Process measurements are instantaneous but analyzer responses never are. From the tap to the analyzer, there is always a time delay. Unfortunately, this delay is often underestimated or misunderstood.
Time delay is defined as the amount of time it takes for a new sample to reach the analyzer. One way to control time delay is with a regulator. Regulators control pressure, and pressure in an analytical system is closely related to time. In the case of gas systems with a controlled flow rate, the lower the pressure, the shorter the time delay.
Delay may occur in any of the major parts of an analytical instrumentation (AI) system, including the process line, tap and probe, field station, transport line, sample conditioning system, stream switching system, and analyzer.08/03/2012
Communicating To the Enterprise Isn't Science Fiction. Wouldn't it be nice to be able to transport any object across great distances almost instantly? In the building automation systems of today's buildings and facilities, real-time information does just that. A modern building management system monitors and operates all technical facilities. Managing these data sources ensures optimal building performance by enabling control of building systems in an integrated manner. However enterprise facility management requires more than just building automation control systems. Download this white paper to learn how you can improve the design and operation of building processes, reducing emissions and improving energy usage, by connecting building automation systems to the enterprise using OPC.07/25/2012
Clearly the need - and potential payoff - for more effective operators is enormous and intuitively understood. But rather than reversing course and simplifying operators' tasks, industry is only increasing the pressure. Learn how to transform your people into strategic assets.07/10/2012
Learn about scalable technologies that can provide high availability and a significant return on investment. Download content on these topics:
- Achieving High Availability in Process Applications — Process industries don't have to accept one-size-fits-all solutions that do – and cost – more than necessary.
- Clean in Place Made Simple — This paper discusses an approach that makes CIP automation a straightforward task and provides ample modularity and flexibility through the use and application of ANSI/ISA-88 (S-88) concepts.
- Process eTalk — This quarterly eNewsletter will help you stay up to date on the latest trends and topics within the process industries.
For the past decade, industrial control systems administrators and engineers wanted to believe that 'air gaps' truly existed between their systems and the rest of the world. They have also hoped that 'security by obscurity' would keep them safe from security threats. Those days are over. While the consequences of cyber attacks and malware are no longer in doubt, the question remains. "Exactly how can an engineer reliably secure his or her control system?" This white paper outlines a simple and cost effective answer - a security solution based on OPC technology that can be deployed in almost any industrial facility today.04/09/2012
Most plants have a huge opportunity to improve control system performance. The control system directly impacts the operation of the plant, and control loop problems lead directly to loss of efficiency, reduced production rates and other factors, affecting the bottom line. Measuring control systems performance is important and there are many ways to do it. Download this e-book to learn how ExperTune's PlantTriage software measures over 80 different aspects of control performance and to learn how you can improve control performance at your plant.11/28/2011
Plant managers are increasingly forced to maintain aging control systems while meeting management calls for improved productivity and quality. If you're ready for a change, this new paper was developed to help you select your best option. The paper covers: How to determine what is "end of life"; The pros and cons of different upgrade options - total system replacement, "gateway" options, I/O replacement; and the relative costs for each approach.09/02/2011
This paper summarizes Sigurd Skogestad's struggles in the plantwide control field.
A chemical plant may have thousands of measurements and control loops. By the term plantwide control it is not meant the tuning and behavior of each of these loops, but rather the control philosophy of the overall plant with emphasis on the structural decisions. In practice, the control system is usually divided into several layers, separated by time scale.
