Depending on the Equipment, Application, and Test Method, You May Be Able to Extend the Full Test Intervals for SIS Valves. This article is written by William L. (Bill) Mostia Jr., PE, of Exida, League City, Texas. Mostia has more than 25 years experience applying safety, instrumentation, and control systems in process facilities. He may be reached at firstname.lastname@example.org/05/2001
PD Flowmeters Quietly Excel in Low-Flowrate, High Viscosity, and Liquid and Gas Metering Applications
Positive displacement (PD) flowmeters are the workhorse of today's flowmeter world. They perform many important flow measurements most people take for granted. For example, they are widely used for metering both water and gas in residential, commercial, and industrial applications. Chances are good the flowmeter that measures how much water you use at your house is a PD meter.10/02/2002
Download this white paper to learn how to calculate total uncertainty of temperature calibration with a fry block and have a system that saves time, reduces costs and increases productivity.01/11/2012
This paper will address the application of Guided Wave Radar (GWR), also known as Time Domain Reflectometry (TDR), in your steam loop. Included will be discussions of how this technology functions and differs from more traditional forms of level indication.
The heart and soul of any boiler based power generation system is the steam loop or circuit. Without the proper availability of water in this system, efficiency suffers. In more extreme circumstances damage to other components from either too much water (carryover) or too little water (low water condition) will occur and shorten a boiler's lifespan. In the most extreme situation a dry fire accident could occur resulting in severe damage and personal injury.
Level indication in the steam loop is critical, yet the methods employed to measure it have been slow to evolve or change. Some of that has been due to code requirements (PG-60 of the ASME Boiler and Pressure Vessel Code) or a simple lack of confidence in "new" technology. It has only been in the past 15 to 20 years (recent in terms of boiler/steam loop history) that technologies such as magnetic level gages or differential pressure devices have been used in place of direct reading glass gauges on applications such as feedwater tanks, high pressure preheaters or hotwells. These same devices are now utilized for drum level indication as well. The most recent addition to the technology basket for steam loop applications has been Guided Wave Radar. Used in conjunction with other technologies it is seen as a reliable cost effective choice for redundant level measurement in all steam loop applications, including drum level.02/17/2012
This paper will address
- Knowing when to do a pH sensor calibration versus a calibration check
- How to properly clean a pH sensor
- How to perform a pH sensor calibration
- A decision tree for step by step guidance
The phrase in the above title is actually incorrect in its sequence of wording. All pH readings are supposed to be taken and accepted only when the pH sensor is clean. After all, a contaminated pH sensor may yield an incorrect reading. So one must make sure the sensor is clean before doing a calibration. Once a pH sensor is installed in the process and operating, how do you determine when it is time to take the sensor out of the process and do a cleaning, or a calibration? Does one perform both a cleaning and a calibration or just a cleaning, or just a calibration, or does one just perform a calibration check in buffers or...?
This is something that can be quite confusing, especially when the operational practices and procedures documented by your company's Quality Control or Environmental Practices department may not be specific enough when they describe the procedure or the timing on when to conduct the pH calibration and maintenance. Inversely, the procedures may be too specific, detailing many more procedures and operations than are actually required.
In practical terms, users must develop their own maintenance and calibration schedule. This schedule is accomplished by taking the pH sensor out of the process after a set amount of time, perhaps after a day or two to perform a visual inspection of the sensor. If after inspection you find no debris or fouling on the electrode and reference surfaces with the naked eye, rinse the sensor off in distilled water and perform a buffer check.02/27/2012
In this white paper, Mike Fahrion discusses 10 basic rules that will help you ensure success in the design and implementation of your wireless network.04/09/2012
The third edition of this handbook has been totally revised to include new chapters on Electrical Measurements, Vibration and Sound, Displacement and Position Sensing, and Transducer Electronic Data Sheets (TEDS). It also includes several new subjects and expands on selected items including Fundamental Signal Conditioning.
All chapters have been enhanced to address more practical applications than theoretical measurement issues. They cover a major topic with sufficient detail to help readers understand the basic principles of sensor operation and the need for careful system interconnections. The handbook also discusses key issues concerning the data acquisition system's multiplexing and signal conditioning circuits, and analog-to-digital converters. These three functions establish the overall accuracy, resolution, speed, and sensitivity of data acquisition systems and determine how well the systems perform.
Data acquisition systems measure, store, display, and analyze information collected from a variety of devices. Most measurements require a transducer or a sensor, a device that converts a measurable physical quantity into an electrical signal. Examples include temperature, strain, acceleration, pressure, vibration, and sound. Yet others are humidity, flow, level, velocity, charge, pH, and chemical composition.04/23/2012
The worldwide Human Machine Interface platform (HMI) market continues to evolve to meet the needs of manufacturers, processors, and OEM users, especially during periods of economic turbulence. This white paper will serve to educate you on the market drivers on through the solution phase. Rest assured this white paper will teach you how to use an HMI to increase productivity and profitability.06/05/2012
Gainsville Regional Utility Leverages Limited Maintenance Resources By Adding an Asset Management System as Part of a Repowering Project.
