Showing posts with label process measurement. Show all posts
Showing posts with label process measurement. Show all posts

Prefabricated Wireless Communications Solution

Wireless transmission of process measurement and control signals has not been new technology for quite some time. In many cases, wireless connection is the installation method of choice over cabled. The benefits in speed of implementation and cost are substantial. That said, as the technology continues to permeate industrial installations of every size, there still remain facilities where it has not made any inroads yet. 

When technology is new to the industrial market, especially if it challenges the current way things are done, early adopters with larger scale, higher dollar operations are needed to put the technology into practical use and generate manufacturing volume for the technology producers. If deployment of the technology proves beneficial, the market grows on the consumer and producer sides. With greater efficiency and scale, coupled with growth in the knowledge base throughout the market with increased penetration, costs tend to decrease, while the range of feasible applications and projects grows.

Wireless communication for industrial applications is well beyond the point of early technology adoption. Protocols are in place, products for the transmitting and receiving of wireless process signals are mature. As a stakeholder at any level of a processing operation, you should confidently consider wireless connections between measurement and control or recording devices as part of any new installation or upgrading of existing facilities.

Analynk's wireless demo kit includes a model A750 receiver and A753 transmitter both housed in NEMA 4 enclosures. The kit operates at 900 MHz with full 1W power. Locate the transmitter and receiver at points where you wish to establish a wireless connection. You can provide your own input signal, or use the provided simulator to show that a wireless connection can be established and function in a manner that will give you confidence to move forward with implementation. The kit is useful for testing out possible new locations for distance and signal strength. You will use it as wireless communications expand through your facility. Test the location first, then order the needed wireless equipment. It's a solid and low risk solution.

An additional use of the prefabricated transmitter and receiver stations is as a temporary portable means of establishing a connection between measurement and control points. The units can even be solar or battery powered, if no power source is available.

Analynk is a manufacturer of both wireless and wired devices for process measurement and control. The company's offering includes a wide array of standard products, as well as integration and customization to meet specific project requirements. Contact the specialists at Analynk to discuss your industrial wireless application requirements.

Wireless Process Connections - DIY May Not Be Your Best Option

industrial wireless gear enclosure options
Analynk can design and fabricate complete systems for
establishing wireless process connections.
Implementing in-house projects takes time, something you may not have enough of on a good day. Establishing wireless connections between remote sensors and control or monitoring equipment can be accomplished with a minimum investment of scarce in-house human resources using Analynk's design and build services. With an extensive range of standard products, accessories and options, Analynk will assemble ready-to-run panels for the transmitting and receiving ends of your wireless link. This saves a substantial amount in resources that would otherwise be devoted to design, layout, assembly and operational testing of each panel needed. Smart outsourcing.

The Analynk application team can design and fabricate a complete package solution for your process measurement or wireless connectivity requirement. Share your ideas and challenges with the wireless and process measurement experts, leveraging your own knowledge and experience for a successful project outcome.

Load Cells in Process Measurement

industrial fluid processing tanks
Strain gauges and load cells are found throughout
industrial processing applications.
In industrial application of process measurement and control, principles of the physical sciences are combined with technology and engineering to create devices essential to modern high speed, high accuracy system operation. Years of research, development, and the forward march of humanity’s quest for scientific knowledge and understanding yield packaged devices for process measurement that are easily applied by system designers and operators.

Load cells are the key components applied to weighing component or processed materials in modern processing. They are utilized throughout many industries related to process management, or just simple weighing operations. In application, a load cell can be adapted for measurement of items from the very small to the very large.

In essence, a load cell is a measurement tool which functions as a transducer, predictably converting force into a unit of measurable electrical output. While many types of load cells are available, the most popular cell in multiple industries is a strain gauge based cell. These strain gauge cells typically function with an accuracy range between 0.03% and 0.25%. Pneumatically based load cells are ideal for situations requiring intrinsic safety and optimal hygiene and, for locations without a power grid, there are even hydraulic load cells, which function without need for a power supply. These different types of load cells follow the same principle of operation: a force acts upon the cell (typically the weight of material or an object) which is then returned as a change in a reference value. Processing the value yields an indication of weight in engineering units. For strain gauge cells, the principle of deformation applies, where extremely small amounts of deformation, directly related to the stress or strain being applied to the cell, are output as an electrical signal with value proportional to the load applied to the cell. The operating principle allows for development of devices delivering accurate, precise measurements of a wide range of industrial products. Advantages of load cells include their longevity, accuracy, and adaptability to many applications, all of which contribute to their usefulness in so many industries and applications.

