Process Measurement and Control: When To Use a Diaphragm Seal

Diaphragm seal for pressure measurement device
Courtesy Wika

Process measurement sensors are not indestructible. Not even the most rugged device is fully immune to the chemical nature of process media or the kinetic impact associated with fluid composition and movement. Balancing degrees of protection, usually to increase the useful life of the device, with sensor response and accuracy is a frequent challenge in the process measurement and control field. 

Industrial processes commonly are associated with corrosive or toxic fluids, often at extreme pressure or temperature and containing various levels of solids. Any of these traits can pose substantial risk to process performance and uptime. Operations that process fluids will employ pressure measurement devices to monitor process performance and maintain system safety levels. There are many instances where characteristics of the process and its media are not compatible with pressure measurement devices. Here are some potentially problematic scenarios for pressure measurement instruments: 

• Corrosive media that will prematurely deteriorate the pressure sensing element. 
• Viscous or fibrous media, also those that may crystallize or polymerize, posing a risk of clogging channels, tubes, and orifices of pressure measurement devices. 
• Media temperature that is beyond the rated range for the pressure measurement device has a potential to damage the instrument or cause error in the pressure reading. 
• A measuring point that is remotely located from where a technician may need to observe the reading. Also conceivable, the pressure measurement device needs to be located away from other potentially damaging environmental conditions. 
• The process requirements dictate specific hygienic requirements that are cause for the measurement device to be isolated from the medium. 
• Toxic or otherwise hazardous media that must be contained. 
• Excursions of system pressure may exceed the acceptable range of the instrument, potentially damaging the device. 

Threaded diaphragm seal
Courtesy Wika

A solution which can provide protection from the items listed above, while still maintaining instrument response and accuracy is a diaphragm seal. Seals are placed between the pressure measurement device and the process media. The space between the diaphragm, which is flexible, and the sensor is filled with a fluid that will hydraulically transfer the pressure condition on the process side of the diaphragm to the sensor. The diaphragm serves as a physical barrier between the potentially damaging media and the instrument. Diaphragm seals are available in a wide variety of configurations to accommodate any media type or connection requirement.

Seal selection involves specifying the connections and form factor to properly mate the diaphragm with the instrument and the process, then selecting the diaphragm material that will be compatible with the media. The best way to achieve a positive solution is to share your requirements with a qualified assembler. They can help select the right diaphragm seal and mate it up with a pressure gauge, providing a complete assembly that is ready to be installed in your process.

Innovations In RTD Signal Conditioning - One Manufacturer's Compilation

RTD Signal Conditioning Units
Courtesy Acromag

Temperature measurement may be one of the oldest components of process control and laboratory research. The measurement of temperature has progressed through a variety of methodologies, some of which are still in use today. Modern industrial process control relies heavily on the use of RTDs (resistance temperature detector) for their accuracy and stability.

Some of us have used RTDs in our process designs for many years, maybe without recognizing the innovations that have come about in the signal conditioning portion of our installations. One manufacturer of industrial signal conditioning equipment, Acromag, has compiled the ten most significant recent advances in RTD signal conditioning. I have included their white paper below.

Browse the paper, as it is brief and informative. You will likely see a few improvements of which you were unaware. Share your temperature measurement and signal conditioning challenges with an application specialist. Combining your process experience with their product application expertise will produce positive solutions.

Top Ten Advances In RTD Signal Conditioning from MSJacobs-Cali

Ethernet I/O Modules Provide Connectivity Advantages

Industrial Ethernet I/O Modules
Courtesy Acromag

Industrial process control relies on the accurate and timely delivery of process measurements and data to the point of control and decision making. As technology affords more opportunities to measure and transmit process variables, the demand for incorporating the additional information in the control and decision making process expands. The frequency at which data can flow from a process has also increased dramatically, and there is often significant value derived from rapid sampling. Transmitting the voluminous measurement data to the point of control can be accomplished using three basic methods:

• Point to point wiring from each measurement device to the control point.
• Wireless linkup from measurement location to controller.
• Wired network connection between measurement and control devices.

Each of these connection topologies has particular attributes which may better suit a particular application.  For a wired network scheme, Acromag has designed a line of I/O modules that make installation and configuration a smooth operation. Helpful features include:

• Power wiring options that allow back connected bus power or top mounted screw terminals. You can even provide primary and backup power sources to the two connections.
• Front facing screw terminals for connections make status checking of inputs a simple operation with your digital volt meter.
• Modules are rail mounted and can be placed immediately adjacent to one another for high density installation.
• Modules have a built in webpage for display of operational information. Configuration is accomplished using a front mounted USB port.
• Operable in temperatures -40 to +70 deg. Celsius.
• Two Ethernet ports on each unit allow modules to be daisy chained, reducing or negating need for local hubs.
• Acromag's Priority Channel Technology assures that data update frequencies are maintained, regardless of other network traffic.

The short video below provides additional detail on the useful features of the Acromag line of industrial Ethernet I/O modules. Watch the video. Share your process measurement and control connectivity challenges with a sales engineer specializing in industrial Ethernet I/O. Combine your process knowledge with the state of the art product knowledge of a product specialist for the best solutions.

