One of the main driving force behind the industrial revolution was the invention of the electric motor more than a century ago. Its widespread use for all kinds of mechanical motion has made life simple and has ultimately aided the advancement of human kind. The advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric motor to new realms that was inconceivable just a mere 30 years ago. Advances in power semiconductors along with digital controls have enabled realization of motor drives that are robust and can control position and speed to a high degree of precision. Use of AC motor drives has also resulted in energy savings and improved system efficiency.
Yaskawa Electric Corporation has been at the forefront of technology, creating reliable drives that consistently push the envelope of engineering achievement. This paper reviews Yaskawa's role in the development and application of the inverter technology to AC motor drives and introduces some futuristic vision for the motor drive technology. The development of more efficient, more powerful electric motor drives to power the demands of the future is important for achieving energy savings, environmentally harmonious drives that do not pollute the electrical power system, and improving productivity. Yaskawa wants to be an integral part of this future and hopes to contribute significantly to achieve this.05/17/2010
Predicting Control Valve Noise in Gas and Steam Applications: Valve Trim Exit Velocity Head vs. Valve Outlet Mach Number
Predicting and managing control valve noise has long been an important consideration in gas and steam applications, with the dual goals of protecting workers from potential auditory damage and preventing excessive vibration that could destroy equipment and piping, possibly leading to a catastrophic failure.
At first glance, it may seem that a logical way to achieve these goals would be to limit valve trim exit velocity head to a maximum of 480 kilopascals (kPa), and this indeed is how some have addressed the issue. In practical application, however, it is an oversimplified approach that, in many cases, will not produce the desired results. First, it typically requires the use of expensive multi-stage or multi-turn trim designs, which can cost up to 30 percent more than a simpler solution. More importantly, it also can create a false sense of safety.
This article will explain why the focus should instead be on keeping the valve outlet Mach number low. Practical examples will be used to illustrate that:
- Even if the trim exit velocity head is kept below 480 kPa, valve noise can be unacceptably high if the valve outlet Mach number is high.
- Even if the trim exit velocity number is above 480 kPa, valve noise can be kept to acceptable levels - without using costly trim designs - if the valve outlet Mach number is kept low.03/18/2010
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
As production runs ever closer to equipment and facility operating limits and new plants come on line in expanding and developing economies, the pressure to design and operate systems more safely and economically is increasing. A key to meeting this goal is having competent people who are knowledgeable and experienced in applying the IEC 61508 and IEC 61511 / ISA 84 functional safety standards. To develop and measure an individual's safety engineering competence, several personnel functional safety certification programs have been created. This paper will discuss why these programs are needed and the benefits they deliver to individuals and companies alike. It will also review the characteristics and differences of the various certification programs on the market today, things to watch out for, and some important questions to ask when selecting a certification program.03/05/2010
Real-time performance monitoring to identify poorly or under-performing loops has become an integral part of preventative maintenance. Among others, rising energy costs and increasing demand for improved product quality are driving forces. Automatic process control solutions that incorporate real-time monitoring and performance analysis are fulfilling this market need. While many software solutions display performance metrics, however, it is important to understand the purpose and limitations of the various performance assessment techniques since each metric signifies very specific information about the nature of the process.
This paper reviews performance measures from simple statistics to complicated model-based performance criteria. By understanding the underlying concepts of the various techniques, readers will gain an understanding of the proper use of performance criteria. Basic algorithms for computing performance measures are presented using example data sets. An evaluation of techniques with tips and suggestions provides readers with guidance for interpreting the results.
Over the past two decades, process control performance monitoring software has become an important tool in the control engineer's toolbox. Still, the number of performance tests and statistics that can be calculated for any given control loop can be overwhelming. The problem with controller performance monitoring is not the lack of techniques and methods. Rather, the problem is the lack of guidance as to how to turn statistics into meaningful and actionable information that can be applied to improve performance.
