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Strategic implementation of wireless

technologies

By Brent E. McAdams

FAST FORWARD

y Key drivers associated with adopting wireless technologies and how the evolution inwireless technologies has opened the door to a new class of automation architecture thatoffers adopters a significant strategic advantage.

y The advantages of spread spectrum over fixed frequency licensed radio transmissions anddetermining whether new systems may interface with existing systems for the purpose ofpreserving investments in existing infrastructure.

y Applications and benefits of wireless technologies for a successful wireless architecturesolution.

The evolution in wireless technologies has opened the door to a new class of plant automationarchitecture that offers adopters a significant strategic advantage. Driven by substantial andmeasurable cost savings in engineering, installation, and logistics, as well as dramaticimprovements in the frequency and reliability of field data collection, automation experts and ITprofessionals are presented with an opportunity to deliver a major, positive impact to theirrespective companies bottom line.

In terms of the key drivers associated withadopting wireless technologies, the cost benefitsare the most intuitive. However, anotherimportant consideration is safety. Some of thekey drivers include:

y Installation savings: Installation ofwirelessly connected assets is up to 10times cheaper than the wired alternativeand offers much faster startups and

accelerated profits. In addition to theinstallation savings, engineering costs aredramatically reduced as extensive surveys and planning are no longer required to routewire back to junction boxes or control rooms. The reduced costs in wiring engineering,installation, and maintenance, combined with the increased data gathering flexibility, isthe primary driver for wireless migration.


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y Better information: Replacement of manual readings with automated measurementresults in information that is more accurate, timely, and consistent.

y Economy of scale: Deployment of additional points in a network is incremental and mayinclude integration into legacy systems.

y Operational savings: The ability to quickly diagnose and troubleshoot plant operationsand support predictive maintenance programs by monitoring facility assets. Additionally,identify costly problems leading to excess use of energy or raw materials.

y Safer operations: By reducing human exposure to hazardous environments. Also, morefrequent measurements and early detection of issues can help reduce or even preventincidents or accidents.

Unfortunately, there is no one type of wireless technology that solves all problems. Therefore, inorder to maximize the return on industrial wireless networking investments, companies must be

able to select the best technology for a given application.

By evaluating the attributes of various wireless technologies, essential technology decisions canbe made to guarantee the successful implementation of a wireless architecture solution. Theseattributes include the RF technology itself, security, interference rejection, sensitivity, powermanagement, and the ability to embed wireless into existing OEM technologies. Furthermore,the determination needs to be made whether new systems may interface with existing systems forthe purpose of preserving investments in existing infrastructure. Determination might also bemade with respect to the radio providers commitment to backward compatibility to extend thelife of the system and drive down the overall lifetime cost of implementation.

Licensed vs unlicensed

In 1985, the Federal Communications Commission (FCC) issued rules permitting use in theIndustrial, Scientific and Medical (ISM) Bands (902-928MHz, 2.4-2.4835 GHz, 5.725-5.85GHz) at power levels of up to one Watt without end-user licenses. There are two very commonspread spectrum modulation methods used in these bands: Frequency Hopping (FHSS) andDirect Sequence (DSSS).

FHSS

Rather than transmitting over a static spectral segment, FHSS radios pseudo-randomly vary

carrier frequency, quickly hopping through multiple channels while sending data. Interference isavoided by hopping over different frequencies, each of which has a different interference effector characteristic. This provides FHSS with collision-free access by allocating a specific time slotand frequency for its transmission. A frequency-hopping scheme, combined with error detectionand Automatic Repeat requests ensures the data is reliably delivered. Further, with FHSSsystems, it is anticipated there will be competition for the airwaves, so interference avoidanceand management are designed into the system. Other modulations are more susceptible tointerference because they do not anticipate interference by design.


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DSSS

Direct Sequence spreads a narrow-band source signal by multiplying it with a pseudo-randomnoise signal. The resulting signal is then spread over a large range of continuous frequencies.This introduces redundancy into the transmission, enabling a receiver to recover the original data

even if parts of it are damaged during transmission.