Flexible Hazardous Gas Detection Monitoring System

Sentry IT Controller For Hazardous Gas Detection Monitoring
Courtesy Sierra Monitor

Industrial processes, by their scale and nature, are rife with hazards. As a process designer, engineer, or operator, protection of the facility, employees, and surrounding community ranks highest among our many responsibilities. Some hazards are apparent, visible, easily detected. Others are not. Technology and ingenuity play a substantial role in providing acceptable levels of safety in modern facilities.

Properly designing a hazardous gas monitoring system starts with identifying the target elements and their sources. Gaseous hazards can generally be divided into three general classes, all of which can be specifically targeted with a properly configured gas monitoring system.

• Combustible gas concentrations subject to ignition and explosion.
• Toxic gas with inherent personnel risk.
• Insufficient oxygen levels to support human respiration.

The best overall system configuration can be achieved through a combination of detectors, communications, and response that will provide accurate sensing of the target hazard, reliable and predictable transmission of information, and preconfigured response when alarm limits are triggered. Some product features for the detector monitor that may prove useful in a well specified installation:

• A means to non-intrusively calibrate all sensors at the same time
• Ability to diagnostically monitor connected sensors for performance.
• Provision of an easily operable interface for users.
• Battery backup to maintain operation during a power outage.
• Network and protocol compatibility with a range of industry accepted standards.
• Simple means to upgrade operating software.
• Compatibility with detection devices from a broad array of sources.
• Input capacity for more sensors than your current requirement.

I have included a bulletin describing such a unit, manufactured by Sierra Monitor. Browse the document and contact a hazardous gas detection application specialist to get more details and discuss your hazardous gas detection challenges. The best solutions come from combining your process knowledge and experience with that of a product application specialist.

Sierra Monitor Sentry IT Controller from MSJacobs-Cali

Industrial I/O Applications Compilation Provides Answers

Process Measurement and Control I/O Devices
Courtesy Acromag

Process measurement always presents two basic challenges, derive a measured value of the process condition, then transmit or deliver that value to a recording or decision making device. Your knowledge and ingenuity applied to the design and implementation of these measurement and transmission functions are the key to how effectively your control system will function. Acromag, a world class manufacturer of signal conditioning equipment and industrial I/O devices, has produced a compilation of applications that illustrate some creative and best practices for establishing effective connections between control and measurement devices. The applications are drawn from defense, power generation, and manufacturing, but the knowledge shared can be broadly applied to many industries.

Look through the applications and you will find something of value. You can always contact a product and application specialist to discuss your process measurement and control challenges and requirements. Combining their product application expertise with your process knowledge will generate the best solutions.

Industrial Instrumentation Application Examples from MSJacobs-Cali

Rotameters For Flow Measurement - Selecting the Right One

Industrial Rotameter Flow Meters
Courtesy King Instrument

Applied extensively in industrial process measurement and control, a rotameter is an instrument that uses a float of given density to establish, for any measurable flow rate, an equilibrium position within the fluid stream where the force of the flowing fluid equals the force of gravity. Let's break that down a little. A rotameter has a tapered tube with a float inside. As the measured fluid flows upward through the tube, it pushes the float upward along the length of the tube. As the float rises in the tube, the cross sectional area of the tube increases and more fluid can bypass around the float. At some point, the upward force of the fluid flow acting on the float will balance with the downward force of gravity. The position of the float along the length of the tube correlates with a certain flow rate when certain properties of the fluid are known. Flow rate scale graduations on the tube can be read by the operator.

Rotameters are very specific to each flow measurement application. It's important that you know your fluid properties, ambient conditions, connection and readability specifications. 

Start with these selection parameters:

• Desired flow rate range
• Fluid specific gravity
• Ambient temperature
• Operating and maximum pressure
• Line size
• Connection type
• Connection orientation
• With or without a valve
• Material requirements to accommodate fluid
• Scale units of measure. Smallest scale divisions needed.

For each application, it's advisable to work closely with a sales engineer to gather all the needed information and coordinate the product selection process.

Here are some things to consider for potential rotameter applications:

• Simple design and operation provide a modest cost solution.
• No external power is required for operation. Inherent fluid properties and gravity are used to measure flow rate.
• Clear glass used for the measuring tube is highly resistant to thermal shock and corrosion.
• Instrument orientation must be vertical, with fluid flowing upward.
• Scale graduations are accurate for a given substance at a given temperature, making the devices application specific.
• Operation of the rotameter may be impacted by changes in the viscosity of the fluid. Consult with a product and application specialist to explore your application.
• Direct flow indication provides resolution that may not be as good as some other flow measurement methods.
• Visual reading of the scale is subject to uncertainty due to float oscillation, parallax, and location on the scale.
• Make sure the fluid turbidity, or another fluid characteristic will not obscure the visibility of the float.

Consult with a product specialist about your flow measurement application. A combination of your process knowledge and their product expertise will produce the best solution.

Analynk Wireless Updated Website

Analynk Wireless has a new website

One of the manufacturers represented by MS Jacobs & Associates, Analynk Wireless, has redesigned and published an updated website. The new site provides access to features, model configurations and datasheets for their entire range of industrial process control and measurement products. Analynk's product line complements those of other manufacturers in the MS Jacobs portfolio of industrial instrumentation and process control products. MSJ employs the Analynk products, often in combination with products of their other manufacturer lines, to provide complete packaged process control solutions for their customers.

