Field Wireless

Open your eyes to a world of new opportunities....

Not being tied to wired communication loop, a Yokogawa wireless system can provide process measurements that were previously too difficult or uneconomical to implement.

  • Yokogawa offers a complete line of ISA100 compliant pressure transmitters. The line includes transmitters that can measure differential pressure, absolute pressure, and gauge pressure.

  • Yokogawa offers the dual-input YTA510 and the multi-point YMTX580 temperature transmitters.

  • Field Wireless Multi-Protocol Module with “Field Wireless Communication Module FN110” acquires sensor data from a connected sensor and transmits it to a field wireless network through FN110.

  • Yokogawa offers an IoT Enabled ISA100 compliant Gateway, a Access Point, a Media Converter, and a Management Station. All to help design a network to meet your needs.

  • Wireless Noise Surveillance is a new digital HSE system to provide a real time sound noise map monitoring system.

2018.03.06   A brochure of ”Gateway Module”(FN110-R1/LN90)is published.
2017.11.21   A brochure of "Yokogawa Releases ISA100 WirelessTM Gateway Module – Ideals for construction of small-scale field wireless systems–
2017.07.18   A brochure of "Yokogawa Field Wirless Solution" has been updated.
2017.03.23   Yokogawa and Cosasco Conclude Agreement for Sale of ISA100 Wireless™-based Products  –To improve maintenance and enhance safety– (Refer to Cosasco’s website:
2016.12.08   Yokogawa Releases ISA100 WirelessTM-based Field Wireless Vibration Sensor with Fast Data Updates and Long Battery Life (Refer to FN510 Field Wireless Multifunction Module)
2016.09.23   Yokogawa Receives SICE Award (Refer to Yokogawa Press Release - September 23, 2016)
2016.08.10   Yokogawa Releases FieldMate® R3.02 Versatile Device Management Wizard - Significantly reduces maintenance workload -
2016.08.08    ISA100 Wireless End User Conference will be held on September 27th, 2016 in Rotterdam, The Netherlands.
2016.07.21    Murata started mass production of 2.4GHz-band wireless communication module which has been certified to be ISA100 Wireless compliant.
2016.06.17    FN310 and FN510 (ATEX Certification) has been released.
2016.04.22    FN110, FN310 and FN510 (Factory Mutual "United States and Canada" Approvals and IECEx Certification) has been released.
2016.03.18    YFGW510 Field Wireless Access Point (ATEX and IECEx Flameproof Approval Options) has been released.
2016.03.18    A Series of Field Wireless YFGWs Comply with New Legislative Framework (NLF Standards)
2016.02.22    Yokogawa Concludes Agreement with Statoil to Jointly Develop a Field Wireless System –Monitoring of plant noise levels in real time–
2016.01.05    New bulletin "Yokogawa Field Wireless Solution"(Bulletin 01W01A13-01EN) has been issued.
2015.11.04    Pharmaceutical solution "Ground Well Level Monitoring" has been added.
2015.10.13    Murata has launched the engineering sample of ISA100 Wireless Module onto the market.
2015.07.28    Two application notes "Temperature Monitoring on PID loop at Steel Process" and “Tubeless tyres performance testing” are added.
2015.07.23    Yokogawa and GasSecure Provide the world’s first SIL2-certified Wireless Gas Detection System for LNG Facility
2015.07.03    Plant Resource Manager (PRM) R3.20 has been released. It includes an improved management function for ISA100 Wireless™ field devices.








New concept "Wireless Anywhere"

“Wireless Anywhere” Concept to Expand Use of Field Wireless Systems Based on the ISA100.11a Standard

Yokogawa Electric Corporation announces the introduction of a new “Wireless Anywhere” business concept on the plant-wide use of ISA100.11a compliant wireless communication technologies for both monitoring and control applications.

anywhere 01_en r01.jpg

For continuous processes that need sophisticated wireless control technologies, Yokogawa released the world’s first ISA100.11a compliant system devices and transmitters in July 2010, giving customers an expanded range of device choices.

Based on the “Grow” concept, in 2012 Yokogawa released three new field wireless system devices and enhanced existing wireless pressure and temperature transmitters to enable its customers to expand their plant wireless networks and make full use of existing assets. These ISA100.11a compliant wireless products can be used to construct highly reliable large-scale plant networks, and may also be incorporated with other Yokogawa products in small- and medium-sized networks, substantially expanding their capabilities.

The ISA100.11a standard ensures high reliability, application flexibility, network expandability, and compatibility with a variety of wired communication standards such as FOUNDATIONTM fieldbus, HART®, and PROFIBUS. “ISA100.11a full functional” field wireless network systems and devices make use of state-of-the-art dual redundant technologies that enable a much higher level of reliability, and allow massive scalability and long-range communications.

Yokogawa will aggressively promote this new “Wireless Anywhere” concept to widen the use of ISA100.11a-compliant products and related services. This augments our existing “Grow” concept, which encourages the introduction of wireless communication technologies by making a case for their inherent reliability, flexibility, and openness.

ISA100.11a Full Functional Field Wireless System Features

anywhere 02_en r03.jpg

Such systems ensure responses in real time by making use of state-of-the-art dual redundant technologies and can be quite large in scale, supporting connections to up to 20 access points and 500 field wireless devices. The data update time is 5 seconds when the system consists of a host system and 500 field wireless devices, and 1 second with a host system and 200 field wireless devices. The field wireless devices are proven to be able to communicate over distances up to 10 km*1, 20 times the range of conventional systems.

Our wireless physical layer (Reliable Radio) and system redundancy technologies ensure a high level of reliability. With our Duocast technology, each field device simultaneously sends the same data to two designated access points, ensuring uninterrupted communication in the event that one of the points experiences a problem. The duplication of gateways and systems further strengthens the reliability of our wireless systems. The field wireless devices are proven to be able to communicate over distances up to 10 km*1, 20 times the range of conventional systems.

*1 With a high-gain antenna. Local regulations may restrict the use of such antennas with field wireless devices.

The Wireless Anywhere Concept

By following up on the Grow concept with this announcement of the Wireless Anywhere concept, Yokogawa is advocating the use of “ISA100.11a full functional” field wireless systems throughout plants. To this end, Yokogawa will pursue the following three initiatives:

1.Modularizing wireless components to accelerate product development
Yokogawa will develop modularized wireless components that incorporate the various technologies in its field wireless devices. This will make it easier for vendors to implement the ISA100.11a technology in new sensor products, and accelerate time to market. By the end of 2013 Yokogawa plans to begin releasing new field wireless devices with these components and expanding product lineup.

