Magnetic Flow Meters

Magnetic flow meters can be easily applied in lined
pipe sections and those of substantial diameter.
Image courtesy Yokogawa

The measurement of fluid flow is a common process control function. Flow measurement can have a range of differing output requirements, depending upon the needs of the process operators. With many technologies and instruments from which to choose, knowledge of the principals behind each measurement technology and basic operation requirements can help in the selection of the best instrument for each application. 

Anywhere there are pipes, somebody wants to know how much fluid is passing through them. Industrial flow meters rely on their ability to measure the change in some physical characteristic of fluid moving within a pipe that can be related to fluid velocity or mass flow. Depending upon the nature of the raw measurement, additional information and processing may be necessary to convert the base measurement into a useful measurement of flow rate.

In the processing industries, differing technologies are used to measure fluid motion. Some common technologies include magnetic, ultrasonic, vortex shedding, Coriolis and differential pressure. This list is not exhaustive, and several other technologies will certainly be found in use. Each methodology survives within a competitive marketplace due to its unique combination of performance and value attributes. Let's look at magnetic flow meters, also referred to as magmeters.

The operational principle of a magnetic flow meter is based upon Faraday’s Law. This fundamental scientific principle states that a voltage will be induced across a conductor moving at a right angle through a magnetic field, with the voltage being proportional to the velocity of the conductor. The principle allows for an inherently hard-to-measure aspect of a conductive fluid to be expressed via the magmeter. In a magmeter application, the instrument produces the magnetic field referred to in Faraday’s Law. The conductor, moving at a right angle to the magnetic field, is the fluid. The actual measurement of a magnetic flow meter is the induced voltage corresponding to fluid velocity. This can be used to determine volumetric flow and mass flow when combined with values of other fluid properties and the pipe cross sectional area. Magnetic flow meters enjoy some positive application attributes.

• Magnetic flow meters have no moving parts.
• The instrument, which often resembles a pipe section, can be lined with corrosion resistant material for use with aggressive media.
• With no sensor insertions or obstructions in the fluid path, the impact of the instrument on the flow is minimal.
• Accuracy, when compared to other technologies, is high.
• Application to laminar, turbulent, and transitional flow profiles is permissible.
• Generally, measurement is not adversely impacted by fluid viscosity, specific gravity, temperature and pressure.
• Magnetic flow meter technology can be applied to a very wide range of pipe sizes.
• Device responds rapidly to changes in fluid flow.
• Can be successfully applied to liquids containing heavy particulates.
• Generally long service life with little maintenance.

Though the roster of positive attributes is strong, magmeters are not universally applied. Consider some of these points with respect to your potential application.

• The fluid acts as the "conductor", as stated in Faraday's Law. Magnetic flow meters only work on liquids with conductivity above a certain threshold. They may be unsuitable for use with hydrocarbons and high purity water for this reason.
• Cannot be used to measure gas flow because gases are not sufficiently conductive.
• Piping must be grounded.
• Generally, rated accuracy requires the pipe cross section to be filled by the liquid being measured.

This listing of attributes is very general in nature. Some magnetic flow meter variants have adaptations that minimize or accommodate the impact of special process conditions. Share your flow measurement requirements and challenges with a process measurement specialist. Your own knowledge and experience will be leveraged into an effective solution by their product application expertise.

Process Automation: Valve Actuator Limit Switches

Municipal water treatment plant

Limit switches are devices which respond to the occurrence of a process condition by changing their contact state. In the industrial control field, their applications and product variations are almost countless. Essentially, the purpose of a limit switch is to serve as a trigger, indicating that some design condition has been achieved. The device provides only an indication of the transition from one condition to another, with no additional information. For example, a limit switch triggered by the opening of a window can only deliver an indication that the window is open, not the degree to which it is open. Most often, the device will have an actuator that is positively activated only by the design condition and mechanically linked to a set of electrical contacts. It is uncommon, but not unknown, for limit switches to be electronic. Some are magnetically actuated, though most are electromechanical. This article will focus on limit switch designs and variants used in the control and actuation of industrial process valves.

Employed in a wide range of industrial applications and operating conditions, limit switches are known for their ease of installation, simple design, ruggedness, and reliability.

Valves, devices used for controlling flow, are motion based. The movable portions of valve trim create some degree of obstruction to media flow, providing regulation of the passage of the media through the valve. It is the movement of critical valve trim elements that limit switches are used to indicate or control. The movable valve trim elements commonly connect to a shaft or other linkage extending to the exterior of the valve body. Mounting electric, hydraulic, or pneumatic actuators to the shaft or linkage provides the operator a means to drive the mechanical connection, changing the orientation or position of the valve trim and regulating the media flow. Because of its positive connection to the valve trim, the position of the shaft or linkage is analogous to the trim position and can be used to indicate what is commonly referred to as “valve position”. Limit switches are easily applied to the valve shaft or linkage in a manner that can provide information or direct functional response to certain changes in valve position.