Analynk Wireless encompasses three groups of products:

• Hazalynk® wireless products for hazardous areas, including explosion proof antennas and hazardous area access point enclosures.
• Sensalynk® single and multi-point wireless transmitters, receivers, and repeaters for industrial wireless networking.
• Telmar® transmitters, tachometers, signal alarms, power supplies, indicators and meters for process measurement and control.

Take a look at the new Analynk website. Discuss your process improvement ideas with product application specialists and develop a plan to generate better outcomes.

Application Suitability of Ultrasonic Flowmeters

Ultrasonic Liquid Flow Measurement System
Courtesy Flexim America

Industrial process control frequently requires the accurate measurement of fluid flow. There are several widely applied methods for measuring flow, each having particular advantages which may apply to a specific application.

Ultrasonic flow meters measure flow indirectly by calculating transit time of a sound wave through, or reflecting from, a flowing fluid. The velocity of the fluid has an impact on the transit time, from which a flow rate can be calculated. Attributes of ultrasonic flow measurement that may determine suitability for a particular application include:

• Transducers can be clamped on exterior pipe surface where measurement is needed.
• Non intrusive measurement technology prevents contact between media and measuring elements.
• No significant pressure drop associated with measuring device installation.
• Reduced leak potential.
• No moving parts.
• Comparatively higher cost than some other technologies.
• Fluid characteristics must be well known for proper application.
• Pipe cross section must be completely filled by media to acquire accurate flow measurement.

Learn more about this process measurement and control technology in the product detail sheet below. Consult with a product application specialist for more detailed product information and tips on how to best apply ultrasonic flow meters to your process.

Flexim Americas - Non-Intrusive Liquid Flow Measurement from MSJacobs-Cali

Avoid Process Downtime With Five Device Protection Considerations

Industrial Process Instruments

Industrial process control is everywhere. Sometimes it is dangerous or complex. In other cases it may be relatively mundane. In all industrial processes, though, maintaining operation is key. Stakeholders rely on the process output and look to the designers, engineers, and operators to deliver, in many cases, uninterrupted performance. The world is a place of many uncertainties, some of which can impact your process in undesirable ways. While it's not practical to design or build to accommodate every possible adverse event, application of experience and good judgement in a few areas may significantly shorten the list of things that can negatively impact your process.

Process control is achieved through the measurement of various conditions and application of regulated adjustments to the process inputs to deliver a desired output. Process variable measurement serves as the input to the control system. In the industrial sphere, it is common to see devices used for the measurement and transmission of temperature, pressure, flow, mass, level, and electrical parameters like voltage, current, capacitance and more. Regardless of what is being measured, there are three common characteristics:

• Device - A combination of a sensor and a translator that together detect some physical condition of the process and produce an output signal that can be correlated to the process condition. 
• Location - The device will have a location that is dictated by the process construction and arrangement. Device locations have a tendency to be inflexible.
• Signal transmission path - Unless the control element is integral to, or adjacent to, the measurement device, there will be some path over which the measurement signal must travel to reach an associated control element. 

Looking at these three elements for each measurement point, consider the five risk categories below in evaluating what you can do to safeguard your process measurement instrumentation. It's advisable to open a conversation with an experienced application specialist and freely discuss your concerns. Gathering additional input from various experienced sources will help you determine how extensive your protective measures should be to deliver a balance between cost and the probability of certain adverse events.

• Local Weather: There is local weather data available for almost every place on the planet. Take the time to procure reliable data and examine the distribution of temperature, humidity, precipitation, and wind conditions throughout all seasons. Clearly, if portions of the process are located outdoors, extreme local weather conditions will need to be accommodated. Even if your process is located indoors, local weather information is important if the process is to operate continuously. Consider whether an indoor process must continue to operate, even if the building HVAC system fails and indoor conditions begin to be impacted by outdoor conditions. Also, depending upon the design of the building climate control system, changing outdoor conditions can have a noticeable and possibly significant impact on the indoor air conditions.
• Process Generated Conditions: There may be specific aspects of your process that produce occurrences of vibration, pressure spike, electrical interference, or a host of other aberrations that may affect the proper operation of measurement devices. Know your process....really know it. Protect instrument sensors from potentially damaging transients and other process conditions that can be reasonably expected to occur. Device location relative to sources of electrical interference, elevated temperature, vibration, shock, and other transient conditions should be considered.
• Security: Your design goal should be to achieve a very high level of certainty that the signals generated by the measurement devices are uninterrupted and reflect the actual process conditions. There are two cases I always consider for security. The first is cyber, which applies in the case of a process measurement device network connection. Necessary steps should be taken to thwart an attempt to breach the network and detect unusual conditions that might indicate an invader's attempt to manipulate the process. My second case is related to device access by those without proper knowledge, training, or permission. Protection from these threats will likely involve a combination of physical barriers and procedures.
• Physical Contact: Industrial settings are, well, industrial. Large, heavy, irregular, unwieldy, and sharp things can sometimes be moved through areas occupied by process measurement gear. Technicians with carts, tools, and materials frequently pass through process areas to do their work. Protecting equipment and instruments from damaging contact pays dividends for the life of the installation. Consider, in your design and layout, the proximity of instruments to areas of traffic. If applicable, also consider areas overhead. The level of protection will need to be balanced with the need for access by qualified individuals for service, maintenance, calibration, and observation, as applicable.
• Moisture: Electronics are a mainstay of modern measurement instrumentation. Clearly, liquid moisture must be kept from contact with electronic circuits. Vaporous moisture will find a path to the internals of your electronic devices. This vapor, which is present in considerable levels in almost every indoor and outdoor environment, can condense when the right conditions are present. It is imperative that enclosures, conduit, boxes, fittings must be provided with barriers to moisture entry and/or a reliable means to automatically discharge accumulated liquid moisture before damage occurs.