The performance analysis techniques discussed in this paper are separated into three sections. The first section details methods for identifying process characteristics using batches of existing data. The second section outlines methods used for real-time or dynamic analysis of streaming process data. These are vital techniques for the timely identification and interpretation of changing process behavior and deteriorating loop performance. The third section outlines techniques that aid in the identification of interacting control loops.02/23/2010
Events over the last several years have focused attention on certain types of loads on the electrical system that result in power quality problems for the user and utility alike. Equipment which has become common place in most facilities including computer power supplies, solid state lighting ballast, adjustable speed drives (ASDs), and un-interruptible power supplies (UPSs) are examples of non-linear loads. Adjustable speed drives are also known as Variable Frequency Drives (VFDs) and are used extensively in the HVAC systems and in numerous industrial applications to control the speed and torque of electric motors. The number of VFDs and their power rating has increased significantly in the past decade. Hence, their contribution to the total electrical load of a power system is significant and cannot be neglected.
Non-linear loads are loads in which the current waveform does not have a linear relationship with the voltage waveform. In other words, if the input voltage to the load is sinusoidal and the current is non-sinusoidal then such loads will be classified as non-linear loads because of the non-linear relationship between voltage and current. Non-linear loads generate voltage and current harmonics, which can have adverse effects on equipment that are used to deliver electrical energy. Examples of power delivery equipment include power system transformers, feeders, circuit breakers, etc. Power delivery equipment is subject to higher heating losses due to harmonic currents consumed by non-linear loads. Harmonics can have a detrimental effect on emergency or standby power generators, telephones and other sensitive electrical equipment.
When reactive power compensation in the form of passive power factor improving capacitors are used with non-linear loads, resonance conditions can occur that may result in even higher levels of harmonic voltage and current distortion thereby causing equipment failure, disruption of power service, and fire hazards in extreme conditions.
The electrical environment has absorbed most of these problems in the past. However, the problem has now reached a magnitude where Europe, the US, and other countries have proposed standards to engineer systems responsibly, considering the electrical environment. IEEE 519-1992 and EN61000-3-2 have evolved to become a common requirement cited when specifying equipment on newly engineered projects. Various harmonic filtering techniques have been developed to meet these specifications. The present IEEE 519-1992 document establishes acceptable levels of harmonics (voltage and current) that can be introduced into the incoming feeders by commercial and industrial users. Where there may have been little cooperation previously from manufacturers to meet such specifications, the adoption of IEEE 519-1992 and other similar world standards now attract the attention of everyone.05/17/2010
Invensys Operations Management division of Invensys was formed in May 2009 by combining Invensys Process Systems - Avantis, Foxboro, InFusion, SimSci-Esscor and Triconex - with Wonderware, Eurotherm and IMServ. The basis for this move was each of these four traditionally separate and excellent business units would provide more value for clients working together to solve difficult business problems that could not be solved by each unit separately. The Invensys leadership believes that the combined business would help to define and develop leadership in an emerging market space referred to as Operations Management. Invensys Operations Management will focus all of its resources to help customers drive Operations Excellence into their businesses.
Attaining Operations Excellence requires that industrial companies maximize the efficiency and profitability from their operations through excellent control, drive maximum business value from all their industrial assets, continually drive and increase productivity from all operations-focused personnel, all while reducing negative environmental impact and improving safety. Therefore, Invensys has defined Operations Excellence along four key themes: Control Excellence, Asset Excellence, Productivity Excellence and Environment and Safety Excellence.10/25/2010
One Code to Save Millions: ASME Codes and Standards Guide Dominion in Efficiency, Cost Savings and Safety
In order to stay on track with technology and provide the safest and most efficient working environment at Dominion's nuclear power plants, Dominion follows the codes and standards developed by ASME. ASME's mission is for its Standards & Certification organization "to develop the preeminent, universally applicable codes, standards, conformity assessment programs, and related products and services for the benefit of humanity." These codes and standards have a significant impact on the industry and save companies millions of dollars per year as well as assist in accident prevention and the development of more efficient production and operational practices. This case study illustrates how ASME has helped Dominion become more efficient, increasing cost savings and improving safety measures.03/25/2010
The manner in which a measured process variable responds over time to changes in the controller output signal is fundamental to the design and tuning of a PID controller. The best way to learn about the dynamic behavior of a process is to perform experiments, commonly referred to as "bump tests." Critical to success is that the process data generated by the bump test be descriptive of actual process behavior. Discussed are the qualities required for "good" dynamic data and methods for modeling the dynamic data for controller design. Parameters from the dynamic model are not only used in correlations to compute tuning values, but also provide insight into controller design parameters such as loop sample time and whether dead time presents a performance challenge. It is becoming increasingly common for dynamic studies to be performed with the controller in automatic (closed loop). For closed loop studies, the dynamic data is generated by bumping the set point. The method for using closed loop data is illustrated. Concepts in this work are illustrated using a level control simulation.02/23/2010
This initiative is the first step in filling a noticeable void in industry - the lack of independent competency training in the Operations Management (MES/MOM) arena. This lack of wide-scale competency is recognized as a major barrier to plant and supply chain optimization and global operations excellence.