In industrial valve terms, a limit switch is a device containing one or more magnetic or electrical switches, operated by the rotational or linear movement of the valve.

What are basic informational elements that can be relayed to the control system by limit switches? Operators of an industrial process, for reasons of efficiency, safety, or coordination with other process steps, may need answers to the following basic questions about a process control valve:

• Is the valve open?
• Is the valve closed?
• Is the valve opening position greater than “X”?
• Has the valve actuator properly positioned the valve at or beyond a certain position?
• Has the valve actuator driven the valve mechanism beyond its normal travel limits?
• Is the actuator functioning or failing?

Partial or complete answers to these and other questions, in the form of electrical signals relayed by the limit switch, can serve as confirmation that a control system command has been executed. Such a confirmation signal can be used to trigger the start of the next action in a sequence of process steps or any of countless other useful monitoring and control operations.

Applying limit switches to industrial valve applications should include consideration of:

• Information Points – Determine what indications are necessary or useful for the effective control and monitoring of valve operation. What, as an actual or virtual operator, do you want to know about the real time operational status of a valve that is remotely located. Schedule the information points in operational terms, not electrical switch terms.
• Contacts – Plan and layout a schedule of logical switches that will provide the information the operator needs. You may not need a separate switch for each information point. In some cases, it may be possible to derive needed information by using logical combinations of switches utilized for other discrete functions.
• Environment – Accommodate the local conditions and hazards where the switch is installed with a properly rated enclosure.
• Signal – The switch rating for current and voltage must meet or exceed those of the signal being transmitted.
• Duty Cycle – The cycling frequency must be considered when specifying the type of switch employed. Every switch design has a limited cycle life. Make sure your selection matches the intended operating frequency for the process.
• Auxiliary Outputs – These are additional contact sets that share the actuation of the primary switch. They are used to transmit additional signals with specifications differing from the primary signal.
• Other Actuator Accessories – Limit switches are often integrated into an accessory unit with other actuator accessories, most of which are related to valve position. A visual local indication of valve position is a common example.

Switches and indicators of valve position can usually be provided as part of a complete valve actuation package, provided by the valve manufacturer or a third party. It is recommended that spare contacts be put in place for future use, as incorporating additional contacts as part of the original actuation package incurs comparatively little additional cost.

Employing a properly configured valve automation package, with limit switches delivering valve status or position information to your control system, can yield operational and safety benefits for the life of the unit. Good advice is to consult with a valve automation specialist for effective recommendations on configuring your valve automation accessories to maximize the level of information and control.

Succeeding: Engineer as Peacemaker

Make Allies, Not Adversaries

Let's take a step away from the technical, but still focus on an important aspect of our work.

As engineers involved in process measurement and control, we are accustomed to everybody else looking to us for answers and solutions. We are the people that make things work. Occasionally the pressure and stress can get a little intense and strip away some of our civility in our dealings with those around us. You may have bitter experience with this as either victim or perpetrator. It never ends well. With a private and candid self-assessment about how we view and interact with other stakeholders in our projects, we may be able to scale down some of our stress and better focus on the reality of the task at hand. Consider the points below. Comment and add a few points of your own.

You are an expert, but so are they.

Accept that, just as you have specialized knowledge that others do not, they have specialized knowledge or insight you may lack. Encourage the sharing of knowledge with those you interface with on a project. Try to be proactive and ask gently probing questions to ascertain the comprehension level of others involved in the project in various roles. Their increased understanding of key project technical concepts will promote more effective communication throughout the duration of the project. It can also help to avoid missteps in your own progress. Good people appreciate the time you take to provide basic explanation of concepts they may not fully understand, but need to know. Make valuable allies of the other project stakeholders by freely contributing your expertise. It is an investment that costs you little, but may pay immense dividends at some future time.

Everybody else's job usually looks easier than it really is.

All jobs have their own special challenges and responsibilities that generate stress. Accept the notion that you probably do not fully comprehend the burdens on those around you. Your portion of the project is certainly critical, but no more so than that of anybody else. Everybody needs to perform or nobody succeeds. Try not to view your project tasks as compartmentalized, but rather as part of the combined joint effort of all stakeholders. Help out others whenever you can. Again, make allies.  

Everybody is somebody's customer.

Whomever you deliver your work product to is your customer. The people delivering their work to you should view you as their customer. Make your customers happy by adjusting aspects of your procedures to better satisfy their needs. In a more technical sense, your modified process output becomes an improved input to their process. Small changes in your delivery may produce comparatively large returns in customer satisfaction. Allies.