Analynk manufactures process measurement and control equipment that utilizes strain gauges in their operation, as well as signal alarms and transmitters that will convert strain gauge output signals into common process control signals. Equipment for further establishing wireless connections among measurement and control devices is a specialty of Analynk Wireless. Share your process measurement and connectivity challenges with the industrial wireless experts at Analynk, leveraging your own process knowledge and experience with their specialized application expertise to develop effective solutions.

Compact Tachometer

DIN rail mount tachometer with analog output
The Analynk 618 Series Tachometer has a compact DIN rail
mount package
Analynk Wireless is best known for the wide array of radio transmitters and receivers enabling wireless connectivity of process measurement and control instruments and equipment. The company also manufactures a many specialty analog wired devices that can easily solve process measurement and control challenges.

The 618 Series of tachometers use a frequency input from a pickup to produce an analog signal output usable by many industrial controllers. The tachometer mounts easily in a control enclosure on a 35 mm DIN rail and can accommodate a wide range of input pulse voltages. The unit can be configured to provide one or two alarm contacts, along with one of several common analog output signals.

More information is provided in the datasheet included below. Share your process measurement and control challenges with the application engineers at Analynk, leveraging your own process knowledge and experience with their product application expertise to develop effective solutions.



Custom RF Cables Can Speed Your Wireless Installation

Custom RF cables with various connector types
Custom RF cables speed installation of industrial
wireless gear.
Upgrading or installing new process instrumentation often requires some level of specialty work that can extend beyond the normal scope of activities performed by in-house technicians. With some planning and smart outsourcing, many gaps in your own capabilities can be filled and expeditious progress made toward the end goal.

Industrial wireless gear will utilize a special cable to connect a remotely located antenna to a receiver or transmitter. Analynk Wireless, as a complement to their line of wireless transmitters, receivers, antennas, and related equipment, custom fabricates RF cables to help provide a complete installation package for their customers and enable the use of fewer source vendors. Any application can be accommodated, and design and planning assistance is available.

Share your wireless connectivity challenges with the experts at Analynk. Leverage your own process knowledge and experience with their product application expertise to develop an effective solution.

Shell and Tube Heat Exchangers

interior view of shell and tube heat exchanger
View of the inside of a shell and tube heat exchanger shows
the tubes through which one of the transfer fluids passes.
Automobiles are part of the backbone of modern society, for both personal and commercial use. While being familiar everyday objects, they also contain systems which need to be constantly maintained and in-sequence to ensure the safety of both the machine and the driver. One of the most essential elements of car ownership is the understanding of how heat and temperature can impact a car’s operation. Likewise, regulating temperature in industrial operations, which is akin to controlling heat, is a key process control variable relating to both process operation and operator safety. Since temperature is a fundamental aspect of both industrial and consumer life, heat management must be accurate, consistent, and predictable. Many devices have been developed for the transfer of heat from one substance to another, with myriad applications throughout modern society.

A common design of heat exchangers used in the oil refining and chemical processing industries is the shell and tube heat exchanger. A pressure vessel, the shell, contains a bundle of tubes. One fluid flows within the tubes while another floods the shell and contacts the outer tube surface. Heat energy conducts through the tube wall from the warmer to the cooler substance, completing the transfer of heat between the two distinct substances. These fluids can either be liquids or gases. If a large heat transfer area is utilized, consisting of greater tube surface area, many tubes or circuits of tubes can be used concurrently in order to maximize the transfer of heat. There are many considerations to take into account in regards to the design of shell and tube heat exchangers, such as tube diameter, circuiting of the tubes, tube wall thickness, shell and tube operating pressure requirements, and more. In parallel fashion to a process control system, every decision made in reference to designing and practically applying the correct heat exchanger depends on the factors present in both the materials being regulated and the industrial purpose for which the exchanger is going to be used.
schematic of shell and tube heat exchanger
Schematic of shell and tube heat exchanger