There is much to think about in the realm of device protection. Balancing the costs of protection, the impact of protective measures on the ability to service and operate the process, and the risk involved with process failure or shutdown requires the application of technical expertise, experience, and sound practical judgement. Draw information and opinion from multiple sources, including sales engineers. Combine their product application knowledge with your process expertise to make good decisions.

Application Advantages of Intrinsically Safe Barriers

2-Wire Transmitter in Hazardous Area With Intrinsic Safety Barrier
Courtesy Ronan Engineering Company

Industrial process measurement and control operations have few boundaries. Land, sea, air, light, dark, dry, wet, hot, cold, indoor, and outdoor environments. Did I mention potentially explosive? Well, there is that, too.

If your experience was anything like mine, it is likely that your first project involving a hazardous area really drove home the fact that you are working at a very serious endeavor. In addition to quality problems or downtime resulting from equipment failure, now you add "the place blows up" to the list of possible outcomes. It's sobering, and not the type of situation where you have the option of real world testing. You need to be right the first time. Every remotely possible source of ignition must be considered and rendered harmless.

One way to provide the necessary level of safety is through the use of explosion proof enclosures, conduit, fittings, and other devices. By their nature, these items are designed to contain an internal explosion and provide for the expansion and cooling of the ignited gases into the surrounding atmosphere. The expansion cools the hot gas to a temperature safe for venting from the enclosure into the hazardous area without causing an ignition.

There is a good solution for measurement and control circuits requiring only low power levels. Intrinsically safe circuit designs employ barriers that allow power limited connections between devices in a hazardous zone and those in a non-hazardous zone. Intrinsic safety relies on the limiting of available energy in the system to a level that will not ignite a hazardous atmosphere (explosive gas or dust). Without significant energy storage, and ensuring that only low voltages and currents enter the hazardous area, intrinsically safe design removes the circuit as a possible ignition source. Where it is possible to utilize an intrinsically safe circuit, there are some advantages over using an explosion proof design.

• Absence of explosion proof enclosures enhances the accessibility of system components.
• Personnel safety is increased with low voltage operation.
• Standard wiring methods and materials may be used. No explosion proof conduit, boxes, fittings.
• Calibration and maintenance can be performed with the system in operation.
• Special skill levels required by an explosion proof design are not required with intrinsically safe design.

A primary device in an intrinsically safe circuit will be the barrier. The intrinsic safety barrier forms the border between the hazardous and non-hazardous areas. There are other design considerations, all of which you should discuss with knowledgeable application specialists. I have included a document below from Ronan Engineering Company, a manufacturer of intrinsic safety barriers. It provides some additional useful information, including a listing of the many I/O applications where the barriers can be employed.

Ronan Intrinsic Safety Barriers from MSJacobs-Cali

Thermal Mass Flow Meters - Mature Technology With Modern Application

Configurations of Thermal Mass Flow Meters
Courtesy Thermal Instrument Co.

Thermal mass flow measurement technology has been used in industrial process measurement and control applications for many years. The technology measures the amount of heat required to maintain a sensor at a constant reference temperature, offsetting the cooling effect of the fluid flow over the sensor. The technology is well suited for installations requiring the measurement of low pressure gases where the fluid components are known and remain constant. Thermal mass flow measurement is also employed effectively in a number of other scenarios.


Potential advantages of thermal mass flow technology for industrial process measurement and control:

• Provides true mass flow reading using a single instrument
• Not significantly affected by fluid pressure or temperature
• Moderate comparative cost
• No moving parts
• Minimal restriction of flow introduced by sensor

Typical applications for thermal mass flow meters:

• Landfill gas outflow measurement
• Compressed air systems
• Gas distribution in semi-conductor manufacturing
• Beverage carbonation
• Tablet coating and compression in pharmaceutical industry
• Flare gas measurement in oil and gas industry
• Natural gas flow to boilers, furnaces, and other consuming equipment

Thermal mass flow sensors have attributes making them very suitable for a family of applications. Like all measurement technologies, there are also areas of caution in their application. Any measurement technology must be properly applied in order to obtain reliable results. Talk to a sales engineer about your flow measurement ideas and applications. Combining your process expertise with the knowledge of a product application specialist will produce good results.

Are You Well Grounded on Grounding? - Part 3

Electrical Drawing Symbols for Ground

Welcome to the third and final part of this series on electrical grounding for equipment and instruments. Part One and Part Two can be found as previous posts to this blog, and I hope you read them too. Those initial parts provided practical knowledge about equipment grounding and personnel protection in a format understandable to anyone. Those of us more deeply involved with electrical matters likely know someone that could benefit from these articles and I urge you to share.

