Understanding the accuracy of a given flowmeter is an important field but it can also be misleading as different specifications are used to explain how accurate a flowmeter measurement actually measures. This paper discusses the different specifications and interprets the impact of them.
Why deal with accuracy?
The reasons for dealing with flowmeter accuracy specifications are many-folded. One important reason is from an economical point of view. The more accurate a flowmeter can measure, the more money you will save as the medium is measured with only very little inaccurately.
Another reason is in terms of dosing, where a given amount of a medium is added. This must be done with a high level of precision and the accuracy is thus important in order to dose correctly. This is critical in certain industries such as in pharma or chemical.
A third reason is in terms of billing purposes. By performing with good accuracy, you know exactly how much fluid flows into the process. Thereby, you are able to determine the right price of the product and thereby bill the customers correctly.
Therefore, knowing how much that flows through your system is paramount in order to make a profitable and solid business. You need to rely on a precise measurement with good accuracy. However, good accuracy must be obtained not only in one measurement, but in all measurements independent of the time.01/21/2013
Learn 5 Reasons to switch to distributed modular I/O01/16/2013
This article describes two independent techniques for ensuring strong security in systems using OPC Classic technology01/14/2013
Preventing the next Stuxnet-like attack on the control world might be impossible, but operators can mitigate the effects and contain worms and viruses through early detection.01/07/2013
Industrial control networks are highly vulnerable to intelligent remote attacks, as well as non-intelligent viruses. With threats to these networks increasing in complexity and scope, decision makers need to take action before it's too late.01/04/2013
This paper examines the benefits and shortfalls of both safety PLCs and configurable safety relays. It also examines a new way of handling safety in industrial automation, "SafetyBridge" technology.01/02/2013
More than 60 percent of all industrial temperature measurement applications in the U.S. use thermocouples. Despite their widespread use, there are many misconceptions about thermocouples. This paper will discuss some of the basic technical issues that engineers need to consider when applying thermocouples.12/30/2012
This white paper identifies the top five challenges typically encountered on the factory floor, and offers some criteria to consider when selecting industrial PCs and associated components.12/28/2012
This White Paper explains:
- What the 3S CoDeSys vulnerabilities are and what an attacker can do with them
- How to find out what control/SCADA devices are affected
- The risks and potential consequences to SCADA and control systems
- The compensating controls that will help block known attack vectors
A number of security vulnerabilities in the CoDeSys Control Runtime System were disclosed in January 2012. In October 2012, fully functional attack tools were also released to the general public.
While CoDeSys is not widely known in the SCADA and ICS field, its product is embedded in many popular PLCs and industrial controllers. Many vendors are potentially vulnerable, and include devices used in all sectors of manufacturing and infrastructure. As a result, there is a risk that criminals or political groups may attempt to exploit them for either financial or ideological gain.
This White Paper summarizes the currently known facts about these vulnerabilities and associated attack tools. It also provides guidance regarding a number of mitigations and compensating controls that operators of SCADA and ICS systems can take to protect critical operations.12/26/2012
Water conservation is becoming a major focal point, both in the public and private sector whether it is due to cost of water, availability of water, or environmental concerns.12/22/2012
Wastewater treatment facilities are generally installed for one purpose - to clean up dirty water so that clean water can be discharged back into the environment. Nearly all municipal treatment plants rely on biological processes for wastewater treatment whereby bacteria and other microorganisms, frequently called 'bugs,' do this job of cleaning up the water.12/20/2012
This white paper provides insight into the evolution of the modern SCADA system and looks to the very near future by discussing such timely topics as:
- Improving system efficiency and security
- Managing field data and
- Open standards
Some 66% of the process control systems now in use globally were installed before publication of today's commonly used safety standards, IEC 61508 and IEC 61511/ISA 84. Here's how to tell if you safety systems are up to snuff.12/13/2012
The editors of Control and Control Design compiled this special report from the 21st annual Automation Fair event, hosted by Rockwell Automation, in Philadelphia, November 5-8. This interactive PDF includes more than 20 articles documenting highlights ranging from executive keynotes and new product announcements to vertical industry forums and Rockwell Automation Process Solutions User Group and Safety Automation Forum meetings.12/11/2012
Halloween in New Orleans this year saw more than the usual array of costumed revelers on Bourbon Street. Indeed, hundreds of process automation professionals descended on the Crescent City to exchange ideas and best practices at Yokogawa's 2012 User Group Conference and Exhibition. The Control editorial team was on hand and developed this exclusive report of presentation highlights--on topics ranging from safety system risk management to the latest in data acquisition technology.12/10/2012
There are over two hundred pressure sensor suppliers around the world, offering products from a few dollars to thousands of dollars. A purchaser or engineer unfamiliar with pressure sensors can become overwhelmed with the price range, quality and options. The first step is to understand his/her application from the media being measured, to the desired electrical output for indication or control. The following is a guide through a variety of options to make a prudent decision.