The industrial and commercial applications of shell and tube heat exchangers are vast, ranging from small to very large capacities. They can serve as condensers, evaporators, heaters, or coolers. You will find them throughout almost every industry, and as a part of many large HVAC systems. Shell and tube heat exchangers, specifically, find applicability in many sub-industries related to food and beverage: brewery processes, juice, sauce, soup, syrup, oils, sugar, and others. Pure steam for WFI production is an application where special materials, like stainless steel, are employed for shell and tube units that transfer heat while maintaining isolation and purity of a highly controlled process fluid.

Shell and tube heat exchangers are rugged, efficient, and require little attention other than periodic inspection. Proper unit specification, selection, and installation contribute to longevity and solid performance.

Analynk Wireless manufactures wireless connectivity solutions for industrial applications and process control. Making cable free connections among process control equipment and instruments, across the room, across the property, across the globe.

Pyrometers

high temperature industrial process for pyrometer temperature measurement
Pyrometers permit temperature measurement without contact
Non-contact measurement technology allows process operators and technicians to evaluate the temperature of process materials, machinery, or piping by measuring their electromagnetic radiation. Through inferential calculation and one or more radiation measurements, specialized instruments can determine temperature without contacting the subject material or surface. While the concept of non-contact measurement technology has existed for many years, more recent advancements in non-contact temperature sensing and the evolution of the pyrometer have allowed temperature measurement at a distance to become popular throughout industrial process operations.

Pyrometers can commonly concentrate light from an object onto a temperature sensing element. The sensed elevation in temperature is proportional to the infrared optical energy. Different instruments may have varying arrangements of concentrating lenses and sensors, but the operating principle is the same. The physical law behind the pyrometer’s operating principle operates on an exponential mathematical basis that is non-linear. This results in one of the limitations of the pyrometer. A single pyrometer can only, with high accuracy, deliver a comparatively narrow range of target temperature. If the need for accuracy is reduced, the applicable temperature range widens. Innovative manufacturers have developed instruments with technology and features overcoming many of the limitations imposed by the physics, delivering instruments with accuracy and applicable temperature range usable in a wide array of applications.

One of the advantages to using a non-contact pyrometer is that their calibration is independent of the distance between the sensor and the object being evaluated. This phenomenon is due to the fact pyrometers have a field of view and can be filled with the target object in a way independent of distance. While the radiation emanating from the target object may be decreasing, the field of view of the pyrometer is measuring a greater portion of the object which is proportional to the amount of radiation being lost, essentially canceling out the distance and allowing the pyrometer to provide useful output. An example of a practical application of a pyrometer in industry would be its use to check the temperature of a ventilation system in the HVAC field.

Share your temperature measurement requirements and challenges with process instrumentation specialists. Their product application expertise will combine with your own process knowledge and experience to produce an effective solution.

Analynk Wireless manufactures wireless connectivity solutions for industrial applications and process control. Making cable free connections among process control equipment and instruments, across the room, across the property, across the globe.

Industrial Wireless as Mainstream Connection Method For Process Measurement

industrial process control wireless transmitter and receiver
Establishing wireless connections for process control operations
is simple, effective, and inexpensive
Wireless connections to process instrumentation has evolved to a point where it is uncomplicated and inexpensive. Many facilities rely on wireless connections, either via a network (wifi) or point to point communications. The benefits of wireless are well known to those already among users of the technology.
  • Safety: Wireless connections can reduce personnel exposure to hazardous environments or situations that previously required human intervention or a manual gauge or instrument reading.
  • Easy Scale-up: Adding points on a network is generally a simple incremental process.
  • Operational Advantage: When deployed to replace manual instrument or gauge readings, real time data for diagnostics and efficiency measurements are now available. Information that is more accurate, timely, and consistent will produce better results.
  • Installation Savings: Installation of wireless connected assets has been reported to be up to 10 times less expensive than wired installation. The reduced space and planning for cables and conduit can make what were once complex and time consuming operations much quicker and easier.
  • Mobility: Wireless technology allows for real time connections to mobile platforms. Whether within a plant, on the road, or on the high seas, there are wireless products that can make the connection.
  • Distance: Don't just think WiFi, think radio, think satellite, think cellular. Connections can be established across very long distances using standard products from the industry.
  • Conversion of Legacy Devices: Many existing in-place devices can have their wired connections replaced with a wireless version. This accommodates a staged transition from wired to wireless in facility.
The transmission is accomplished in either the 900 MHz or 2.4 GHz band, delivering adequate range and power for most facility-wide applications. Obstructions can be overcome with the use of a strategically located repeater. Properly planned and configured, there are few limits to the distance a wireless connection can span.