2.Promoting adoption of the ISA100.11a standard
Yokogawa will work with other members of the ISA100 Wireless Compliance Institute (ISA100WCI) to increase the number of WCI member companies and promote acceptance of the ISA100.11a standard, thereby expanding the field wireless market. To make a wider range of ISA100.11a-compliant products available to the market, Yokogawa may supply modularized components to other vendors.

3.Facilitating host connectivity for both wired and wireless field networks
To encourage the use of field wireless systems in both monitoring and control applications, Yokogawa will seek to improve the effectiveness of plant-wide field digital networks by making it possible for wired and wireless field devices and systems to connect with host monitoring and control systems. This will necessitate the development of technologies that will ensure host systems and field devices can communicate with each other using a variety of protocols. For example, an ISA100.11a-compliant adapter would enable a wired field device to link up with a wireless network.

anywhere 03_en r01.jpg


Yokogawa is advocating the new Wireless Anywhere concept for solutions that work seamlessly with the diverse devices and advanced information technologies used at production sites. Yokogawa will continue to develop field wireless devices for both monitoring and control applications, and will partner with its customers to assure their long-term growth through the achievement of ideal plant operations.

Large-scale, reliable, next-generation plant-wide field wireless system

A new architecture for our “Grow” concept

Yokogawa launched the world’s first wireless field products conforming to the ISA100.11a standard in 2010 and has led the business ever since. Now, Yokogawa has released a new, large-scale, reliable, next-generation plant-wide field wireless system.  
In developing this system, which forms the core of field digital solutions, Yokogawa has focused on the following three key features.

  1. Reliability: reliable high-performance field wireless and redundant technologies
  2. Flexibility: flexible architecture that supports the full range, from small to large-scale plants
  3. Openness: open ISA100.11a standard that allows third-party field wireless devices to be connected

This new system has been developed in line with Yokogawa’s “Grow” concept of helping customers to grow and enabling ourselves to evolve and continue to offer timely solutions.


Advantages of the next-generationfield wireless system

Although most field wireless systems are currently installed in relatively small areas, demands are rising for increasing the number of monitoring points, covering wider areas, and expanding to process control as well as diagnosis, monitoring, and measurement.
To respond to these demands, Yokogawa has developed a large-scale, reliable, next-generation plant-wide field wireless system, which will manage up to 500* wireless field devices.
*The number of Wireless Field devices which can be handled depends on software version of YFGW410.

Conventional small field wireless systems are mainly installed as additional monitoring tools in areas with a clear line-of-sight such as tank yards and wastewater treatment facilities. Such systems offer only limited advantages such as improved inventory management, reduced regular visual checking, automated environmental measurement, and reduced wiring costs.
In contrast, plant-wide field wireless systems can cover both a large number of measuring points in a small area packed with production equipment where wireless devices are difficult to install, as well as the entire plant. This allows customers to set up wireless devices anywhere in their plants and manage data from those devices to improve plant-wide production efficiency.

Architecture of the large-scale, flexible, field wireless system

Yokogawa has developed the following new products for the new field wireless system:

  • YFGW410 field wireless management station
  • YFGW510 field wireless access point
  • YFGW610 field wireless media converter

Our YFGW710, the existing all-in-one type field wireless integrated gateway, combines all the functions of access points and wireless management, enabling small wireless systems to be easily installed.
In the new architecture, the YFGW510 serves as an access point and forms the wireless backbone network with the YFGW410 field wireless management station.
Therefore, by installing multiple YFGW510 field wireless access points throughout the plant, wireless sub-networks can be built and then connected to each other to create a large-scale, plant-wide field wireless system.
The YFGW510 and YFGW410 can communicate via Ethernet, optical Ethernet, wireless LAN, instrumentation cable communication*, and so forth, allowing flexible installation in plants.
*Instrumentation cable communication will be supported in the next phase.
An example of the system configuration is shown below.


Technologies to support a highly reliable field wireless system

YOKOGAWA Field Wireless has excellent receiving efficiency and the feature is high reliability of wireless physical layers(Reliable Radio).The technology enabled the 600m long distance communication with standard antenna if there is no obstacle. The low packet error rate is realized under the environment of multi path in “Pipe Jungle”.

The reliability of network layer is enhanced with the import of new technology. YOKOGAWA proposals are next two technologies.

1. Duocast

Duocast is a redundancy technology for the wireless path specified in the ISA100.11a standard. In the conventional mesh-topology network, if communication is not established in a path, data is then sent via another path. However, this may affect real-time performance because the data is not sent in the same time slot, but in a later time slot even in the same superframe.
On the other hand, Duocast simultaneously sends two identical data in the same time slot, and provided either data is successfully transmitted, real-time performance is maintained. Therefore, Duocast is ideal for ensuring the redundancy of mission-critical wireless paths and helps improve reliability while securing low latency (see the figure below).


Duocast can overcome failures of either access point as well as errors in a wireless path.

2. Dual wireless backbone network

The network between the YFGW510 and YFGW410 is called a wireless backbone network. Its redundancy is specified by the ISA100.11a standard to improve the reliability of the network and is achieved by the redundant YFGW410 stations. Either of the dual YFGW410 stations can deal with disconnections and errors of the wireless backbone network, and malfunctions of the other YFGW410 (see the figure below).

Redundant_00_65E R01.jpg

stations, one set to Active and the other to Standby, are connected with each other via a synchronous communication cable. If any trouble in the Active YFGW410 is detected, the functions and data are quickly shifted to the Standby YFGW410 to seamlessly continue communication.

Enhanced Version of Wireless Transmitters

Wireless Differential Pressure/Pressure Transmitter and Wireless Temperature Transmitter have enhanced with the release of Plant Wide Field Wireless System.

The improvement of communication quality with detachable antenna

The detachable antenna type model has released. The antenna extension cable and high-gain antenna* can used with this model. The placement of antenna can be adjusted with the antenna extension cable without change the installation of transmitters.

And the expansion of communication distance becomes possible with high-gain antenna*.
*Subject to the Radio law regulation of each country.

The extension of battery life with low power consumption

The battery life of the detachable antenna type model becomes longer than conventional product with low power consumption. It depends on the condition, from 1.5 times to 2 times of battery life is realized. The examples of the battery life is shown below.

EJX B Series Wireless Differential Pressure/Pressure Transmitter (Amplifier housing code 8 or 9)

 Update time 10 years at 30 seconds
 Update time 5 years at 10 seconds

YTA510 Wireless Temperature Transmitter (Amplifier housing code 8 or 9 and low power mode)

 Update time 10 years at 10 seconds
 Update time 8 years at 5 seconds


Yokogawa has been researching and developing industrial wireless technologies for ten years and has compared a variety of standards, with the following conclusion: in adopting wireless systems in the fields of industrial measurement and control, wireless physical layers must eliminate instability as far as possible (Reliable Radio) and the system must reinforce it.