To meet growing power demans in the area, the John R. Kelly Generating Station in Gainsville, Fla., repowered an existing 48 MW steam unit by constructing a combined cycle facility. It uses a General Electric gas turbine and an ATS heat recovery steam generator to drive the existing steam turbine.06/07/2012
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
Let's take a closer look at the process of vaporization and how we can manipulate the variables -- temperature, pressure, and flow -- to ensure proper vaporization and an accurate analytical result.08/09/2012
The thermal mass flow meter's ability to deliver a direct reading of mass flow rates of air, natural gas and other fuel gases provides a simple, reliable, and costeffective method for tracking and reporting fuel consumption.
Accurate, repeatable measurement of air and gas, at low and varying flow rates, is also a critical variable in combustion control. Conventional flow meters require pressure and temperature transmitters to compensate for density changes. The thermal mass flow meter, however, measures gas mass flow directly, with no need for additional hardware. The thermal meter also provides better rangeability and a lower pressure drop than orifices, venturis, or turbine meters.
Energy prices are subject to frequent and abrupt changes and fluctuations. When energy prices are high, daily accounting of natural gas usage should be made a priority for large industrial facilities with multiple processes and/or buildings. Fuel gas flow meters are used to analyze demand, improve operating efficiency, reduce waste and adjust for peak usage. Thermal mass flow meters are frequently used for these energy-accounting applications. In addition, thermal flow meters can help plant managers provide accurate usage reports for environmental compliance, as well as compare measured usage to billing reports from gas providers.08/13/2012
Every manufacturing industry is experiencing an increasing speed of business in several areas including changing schedules, customer needs, costs of materials, business models, and technologies. At the same time, many manufacturing sites - particularly in the discrete industries - have growing complexity in their operations which makes it more difficult to adapt. There are more SKUs and data to keep track of due to product proliferation, smaller lot sizes and compliance to government regulations.
The demands for improved speed and agility conflict with the plants' ability to respond. Visibility into current operations, including the control system, is the primary reason manufacturers buy Manufacturing Execution Systems (MES). This visibility provides the information necessary for informed decision making in real-time by all levels of personnel - plant floor to the executives.
MES applications contain the critical business processes for executing a production schedule. These systems perform the production-centric functions of planning, controlling, operating and informing. Control systems execute these functions to produce the goods needed to fulfill customer orders. By integrating MES with control systems, manufacturing becomes more agile for responding to change in this increasingly dynamic business environment. Integrating the control system with the MES allows for more effective and broader set of production management functions to improve operational performance.
To improve their response to operational issues, managers look to technology for connecting plant floor and business systems for automated business processes. Some manufacturers have implemented point solutions on a case-by-case basis. Because of the higher development costs and support issues, this approach is not acceptable. An integration platform is needed.08/20/2012
With any new tech device, whether a cell phone or plant-floor controller, there is inevitably a helpful feature or two you overlooked while reading the manual or taking the introductory tutorial. Although these technological devices still perform their desired, basic functions - discovering an underutilized feature makes you wonder how you ever operated the device without it.
Interacting with alarms is one of the basic functions your operators expect from their human-machine interface (HMI) software. However, if you're only using the standard alarming functions, you may be missing out on lesser-known features that could help you save time, ease troubleshooting and reduce headaches. The five FactoryTalk Alarms and Events functions listed below are often overlooked and underutilized. See where they fit and if you can find some hidden tools in your plant-floor applications.08/29/2012
The technology advancements in measurement instruments and final control elements provide greater process insight, reduce engineering costs and contribute to improving the overall operational performance of the plant. These instruments are often collectively referred to as smart devices.09/04/2012
With the advancement of computer and data transmission technologies, systems formerly reserved for the office environment are now critical components of the manufacturing floor. The demands of factory automation, in addition to computer hardware and software, have brought the wire and cable networking products that interconnect these technologies into the industrial setting as well.
With the vast differences between an office and an industrial environment, networking cables such as gigabit Ethernet have had to adapt to these harsh new surroundings, not only from a physical perspective but from a performance perspective as well, in order to function reliably.
This white paper discusses the constructional differences between standard Gigabit Ethernet and the specifications required for similar cables utilized in an industrial manufacturing environment. Additionally applications for these ruggedized designs are also reviewed.09/26/2012
Human operators are a key part of any process control system. As such, they constitute part of a complex, causal chain of overall system processing. Human machine interfaces (HMIs) form a key link in that chain by bridging the physical world where processes reside with the perceptual reconstruction and representation of those processes in the heads of human operators and supervisors.
If an HMI design gives rise to a flawed or inaccurate representation of a process, then error and suboptimal task performance may result. HMIs have become increasingly important links in this chain for two reasons. First, the arrival of distributed control systems (DCS) in the 1970s distanced operators from the physical entities they controlled, requiring all interaction be mediated by HMIs. Second, the ongoing introduction of complex automation into process control is increasingly changing human operators into supervisors. Supervision has complex decision-making requirements that must all be conveyed via HMIs.