Do not embarrass or demean others...especially in public settings.

Embarrassment breeds anger, a desire for revenge, and other bad and unproductive things. Avoid words and deeds that will make a coworker or stakeholder look bad in front of others. If there is a problem, if there is a mistake, try to deal with it discreetly whenever possible. Giving a someone a chance to repair a mistake before it becomes public builds value in your relationship. Certainly, there can be instances where more is at stake than someone's pride. Use good judgement to recognize when you can privately give someone an opportunity to amend a situation without causing harm.

Reach a common understanding of project scope and technical details

Your organization's management or your company's client, whatever the case may be, will likely have project expectations which will be clearly understood in their mind, but perhaps not fully described to all those tasked with specific performance. It is also possible, even probable, these same stakeholders will have misconceptions or a lack of technical knowledge about certain facets of the project. Omissions from the project specs and gaps in the common understanding of technical aspects related to the work requirements can easily turn a fairly straight forward task into a wildfire of organizational mayhem. The way in which these situations are handled must be diplomatic. Injured egos can do more damage to project harmony and progress than the facts ever will. The delivery method for the facts will likely be more crucial than the facts themselves.

It's not about being right. It's about being successful.

At our company we recognize customers are more than merely people that buy things from us. They are people to whom we contribute our time and talent to help achieve their success,... which inevitably will lead to ours. Never hesitate to let us know how we are doing, or how we can help.

Pressure Relief Valve - Guardian of the Vessel

Pressure relief valves protect this industrial boiler
from conditions beyond maximum allowable working pressure

Danger and hazards are an integral part of industrial processes. The mitigation of these dangers and hazards, as well as reducing the probability of their occurrence, is the primary charge of industrial process engineering. Every product intended for use in a process control setting has safety and protection included in its design criteria. Pressure relief valves fall in that category of products designed and intended solely for safety purposes.

Manufacturers of what most generally refer to as pressure relief valves break the genre down into two distinct groups, relief valves and safety valves. One manufacturer, Anderson Greenwood (a Pentair brand), distinguishes the two valve types in their "Pentair Pressure Relief Valve Engineering Handbook"...

Relief Valve: A pressure relief valve characterized by gradual opening or closing generally proportional to the increase or decrease in pressure. It is normally used for incompressible fluids.

Safety Valve: A pressure relief valve characterized by rapid opening or closing and normally used to relieve compressible fluids.

The difference between the two valve types is found in their response to an excessive pressure condition. The relief valve, according to the definition, responds proportionally to the pressure increase, whereas the safety valve provides a non-proportional rapid response. Note also that the relief valve is generally intended for use with liquids (incompressible) and safety valves are commonly applied to compressible fluids, which would include steam and air.

Pilot Operated Pressure Relief Valve
Courtesy Anderson Greenwood

Pressure relief valves are found anywhere pressure is contained, be it a piping system, vessel, even a

household pressure cooker. The purpose of the relief or safety valve is to protect a pressurized system or vessel, should the system pressure exceed the maximum allowable working pressure. Simply put, keep it from breaking apart.

Because of the potentially catastrophic nature of a pressurized system failure, there is a high level of scrutiny, regulation, and testing focused on pressure relief and safety valves. The proper sizing and selection of the valves is also critical to providing proper function.

I have included a product bulletin from Anderson Greenwood with this article. Browse through it. It provides solid technical information, along with some excellent cutaway illustrations showing how the valves function. You are bound to discover something you did not know about safety and relief valves and their proper application. You can also contact the specialists at Miller Energy for assistance in proper valve sizing and selection.

Anderson Greenwood Pilot Operated Pressure Relief Valves from Miller Energy, Inc.

Connecting Modbus Transmitter to USB Converter

EJX910 Multivariable Transmitter
Courtesy Yokogawa

Industrial process measurement and control utilizes transmitters in abundance. There may be instances where, for convenience or due to equipment changes, the output signal from the transmitter will need to be converted to a different protocol or format. Yokogawa has produced an instructional video showing, in a clear and understandable way, how to install a signal converter on their EJX910 Multivariable Transmitter. While the instructional video shows a conversion from Modbus to USB, the knowledge and understanding gathered from the short video will help you to meet other signal conversion challenges that may arise in your facility.

Your investment of five minutes to watch the video will generate returns by increasing your understanding and allowing you to move forward with confidence when a signal conversion task inevitably comes up. More information on signal conversion products, as well as process measurement transmitters, is available from an application specialist. Enlisting their help to generate solutions to your industrial measurement and control requirements is also a good investment of your time.