Point to point wireless connections between, for example, a temperature transmitter and a recorder are easy to create. Most process sensors have very small power requirements, as do the Analynk transmission units. Power, if line voltage is not available at the location, can be provided by batteries, or combination of battery and photovoltaic. The 4-20 mA signal from the temperature transmitter serves as the input signal to the wireless transmitter. The analog signal is converted to a digital value and encrypted prior to transmission. A receiver at the recorder decrypts the digital signal and converts it back to a 4-20 mA analog output that serves as the input signal to the recorder. Wireless transmitter and receiver must be set to the same channel, but otherwise, the equipment handles all the work. If you can find your way around a smart phone, you can make a wireless point to point process connection.

There are likely many applications going unfulfilled because the cost or feasibility of making a wired connection is holding the project back. Reconsider the project using industrial wireless technology and you may find that the project becomes an attractive prospect.

Analynk Wireless designs and manufactures wireless communication equipment and systems for use in commercial and industrial settings. Share your connectivity challenges with the experts at Analynk, combining your own process knowledge and experience with their wireless communications expertise to develop an effective solution.

Video From Analynk Wireless



Analynk Wireless manufactures equipment used to establish wireless connections among process measurement and control devices. Receivers, transmitters,repeaters, antennas, and other devices can be used to easily establish connections between standard industrial process control instrumentation. Single and multiple point installations can be accommodated. Analynk also provides wireless access point enclosures and antennas for hazardous locations.

Analynk gear enables customers to create wireless connections across the room, across the street, and across the globe. Share your wireless connection ideas and challenges with the experts at Analynk. The combination of your process knowledge and their wireless communication expertise will lead to an effective solution.

Wireless Communications For Process Control

The incidence of wireless connections between process measurement devices and their monitoring and control stations has been expanding for years, with costs receding and performance increasing. Designers, engineers, and operators of industrial processes and facilities continue to find new applications and create continuous wireless connections to devices and equipment that were previously isolated by distance or other barriers. They are also saving cost, promoting flexibility, and reducing "clutter" in facilities by eliminating cables, conduits, and junction boxes previously used to transmit measurement signals between instruments and control or recording gear.

Analynk Wireless builds the wireless transmission and receiving equipment needed to establish connections among your process measurement and control equipment and instruments. Transmitters, receivers, and repeaters that are rugged and uncomplicated in their application. Share your wireless connectivity challenges with the experts at Analynk, combining your process knowledge with their technical expertise to develop an effective solution.


Solar Powered Wireless Communications for Industrial Process Measurement and Control

solar energy power unit for industrial instruments measurement control
Analynk Model A650 Solar Power Supply
Wireless connections of process measurement and control equipment sometimes are accomplished in remote locations without readily available electric power. Analynk, as part of its full line of industrial wireless connectivity products, provides their model A650 Solar Power Supply for locations that require a small amount of DC power to operate instrumentation and an Analynk transmitter.

The power supply unit comes complete with solar panel, battery, charge controller, and NEMA 4 enclosure. Options are available to accommodate specific installation requirements. Custom units can be designed for larger power requirements and other special applications.

The data sheet below provides more detail. Share your wireless process measurement and control connectivity challenges with Analynk for effective solutions.