Download this entire white paper to learn more.10/09/2012
Juniper Research forecasts that there will be a total of 400 million connected devices in service across all industry segments by the end of the forecast period in 2012. From a sector perspective, the last 18 months have seen significant take up of embedded consumer electronics devices, specifically eReaders, a trend which is expected to continue over the forecast period. In addition consumer and commercial telemantics will show increasing device numbers as automotive manufacturers aim to embrace embedded connectivity in the next five years in a new vehicle sales.
While the reality of the M2M market may have fallen short of expectations since its early days, in the 2011 to 2012 period Juniper Research has observed an increasingly coherent approach to the market of both operators and M2M-enablers. On one hand, the interfaces built by companies to manage devices are becoming more sophisticated as the power of the Internet and the cloud are leveraged to their full extent. On the other hand, the automation of delivery and control means that the costs associated with M2M roll outs are reduced, improving the economic viability of M2M projects.
This coincides with a reappraisal by operators of how M2M will deliver revenue, away from standard revenue-per-device towards a revenue model which is defined by the service that is delivered. Both operators and M2M enablers now see the M2M market as a market in its own right, with its own characteristics with respect to revenue generation.
Juniper Research believes that the combination of cloud-based infrastructure and the introduction of technologies such as Bluetooth low-power at an affordable cost will give the market further impetus, while the acquisition route is strengthening some of the most respected M2M companies, affording them an increased level of sophistication.10/24/2012
For many process plants, there are three distinct tasks with respect to their control, instrumentation and information systems -- otherwise known as the automation system. The first task category is operations. and maintenance. The plant must be kept up and running with minimal downtime, with maintenance, performed as needed.
The second task includes continuous improvements. The existing automation system must be made to increase throughput, reduce downtime, cut energy costs, improve quality and make other enhancements to the production processes. These improvements are necessary to stay competitive in worldwide markets, and firms that neglect this task will fall hopelessly behind.
Third, capital projects must be planned and executed for a variety of reasons, from adding capacity to regulatory compliance to changing the range of products produced. In many process plants, operations and maintenance tasks can consume all the available automation professional man-hours from on-site staff, leaving little or no time for continuous improvements and capital projects. In the worst cases, many plants find it difficult to recruit and maintain even the minimal staffing required for operations and maintenance.
There are two possible approaches to address these staffing issues. The first is to add more permanent staff at the plant level, and the second is to seek assistance from an outside service provider such as a systems integrator -- also known as staff augmentation or outsourcing. Adding permanent staff can be problematic at many process plants for a number of reasons as explained below.
As detailed in a recent Control magazine cover story, demand for experienced automation personnel relative to supply is at an all-time high by many indicators. A quote from the article illustrates the point.
"The demand for process automation professionals is high, and the talent pool is small and shrinking," said Alan Carty, president of recruiting firm Automationtechies in Minneapolis. "Systems integrators, end users and process control product manufacturers are all seeking these people. I've been recruiting for 12 years, and I feel that current demand relative to supply is at an all-time peak."
Exacerbating the situation, many process plant managers have trouble recruiting workers to their. specific locales, which are almost always far from the urban areas favored by many automation, professionals, particularly recent graduates.
Another significant issue primarily affects staffing for plant automation operations and maintenance positions, and that's the requirement for 24/7/365 support. When faced with the choice between working regular hours versus being on-call around the clock -- including weekends and holidays - many automation professionals, opt for the former.
Even if these problems are overcome with sufficient staffing for operations and maintenance, providing sufficient personnel for continuous improvement and capital projects remains an issue.
This task in particular often requires specialized skills that existing plant operations and maintenance staff may not possess. Furthermore, many continuous improvement projects and larger capital projects often require relatively high staffing levels for implementation, then much lower staffing levels for ongoing operations and maintenance.10/30/2012
An Objective Look at the Roles of Cesium-137 and Cobalt-60 in Nuclear Measurement Systems for Industrial Processes
Level and density measurements in process control are performed by a number of technologies. When the process temperature, pressure, or chemistry is an issue, then nuclear measurement systems have the advantage. These are non-invasive to the vessel and unaffected by the process pressures and chemistries.
Overall, a nuclear measurement system used for process control consists of a gamma energy emitter and detector. An emitter is placed on one side of a vessel to broadcast a beam of energy to the opposite side of the vessel. The detector is placed in the beam on the opposite side of the vessel. The detector will scintillate in the presence of gamma energy and register counts proportional to the field strength. When the process value (level or specific gravity) is low, the detector will register a high number of counts since less gamma energy is blocked by the process material. When the process value is high, more of the gamma energy is blocked which leads to fewer counts.
The two most common gamma emitters used for level and density process measurements are isotopes of cobalt and cesium. The goal of this article is an objective comparison of the roles of cesium-137 and cobalt-60 in process measurement. This will be accomplished by reviewing the properties of the two materials and then comparing the use of the materials in process measurement.11/05/2012