Liquid Density Measurement for Industrial Process Control

DM8 Liquid Density Meter
Courtesy Yokogawa

Density is certainly a fundamental physical attribute of any liquid that is the subject of a process control operation. The ability to accurately measure liquid density in a process application is achievable using specially applied technology from Yokogawa.

The company's latest version, the model DM8, is a vibration type liquid density analyzer with reliable, multi-function operation. It is the culmination of manufacturing and density measurement technology experience extending back over 40 years. The DM8 employs a converter with an incorporated microprocessor to directly convert sensor frequency signals into displayed density values. One touch calibration, internal diagnositics, and digital communications are also provided.


The DM8 liquid density analyzer measures liquid density of general process liquids with high sensitivity and excellent stability. It has a measuring density range of 0 to 2.0 g/cm3, and is unaffected by flow rate and viscosity. Sensor options include general-purpose, sanitary, and explosion proof versions.

The brochure below provides additional detail on application configuration, product specifications, and operating principle. Share your process process measurement challenges with a product specialist to achieve the best solution for your application.

Yokogawa Vibration Type Density Meter from Miller Energy, Inc.

Improve Process Safety Compliance With Safety Transmitters

Oil Refinery

Industrial processes often are characterized by substantial hazard through their operation. As operators, engineers, and designers, we are responsible for keeping those actual and potential hazardous conditions and occurrences in check. I recently wrote about safety transmitters that can be used to enhance safe industrial process operation and provide compliance with applicable standards.

I located a single sheet document that summarizes the features, benefits, cost savings, and compliance ratings for the safety transmitters from United Electric. You can get more detailed information on these devices and how to properly apply them in your process control scheme by contacting a product specialist. Combining you process expertise with their product application knowledge will generate a solid solution.

United Electric One Series Safety Transmitter from Miller Energy, Inc.

Safety Transmitter for Temperature and Pressure in Industrial Processes

One Series Safety Transmitters
Courtesy United Electric Controls

United Electric Controls has developed a safety transmitter that combines transmitter, safety switch, and display gauge in a single, easily deployed device. The One Series Safety Transmitter includes the manufacturer's patented self diagnostics, along with diverse and redundant signal processing that feed algorithms to detect and respond to internal faults and process abnormalities.

The safety transmitter provides a local switch that can be used for rapid emergency shutdown at the point of measurement or detection, eliminating the need to communicate with other safety controllers and await a response. The safety relay output is programmable and can handle high voltages and currents associated with shutting down control valves, compressors, and other industrial equipment.

In addition to the safety relay output, the One Series Safety Transmitter provides logic outputs that can be employed in voting logic schemes often used to produce warnings prior to a shutdown. For reliability, the unit employs no moving parts and includes self diagnostics with a local display of device status.

There is a whole lot more to learn about these "Safety right out of the box" industrial pressure and temperature transmitters. The product brochure is provided below, but you can get the latest and most detailed product and application information from a specialist in industrial process measurement and control.

United Electric One Series Safety Transmitter from Miller Energy, Inc.

Thermal Mass Flow Controller - Product Enhancement

Newly Enhanced Thermal Mass Flow Meters
And Electronic Pressure Controllers
Courtesy Brooks Instrument

Brooks Instrument, world recognized leader in thermal mass flow controllers and mass flow meters, has improved upon its premier family of smart digital thermal mass flow controllers and meters. The newly enhanced SLA Series features:

Enhanced temperature stability
Upgraded electronics
Improved accuracy
Zero-drift diagnostics
High turndown ratio

Multiple communication protocol support, and more.

The video included below will show you all the latest improvements on this product line that has thousands of units in its installed base throughout many industries and applications.

Application assistance and detailed information is available from product specialists. Combine their product and application knowledge with your own process expertise to generate a positive outcome.

High Speed, High Performance Control for Weighing Operations

Industrial Batch Process Tanks

Industrial process control implies the presence of industrial process measurement. Throughout our operations, we seek to measure "how much" of something is present. In the case of many materials, weight is the preferred measurement.


Weight is a measurement of force. We can use it as a statement of "how much" because gravity is considered constant across the planet surface. The force I measure for a batch of material in the US will, for commercial purposes, be the same force measured for that material after I ship it to somewhere else. Measurement of weight can be used for establishing proper mixing ratios of components to be combined in a particular manner. The level of material in a tank or other container can be ascertained through a measurement of weight.

In our processes, higher throughput and accuracy are always in demand.

The Vishay Precision Group's BLH/Nobel Weighing Systems operating unit manufactures a high speed, high performance control for industrial weight/force measurement applications. Their G4 line of controllers provides the user a wide range of configurable options, from multiple input channels to analog and digital outputs. The clean user interface provides access to all functions and channels and the unit is available as a freestanding desktop, DIN rail mount, or panel mount unit. There is also a model configured for harsh environments.