Specialty Valve for Transmitter Isolation

specialty transmitter isolation valve
Transmitter Isolation Valve
Courtesy PBM Valve Solutions
Fluid process control applications frequently employ tanks and vessels as part of the processing chain or for storage and holding. Level transmitters can be installed on the tank to provide indication of liquid level. While there are numerous combinations of fittings and valves that could be used to mount and connect the transmitter to the tank, one manufacturer, PBM Valve Solutions, has designed a specialized valve intended to mate a transmitter to a tank fitting with great advantage.

The specialized transmitter isolation valve minimizes dead space to prevent media residue buildup. It can be configured to accommodate CIP and drainage without process interruption. Calibration ports and industry standard mountings allow for broad application throughout the fluid process control industries.

Establishing a connection between the transmitter and its associated monitoring or control equipment is a specialty of Analynk Wireless. Analynk provides end to end solutions for delivering transmitter signals using wireless communications that can span across the room or around the globe. Reach out to Analynk for effective and easy to implement wireless solutions.

Analynk's Telmar Brand of Process Control Products

enclosed industrial process controller
Telmar enclosed 2-wire transmitter
Analynk Wireless, in addition to wireless process signal transmitters, receivers, and repeaters, manufactures a broad line of industrial process control products under the Telmar brand.

  • 2-Wire Transmitters with AC, DC, mA, slidewire, RTD, or tachometer inputs. General purpose enclosure is standard, with options for others to meet any rated environment.
  • 4-Wire Transmitters with dozens of combinations of input and output signals. Alarm outputs available as option.
  •  Signal Alarms that accommodate inputs from thermocouple, DC current, DC voltage, RTD, AC voltage, AC current, tachometer, slidewire, or strain gauge.
  • Pneumatic Transmitters for pressure to current, current to pressure, pressure to voltage, and voltage to pressure applications.
  • Tachometer Transmitters
  • Explosion Proof Transmitters with or without local indicator for thermocouple or RTD input.
    • industrial process transmitter RTD with explosion proof enclosure and display
      RTD transmitter with explosion proof enclosure and display
  • Indicators and Meters with general purpose or explosion proof enclosures in loop powered or external powered versions.
  • Sensor Assemblies for general, corrosive, or explosion proof applications. Thermocouple or RTD.
The Telmar brand provides complementary products for wired process control applications, or can be supplemented by Analynk's wireless products to provide wireless connectivity between point of measurement and point of control.

Reach out to Analynk with your process control challenges, combining your process knowledge with their product expertise to develop effective solutions.

Introduction to Level Measurement


In many industrial processes, the measurement of level is critical. Depending on the nature of the material being measured, this can be a simple or complex task. Several different technologies for sensing level are briefly explained here.

Level Gauges or Sightglasses
vessel with sight glass level gauge
Sight Glass or Gauge

The simplest form of level measurement for direct measurement of level (almost always visually) in a vessel. A level gauge (sightglass) is usually a clear tube connected to the a vessel at the highest and lowest part of the level range. The fluid level inside the vessel will be at the same hight as the level in the tube.





Floats

tank or vessel with cable and float level indicator
Float level indicator



Another very simple approach to level measurement for fluids or solids is the float. The float sits on
top of the material being measured and is visually, magnetically, or electronically located and equated to the level inside the vessel. It is important that the float material be compatible with the process media and that it freely moves on top of the process.








hydrostatic level measurement
Hydrostatic Pressure

Hydrostatic Level


A very popular way to measure level because of the ease in equating the pressure of a fluid column with the level inside the vessel. In it's simplest form, a pressure sensor (gauge or transmitter) is attached to the bottom of a vessel and measures the pressure of the column. This pressure reading is then interpreted as level.


Bubbler Principle

Bubbler Systems

A variation of the hydrostatic pressure method, bubbler systems measure the pressure of a purge gas being injected into the fluid in a vessel through a dip tube. This approach comes in handy when sensing the level of corrosive fluids. The principle of operation is that the amount of pressure to "push" an inert purge gas through the dip tube will change according to the level in that vessel, and therefore can be correlated to the level.