My interest in this field of plantwide control dates back to 1983 when I started my PhD work at Caltech. As an application, I worked on distillation column control, which is excellent example of a plantwide control problem. I was inspired by Greg Shinskey's book on Distillation Control, which came out with a second edition in 1984 (Shinskey, 1984). In particular, I liked his systematic procedure, which involved computing the steady-state relative gain array (RGA) for 12 different control structures ("configurations"); the DV-configuration, LV-configuration, ratio configuration, and so on. However, when I looked in more detail on the procedure I discovered that its theoretical basis was weak. First, it did not actually include all structures, and it even eliminated the DB-configuration as "impossible" even through it is workable in practise (Luyben, 1989). Second, controllability theory tells that the steady-state RGA by itself is actually not useful, except that one should avoid pairing on negative gains. Third, the procedure focused on dual composition control, while one in practise uses only single end control, for example, because it may be optimal economically to use maximum heating to maximize the recovery of the valuable product.01/25/2011
Registration Evaluation Authorization and Restriction of Chemical Substances
It is certainly no secret to anyone that the past decade has placed a renewed focus on the environment and how all members of the world community, to include business organizations, affect it. Concerns about protecting the world in which we live have been the impetus behind such worldwide movements as recycling and renewable energy. From a manufacturing standpoint, RoHS (Reduction of Hazardous Substances) has impacted businesses as well as REACH, a more recent set of regulations that are becoming more significant to North American based manufacturing operations that are part of a supply chain that directly or indirectly supplies products into the European Union.
As with any new regulatory requirements, the initial exposure to the documentation can create a degree of uncertainty among those who will be asked to comply. From this perspective, REACH is no different from any of its predecessors. In an attempt to offer some understanding of the REACH regulations and some clarification of the requirements it places on manufacturers, C&M Corporation gathered Michael Karg, Director of Product Development, along with Randy Elliott, Regulatory Compliance Engineer, and Ariann Griffin, Regulatory Compliance Technician, to discuss some of the particulars of REACH and respond to some of the questions C&M has been discussing with members of its client base.
What is the purpose of REACH?12/13/2010
Klargastechnik Deutschland GmbH's equipment and processes help customers address organic biomass fermentation and recovery while supporting electric power co-generation. The result is clean, green electric power that also reduces both solid waste and hazardous toxic gases such as carbon dioxide and methane, which pollute the environment and contribute to global warming.
In order to provide these benefits, the company's equipment and systems rely on highly precise and reliable flow measurement of process waste gases. Measuring biogas flow at several points in the system provides operators with critical information for optimal gas production, control, safety and reporting. However, Biogas applications present several challenges in selecting the proper flow meter.
Download this application note to learn how a biogas processinf system manufacturer can identify the best flow meter for gas measurements.10/28/2010
Manufacturing and production processes have had to be controlled and managed in real time from inception because they change in real time frames. This has been a natural premise of industrial systems from the very beginning.
A major shift in the business of manufacturing has occurred over the past decade which is driving the dynamics of the business of production and manufacturing into the real time domain. Business variables, such as energy prices, feedstock prices and even product prices have rapidly transitioned from highly transactional time frames into real time frames. For example, a decade ago it was not unusual for an industrial plant to establish a contract with its energy supplier that essentially set the price over an extended time period, of often 6 months or even a year. Today, in most parts of the world, long term fixed price energy contracts are not being offered and the price of energy can change multiple times in a day. The implications of this transition are clear. Industrial business functions must operate in real time to be effective and efficient. Industrial companies that do not move to real time business operations will be at a severe disadvantage in their marketplace.10/25/2010
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
Process engineering focuses on the design, operation and maintenance of chemical and material processes in a vast range of industries. This white paper identifies process simulation tools to seamlessly integrate throughout the process design life cycle and discusses best practices for facilitating engineering workflow.08/11/2010
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
In the past, DCS systems were large, expensive and very complex. This drove many control engineers to use programmable logic controllers (PLCs) and human machine interface (HMI) in order to lower cost. Today, these implementations are consistently more expensive than DCS systems for the same process or batch application. Many forward thinking engineers using PLCs and HMI in process or batch applications have learned there are ways to significantly reduce costs, speed implementation and improve operations. Download this white paper to learn key advantages of DCS systems over PLC/HMI engineered systems and the typical value of each.04/20/2010
With the significant threat that system interruptions pose to business performance and profitability, businesses are increasingly seeking to gain a competitive advantage by re-engineering their solutions, driving the need to deliver higher levels of availability.
Commonly used in process industries, high availability solutions can also benefit discrete manufacturers that have high-speed, complex operations, where the economic impact of even a short period of downtime or momentary interruptions can have huge financial, operational, and reputational costs.
This paper demonstrates the financial upside of investing in high availability technology and takes a closer look at the latest features and benefits of such solutions for continuous, efficient operations.04/20/2010
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