The video below provides a good overview of the unit and its potential applications. Contact a product specialist to receive more details, or to discuss how the G4 might be helpful to your process operation.

New Product From United Electric - Hybrid Transmitter for Industrial Use

Series One HART Transmitter
Courtesy United Electric

By mid November, United Electric will begin shipping its new One Series hybrid transmitter-switch models that include HART® Communications Protocol. The newly designed product offering includes a transmitter-only model, as well as another model providing a transmitter plus two solid-state relays. Monitoring pressure or temperature in harsh, hazardous and heavy industrial process measurement and control settings is the target application for these loop-powered transmitters. Models will include UL and ATEX approvals for Divisions 1 & 2 (Zones 1 and 2). With the introduction of the One Series, UE is declaring a number of older models obsolete. You can get a listing of the newly obsolete models from your local UE distributor.

The new combination transmitter and switch model provides a HART® 7 loop-powered transmitter, and includes two programmable solid-state relays, an improved backlit LCD display, and a separate IAWTM health status discrete output.The transmitter-only model is a HART® 7 loop-powered transmitter and also features an improved backlit LCD display.

Some operational benefits, quoted directly from United Electric's product announcement documentation:

• With HART® 7 capability, all of the functions available with the two-button keypad are also available via the HART® Communications Protocol. Using a HART®-compatible hand held communicator or a PC with a HART® modem and appropriate asset management software, users have the ability to quickly configure the One Series, including the switching parameters, and save the configuration in their library for cloning additional controls with the same parameters. We believe this is the only Division 1 electronic switch on the market with HART compatibility!
• If the units are connected to a control system with HART® IO allowing bi-directional communication, configuration can be performed remotely, without the need to remove the enclosure cover in a Division 1 (Zone 1) area.
• Using a HART® capable asset management system, the comprehensive diagnostic functions of the One Series can determine the health status 24x7, saving time and money while allowing operators to focus on other critical issues.
• For cybersecurity purposes, the HART® communications can be set to read-only mode that prohibits parameter changes from unauthorized users and creating a potentially dangerous condition.

You can explore these new products in more detail with your United Electric distributor, taking advantage of their freshly acquired new product knowledge. Find out how the advanced new features of the One Series transmitters can enhance the operation and management of your industrial process.

Recording, Data Logging, and Process Control - Consolidated or Separate Devices?

Integrated  Controller and Data Acquisition Device
Courtesy Yokogawa

Are you a designer or builder of process control systems? Selecting hardware and componentry to provide the functionality, accuracy, and accessibility required to meet process or equipment performance demands can pose some very distinct challenges. When faced with a scope of work that includes multiple PID control loops, data recording, and networking, do you tend to favor using a collection of separate devices for each function, or a consolidated unit that integrates all of the needed functions?

I have designed many control systems throughout my career, and tended toward using separate devices initially. As I gained experience and the feedback that comes from having units in the field for a number of years, my thinking changed and my preference for integrated "single box" solutions began to predominate.

Some reasons to use a consolidated device:

• Likely to take up less panel space than a combination of individual devices.
• Substantially reduced wiring, cabling.
• No tasks associated with getting individual devices to work together, if that is needed. The integrated unit comes out of the box with all of that already accomplished.
• Reduced parts count.
• Simplified panel wiring plan.
• A single HMI encompassing all the provided functions.
• Anyone, end users, service techs, trainers, quality control, that needs to learn about the operation of the system has a single instruction manual to review or learn. Since the functions all come in one unit, there is often some streamlining to the learning process.
• OEMs may be able to use a single component to provide the necessary functions for numerous product versions, bringing measurable time savings throughout the product design, fabrication, and support functions of their organization.
• If spares are required, there is only one.

I have enjoyed good results employing devices that combine numerous functions into a single package. There is a data sheet below, so you can see more about an industrial control, recording, networking device that packs a useful range of functions into a compact unit. 

On your next process control project, consider whether going consolidated or discrete is better for your needs. Talk to a process controls expert and get some additional input. Good solutions are out there.

Yokogawa CX 2000 DAQ Station from Miller Energy, Inc.

Five Things to Know About Process Instrument Protection

Wireless Process Instrument
Courtesy Yokogawa 

The performance of every process is critical to something or someone. Keeping a process operating within specification requires measurement, and it requires some element of control. The devices we use to measure process variables, while necessary and critical in their own right, are also a possible source of failure for the process itself. Lose the output of your process instrumentation and you can incur substantial consequences ranging from minor to near catastrophic.