Among various industrial wireless communication standards, the ISA100 standards were the most suitable for achieving Yokogawa’s policy. Therefore, Yokogawa adopted this standard and released the world’s first ISA100-compliant products in the market in 2010.

Yokogawa has since released various wireless applications while its development engineers have visited over 100 sites worldwide for survey.

The accumulation of such experience as well as the information obtained from many customers have been reflected in the development to make full use of the advantages of the ISA100 standards (ISA100 Full Functional), and to make the role of wireless communication clearer and securer toward Field Digital Innovation.


Reliability of Wireless Communication

The general perception that wireless communication is easily disconnected seems to be attributed to our daily experience with mobile phones and wireless LANs. The rapid progress of mobile phone technology meant that the latest digital wireless communication technology could be used to solve the very tough challenge of ensuring that high-speed data transmission rates and reliability are maintained while users are walking or moving at high speed in cars and trains.
However, the facts that a user moves at a certain speed and that the location of use is not fixed impose difficult conditions on wireless communication for which the radio wave environment changes dynamically, resulting in the instability typical of wireless communication.
Meanwhile, in many industrial measurement applications, the measurement location is considered and then fixed at the point of installation, and even if the user moves, the movement speed is very moderate and the movement range is also limited, and the required data transfer rate is also relatively low, so the environment is such that reliability can be easily maintained for wireless communication. In other words, it is possible to set conditions to ensure sufficient stability for wireless communication beforehand.
By introducing the latest digital wireless technology in such a relatively privileged environment, reliability comparable with wired communication can be ensured.

Security by digital communication technology

Even for fixed wireless communication, there are some concerns, such as interference and cross-talk from other wireless communication and jamming using the same frequency for malicious purposes.
Furthermore, wireless communication signals travel through the air and reach the surrounding areas, so there are concerns such as interception and eavesdropping by a third party, or penetration into the wireless network from the outside.
One answer to these concerns is the evolution from analog to digital technology for wireless communication.
Wireless communication in the analog era was vulnerable in terms of security as it could be intercepted by anyone using a receiver with the same frequency, and intentional interruption and interference were easy.
However, the introduction of digital technology to wireless communication reduced these concerns significantly. The following provides an overview of digital technology.

Security by digital communication technology

Environmental Conditions and Wireless Communication

There are some misunderstandings regarding the concerns about the environmental impact of wireless communication.
For example, it is not true that field wireless communication is vulnerable to strong magnetic fields, or communication is interrupted by rainfall. In some cases, wireless communication is more advantageous than wired communication. The following summarizes the relations between the environmental conditions and wireless communication.

  • Damage by lightning surge
    Lightning surge is a phenomenon that a surge current generated by lightning flows through the power supply cable and communication cables and damages the connected electronic devices. Therefore, the lightning surge risk for wireless transmitters is rather small because they are not connected by cables. However, an on-site lightning protection measure is required to prevent a direct lightning strike.
  • Communication interference by lightning
    The frequency of electromagnetic waves generated by an electric discharge produced by lightning is said to have a wide range between a couple of hertz and 1 gigahertz. However, the higher the frequency, the lower the power becomes, and the problem only occurs when electric discharge and intermittent communication happen to occur at the same time. Even if that happens, the problem can be covered by retransmission control.
  • Impact of rain, snow, and fog
    The 2.4 GHz range used for field wireless communication suffers little impact from rain and snow. This has been proven by experiments.Generally it is said that communication begins to be impacted from 10 GHz and higher.
  • Disconnection risk
    Wireless communication is free from the cable disconnection problem typical of wired communication, which occurs when a cable is broken as a result of a disaster or deterioration in a bad environment, when a cable is damaged by wild animals, or when a cable is cut intentionally by a malicious person.
  • Impact of strong magnetic field
    A magnetic field that causes a problem is generally not one in the high frequency range of wireless communication but one in the low frequency range. Wireless communication is advantageous in this respect as an induction current generated by a magnetic field is produced with regards to the conductor (wire).

Unique Battery Pack Technology

Efficient battery replacement made possible by our unique battery pack technology.

Battery pack

The uniquely designed battery housing compartment and battery pack within our wireless transmitters allows it to be exchanged in the field, even within a hazardous area. The battery pack further enables convenient access to the internal batteries so that they may be replaced as is necessary and restocked. Thus minimizing both waste and cost, while making the battery replacement process as efficient as possible. The batteries used within the battery pack are standard ‘D’ cell Lithium/Thionyl Chloride batteries. These have excellent power versus temperature characteristics along with a long in service life that makes them suitable for use within environments.

ISA100 and DPharp for the Digital World

A combination of two unique technologies has enabled true end to end, through the air digital sensing. Marrying the renowned benefits of the DPharp digital sensing with ISA100.11a, the new industrial standard for wireless sensor network, has brought a truly unique proposition. Advanced high precision digital sensing with all the benefits of wireless deployment; reduced engineering and commissioning with the flexibility to expand the wireless sensor network to meet future demand.

The bringing together of DPharp with ISA100.11a represent Yokogawa’s commitment to continue delivering unsurpassed leading edge solutions to the industrial automation industry. Reliable, secure, flexible and intuitive the new wireless transmitter series simplify all aspects of wireless deployment, management and operation while delivering excellence as standard.

Whether installed upstream on remote pipelines and wellheads or downstream in tank farms, vacuum columns or loading piers our wireless transmitters will continue to deliver secure, precise, reliable, high integrity process measurements that meet your demand.

Our wireless transmitters will increase your process visibility by reducing operational blind spots, which in turn will reduce your process variability, increased yield, and improved product reproducibility while reducing costs and increasing flexibility.

ISA100 brings you real sustainable lifecycle benefits to meet your requirements now and in the future.

The ISA100.11a Wireless Communication Standard

Wireless technology such as mobile phones and wireless networks has become an indispensable part of our lives. Now there is greater demand for compatibility with instrumentation of that wireless technology. So, what is the best wireless technology to use?

A variety of vendors including Yokogawa Electric have been providing simple implementation over wireless communication, but they have just not been widely accepted for reasons such as:

  • Most use proprietary communication protocols thus limiting potential applications.
  • It has not been possible for one set of wireless instrumentation to handle multiple brands of products.
  • Engineers were unable to ignore concerns about communication channel security and reliability.

But now, Yokogawa has adopted the ISA100.11a wireless communication standard that is geared toward Industrial Automation, and worked to make user-friendly wireless devices that meet international standards.