With members in 85 countries globally, MESA is an independent, objective community of like-minded people and enterprises working to make Operations more reliable, capable and profitable. Some of the foremost experts across the Operations Management landscape are leading the knowledge sharing within the MESA community by offering programs across 4 continents by mid-2011.
MESA Certificate of Competency (CoC) for MES/MOM* Methodologies: A 4-day, comprehensive program of MES/MOM Methodologies courses aimed at Systems Analysts, Architects, Programmers, Project Managers and Consultants.
MESA Certificate of Awareness (CoA) for MES/MOM Business Awareness: A 2-day, high-level program of MES/MOM Business Functions courses geared for executives, manufacturing/operations and IT personnel and sales professionals. The CoA courses are higher level, short versions of the CoC program.
This white paper argues strongly that meeting greenhouse gas emissions targets set within the Kyoto Protocol will fail unless Active Energy Efficiency becomes compulsory.
Active Energy Efficiency is defined as effecting permanent change through measurement, monitoring and control of energy usage. Passive energy efficiency is regarded as the installation of countermeasures against thermal losses, the use of low consumption equipment and so forth.
It is vital, but insufficient, to make use of energy saving equipment and devices such as low energy lighting. Without proper control, these measures often merely militate against energy losses rather than make a real reduction in energy consumed and in the way it is used.
Everything that consumes power - from direct electricity consumption through lighting, heating and most significantly electric motors, but also in HVAC control, boiler control and so forth - must be addressed actively if sustained gains are to be made. This includes changing the culture and mindsets of groups of individuals, resulting in behavioral shifts at work and at home, but clearly, this need is reduced by greater use of technical controls.03/05/2010
The field instrumentation in process plants is beginning to come under more sophisticated metrological discipline. Most new field instruments are now smart digital instruments. One popular digital protocol is the HART (Highway Automated Remote Transducer) protocol, which shares characteristics of both analog and digital control systems.
This white paper talks about the maintenance and calibration of HART field instruments. To properly service these instruments, precision analog source/measure capability and digital communication are both required. In the past, this operation required two separate tools-a calibrator and a communicator. Now these capabilities are available in one HART documenting process calibrator. Download this white paper to learn more.03/23/2010
Selecting the right MCC equipment leads to improved plant safety, helping protect people and capital investments.
Measures to increase equipment and personnel safety in manufacturing are reflected in new approaches and technologies designed to help minimize the risk of workplace dangers. One rapidly growing area of focus is reducing the potentially serious hazards associated with arc-flash events. This white paper examines the causes of arc flash, discusses the standards guiding arc-flash safety and details the role arc-resistant motor control centers (MCCs) play in helping contain arc energy. It also highlights the key features of an effective arc-resistant MCC design.
Managing safety hazards and reducing risks are top priorities for manufacturers across all sectors of industry. With a multitude of potential dangers and new ones continuously emerging, companies must be diligent in their ongoing efforts while considering new approaches and technologies to improve plant safety. One rapidly growing area of focus is implementing techniques and practices designed to reduce hazards and minimize risk for workers who must enter an area with an electrical arc-flash potential.02/08/2010
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
Protection from noise and ground loops due to ISO-Channel architecture.
Precision measurement systems are often limited in that all inputs are connected to a single ground. Typically, multiplexer input configurations are set up this way, since all signal inputs are connected to the same return. Even differential input configurations use the same ground reference. The result is that accuracy and flexibility for accurate measurements can be severely compromised when noise or common mode voltage is present.
Crosstalk from one input signal can easily be reflected onto another input. The design movement to an A/D per channel can help this problem. But that is not sufficient in many cases.
To minimize noise and ground loops, some newer systems offer isolation between the input signal ground reference and the computer ground. This effectively separates the computer ground from the measurement portion of the system. But still, there is no isolation between input sensor channels, which is a common source of error and frustration for user applications. Why?01/06/2010
ISA100 is one of three standards competing in industrial wireless sensing. What is distinctive about ISA100? What are the prospects for convergence of standards? What would convergence be worth to the industrial wireless market?