Displacer Level

Displacer Level

Based upon the laws of buoyancy, a float (either inside its own isolated cage, or hanging in the process directly) is calibrated the the level of the fluid being measured. The displacer is usually a sealed metal tube and hang's in place in the process media. As more of the displacer’s volume becomes submerged, the buoyant force is increased on the making the displacer "lighter".






Radar level measurement device in tank or vessel
Echo level measurement

Echo (Ultrasonic, Radar, Laser)

Level measured by bouncing some wave form (sound, light, electromagnetic) off the surface of liquids and measuring their time of flight.



















Radar level measurement device in tank or vessel
Capacitance level measurement

Capacitance Level

Capacitive level instruments measure the electrical capacitance of a conductive rod inserted vertically into a process vessel. As process level increases, the capacitance between the rod and the vessel walls increases, causing a signal change in the instruments circuitry.






Weight

Level is measured by knowing the empty weight of a vessel and the full weigh of a vessel and calibrating the points between. The shape of the vessel is can also be a factor.

Industrial level control requires deep knowledge and understanding of many process variables, such as media compatibility, interfaces, head pressures, material densities, and mechanical considerations. It's always recommended that an experienced consultant be involved with the selection and implementation of any industrial level device.

Image attribution: courtesy of "Lessons In Industrial Instrumentation" by Tony R. Kuphaldt

Understand Petroleum Refining for Better Process Control Support

Oil refinery petroleum refinery
Oil refineries can have different specialties and function
The petroleum refining industry provides an expansive market for process measurement and control instrumentation and equipment, valves, and process analyzers. Having a basic understanding of the industry can help purveyors of instrumentation and equipment properly address customer needs, as well as recognize where opportunities may lie. Here is a summary of the types of plants and processes.

Petroleum refineries produce liquefied petroleum gases (LPG), motor gasoline, jet fuels, kerosene, distillate fuel oils, residual fuel oils, lubricants, asphalt (bitumen), and other products through distillation of crude oil or through re-distillation, cracking, or reforming of unfinished petroleum derivatives.

There are three basic types of refineries:
  • Topping refineries
  • Hydroskimming refineries
  • Upgrading refineries (also referred to as “conversion” or “complex” refineries). 
Topping refineries have a crude distillation column and produce naphtha and other intermediate products, but not gasoline. There are only a few topping refineries in the U.S., predominately in Alaska.

Hydroskimming refineries have mild conversion units such as hydrotreating units and/or reforming units to produce finished gasoline products, but they do not upgrade heavier components of the crude oil that exit near the bottom of the crude distillation column. Some topping/hydroskimming refineries specialize in processing heavy crude oils to produce asphalt.

The vast majority (75 to 80 percent) of the approximately 150 domestic US refineries are upgrading/conversion refineries. Upgrading/conversion refineries have cracking or coking operations to convert long-chain, high molecular weight hydrocarbons (“heavy distillates”) into smaller hydrocarbons that can be used to produce gasoline product (“light distillates”) and other higher value products and petrochemical feedstocks.

Figure 1 provides a simplified flow diagram of a typical refinery. The flow of intermediates between the processes will vary by refinery, and depends on the structure of the refinery, type of crude processes, as well as product mix.

Figure 1 - Refinery Flow Diagram
Wikipedia - www.en.wikipedia.org/wiki/Petroleum_refining_processes
The first process unit in nearly all refineries is the crude oil or “atmospheric” distillation unit. Different conversion processes are available using thermal or catalytic processes, e.g., delayed coking, catalytic cracking, or catalytic reforming, to produce the desired mix of products from the crude oil. The products may be treated to upgrade the product quality (e.g., sulfur removal using a hydrotreater).

Side processes that are used to condition inputs or produce hydrogen or by-products include crude conditioning (e.g., desalting), hydrogen production, power and steam production, and asphalt production. Lubricants and other specialized products may be produced at special locations.

Application Example - 900 MHz Wireless Delivery of Industrial Process Control Signal

We have a new video with an application example where wireless signal transmission provides a powerful solution. You can always get help with your applications by contacting us.

Two-Wire vs. Four-Wire Transmitter For Analog Process Measurement and Control Signals - What Really Matters?