ISA100.11a has the following noteworthy features:

Featutes Notes
Security Robust encryption technology
High reliability Achieves 24-hour, 365-day down-time–free communication
Power management Longer battery life and battery replacement prediction
Open Devices can be purchased from multiple suppliers
Multi-speed Devices with both high- and low-speed update rates
Multi-tasking Multiple applications on a single wireless network
Scalable Numbers of wireless field devices, longer distance communication, and update rates
Global Technology supported by many countries
Communication QC Control of latency, and low error rates
Multi-protocol Requires minimal investment because it can be integrated with existing wired systems
Supports control Expands the range of wireless applications

These are based on user requests for industrial wireless sensor networks; the ISA100.11a industrial wireless standard meets all of these requests at once.

By adopting industrial wireless technology based on the ISA100.11A standard, we will be able to build highly-reliable, promising new styles of instrumentation that we are confident to solve many problems.

Demo of Using ISA100 Wireless Technology for Control Application

–Paving the way for the smooth integration of plant monitoring and control applications using a single wireless infrastructure


The system designed for this demonstration was comprised of a prototype wireless D3 valve positioner from Flowserve Corporation and Yokogawa’s flagship integrated production control system “CENTUM® VP”, wireless gateway devices, and the DPharp EJX B series wireless differential pressure/pressure transmitter. The field wireless devices were all compliant with the ISA100 WirelessTM by ISA100 Wireless Compliance Institute and featured a fast 1-second data update time. Redundant wireless communications paths were employed to ensure high reliability.

Yokogawa products in this demonstration system:

  • CENTUM VP integrated production control system
  • DPharp EJX B series differential pressure/pressure transmitter
  • YFGW410 field wireless management station
  • YFGW510 field wireless access point


The feature of the wireless control demonstration of the water level

  1. Field wireless devices controlled by the PID control of the DCS
  2. Fast data update : 1 second
  3. state-of-the-art redundant technologies Duocast and the redundant Field Wireless Management Station
  4. The prototype product of wireless D3 valve positioner by Flowserve Corporation


The detailed wireless control demonstration of the water level

Purpose: Yokogawa assures the appropriate wireless control is updated every 1 second.

Method: A distribute controller communicates with a wireless valve positioner and a wireless differential pressure/pressure transmitter and controls water level as target four levels.

Constitution: "CENTUM VP" distributed control system communicates with the infrastructure of ISA100.11a wireless system and controls the water level by PID control.

Yokogawa developed reliable ISA100 Wireless System for Control Application-- Live Demo

ISA100 Wireless Technology has paved the way to smoothly integrating the plant wireless monitoring and control applications under single wireless infrastructure. Yokogawa is working on the application of wireless technologies that can be suitable for both monitoring and control purposes throughout plants. The demonstration conducted by Yokogawa showed for the first time how CENTUM VP could be used under actual plant conditions in a wireless control application.

Cost Savings in Wireless Sensor Networks using Yokogawa ISA100.11a Devices for Increased Communication Distance

Tired of adding extra repeaters and devices to your wireless sensor network to get proper coverage? Switch to Yokogawa's ISA100.11a wireless system and save money by using less hardware to cover larger areas. Yokogawa's access points and wireless transmitters can reliably transmit 3.4km between devices using our remote antenna option. This means that in a standard 4hops network, your Yokogawa wireless system can cover a 13.6km radius area!

Choose Reliable Wireless System Suitable for Your Small or Large Applications

Reliable wireless solution is always one of the top concerns for industrial users. This video demonstrates Yokogawa newly released wireless system solution. It combines the best of ISA100.11a wireless technology with Yokogawa system design expertise. The Yokogawa new wireless system further enhanced the “Reliable Radio” in field device, deployed Duocast communication method in Access Point (YFGW510), and enabled two redundant management station (YFGW410) that able to work simultaneously to achieve overall wireless system reliability. Because of this unique design, one single Yokogawa wireless system can be very flexible for your need to support as much as 500 field devices reliably. Enjoy this demonstration.

Yokogawa Wireless brings "Reliable Radio Evolution"

Yokogawa Wireless Solution has a very reliable radio-link feature based on a world-class receiver sensitivity. We found this feature brings dramatically new benefits to customers.

  • Long Range Communication: (600 m with 10 mW)
  • Stable in Pipe Jungle
  • Robust in Wi-Fi Co-Existence

Yokogawa Field Wireless: Long Range Communication Test (600 m)

Yokogawa's engineers tested "Long Range Communication" feature of Yokogawa Wireless Solution. 600 m communication with very low Packet Error Rate (PER) is shown in this video.
We named this dramatic change "Reliable Radio Evolution" and would like to propagate this concept for customers' benefits. This video is a conceptual video of "Reliable Radio Evolution".

Yokogawa Receives Frost & Sullivan 2014 Global Enabling Technology Leadership Award in Wireless Solutions Category

Yokogawa Electric Corporation announces that it has received the Frost & Sullivan 2014 Global Enabling Technology Leadership Award in the wireless solutions category. The Enabling Technology Leadership Award is presented to companies around the world that are best-in-class in a specific category.
Field wireless systems enable a plant’s field devices and host-level monitoring and control systems to communicate wirelessly with each other. This has numerous advantages such as allowing the placement of field instruments or analytical sensors in difficult to wire location, which eliminates the need for cables to connect devices, and reduces installation costs.
Yokogawa released the world’s first ISA100.11a compliant wireless system devices and wireless pressure and temperature transmitters in July 2010, and the company continues to enhance its lineup of wireless solutions. In accordance with the Wireless Anywhere concept, which was announced in April 2013, Yokogawa is seeking to promote the plant-wide use of field wireless systems by developing new ISA100 Wireless™ devices. In December 2013, the company started providing a wireless communications module with a built-in antenna that can help field device manufacturers significantly shorten the time needed for developing wireless solutions. Later this year, the company also plans to release a multi-protocol wireless adaptor that will enable wired field instruments or analytical sensors to be used as ISA100 Wireless devices.
Frost & Sullivan selected Yokogawa for this award because of the company's efforts to develop ISA100 Wireless solutions that enable high-reliability, openness, and interoperability. In selecting the award recipient, Frost & Sullivan evaluated companies based on whether they enabled the creation of new products, enhanced current products, enabled new applications, had potential for market acceptance, and had a breadth of access to technology. Yokogawa was recognized for making a superior contribution in developing innovative field wireless solutions.
In line with the Wireless Anywhere concept, Yokogawa will continue to expand its lineup of ISA100 Wireless solutions and promote the use of field wireless technologies. The company is working on the application of wireless technologies that can be suitable for both monitoring and control purposes throughout plants.
The names of companies, products, and brands in this text are registered trademarks or trademarks of the respective holders.