The white paper that I have included below was produced by the folks at Acromag, a world class manufacturer of signal conditioners and other industrial I/O devices. They have done a fantastic job of presenting technical subject matter in a compact and very understandable form. The subjects covered in the series include:

• Ground as protection
• How a ground fault circuit interrupter (GFCI) works
• Ground as a voltage stabilizer and transient limiter
• Tips on improving safety and signal integrity
• The importance of circuit grounding
• Description of the US AC power system and its use of earth ground

This third installment includes a section entitled "Some Basic Ground Rules For Wired Equipment" which lists out an array of useful tips for connecting wired signals to devices, and more.

Product specialists are always on hand to discuss and solve your process measurement and control issues. Combine the process knowledge of the on site stakeholder with the product and application expertise of the professional sales engineer to produce the best outcomes.

Electrical Grounding Practices - Part 3 of 3 from MSJacobs-Cali

Are You Well Grounded on Grounding? - Part 2

Drawing Symbols for Ground

Electricity, like many beneficial trappings of modern society, is both beneficial and dangerous. Protecting users of equipment and appliances from the potentially harmful impact of electric shock is a socially accepted mandate that has been codified everywhere in the developed world.

Acromag, a manufacturer of input and output devices for industrial control systems, has produced a three part series of white papers that provide readable, non-technical descriptions of various aspects of electrical grounding and its relationship to safety and operational integrity. The subjects covered in the three part series include:

• Ground as protection
• How a ground fault circuit interrupter (GFCI) works
• Ground as a voltage stabilizer and transient limiter
• Tips on improving safety and signal integrity
• The importance of circuit grounding
• Description of the US AC power system and its use of earth ground

You can find the initial installment on our previous blog post, and the third installment follows this blog post. All three parts are recommended reading for anyone, but stakeholders in process measurement and control will benefit from refreshing and enhancing their understanding of this important subject. It is a quick read and presents technical subject matter in a way that can be comprehended by anyone.

Product and application specialists are always eager to hear about your application issues and questions. Never hesitate to contact them. Your process knowledge, combined with the product and application familiarity of a professional sales engineer, will generate good outcomes.

Electrical Grounding Practices- Part 2 of 3 from MSJacobs-Cali

Are You Well Grounded on Grounding? - Part 1

Some Drawing Symbols Used For Ground

Grounding of electrical equipment and electronic instrumentation is an aspect of project design and implementation that sometimes gets taken for granted. To say that proper electrical grounding is important is an understatement because, without it, certain safety aspects that we rely upon will simply not work. Additionally, and often more confounding, is the intermittent, unexpected, or bizarre behavior of electronic measurement and control devices when proper electrical grounding is not established.

I came across a series of white papers written by some knowledgeable people at Acromag, a manufacturer of industrial input and output devices (industrial I/O). The comprehensive three part series covers best practices involved in the grounding of electrical equipment and electronic instrumentation, in language understandable to a reader of any technical level. The subject matter includes:

• Ground as protection
• How a ground fault circuit interrupter (GFCI) works
• Ground as a voltage stabilizer and transient limiter
• Tips on improving safety and signal integrity
• The importance of circuit grounding
• Description of the US AC power system and its use of earth ground

In my reading of the white papers, I gathered a few things I did not know, refreshed a few I had forgotten, and reinforced my understanding of the topic. There is something in the documents for everyone, and a small investment in time will yield some benefit. All stakeholders in industrial process measurement and control, from the factory floor to the executive office, should have the basic understanding contained in these papers.

Part One of the three part series is below. Part Two and Part Three will be published simultaneously in posts following this one. You can get any level of application assistance you need from the sales engineers that specialize in industrial process equipment, measurement, and controls. Their product knowledge and technical resources, combined with your process mastery, will yield the best solution to any issue.

Electrical Grounding Rules - Part 1 of 3 from MSJacobs-Cali

Big Signal Loop? Consider Using a Splitter.

Industrial Signal Transmitters
Courtesy Acromag

Industrial process measurement and control requires the transmission of signals from point to point with no significant distortion. Even with the growing prevalence of wireless signal transmission, over-wire transmission of signals is still a primary means of connecting one device to another.
In the cabled process measurement and control world, the 4 to 20 milliampere signal is generally considered the standard for transmitting analog control and measurement signals over any distance.
There is an immense array of instrumentation and controllers available for use with 4-20 ma signals, so expertise in routing and delivering those signals should be part of your process M&C skill set.

Like just about everything else, routing 4-20 ma signals presents its own set of challenges that require some thought and planning to overcome. Electrical interference is always a concern and must be prevented from impacting the operation of measurement and control devices. Additionally, there must be sufficient power in the signal loop to accommodate the resistance load of connected devices. There are other considerations, but I'm going to focus on these two.

One scenario that can present significant issues is multiple devices requiring connection to the same signal, but with great distance between them. A simple solution can be implemented using an isolated signal splitter.

Features of these units making them an attractive, single box, solution:

• One 4-20 ma input channel for the measuring or controlling device.
• The input signal is retransmitted as identical isolated 4-20 ma signals
• Galvanic isolation from input to output
• Isolation between channels for safety and increased noise immunity. Fault in one output channel does not impact the operation of the other channels.
• Reliable operation in industrial environments, with protection from RFI, EMI, ESD, and surges.
• Low radiated emissions in accordance with CE requirements. 
• DIN-rail mounting of the unit
• Plug-in terminal blocks

If you have a very long signal loop, connecting multiple devices, consider breaking the devices into two groups that may allow for a substantially shorter cable length for each group. Connect each group to one of the isolated outputs of the splitter, giving each group of instruments the identical signal without the risks or impractically of an excessively long cable run.