DIN rail mount industrial two wire transmitter
One of many form factors of two wire transmitters
for industrial process measurement and control
Courtesy Telmar Instruments
Transmitters are everywhere in process control. They take a sensor output signal,amplify and condition it, then send it to monitoring and decision making devices. The most common analog electrical signal used for transmitting process control signals is a 4-20 mA (milliampere) current flow. It has succeeded in its adoption for a number of reasons, not the least of which are its resistance to interference and ability to transmit a signal across a substantial length of cable.

Aside from the sensor connection, there are two basic wiring schemes for these devices. The simplest employs just two conductors to transmit the signal and coincidentally provide operating power for the transmitter electronics. This type of transmitter is commonly referred to as a "loop powered" or "two-wire" device. A DC power supply, typically 24 volts, is wired in series with the 4-20 mA output signal and the transmitter derives its operating power from this source. Loop powered devices generally consume very little power, but process designers must consider the total resistance imposed on the loop by all connected devices. The cable, unless the length is monstrous, poses a measurable but comparatively small resistance. Careful consideration should be given to the resistance imposed by receiving devices, especially if there are several in series, receiving the loop signal. The output voltage of the power supply and the maximum tolerable voltage of the connected devices will serve as limiting factors on loop instrument quantity. Where they can be applied, two-wire transmitters offer a straight forward solution for delivery of analog process measurement signals.

industrial process control cable

A "four-wire" transmitter gets its name from, you guessed it, the two pairs of wires used to provide operating power and a signal transmission path. Provided with a separate power source, possibly even 120 volts AC, this transmitter type will often be found in applications where the sensor may have power requirements that cannot be met with the limitations inherent in the loop powered device. While it may seem that the separate power supply negates the need to consider total resistance load on the signal loop, this is not the case. The signal loop still will be limited by the DC power supply that serves as the driving force of the loop.

In many cases, the question of "two-wire or four-wire" will be answered by the transmitter manufacturer. Since the two-wire scheme is a less burdensome installation, it may be the only product offering when a suitable device can be designed for an application. That said, a diligent search will probably find two and four-wire versions of transmitters for almost every application.

What are some decision making guidelines?


  • Some types of transmitters have sufficiently high power requirements that they cannot be loop powered. In this case, four-wire may be the only option.
  • For low resistance loads, use 2 wire transmitters for a simpler installation.
  • Allow some headroom in the loop resistance to accommodate at least one added receiving device in the future. For example, a temperature signal may serve as an input to a controller now, but need to service a recording device potentially added in the future.
  • Distance should not be mindlessly overlooked, but is generally not a limiting factor, as most installations would be compatible with the distance limitations for two- or four-wire device output signals. 
  • When signal transmission distances become unwieldy, due to cabling costs or other factors, consider a wireless transmitter instead of a wired device.
The important aspect of applying 4-20 mA signal loops is to maintain the capability to add another receiving device to the circuit. The use of information in the form of process signals has been growing for a long time and is likely to continue. It is certainly easier to wire an additional device into an existing loop, than to install an additional sensor, transmitter, power supply, and cabling to accommodate the additional device. 

Analynk provides wired and wireless solutions for delivering analog process control signals. The wired devices carry the company's Telmar brand name. Wireless solution products carry the Analynk and Sensalynk brand name.

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Creating Wireless Process Connections Is ABC Simple

Industrial wireless is not new, it is a mature technology. With the products available today, implementing a wireless process signal connection is no more difficult than installing a simple process controller. Analynk is a part of that simplicity, manufacturing modular receivers, transmitters, and companion products enabling operators at any scale to effectively deploy a 900 MHz or 2.4 GHz wireless solution.

There are many instances where a wireless solution provides distinct advantages over wired installations. Understanding the simplicity of wireless installations, and that product based solutions are readily available, can unleash your ingenuity at solving process control challenges using wireless communications. A previous article may help you recognize opportunities to avoid expensive or difficult cabling, or actually make connections you thought were impossible.

Let's look at a basic installation that measures temperature at a remote location (the measuring station) and transmits the signal to your office (the monitoring station).