Licensed

In addition to the unlicensed ISM Band, licensed radios operate in the UHF and VHF bands, andas the name indicates, users must purchase a site license to operate radios in a specific area.Consequently, these systems can be expensive to setup and offer slow data rates (i.e., typically 9600 kbps), which are not likely to support industrial data communication requirements in thefuture. However, UHF/VHF radios are allowed higher transmit power, which increase the range,and because they operate at lower frequencies, they typically have better propagationcharacteristics. However, one of the drawbacks of a licensed system is only one system canoperate at that location. Therefore, overlapping networks and other communication capabilitiesusing the same frequency band is not possible.

Spread spectrum advantages

Spread spectrum has two significant advantages over fixed frequency licensed radiotransmissions. The first is no FCC license is required by the user. Even though licensed spectrumis available, the user must go through the process of obtaining the license. Once obtained, theyare good for a single site and have a defined term.

The second advantage spread spectrum, specifically FHSS, has over fixed frequencytransmission is spread spectrum radio transmissions are far less susceptible to interference. In anindustrial plant environment, machinery and other equipment generates interference over a verybroad spectrum of frequencies. Therefore, if one frequency is affected in a FHSS system, forexample, the data is quickly transmitted over another, clear channel. This gives the technique


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greater coverage, channel utilization, and resistance to noise than comparable direct sequencesystems. A licensed solution has no such capability.

FHSS characteristics

FHSS technology has immediate advantages in terms of security, immunity to interference,robustness, and network reliability.

FHSS systems were originally designed for military applications during World War II. The veryimpetus for these systems was data security and interference avoidance that existing fixedfrequency systems could not reliably provide. Concerns about the integrity of signal transmissionand reception are prevalent amongst adopters who are worried about leaving their control andbusiness networks vulnerable to hacking or denial of service attacks. In fact, the issue of securityis widely seen as the most significant barrier to industrial wireless adoption.Since, as the radios communicate, their communication frequency is changing rapidly (as muchas 1,000 times per second), FHSS provides an additional layer of security and makes

transmissions very difficult to detect.T

o outside listeners, transmissions simply look like noisespread over the spectrum, with only a small signal at any one given frequency.

This technique assures the integrity of the data, because without the hopping sequence, nooutside sources can listen to a communication. This technique also allows communications tocontinue even if a number of the frequencies in the 26MHz band are blocked. The devicessimply hop to another frequency.

Additional data security is gained through 128bit and 256bit Advanced Encryption Standard(AES). The AES algorithm uses an encryption key (password). Each encryption key size causesthe algorithm to behave slightly differently, so the increasing key sizes not only offer a larger

number of bits with which you can scramble the data, but also increase the complexity of thecipher algorithm.

Data integrity

As with existing data transmission over wire, Packet Protocol Acknowledgment is supported byerror checking. Error checking is designed to ensure the data received by any spread spectrumradio is not forwarded from its buffer until it is acknowledged as a correct transmission,guaranteeing what is received is identical to what is sent. In order to accomplish this, CyclicRedundancy Check (CRC) is generated giving the packet a unique digital signature.

Data packet

The probability of detecting any random error increases as the width of the checksum increases.Specifically, a 16-bit checksum will detect 99.9985% of all errors. This is far better than the99.6094% detection rate of an eight-bit checksum, but not nearly as good as the 99.9999%


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detection rate of a 32-bit checksum. With a 32-bit CRC, there are over 4 billion possible CRCvalues. To be exact that is 232 or 4,294,967,296. By comparison, the commonly used 16-bitCRC offers a chance data error in one in 65,536 transmissions (216), a relatively small numberof transmissions in a work cycle, especially given that many radios transmits packets as often as50 to 100 times per second.

Sensitivity

Receiver sensitivity is an important specification to consider. The more sensitive the receiver, theweaker the transmitted signal can be yet still get through. In other words, the distance andobstructions between a transmitter and receiver can be greater.