There are other devices available that may combine special characteristics that solve your signal transmission challenges. Contact a product specialist and discuss your existing or anticipated project requirements. I continually urge engineers to take their process expertise, combine it with the extensive product knowledge of a professional sales engineer, and produce the best possible outcome.

Process Signal Isolated Transmitters, 4-20 ma from MSJacobs-Cali

Electric Power Where There Is No Grid

Humankind's quest to continually do more than has been done before takes engineers and technicians, along with their equipment, instruments, and other gear, to all corners of the Earth. Wherever the project goes, electric power will be needed to power it. Unless the needs are short term and very small, a reliable means to produce electric power on site must be put in place to operate equipment, instruments, and other systems necessary for the installation to function as needed.

The potential applications for remote power are vast, ranging from simple land based off-grid locations to ocean platforms, even polar stations. Industrial process measurement and control is found everywhere, which means that sometimes you need to provide the power to operate your own measurement and control equipment. To some, this will be a new challenge to their project management, design, or implementation skills.

Gentherm Global Power Technologies is not only the world leader in thermoelectric generation for remote power systems, they also employ solar and engine driven generator sets in their turnkey systems that can be specifically tailored to your application and installation site. As providers of a wide range of generation technologies, Gentherm is in a unique position to propose the most reliable and cost effective solution for each particular project. Become familiar with this company. You never know where your next project may be located.

A short video, included below, will get you started. You can also contact a product specialist to discuss any aspects of applying the technology.

Delivering Electric Power to Remote Sites

Thermoelectric Generator
Courtesy Gentherm

Industrial companies accomplish some amazing feats in some very inaccessible and remote places. If you are in the natural resource business, you go where the resources are to extract them from the earth. The telecommunications industry locates equipment where needed to forge links and deliver signals. Environmental monitoring, navigation aids, buoys, lighthouses, and airstrips can all be situated in areas without grid power. Often, these installations are unattended, and require continuous reliable electric power to operate. When there is no grid to which the installation can be connected, a challenge arises regarding how to provide electric power to the site equipment.

There are several possible solutions for providing remote power, each with its own set of operating attributes which may make it more or less suitable for any particular application. When considering a remote power generator, you should include thermoelectric generators on your list of prospects.

Thermoelectric generators convert heat directly into electricity using a fuel source for heat, a hermetically sealed thermopile, cooling fins, and no moving parts. These generators are a positive and cost effective solution for remote power requirements, having operational and cost benefits over engine driven generators, batteries and solar sources for many applications.

The short document below provides an overview of thermoelectric generator operation and application. Talk to a product specialist about your need to power a remote site. A thermoelectric generator may be an option you had not considered, but may prove to be the best solution.

Thermoelectric Generators - Gentherm Power Technologies from MSJacobs-Cali

Practical Considerations for Thermocouple Selection

Industrial Thermocouples, Fixed Bend Bayonet Type
Courtesy Wika

It would be difficult to chart a career course in the industrial process control field without being exposed to thermocouples. They are the ubiquitous basic temperature measuring tools with which all process engineers and operators should be familiar. Knowing how thermocouples work, how to test them, is essential. Sooner or later, though, you may be in charge of selecting a thermocouple for a new application. With no existing part in place for you to copy, what are the selection criteria you should consider for your process?

Thermocouple sensor assemblies are available with almost countless feature combinations that empower vendors to provide a product for every application, but make specifying a complete unit for your application quite a task. Let's wade through some of the options available and see what kind of impact each may have on temperature measurement performance.

• Thermocouple Type: Thermocouples are created using two dissimilar metals. Various metal combinations produce differing temperature ranges and accuracy. Types have standard metal combinations and are designated with capital letters, such as T, J, and K. Generally, avoid selecting a type that exhibits your anticipated measurements near the extremes for the type. Accuracy varies among thermocouple types, so make sure the accuracy of the selected type will be suitable.
• NIST Traceability: This may be required for your application. The finished thermocouple assembly is tested and compared to a known standard. The error value between the thermocouple shipped to you and the standard are recorded  and certified. The certified sensor assembly will be specially tagged for reference to the standard.
• Junction Type: If your sensor will be contained within a tube or sheath, the manner in which the actual sensor junction is arranged is important. The junction can be grounded to the sheath, electrically insulated from the sheath (ungrounded), or protruded from the sheath (exposed). If your process environment may subject the sensor assembly to stray voltages (EMF), it may be wise to stay away from a grounded junction, even though it provides fast response to a change in temperature. Exposed junctions provide very quick response, but are subjected to potential damage or corrosion from surrounding elements. The ungrounded junction provides protection within the enclosing sheath, with a slower response time than either of the other two junction types. When using ungrounded junctions, keep the mass and diameter of the sheath as small as might be practical to avoid overdamping the sensor response.
• Probe Sheath Material: This applies to assemblies installed in a tube or sheath which houses and protects the sensor junction and may provide some means of mounting. Material selections include a variety of stainless steel types, polymers, and metals with coatings of corrosion resistant material to suit many applications. Make sure the sheath material, including any coatings, will withstand the anticipated temperature exposure range.
• Probe Configuration: Sheath tube diameter and length can be customized, along with provisions for bends in the tube. Remember that as you increase the mass around the junction, or increase the distance of the junction from the point of measurement, the response time will tend to increase.