Here is all you need:

  • Power supply to operate the temperature measurement instrument and the Analynk transmitter. Analynk transmitters consume little power and can be provided with photovoltaic power supplies, if needed.
  • Temperature measuring device of your choice with 4-20 ma output signal and up to two discrete outputs. It does not need to be wireless. 
  • Analynk transmitter located at the temperature measurement station to convert the 4-20 ma temperature signal to digital format and send it to the monitoring station. The connection between the temperature measuring device and the Analynk transmitter is wired.
  • Analynk receiver located at the monitoring station to receive and decode the signal from the Analynk transmitter, converting it back to 4-20 ma. A wired connection between the receiver and your monitoring or recording equipment delivers the 4-20 ma temperature signal to its destination.

The simple wiring connections to the transmitter and receiver differ little from those of most other devices (see the ABC’s on the illustration).

A - Connect a power source to operate the unit
B - Connect the input signal (if it's a transmitter) or output signal (if it's a receiver).
C - Connect discrete inputs (if it's a transmitter) or outputs (if it's a receiver).

wiring diagram for Analynk wireless receiver or transmitter
Wiring diagram for Analynk Model A753 wireless transmitter
Setting up the transmitter and receiver takes no more technical knowledge than other modern control devices. You follow instructions to set a few parameters, calibrate, and put the system into operation.

You can gang inputs and outputs together with an expander module and use a single transmitter and receiver to deliver multiple sensor signals. All units are DIN rail mounted with removable terminals for simple, organized installation and replacement.

Wireless connections can expand your operating capabilities, as well as business opportunities. Analynk has made the implementation easy. Use your creativity and ingenuity to bring new applications to your operation. Contact Analynk anytime to discuss your ideas or get the help you need to put your ideas into action.







Process Monitoring and Control - Where You Can Make Good Use of Wireless

Analynk empowers industrial process operators at any scale to bring the functional benefits of industrial wireless communication to their applications. The company provides easy to implement wireless hardware solutions that can be economically applied to even as single data point.

Talk a look at our short video for some application suggestions. Ramp up your ingenuity and develop ideas for your facility or operation. Contact the experts at Analynk for solutions. We enjoy hearing new and creative ideas for meeting process control challenges with wireless.


Will Wireless Work For My Process Control Application?

Industrial Wireless Receiver demonstration unit
Model A750/753 Wireless Demonstration Unit
Wireless transmission of process measurement and control signals has not been new technology for quite some time. That said, there still remain many facilities where it has not made any inroads yet. When technology is new to the industrial market, especially if it challenges the current way things are done, early adopters with larger scale, higher dollar operations are needed to put the technology into practical use and generate manufacturing volume for the technology producers. If deployment of the technology proves beneficial, the market grows on the consumer and producer sides. With greater efficiency and scale, the trend for the technology costs tends to decrease, while the range of feasible applications and projects grows.

Wireless communication for industrial applications is well beyond the point of early technology adoption. Protocols are in place, products for the transmitting and receiving of wireless process signals are mature. As a designer, engineer, manager, or operator of a process, you should confidently consider wireless connections between measurement and control or recording devices as part of any new installation or upgrading of existing facilities.

Regardless of what I have just written, sometimes we just need to see things work before we can make the leap of adoption. New ways of doing things bring the promise of reward, but also the concern of the unfamiliar.
Analynk has a solution for you.
Analynk's wireless demo kit includes a model A750 receiver and A753 transmitter both housed in NEMA 4 enclosures. The kit operates at 900 MHz with full 1W power. Locate the transmitter and receiver at points where you wish to establish a wireless connection. You can provide your own input signal, or use the provided simulator to show that a wireless connection can be established and function in a manner that will give you confidence to move forward with implementation. The kit is useful for testing out possible new locations for distance and signal strength. You will use it as wireless communications expand through your facility. Test the location first, then order the needed wireless equipment. It's a solid and low risk solution.

Analynk is a manufacturer of both wireless and wired devices for process measurement and control. The company's offering includes a wide array of standard products, as well as integration and customization to meet specific project requirements. Contact the specialists at Analynk to discuss your industrial wireless application requirements.