ISA100 is a major standards initiative managed by the International Society of Automation (ISA). In addition to standards development, a new organization, the ISA100 Wireless Compliance Institute (WCI), is charged with delivering compliance certification services for the work of ISA100.
The ISA100 committee establishes standards, recommended practices, technical reports, and related information for implementing wireless systems in the automation and control environment, with an initial focus on the field level. Given the committee's broad scope, they have formed a number of working groups to pursue specific tasks. The primary deliverable from the Committee thus far is the standard ISA-100.11a, "Wireless Systems for Industrial Automation: Process Control and Related Applications". However a quick glance at the list of working groups shows that several other topics will be addressed by future ISA100 deliverables.
In 2006, at about the same time ISA100 was forming, the ISA also created the non-profit Automation Standards Compliance Institute (ASCI). This organization manages certification, conformance, and compliance assessment activities in the ISA's automation domain.
ASCI extends the standards work of ISA by facilitating the effective implementation and independent testing of ISA standards. It creates a vital link between the development of standards and industries' implementation of the standards. The ISA100 Wireless Compliance Institute (WCI) functions as an operational group within ASCI. Operating the ISA100 Wireless Compliance Institute within ASCI allows it to leverage the infrastructure of ASCI, which in addition to WCI, is shared by several ASCI compliance programs.11/22/2010
The purpose of this paper is to explore the particular ways in which operators can tightly integrate wireless instrumentation networks with SCADA and realize.
Integrating wireless instrumentation with SCADA systems can drive operational efficiency and reduce deployment costs.
The use of wireless instruments in pipelines and gas production operations has been gaining momentum over the past few years. Driven by cost cutting measures and the need to gain more operational visibility to meet regulatory requirements, wireless instruments eliminate expensive trenching and cabling while providing access to hard-to-reach areas using self-contained, battery-powered instruments. However, SCADA engineers and operators are facing the challenge of integrating wireless instrumentation networks with other communication infrastructure available in the field. Managing and debugging dispersed wireless networks presents a new level of complexity to field operators that could deter them from adopting wireless instrumentation despite the exceptional savings.
This paper will look into the particular ways in which operators can tightly integrate wireless instrumentation networks with SCADA and realize the full benefits of such an integrated solution.06/29/2010
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
HIGH-SLIP BRAKING SOFTWARE PUTS THE BRAKES ON TRADITIONAL LOAD-BRAKING METHODS WITHOUT EXTERNAL EQUIPMENT
The techniques for braking of high inertial loads to a stop traditionally involved either Dynamic Braking or DC Injection Braking technology.
This article examines a new load-braking alternative called High-Slip Braking (HSB). We identify the different aspects of HSB, look at what it does, how it works, and how it is different from other braking methods. We also provide examples of "real world" successes, and discuss the new technology's cost effectiveness.
WHAT DOES HSB DO?
High-slip braking allows the stopping of larger inertial loads without the need for expensive and bulky braking options such as Dynamic Braking packages. Inertial loads involve only inertia and friction and given enough time, will tend to stop on their own when power is removed. HSB is most effective in applications involving infrequent stopping of inertial rotating loads where speed control during stopping is not required. Typical applications of this sort include; laundry equipment, centrifuges, large commercial fans, punch presses, blowers and mixers. Do not use HSB on overhauling static loads like; hoists, winches, elevators, product lifters, and similar applications. HSB is applicable only for complete stopping of the load and not as a means of braking for speed changes.
The HSB feature has proven to cut braking times in half without requiring extra equipment. The overall stopping time, however, does depend on the inertia of the load being stopped and the characteristics of the motor. HSB can achieve braking torque of more than 100% of the full motor torque.05/17/2010
Differential pressure transmitters were first implemented in the 1950s but are still one of the most commonly used technologies for measuring liquid level in process industries. In many areas of the industrial level measurement market - including chemical, petrochemical, refining, and electric power generation—differential pressure transmitters have captured the vast majority of level applications; and still represent the largest worldwide sales volume of process level measurement equipment. Their popularity and installed base is so prevalent because DP transmitters are versatile, cost-effective, and due to their long history, plant personnel are familiar with their operation.04/27/2010