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.
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.
Mitsubishi Electric Automation, ARC Advisory Group
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.
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.
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.
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.
Dirk Beer, Harvey Smallman, Cindy Scott, Mark Nixon
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.
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.
PD Flowmeters Quitely Excell 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.
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.