Industrial Thermocouples, Showing Various Termination Options
Courtesy Wika

• Fittings and Terminations: There are innumerable possibilities for mounting fittings and wiring terminations. Give consideration to ease of access for service. How will the assembly be replaced if it fails? Are vibration, moisture, or other environmental factors a concern? What type of cable or lead wires would be best suited for the application?

Your options are so numerous, it is advisable to consult a manufacturer's sales engineer for assistance in specifying the right configuration for your application. Their product knowledge and application experience, combined with your understanding of the process requirements, will produce a positive outcome in the selection procedure.

Expanded Hazardous Area Wireless Access Point Enclosure From Analynk

Hazardous Area Access Point Enclosure
Courtesy Analynk Wireless

As an engineer, I always welcome products that are well conceived, showing through their design and feature set that the developers really understand what I need to accomplish. Implementing industrial wireless communications in hazardous areas presents particular challenges to engineers responsible for achieving project goals of robust communications and safety. Analynk Wireless has developed several lines of products specifically targeted at wireless communications in hazardous areas, exhibiting a recognition of the needs of those responsible for providing industrial wireless communications in these specialized areas

Today, I am writing about Hazardous Area Access Point Enclosures, but recently have also written about two other Analynk products with which anyone involved with industrial wireless communications should become familiar. Check out New Antenna for Hazardous Area Wireless Communication and Cellular Device Data Links for Industrial Process Monitoring and Control (long titles, but short easily read articles).

Access point enclosures for hazardous areas must be specifically designed to accommodate the access point product selected by the customer....Cisco, Symbol, Meru, Aruba, Hewlett Packard, Motorola, and others. The matching enclosure for an access point will have:

• Custom mounting bracket mating to the customer's access point.
• UL listed enclosure for subject hazardous area, including antenna locations coordinated with access point device arrangement.
• UL listed explosion proof antenna, one or more as need for the subject access point.
• All hardware, mounting plate, and RF cables to simplify installation and startup

A product specialist can help you with the latest available information. Contact them to discuss your application and how to best fulfill your hazardous area wireless communication requirements.

New Antenna for Hazardous Area Wireless Communication - Updated With Data Sheet

Hazardous Area Antenna and Enclosure
Courtesy Analynk Wireless

Wireless communication has seen increasing prevalence in the industrial process measurement and control field for a number of years. Vendors, in response to customers' desire to incorporate the technology across an ever widening array of application scenarios, continue to develop and release new products and technologies that expand the potential for industrial wireless communication. One company, Analynk Wireless, is now shipping a new version of their patented wireless antenna for hazardous areas. We published an article last week about their cellular device data links.

Analynk Antenna
for Hazardous Areas
Courtesy Analynk Wireless

The newest Analynk Hazardous Area Antenna provides remote data links for customers using Iridium, GPS, and GLONASS. This new product adds to the company's already expansive line of wireless communication products specifically designed for industrial application, providing wireless data links to mobile or very remote locations not always accessible to other communication networks.

Analynk's antennas are operable across a very wide temperature range and provide substantial impact resistance, signal output, and ratings for hazardous environments.

Contact a product specialist about the Analynk Wireless products and discuss the potential benefits of incorporating or expanding wireless data links of all types into your operation.

Industrial Wireless Explosion Proof Antenna for Hazardous Area GPS/GLONASS/Iridium Satellites from MSJacobs-Cali

Cellular Device Data Links for Industrial Process Monitoring and Control

Wireless Transmitter and Receiver
Courtesy Analynk Wireless, LLC

Industrial process measurement and control is not restricted to the factory floor and fixed installations any longer. Increasingly, there are remote, as well as mobile, installations with a need for remote control command execution, or producing useful and valuable data that can be put to use by operational, safety, and financial stakeholders. Industrial process operators, as well as other levels of the business enterprise, can now have real time access to information that can be used for business and industrial process improvement.

The advent of wireless communications made gathering data from, and issuing control commands to, remote and mobile installations possible. A continuing path of vendor innovation and improvement has:

• Improved wireless technology reliability in the industrial setting.
• Expanded industrial wireless communications applicability.
• Simplified the implementation of a wireless communications strategy in an industrial process measurement and control setting.
• Reduced the cost and timeline associated with installation of a wireless solution.

Analynk Wireless, a designer and manufacturer of wireless devices and instrumentation for the process control industry, is adding newly designed cellular devices to their already extensive industrial wireless communications offering.  The deployed devices will feature cellular/GPS/GPRS connectivity to allow worldwide transmission and receipt of data via cellular and internet, providing remote monitoring and control through the use of additional connected devices.

The applications and opportunities for process improvement through wireless data gathering are vast. The cost and simplicity of these systems make them an option to be considered. More information is available from product specialists, with whom you can discuss your application ideas.

New Product From Cameron - CamCor Coriolis Flow Meters

CamCor Pro - Industrial Coriolis Flow Meter
Courtesy Cameron

Whether it's high viscosity crude oils, ultra-low flow conditions or applications at the extremes of temperature, Cameron's new CamCor™ range of Coriolis flow meters deliver value beyond the whole-life operational benefits associated with non-mechanical architectures.