Just as your PLC or other master control system emulates decision patterns regarding the process, the measurement instrumentation functions as the sensory input array to that decision making device. Careful consideration when designing the instrumentation layout, as well as reviewing these five common sense recommendations will help you avoid instrument and process downtime.

Process generated extremes can make your device fail.
Search and plan for potential vibration, shock, temperature, pressure, or other excursions from the normal operating range that might result from normal or unexpected operation of the process equipment. Develop knowledge about what the possible process conditions might be, given the capabilities of the installed process machinery. Consult with instrument vendors about protective devices that can be installed to provide additional layers of protection for valuable instruments. Often, the protective devices are simple and relatively inexpensive.

Don't forget about the weather.
Certainly, if you have any part of the process installed outdoors, you need to be familiar with the range of possible weather conditions. Weather data is available for almost anywhere in the world, certainly in the developed world. Find out what the most extreme conditions have been at the installation site....ever. Planning and designing for improbable conditions, even adding a little headroom, can keep your process up when others may be down.
Keep in mind, also, that outdoor conditions can impact indoor conditions in buildings without climate control systems that maintain a steady state. This can be especially important when considering moisture content of the indoor air and potential for condensate to accumulate on instrument housings and electrical components. Extreme conditions of condensing atmospheric moisture can produce dripping water.

Know the security exposure of your devices.
With the prevalence of networked devices, consideration of who might commit acts of malice against the process or its stakeholders, and how they might go about it, should be an element of all project designs. A real or virtual intruder's ability to impact process operation through its measuring devices should be well understood. With that understanding, barriers can be put in place to detect or prevent any occurrences.

Physical contact hazards
Strike a balance between convenience and safety for measurement instrumentation. Access for calibration, maintenance, or observation are needed, but avoiding placement of devices in areas of human traffic can deliver good returns by reducing the probability of damage to the instruments. Everybody is trained, everybody is careful, but uncontrolled carts, dropped tools and boxes, and a host of other unexpected mishaps do happen from time to time, with the power to inject disorder into your world. Consider guards and physical barriers as additional layers of insurance.

Know moisture.
Electronics must be protected from harmful effects of moisture. Where there is air, there is usually moisture. Certain conditions related to weather or process operation may result in moisture laden air that can enter device enclosures. Guarding against the formation of condensate on electronics, and providing for the automatic discharge of any accumulated liquid is essential to avoiding failure. Many instrument enclosures are provided with a means to discharge moisture. Make sure installation instructions are followed and alterations are not made that inadvertently disable these functions.

Developing a thoughtful installation plan, along with reasonable maintenance, will result in an industrial process that is hardened against a long list of potential malfunctions. Discuss your application concerns with your instrument sales engineer. Their exposure to many different installations and applications, combined with your knowledge of the process and local conditions, will produce a positive outcome.

Application Advantages of Wireless Sensors for Process Measurement and Control

Industrial Wireless Access Point
Courtesy Yokogawa

Wireless sensor technology is not new, but is still in an adoptive stage in many industries. New technologies are commonly adopted first by companies and industries that can justify the premium cost of newly released technology. The adoption process is similar to that of business computers. Early models were incredibly expensive to purchase and required a very large budget to keep operational. As time passed, the machines became less expensive to purchase and own, allowing a greater segment of the business world to justify their purchase and use. Wireless process measurement and control is following a similar path, with more and more facilities considering the potential for application of these devices.

I had always considered wireless sensing devices as a great way to be rid of cabling, but limited my thinking to fixed installations. A personal confession....Sometimes it's really hard to get my mind out of the box when I tape it shut. Anyway, I came across this application case from Yokogawa, a leading worldwide manufacturer of process measurement and control equipment and an enormous array of other industrial equipment. The case study illustrates how a tire manufacturing operation used wireless sensing technology to enhance the performance of their pressure test setup. The case study, shown below, shows the actual product part numbers used and provides a schematic and description of how the system was beneficially used. After my own reading of the case, I am now thinking of more potential applications that could benefit from a wireless configuration.

Read the case, it's short and concise. A sales engineer can provide you detailed information on the specific products used in the application. If you come up with some potential wireless process measurement applications of your own, contact an application specialist and explore the possibilities.

Wireless Process Measurement - Case Study of Plant Floor Testing Rack from Miller Energy, Inc.

Know Your Control Valve Basics?

Industrial Control Valve Cutaway View
Courtesy Cashco

Understanding basic operation and function of control valves, an integral part of many industrial process control loops, is essential for the process engineer, operator, or other stakeholder. This presentation outlines control valve operation, major components, and terminology used to describe valve parts, functions, and principles of operation. A useful reference for stakeholders in need of a refresher course in order to understand what the engineers are saying, it also provides detailed illustrations, charts, and description that will prove valuable to the more technical minded.