The client wanted to monitor the pressure of the gas well at offshore platform remotely to reduce maintenance cost and increase safety of maintenance personnel.


Remote leak detection for pipe line was needed to meet new environmental statute. However cabling earthwork is strictly restricted to protect land environment.


The client wanted to monitor the injection gas pressure of gas lift remotely in central control room. Antitheft measures are needed to install new equipments and cables.


In the event of a gas line shut down, gas supply must be maintained for a period of time with the use of LNG stored in road tankers. Each tanker must have its pressure monitored to prevent an over pressure situation arising.


ISA100 wireless pressure transmitters


ISA100 wireless temperature and pressure transmitters.


Delayed Coker is a type of coker who's process consists of heating residual oil feed to its thermal cracking temperature in a furnace. The most important variable in industrial furnace control is temperature. Temperature is measured throughout the furnace in different zones and temperature effects the materials being manufactured and therefore must be precisely monitored to prevent deviations in quality of the final product.


The client wanted to monitor the temperature on a chimney. Exhaust air is exposed to the heat on the way traveling from the inlet to the outlet in the chimney. Then constituent of the air transform to harmless elements. It is important to keep the temperature in the chimney as designed.

Application Note

A battery room is used to storage batteries for emergency power management in the plant. Each substation has battery room and the storage batteries are lead-acid batteries which must be maintained within specified operating temperature limits. Temperature management is important to ensure a long service life of the batteries especially for the plant in desert climates.



  • The distance is not so long, but there are many pipes and tanks ("Pipe Jungle") in the field.
  • Had to avoid the obstacles and take care multi path condition.  


Repeater is installed on high place between control room and monitor position. The extend cable is used for antenna of Gateway.

  • Temperature Transmitter (YTA) x1, Pressure Transmitter (EJX) x2

Geothermal power plants create electricity from geothermal energy. These power plants are similar to other steam turbine station; however their heat source is that of the earth's core. The created steam is used to turn the turbine for the production of electricity. Technologies include Dry steam, Flash steam and Binary cycle power stations with Binary cycle being the most common geothermal plant in current production. In the process of geothermal power generation the facility needs to monitor various processes, as in this case steam line pressure sits in remote from control room's location.


Employ the ISA100.11a-compliant YTMX580 Multipoint Wireless Transmitter. The YTMX580 has 8 channels of universal input, which is perfect for multipoint measurement applications, and it can withstand harsh operating temperatures of -40 to 85 °C.

  • Wireless temperature measurement gateway x1, transmitter (YTA) x1: on a buoy
  • High quality wireless communication was confirmed.
    Note: as the PER may increase due to antenna direction changes on the buoy, a repeater on the buoy is recommended

Pressure measurement of tubeless tyres to monitor the air loss is one of the key performance tests in the tyre manufacturing units. Relocation of tyres from one testing rack to the other for various tests and frequent movement of the testing setup for conditional tests to various locations calls for cable free implementation for ease of handling.

Application Note

A horizontal rotary miller used to grind the limestone rocks with metallic balls as grinding stones. This is used as the raw ingredient to produce cement powder. The temperature needs to be monitored in order to control the process and the quality of the final product. The user was using an induction temperature measurement based on a rail system that was very fragile and therefore unreliable.


Both bulk and finished inventories are stored in distributed tank farm remote from the site operations. These are difficult to instrument due to the infrastructure cost involved. These are then monitored daily by patrol rounds. While effective, this method does require a large skilled labor force to monitor all of tanks. This can impose an additional risk when the stored medium is of a hazardous nature.

  • Temperature monitoring is required to prevent wind-fueled fire hazards.
  • The measuring points are up to 600 meters away from the control room.
  • Daily manual reading of pressure and temperature gauges with report by phone.
  • The customer wants to change measurement from off-line to on-line.
  • Cabling for wired transmitters in huge plants (up to 300 meters long) is expensive.

Install a YTMX580 on the side of the rotating furnace that can wirelessly transmit measured values from multiple temperature sensors.

  • Temperature is monitored to maintain consistency of the viscous fiber entering the drum.
  • Existing system requires manual temperature readings.
  • Wired temperature measurement is not available because the tank is rotating.
  • Manual temperature reading requires walking about 130 m and climbing up and down elevated sections of the dryer stages.
  • Multiple temperature measurement points along the various stages of the dryer require many cables to the control room.
  • Very high humidity.
  • Wireless temperature measurement
    Gateway x1, transmitter (YTA) x1, repeater x2 (The 2 repeaters are for redundancy)
  • Extended antenna to circumvent obstacles and improve the radio path for stable measurement (communication was unstable when the height of the antenna was low).
  • Wireless pressure and temperature monitoring.
  • Repeater was set under the gateway.
  • The maximum distance between the repeater and transmitters is approximately 500m.

ISA100 wireless temperature and pressure transmitters with orifice plates allow:

  • No cabling installations or maintenance.
  • Small amount of hardware and simple equipment implementation means minimizing potential vandalism.

ISA100 Wireless Monitoring  

  • Gateway x1, Temperature Transmitter (YTA) x3, Pressure Transmitter (EJX) x1, Repeater x1

Gateway is installed at control room and 3m height extended antenna is set.

  • Temperature Transmitter (YTA) and Pressure Transmitter (EJX) are installed at each monitoring point.
  • Repeater is installed on high position.
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 Ground water well level monitoring is needed.

Application Note

Blending plays a key role in industries such as food, healthcare and chemicals etc. Temperature and vacuum measurements are very important in minimizing the moisture content to ensure the quality of the final product. Strictly maintaining them throughout the process ensures the final product yield.


Temperature plays a key role in storage of Molasses to maintain the chemical properties of molasses. When temperature rises over 40.5 degree C, destruction of structure in sugar occurs, which results in losing the feeding property of molasses. There is also a safety concern that a rise in temperature can lead to a rise in storage tank pressure leading to an explosion of the tank.

Application Note
  • Temperature monitoring at a tank farm
  • Temperature and pressure monitoring in tank jungles, three vertical monitoring points.

ISA100 Field Wireless transmitters


Direct Reduction Iron (DRI) is one of the processes to reduce oxygen from iron oxide pellets for steel plant. More than 90% of DRI processes use heated LNG as process gas where PID control for temperature or interlock control is of vital importance.


Customer needed efficiency improvement of steel manufacturing by temperature monitoring for heat/cooling equipment. Previous system required periodic compensation lead changing.