Media is the most important item when selecting a pressure sensor for an application. Most sensor suppliers only sell sensors that are rated for benign environments such as clean, dry air. The next tier of suppliers will sell products that will handle mild environments through to difficult/corrosive environments. Clean water, steam, some forms of hydraulic oils and Freon can be considered mild environments. Difficult media tends to be corrosive liquids and gases such as hydrogen sulfide, hydrochloric acid, bleach, bromides, waste water and hydrogen. Wrongful selection of a pressure sensor can lead to catastrophic failure and serious injury. When unsure, ask the pressure sensor manufacturer to provide a chemical compatibility chart with their products. In fluidic systems, such as water and hydraulics, one must understand how the water hammer and pressure transients effect the pressure sensor.11/15/2012
Differential pressure transmitters are extremely versatile instruments fitting a broad range of applications in various process industries.11/14/2012
Proper Media Compatibility, Sensing Topology and Grounding Ensure Long-term, Trouble-free Pressure Measurements in Wet and Noisy Electrical Environments
Water is a key element to life. It plays an important role in the world economy, as it functions as a solvent for a variety of chemical substances. 71% of the Earth's surface is covered with water and 97% of that water is in oceans and saline. Only 3% of the earths water is fresh and can be found in the polar caps, glaciers, ground aquifers, lakes, swamps and rivers. In parts of the world where there is limited or no access to fresh water, desalination is being used to convert saline water to drinking water. To manage resources and the flow of water, modern electrical pumps and control systems are employed. Water chemical compatibility and electrical interference are two major challenges for the control systems. Let's ook at two major sources of fresh water and the issues that can limit the performance of the control system.11/14/2012
New Differential Pressure Sensor Incorporates LVDT Technology to Create More Environmentally-Resistant, Dependable and Economical Pressure Sensing Solution
Differential pressure (dP) sensors with electronic signal processing are increasing being used to monitor flow, filter condition and level. Since these devices offer linear and accurate output, they are also replacing the differential pressure switch that only support on-off condition and useless for closed loop control system. These dPs are often configured with expensive valves and fluid filled remote seals for added protection against corrosive media, radiation and/or extreme media temperature ranges when operating in demanding environments. In cold ambient environment specially operating in temperatures below -4 deg F (-20 deg C), the sensor need to be heated either by trace heater or within a heated enclosure to maintain the operation of the dP sensor. In addition to being expensive, these valves and seals tend to be bulky and require time to install and maintain. In many critical applications such as food and pharmaceuticals, filled fluids are a serious concern due to process contamination. In gaseous systems such as hydrogen and oxygen and semiconductor applications, fluid filled sensors are being banned since the leakage of fluid into the process could lead to an explosion and serious safety issues.
A new series of LVDT (linear variable differential transformer) based oil-less dP sensor with dual channel ASIC (applications specific integrated circuit) have been developed that can operate in a wide range of corrosive materials, radiation and temperature without any oil filling and bulky sealing systems. By encapsulating LVDT proven technology with digital compensation, the pressure sensors combine the benefits of friction-free operation, environmental robustness and unlimited mechanical life. By selecting the diaphragm thickness and material properties, Table 1 show the dP ranges that can be produced using the LVDT technology.11/14/2012
Updated government regulations created a need for a major international oil and gas company to install a direct, real-time communications link at a platform located off the coast of Louisiana in the Gulf of Mexico.
ENI Petroleum is an Italian multinational oil and gas company with around 78,400 employees at sites in 77 countries. ENI operates in the oil and gas, electricity generation and sales, petrochemicals, oil field services construction and engineering industries. It has oil and natural gas production of almost two million barrels per day, with exploration and production efforts at sites throughout North American, Africa and Asia.
One of these production locations is an oil well platform called the "Devil's Tower" that is located just off the coast of Louisiana in the Mississippi Canyon region of the Gulf of Mexico. The platform rises 5,610 ft. above the sea bed. Until 2010, it was the deepest production truss spar in the world. Drill ships perform periodic operations within close proximity to subsea pipelines that transport oil and gas to and from the production platform.
In this white paper, you will learn how a new data concentrator system allowed the control room and drill ships to communicate at a distance of more than 100 km, providing security in case of an incident while avoiding costly shutdowns.11/08/2012