CamCor comes in two architectures, CamCor CT for custody transfer, where the emphasis particularly is on high accuracy, and the Cameron CamCor PRO for process operations.

CamCor CT offers flow rate accuracy of ± 0.1% for liquids, as a result of its deep “U” shaped dual sensors, with outstanding zero stability performance (0.071 lb/min for 2” model). The range includes models purpose-designed for application extremes, covering temperatures from -200°C (Cryogenic/ LNG) up to 350°C. Nominal sensor sizes go from less than 2mm to 250mm, with 1/4” to 10” end connections, offered in ANSI class 150 to 900, other flange types, threaded, or Tri-Clover.

The unit is manufactured of 316/316L stainless steel and Hastelloy Alloy C22.

The CamCor PRO Series possesses a flow rate turndown ration up to 50:1, flow rate accuracy of
+/- 0.2% and density accuracy of +/- 0.003 g/ml. It comes with the same transmitter, output, communications, diagnostics and configuration as the CamCor CT and is available in four nominal sensor sizes, from 6mm to 50mm, with 1/2” to 2” end connections in ANSI flanges and Tri-Clover.

Review the product brochure below, or contact a product specialist for more details or a discussion of your application.

Coriolis Flow Meter - Cameron Camcor Brand from MSJacobs-Cali

New Stainless Steel Fuel Control Regulator From Fairchild

Cutaway of the Model 67
Precision Stainless Steel Fuel Control Regulator
Courtesy Fairchild Industrial Products

Fuel control is an essential and critical variable for engine and combustion testing. Fairchild Industrial Products Company has developed a stainless steel high precision fuel control regulator for use in engine testing. The new Model 67 combines durability, flexibility, and accuracy into a single product to improve your engine testing process. Some of the basic benefits:

High level of accuracy.

Reliability in engine under test fuel supply.

Stainless steel construction for wide range fuel suitability.

Constant output, even with fluctuating supply pressure or downstream pulsation.

Design allows for quick fuel changeover.

Washdown and internal purge capability.

Review the literature below and contact a product specialist for more detailed information, or to discuss your application.

Precision Stainless Steel Fuel Control Regulator - Fairchild Industrial Products Company from MSJacobs-Cali

Multivariable Vortex Flowmeter

Multivariable Vortex Flowmeter
Courtesy Azbil North America

A new multivariable vortex flowmeter has recently been added to the product line at MS Jacobs & Associates. It is intended for industrial process measurement and control. The AX Series, from Azbil North America, utilizes a vortex shedding velocity sensor, solid state pressure transducer, and resistance temperature detector in a single unit to allow accurate measurement of mass flow in gases, liquids and steam. The combination of multiple variable measurement in a single package simplifies installation and setup cost, while reducing potential leakage paths of an arrangement employing separate instruments for each variable. The AX Series is available for in-line or insertion installation. Your product sales engineer can provide a sizing guide and other assistance in selecting and configuring the best product for your application.

Azbil Mulitvariable Vortex Flowmeter from MSJacobs-Cali

Selecting the Right Valve Type - Gate Valves

When it comes to controlling flow in an industrial fluid handling system, there are more choices than you can count. The journey of focusing in on the best option for your application can be shortened by employing some coarse filters to the vast array of available products and technologies, discarding choices that do not meet the basic criteria deemed essential to a successful project.

A common type of industrial valve is the gate valve. It regulates fluid flow by sliding a round or rectangular wedge, known as the gate or disc, in the flow path of the fluid. When the gate is fully retracted from the fluid path, flow is enabled to its fullest. Gate valves close by sliding the gate, which is commonly attached to a threaded shaft of other similar mechanism, into the path of the flow until it is fully obstructed. It is the movement of the gate, combined with the way in which a gate valve is constructed, that attributes this valve class with its positive and negative values.

Positives for gate valves:

• When fully open, there is low resistance to fluid flow. The opening in the valve tends to mimic the cross sectional characteristics of connected piping and fluid can flow through the valve without a directional change.
• Changing the gate position (opening or closing the valve) does not require as much force or power as some other valve types, due to the gate movement being perpendicular to the flow direction.
• Gate valves work in both directions. The flow in the connected line can be reversed and the valve function is unimpaired.
• The gate valve assembly tends to be shorter in length along the path of flow than some other designs.



Gate Valves in Process Pipeline

• The rate of closure is generally slow, providing a graduated reduction in fluid movement and reduced physical shock to the piping system.

Operating or construction characteristics that may be an advantage to gate valve employment on one application may prove a disadvantage in another.

“Not so positives” for gate valves:

• When the valve is open, the seals are exposed to the fluid flow. Foreign material, even elements of the process fluid, can deteriorate or contaminate the seals and impact the sealing of the valve when closed.
• The gate valve opens at a comparatively slow rate, making it unsuitable for applications that may require rapid or immediate shutoff.
• The service and maintenance space requirements, often extending overhead of the valve, can be substantial and may impact the ability to locate the assembly where desired.
• Gate valves are not well suited for throttling fluid flow. Fluid flow through a partially open valve of this type may cause the gate to vibrate.

There are certainly more elements involved in proper valve selection than are shown here, but this quick check may help you focus on gate valves or another technology for further consideration. It is always beneficial to bring in experts and those with experience to participate in the selection process.