Application Note

An induction furnace melts metal by creating very large currents in the material. These currents are induced using three electrodes positioned inside the furnace. The furnace is automated so that once the material has been melted, the electrodes are removed and the furnace then tips the molten metal into a crucible where it can be easily transferred to the production line where it will be cast into ingots. The atmosphere is extremely aggressive and the wired infrastructure is both expensive and very unreliable to maintain. The furnace control requires a total of 20 measurement points distributed around and inside the furnace. The harmonic field effects caused by short circuit 40,000 A (300V). The causes significant interference.

  • Wireless temperature measurement 
    gateway x1, transmitter (YTA) x1
    repeater x1: between gateway and YTA.
  • High quality wireless communication was confirmed.
    With repeater at center: The packet error rate was 0%.
  • Oil level measurement of diesel tanks that feed fuel to their diesel generator's which are at three locations and 400 meters apart from each other.
  • Also to measure level , pressure and flow to and from their main storage yard.

ISA100 Wireless Temperature and Pressure Transmitters

  • Gateway x1, Temperature Transmitter (YTA) x1, Pressure Transmitter (EJX) x1

High quality wireless communication confirmed

  • Packet Error Rate (PER) is 0 to 2.5%/ 5 days

Caustic soda and hydrochloric acid, produced in electrolyzer plants, are fundamental materials used in varieties of industries; chemicals, pharmaceuticals, petrol-chemicals, pulp and papers, etc. Profit is the result of the effective production with minimized running / maintenance cost. Proper control of the process brings you stabilized quality of products with the vast operational profit.


Continuous technology improvement is ongoing in the pulp & paper industry to obtain the best possible performance. The improved plant performance translates to the higher quality improvement and lower cost, and simultaneously environmental friendly plant operation.


One important risk to manage with regard to coal stacks is preventing fires due to spontaneous combustion.

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The use of wireless technology in industrial automation systems offers a number of potential benefits, from the obvious cost reduction brought about by the elimination of wiring to the availability of better plant information, improved productivity and better asset management. However, its practical implementation faces a number of challenges: not least the present lack of a universally agreed standard. This article looks at some of these challenges and presents the approach being taken by Yokogawa.


Standards provide many benefits to the automation end user. Standards promote choice, interoperability, transparency and ensure that things work as they should (at least insofar as the standard is defined). The influx of wireless technology into the world of process automation has brought forth its own standard—ISA100—a major standards initiative managed by the International Society of Automation (ISA).


When distributed control systems (DCS) first appeared on the industrial automation scene in the mid-1970s, the focus was on control and operator interface. While control and human machine interface (HMI) are still important, today's DCSs have evolved to place increased emphasis on integrating plant-wide asset and operational information to enable operational excellence. 


Wireless trends: Choosing a wireless network requires evaluation of communication protocols, device availability, and present future user needs.


Temperature control of exhaust gasses coming off various combustion processes in refineries and related facilities is often critical to effective pollution abatement and compliance with applicable regulations. There are specific temperature windows where toxic gasses can form or other substances can condense, causing corrosion and other harmful effects, so operators need to make sure the process is running at the correct levels.

Stacks, chimneys and other gas handling equipment can take all sorts of forms depending on the application. Some may include scrubbers, gas cooling, chemical injection, afterburners or ambient air mixing—but a common element is the need for effective temperature measurement of the gas at various points in chimneys (Figure 1).

Given the length and height of a chimney, its associated ductwork and ancillary systems—there can be dozens of sensors inserted at strategic points from one end to the other—providing the process automation system and the plant operators with critical temperature data. These sensors are often in hard-to-reach locations where installation and maintenance are difficult. While these sensors are often spread over a great distance, they must connect back to one central point where the larger gas treatment system is controlled.

Figure 1. Chimneys found in refineries

Figure 1. Chimneys found in refineries and other hydrocarbon processing facilities often require temperature monitoring.

Monitoring a Refinery Main Chimney

At a refinery in the Americas, the main chimney is located 300 m away from the main control room, and there are about 30 temperature sensors mounted on the structure, the highest of which are 30 m above the ground. Wiring for such an installation was going to very challenging, so the company instead installed an ISA100 wireless network.

When the refinery was designing the system initially, it was clear the cost of individual wireless transmitters for each temperature sensor would be expensive and take too long to install. To alleviate these issues, the refinery selected Yokogawa YTMX580 Multi-Input Temperature Transmitters, each of which can accept up to eight individual sensors and send the data back via a single wireless transmitter (Figure 2). Each unit can accommodate a variety of RTD and thermocouple types to meet application demands.

This approach minimizes the amount of required wiring while also cutting the cost of the wireless infrastructure. Four of these multi-input transmitters are installed at the facility to service the group of temperature sensors, eliminating the need to add cabling to the control room. The plant’s wireless network backhaul infrastructure brings data from the chimney to the operators so they can monitor system performance in real time.

The success of this installation has given the plant the confidence to extend the ISA100 wireless network using Yokogawa’s Plantwide Field Wireless infrastructure.

Figure 2. YTMX580 Multi-Input Temperature Transmitter

Figure 2. Wiring temperature sensors installed in a chimney back to a control room can be challenging and expensive, so many plants and facilities are instead implementing wireless solutions, such as this Yokogawa YTMX580 8-input temperature transmitter.



The greatest advantage of native wireless field instrument and actuator devices is their lack of cables for data transmission or power. Eliminating these tethers also eliminates their associated costs in time and money for installation and ongoing maintenance. Companies have adopted the ISA100 wireless standard for a variety of reasons, but the most critical is its ability to support reliable communication in process manufacturing environments. ISA100.11a (IEC 62734) was designed through cooperation among device and system vendors working with process automation end-users to create a platform able to satisfy all involved. Figure 1 illustrates a typical device-level network topology using ISA100.11a wireless instruments.

Figure 1. A typical device-level network topology using ISA100.11a wireless instruments

Figure 1. The ISA100.11a network exists at the device level, supporting communications between field instruments and actuators.

Wireless field devices provide many possibilities for operational cost reductions along with improved performance and facility management. But in many existing plants, most field devices are already installed on wired networks, which often are not capable of providing all the information available from HART-compliant smart devices. Wireless can be used with new devices, but it can also extend the communication capabilities of existing instrumentation, realizing their diagnostic and other extended capabilities.

The User Case for Wireless Adapters

Unless there is something seriously wrong with existing wired networks, no end-user is going to rip out and replace working wired devices in a process plant. However, when new devices are added, the plant may decide not to extend the wired networks. New field instruments and actuators may be available as self-contained wireless devices, or they may only be made in a conventional wired version. Those of the latter category will need to be configured to communicate with a wireless network by adding a wireless adapter.

A wireless adapter can function in two modes. First, it can add complete wireless communication capability to a conventional wired instrument. All the data from the device can be sent via the wireless network without the need for any data cables.