What you will find:

• Terminology: A glossary of terms commonly used in the control valve world.
• Control Valve Basic Designs: Control valve classifications, cutaway illustrations showing the operating structure of different valve types, comparisons of varying valve designs.
• Characterization and Trim Design: Flow characteristic curves and comparisons for different valve types, showing how flow responds to valve position change.
• Control Valve Technical Considerations: FTC vs FTO, illustrations showing valve operation.
• Force-Balance Principle: Illustration and formula explanations of this basic operating principle.
• Actuator Basic Designs: Illustrations showing the differing arrangements for actuator operation.
• Control Valve Unit Action: Illustrations, diagrams, and explanations of a range of valve operating conditions, including loss of electrical power and loss of instrument air supply.
• Actuator Benchset Range: Shows practical relationship between instrument air pressure and valve ability to properly operate at various pressure conditions.
• Valve Positioner Basics: Definition of valve positioning, reasons to use a positioner, schematic illustrations of control loops.
• Control Loop Action: Charts and provides examples of 16 combinations of Process, Controller, Positioner, and Control Valve combinations.
• Control Valve Packing Designs: Describes and defines packing, common problems, current state of the art. Cutaway illustrations of various packing arrangements.
• Seat Leakage: Classifications, comparisons of different materials.

There is something of value in the document for everyone, and you will undoubtedly pick up something useful. Thanks go out to the engineers at Cashco for putting this together. You can discuss any aspect of your control valve applications with a product specialist. Your contact is always welcome.

Basic Operation & Function of Industrial Control Valves from Miller Energy, Inc.

Eliminate Glass Tube Level Gauge Maintenance Costs

Magnetic Level Indicators
Courtesy Orion Instruments

Industrial process control often requires the accurate measurement of liquid level within a tank or other vessel. There are numerous device technologies and vendors from which to choose. A recent post on this blog detailed one of the available methodologies, the magnetic level indicator. I urge you to review that short post to familiarize yourself with the operating principles and advantages of applying a magnetic level indicator, not only on future projects, but as a possible replacement of some of your existing level indication instruments.

Orion Instruments, a Magnetrol company, has authored a case study showing how the replacement of glass tube level gauges with magnetic level indicators can reap substantial cost savings over the product lifetime. The case study, included below, takes but one minute of your time to read, and delivers a compelling incentive to consider magnetic level indicators (MLI) for your new projects, even as cost saving replacements for existing glass tube level gauges.

Read the case study. Contact a product specialist to discuss your application for new or replacement level indicators.

Orion instruments magnetic level indicators case study from Miller Energy, Inc.

Magnetic Flow Meter – When Is It the Right Selection for Your Project?

Industrial Magnetic Flow Meter

Courtesy Yokogawa Corp.

Flow measurement is a ubiquitous function in the industrial process control field. Anywhere there are pipes, somebody wants to know what, and how much, is passing through them. Fortunately for us engineers, there is a wide array of industrial flow meters capable of measuring some physical characteristic of fluid moving within a pipe that can be translated into a useful measurement of flow rate.

In industry, there are a number of different technologies used to measure a physical property related to fluid motion, referred to as magnetic, ultrasonic, vortex, Coriolis, differential pressure, and several others. Each methodology exists in the market because it may perform better or cost less when meeting certain performance requirements. This article is focused on magnetic flow meters and when they may be a good candidate for your project.

Here is a list of some of the positive attributes of magnetic flow meters.

• Magnetic flow meters have no moving parts, always a plus.
• General construction arrangement allows for use of an interior liner for corrosion resistance.
• With no sensor insertions into the fluid flow, the impact of the instrument on the flow is minimized.
• Accuracy, when compared to other technologies, is high.
• Application to laminar, turbulent, and transitional flow profiles is permissible.
• General insensitivity to fluid viscosity, specific gravity, temperature and pressure.
• Magnetic flow meter technology can be applied to a very wide range of pipe sizes.
• Device responds rapidly to changes in fluid flow.
• Can be successfully applied to liquids containing heavy particulates.
• Generally long service life with little maintenance.

There are, though, some points about magnetic flow meters which may make them unsuitable for your application.

• Magnetic flow meters only work on liquids with conductivity above a certain threshold. They may be unsuitable for use with hydrocarbons and high purity water for this reason.
• Cannot be used to measure gas flow.
• Pipe must be grounded.
• Typically, the pipe cross section must be filled by the fluid being measured.

This listing of positives and negatives is intended to be very general in nature. Some manufacturers may have product application solutions that overcome some of the negatives, while others may not be able to deliver all of the positives.

