper is to provide the reader with objective information about the draft to enable them to determine if these goals are met and to assist them in providing comments to the ISA100 committee.09/25/2008
Alexi Beck Gray Visits Waterford Township Department of Public Works and Learns How They Treat and Transport Water to Its Over Seventy-Four Thousand Residents05/07/2008
Application of Advanced Process Control to an Ethanol Dry Mill Process: East Kansas Agri-Energy04/18/2008