Second, it can extend the communication capability of an existing wired device. Many wired device-level networks are not capable of communicating any information beyond the most basic analog signal representing the measured process variable. Smart devices installed on such a network cannot send the additional information they generate, stranding it at the source. Adding a wireless adapter allows it to send the additional information using the wireless network while continuing to use the wired network for the transmission of the process variable.

When an adapter is added to a conventional wired device, there are multiple powering options. The adapter can be outfitted with its own internal power supply and function independently. If the instrument needs power, the adapter can support it, eliminating the need for power cables.

Features of the Wireless Adapter

The Field Wireless Multi-Protocol Module is designed to work with HART-compliant field devices and provides a range of basic communication and operational functions:

  • Converts HART data into a format suitable to send via an ISA100.11a network,
  • Sends HART commands for configuration and troubleshooting,
  • Provides its own internal power for data transmission, and
  • Provides power for a device needing an external source.

Figure 2 shows an example of how to use the Field Wireless Multi-Protocol Module with HART-compliant devices. This adapter has all the necessary ISA100 communication functions built in and only requires connection to the field device.

Figure 2. An example of how to use the Field Wireless Multi-Protocol Module with HART-compliant devices

Figure 2. The Field Wireless Multi-Protocol Module can be connected to a HART-compliant device. The module mounts separately, allowing it to be positioned for most effective wireless propagation regardless of where the instrument is located.

Typical Wireless Adapter Applications

There are many ways in which the Field Wireless Multi-Protocol Module can be used in a process plant, but most applications fall into one of these categories:

Realizing full functionality of existing devices while saving on cabling costs, installation hassles, and future maintenance.

Most plants have large numbers of HART-compliant devices installed to monitor and control all manner of process variables (Figure 3). Most of these are connected via wired device-level networks. The Field Wireless Multi-Protocol Module converts these into ISA100.11a-compliant wireless devices without any modifications. If a plant or process unit requires renovation, the plant can decide to repair and maintain the wired network, or simply eliminate parts of it. If it costs $100 per meter of cable installation in explosion-proof zones, replacing just 100 meters of cabling with wireless means saving $10,000 in site work. In the case of a major plant upgrade, where sensing points are being removed or where aging cables must be replaced, wireless adapters allow the use of existing HART-compliant devices without cable reinstallation and maintenance.

Figure 3. Any HART-compliant field device can be mated with the Field Wireless Multi-Protocol Module

Figure 3. Any HART-compliant field device can be mated with the Field Wireless Multi-Protocol Module.

Extending wireless communication to conventional devices.

Companies embracing wireless field devices and networks may be constrained by the limited selection of native wireless devices available today. While the range of choices is growing, some types of devices, particularly those with high power consumption, are only available in conventional wired configurations. In such cases, the Field Wireless Multi-Protocol Module can convert any wired HART-compliant instrument or actuator from any vendor to wireless.

Gathering and sharing data from smart devices. 

While the process variables from HART-compliant devices in an existing plant are sent to the plant’s automation system through the field device network, other information, such as device condition information and other diagnostic capabilities, can be of great value to the maintenance department. It can collect and manage such data, and use it when analyzing maintenance schedules, maintenance records, repair parts usage, and so on. If the existing wired field-device network cannot extract that information and collect it for sharing interdepartmentally, those gains cannot be realized. Upgrading the network can be a complex and costly undertaking, but the information can be sent via the wireless adapter. Adding a Field Wireless Multi-Protocol Module allows maintenance department to capture HART commands and diagnostic information from the 4-20 mA line with little change to the installation. The adapter can work with two-wire and four-wire device types. In case of four-wire devices, an external power source can be connected to the device, making it easy to support devices with high power usage.

Deploy HART-compliant devices in remote areas where no data or power cables are available.

The Field Wireless Multi-Protocol Module can extend power to an external device, which makes it simpler to deploy HART-compliant devices in locations where wired field-device networks don’t reach and where no power may be available. Under favorable conditions, the adapter can cover a distance up to 500 m in any direction, and more than 1 km if routers are used. For example, combining a HART-level instrument with a Field Wireless Multi-Protocol Module provides a means to measure the water level of rivers and reservoirs (Figure 4). And since the adapter weighs less than 1 kg including its batteries, it and its connected HART-compliant device can be moved easily, enabling flexible measurement point changes.

Extend wireless network range by acting as a router.

In situations where distances between wireless field devices are very long or where large metallic structures create barriers to effective wireless signal propagation, a Field Wireless Multi-Protocol Module can be used as a router to relay communication to and from other wireless field devices (Figure 4). Another ISA100.11a native wireless instrument can serve the same function, however, in many situations, it may be easier to use an adapter as a dedicated router since it is light and compact. It can also be located strategically to fill out the network most effectively.

Figure 4. A Field Wireless Multi-Protocol Module can be used as a router to relay communication to and from other wireless field devices

Figure 4. The geographical coverage of a network can be extended by adding routers to relay signals and reinforce weak sections of the mesh. Routers can be located wherever they can do the most for the network, separate of any specific instrument.


The Field Wireless Multi-Protocol Module is designed to convert existing wired HART-compliant instruments and valve actuators into wireless devices. It provides flexibility to add new devices in existing plants using wireless field-device data networks, reducing cabling installation and maintenance costs. It also expands the types of wireless sensors available and simplifies device installations. Many plant operators find the wireless adapter to be a useful device able to help existing plants enjoy the benefit of wireless sensing.


One of the first steps when creating a new wireless instrumentation network using ISA-100 wireless, or any other industrial wireless network, is a site survey. This step is not part of any wireless standard, nor is it likely part of any network management platform, so it requires some creativity. Radio propagation patterns can be difficult to predict, but following a few basic design guidelines ensures a much higher level of success.

Some wireless consultants make the process very complex using simulations and reading test signals, but these often do not ultimately match the real world. Other approaches are simpler and involve taking a few distance measurements and establishing sight lines, which often works just as well. For this article, we will concentrate more on the latter, simpler approach.

ANSI/ISA-100.11a-2011 (IEC 62734), Wireless Systems for Industrial Automation: Process Control and Related Applications, networks are designed to support wireless field instrumentation. This protocol specification is part of the larger ISA-100 wireless series. Although network management platforms have an extraordinary capability for self-organization, this feature cannot overcome unreliable radio links.

But, the network management platform can use its diagnostic capabilities to measure the health of the communication and the devices. It can identify unreliable links so they can be fixed, and with improved communication, the network manager can reestablish a reliable link.