Your best course of action:

Use this general overview to start shaping you understanding of where magnetic flow meters may be a good option, and contact a product application specialist to discuss what you want to accomplish. Combining your process knowledge with their product knowledge should move you toward a good solution.

Industrial Flowmeter Handbook From Yokogawa

Magnetic Flowmeter
Courtesy Yokogawa Corp.

Measuring the volume, mass, density, and temperature of flowing fluids is a common and necessary function of industrial process control. Industrial flowmeters employ various measuring technologies to deliver accurate measurements, which are utilized to make safety, operational, and financial decisions.

Each measurement technology; magnetic, Coriolis, vortex, differential pressure, rotameter, ultrasonic, or another, has specific attributes of meter design and measurement principle making it more suitable to differing application classes. Yokogawa Corporation has summarized the suitability of the different flowmeter types for a range of process and operational conditions in a table that provides the user a consolidated comparative view of flow meter technology for almost every application. It is a useful tool that allows the engineer to quickly focus in on one or two technologies that will best suit project requirements.

Preview the handbook below, and obtain a copy of the handbook from a Yokogawa product expert, from whom you can also get expert level application assistance.

Flowmeter Handbook by Yokogawa from Miller Energy, Inc.

Dynamic Compensation for Static Pressure Effects in Differential Pressure Measurement

Differential Pressure Transmitter
Courtesy Yokogawa Corp.

Attaining the best available performance and accuracy from any measuring device utilized in an industrial process is always advantageous. The scale of most industrial processes is such that even small inaccuracies in process measurement produce financially tangible impact. Differential pressure measurement, with wide application in the industrial process sphere, can be improved with the addition of a means to compensate for the real world effects of static pressure upon instrument performance. Yokogawa Corporation has developed a means to dynamically compensate for static pressure effects in field measurements. The brief technical presentation below will help you understand how static pressure effects can impact your field measurements, as well as how Yokogawa’s Real-time Dynamic Compensation works to offset its impact. More detailed product and application information is available from your Yokogawa specialist.

Real-Time Dynamic Compensation for Static Pressure Effects in Differential Pressure Measurement from Miller Energy, Inc.

Data Acquisition - A Step in the Direction of Process Improvement

Data acquisition, like an equipment acquisition, is the procurement of an asset. Data is an asset. It helps an operator evaluate process or business conditions and make decisions that impact the success of the organization. Let’s define data acquisition as the sampling of signals that represent a measurement of physical conditions and the conversion of those signals into a numeric form that can be processed by a computer. A data acquisition system will generally consist of sensors, transmitters, converters, processors, and other devices which perform specialized functions in gathering measurements and transforming them into a usable form.

DAQ incorporating data acquisition, process
control, recording, display and networking
in a single compact unit
Courtesy Yokogawa Corp.

Industrial process operators and stakeholders benefit from the collection and analysis of data by enhancing performance of valuable facets of the process or activity. Data acquisition, commonly known as DAQ, is widely employed in high stakes and sophisticated processes where there is a true need to know current conditions. A desire for increased profit drives the need for increased process output and efficiency. A desire to reduce risk of loss drives the need for reduced downtime and improved safety. Today, there are likely many useful applications for data acquisition that are not being tapped to their fullest potential. The modest cost and simplicity of putting a data acquisition system in place, compared to the benefits that can be derived from a useful analysis of the data for your operation or process, makes the installation of a data acquisition system a positive move for even small and unsophisticated operators in today’s market.

What we call DAQ today started in the 1960’s when computers became available to businesses of large scale and deep pockets. By the 1980’s, personal computers employed in the business environment could be outfitted with input cards that enabled the PC to read sensor data. Today, there is an immense array of measurement and data collection devices available, spanning the extremes of price points and technical capability. For a reasonable cost, you can measure and collect performance data on just about anything. You can get an impression of the simplicity, modularity, and compactness of a modern system with a quick review of this product.

Data acquisition has an application anywhere an operator or stakeholder can benefit from knowing what is occurring within the bounds of their process or operation. Here is a partial list of the many physical conditions that can be measured in industrial settings:

Other examples of industrial data acquisition equipment
Courtesy Yokogawa Corp.

• Temperature
• Pressure
• Flow
• Force
• Switch Open or Closed
• Rotational or Linear Position
• Light Intensity
• Voltage
• Current
• Images
• Rotational Speed

Consider your industrial process or operation. Are there things you would like to know about it that you do not? Would you like to increase your insight into the workings of the process, how changes in one condition may impact another? Do you know what operating condition of each component of your process will produce the best outcomes? Is reducing maintenance, or heading off a failure condition before it occurs something you would like to have in your operation? Applying your creativity, ingenuity and technical knowledge, along with the help of a product expert, will help you get the information you need to improve the outcomes from your industrial process or operation.