How Signals Propagate

Although it is not a perfect model, thinking of radio in the same way as visible light is accurate much of the time. Wireless networks depend largely on line of sight (LOS). If a wireless flow meter is trying to transmit to a gateway in its LOS, the likelihood of a good link is very high. More potential obstructions are transparent to radio frequencies than visible light, but this is affected by frequency. A leafy tree is transparent to signals at 90 MHz, but 2.4-GHz signals will suffer some attenuation.

Metallic objects are the great enemy of radio propagation, but can also help under the right conditions, which is why refineries and chemical plants provide many challenges for wireless networks. In one case, a steel-shell storage tank can be helpful by reflecting a signal, while other times it is as an obstacle. Like visible light, much depends on the surface angles.

General wireless principles say to avoid metallic surfaces when placing antennas for field devices, such as process instruments and actuators, routers, and gateways. The best situation is to mount the antenna vertically so that it is unobstructed on all sides (figure 1). If a gateway is mounted next to a metallic pole, the signal will be attenuated, even on the side away from the pole. It is far better to move the antenna to the top of the pole, so it can extend into free space, or to extend the antenna mounting horizontally, so there is at least a 1-meter gap between the antenna and the pole.

Figure 1. The best signal propagation

Figure 1. For the best signal propagation, each antenna should be mounted vertically with at least 1 m of clear space around it horizontally. This normally means mounting the antenna as high on a structure as possible.

Understanding the Fresnel Zone

Elevated antenna placement is important, because radio communication does not move in a tight beam like a laser. To send the signal from one point to another efficiently, some area in the shape of an ellipse is required. This area is called the Fresnel zone (figure 2). The amount of room available for the signal to spread has a huge effect on signal strength and the distance it can carry, since the longer the distance, the fatter the zone needs to be in the center. Anything violating the zone, which could even be the ground itself, attenuates the strength. Therefore, trying to squeeze a signal through a narrow space, even though it may allow direct LOS, can result in signal attenuation.

For example, where the LOS side clearance has an open space with a radius of 4 m, the communication range can be 500 m. However, when trying to send the signal through a more constricted area where the open space radius is only 2 m, the effective distance will be cut by 75 percent to 128 m. Having open, unobstructed space makes a huge difference, but this is typically a problem in most congested plant environments. This is why mounting devices and antennas as high as possible is so important.

Figure 2.  The Fresnel zone area

Figure 2. Radio waves tend to propagate through an elliptical space formed between the two antennas. The longer the distance, the larger the required diameter at the center. This space should be as unobstructed as possible to avoid signal attenuation.

Meshing vs. Routing Devices

ISA-100.11a has mechanisms for device-to-device meshing, but the more desired network topology is one where a field device can communicate directly with the gateway, or directly to a router connected to the gateway (figure 3). The goal is to avoid the need for meshing device-to-device, because sending signals between multiple field devices slows down data movement and taxes the devices' batteries.

To facilitate these transmissions, gateways and routers should be mounted as high as practical to clear any surrounding equipment and permit clear LOS connections. My company calls this practice of having a mesh of routers communicating above the plant equipment a sky mesh, and it takes advantage of more powerful transmitters than are practical for individual wireless field devices.

Placement of individual field devices is not as simple. Most native wireless devices, such as a differential pressure instrument, have an integral wireless transmitter and antenna (figure 4). This is very convenient, but can complicate signal propagation. Placement in the process piping or vessel often dictates where the device must be mounted, the antenna orientation, and the surrounding obstructions. Using an antenna extension can address these issues. Another alternative is to add a router mounted as near to the instrument as possible and clear of obstructions. If more than one instrument is in the same difficult location, a single router can service a group.

Figure 3. Desired network topology

Figure 3. The gateway is the end point of the network, and is connected to the control and monitoring system via hardwiring. Routers serve as relay points, gathering information from the field devices and passing it to the gateway.


Figure 4. Placement of individual field devices

Figure 4. Having an antenna mounted on the field device is common, but placement of the field device may put it in a location prone to interference. An external add-on antenna may be needed to improve communication.

Laying out a Network

Most networks are designed from two ends, the field and the control room. Field devices must be located according to their process function, which could easily be in a congested pipe jungle where equipment interferes with clear signal propagation. The final gateway is often placed near the control room, because it is hardwired to the control system. The network must bridge this gap.

Creating a sky mesh requires finding where it is practical to place routers. Ideally, these should be high off the ground and as close to the individual field devices as possible. Ensuring reliable communication between the field devices and the nearest sky mesh router may involve a secondary router in between to compensate for signal loss.

In most process plants, it is not difficult to find tall structures, such as distillation columns, but they may not be located where they are useful for router placement. Positioning antenna to avoid signal blockage problems associated with such large metallic structures can be tricky. As a rule of thumb, if the router is placed 30 m above the ground, it can reach individual field devices close to ground level up to 50 m away (figure 5). This assumes a few beneficial reflections, balanced against some obstructions from piping.

The connection from each field device to the closest router is the most challenging because it often has the most obstructions. Communication between routers and the gateway is easier to visualize and evaluate, since those components are mounted higher above the process equipment in more open space.

Figure 5. Routers in high positions

Figure 5. Routers in high positions can reach down to communicate with field devices closer to ground level. The practical area of coverage under favorable conditions is roughly a 90º to a 100º cone, with the router as the cone's apex.

Evaluating Performance

The two most common measures of network performance are bit error rate (BER) and packet error rate (PER). The former uses predetermined bit patterns to check which are received incorrectly, a process requiring dedicated software on all the field devices, routers, and gateways. It must be performed as a specific test, sending the designated patterns.

PER performance measurements, on the other hand, deal with complete packets and can be done without special tools during normal communication. If a problem is developing, there will be a detectable change in the PER.

The most important indicator is determining how often packets get through correctly the first time. Getting the PER as low as possible is the objective, but this can only be done when all radio links are working reliably.

A well-designed ISA-100.11a wireless instrumentation network can operate as dependably as wired I/O in most applications. When the communication links connect reliably, latency will be minimized, allowing control room operators and other plant personnel to have all the information they need in a timely manner.


Media Publication
Leverage Wireless Communication for Vibration Monitoring
(Leverage Wireless Communication for Vibration Monitoring)
Yokogawa Technical Report

The introduction of wireless into industrial monitoring and control not only reduces wiring and maintenance costs but also expands its applications to include those which are impossible with wired systems, such as monitoring points which have to be given up due to the difficulty of the construction, and monitoring of points on rotating or frequently moved objects.

Yokogawa Technical Report

Yokogawa has been leading the process automation industries as one of the pioneers in field digital technologies represented by the FOUNDATION fieldbus™ and Field Device Tool/Device Type Manager (FDT/DTM).

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