One reason receive sensitivity may be confusing is it is expressed in a unit of measure known asa decibel (dB). A decibel is a ratio expressed on a logarithmic (exponential) scale. A 10:1 ratio is10 dB, and a 2:1 ratio is 3 dB. A 1:1 ratio is 0 dB, while ratios of less than 1:1 are expressed asnegative numbers. For example, a 1:2 ratio equals -3 dB.

Because receive sensitivity indicates how faint a signal can be successfully received by the radio,the lower power level, the better. This means the larger the absolute value of the negativenumber, the better the receive sensitivity. For example, a receive sensitivity of -110 dBm isbetter than a receive sensitivity of -107 dBm by 3 dB, or a factor of two. In other words, at aspecified data rate, a receiver with a -110 dBm sensitivity can hear signals half as strong as areceiver with a -107 dBm receive sensitivity.

Fresnel Zone & antennas

For the shorter range installations in industrial facilities, a common question is, Is line of sight

required for all radio links?T

he answer is often, no, but radio waves can travel through avariety of objects with different levels of attenuation. The area over which the radio wavespropagate from the antenna is known as the Fresnel Zone. Like the waves created by throwing arock into a pool of water, radio waves are affected by the presence of obstructions and may bereflected, refracted, diffracted, or scattered, depending on the properties of the obstruction and itsinteraction with the radio waves. This is often how the signal gets to the receiver when there isno line of sight. However, this effect attenuates the signal, and affects how a radio will operatewithout line of sight.


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Proper use of antennas and the ability to adjust output power provide a great degree of assistancein overcoming these issues and getting messages through. Industrial quality directional and high-gain omni-directional antenna allow the radio communications at long distances through acrowded industrial facility. At the same time, the use of low-gain antennas can be used to keepradio signals from straying unwanted distances or directions.

Flexibility

With many existing wired networks, the user is locked into using only one particular protocolsimultaneously. Alternatively, by using wireless architecture, several protocols operating overthe same communications layer is possible given the user greater flexibility.

Any wireless device needs to tie into existing control systems. Getting information into themyriad of existing control systems is not a small task. The 420 mA signal and switch closuresare universally translatable. Digital input allows more data flow at significantly lower cost, butgenerally adds a level of complexity to any system. Modbus and OPC servers offer degrees of

acceptance where large data flows are required.

Temperature range

Products intended for industrial applications should use industrial-rated components andtherefore reliably operate over industrial temperature ranges (-40 to +75C). Temperatureextremes are commonplace in many applications. In addition, these products are generally betterconstructed than consumer devices and continue reliable operation under shock and vibrationconditions.

Operation in hazardous environments

Industrial wireless modems typically carry some form of UL certification. Most commonly thisUL certification is for Class 1, Division 2 environments, which permits radio operation in thepresence of flammable or explosive gases, fluids, or vapors. Having this certification is alsobeneficial because a company can standardize on a single type of device, and use it for manyapplications, regardless of the environment.

Applications

y Wireless I/O:Asset information is available from applied and embedded sensory pointsenabling sophisticated diagnostics, remote monitoring and control, and plant

optimization.T

he form factor of wireless devices allows for easy integration into existingOEM technologies and housings.

y Safety: Environmental alarms and personnel management allows for greater safety andcompliance with OSHA regulations, especially in dangerous environments and inlocations where the plant is in close proximity to residential areas. Also, completelyunmanned first response systems are now available limiting human exposure in the eventof a release or catastrophic incident.


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y Security: Detect intrusions, control access, report smoke/fire, or perform videosurveillance within the facility.

y Workforce mobility: Wireless connectivity allows mobile workers to access theirapplication and perform their job where they work. Whether it is logging data or

managing operations, worker mobility impacts productivity and efficiency.

y Mobile asset and material tracking: Tracking asset location allows for better use ofassets as well as regulatory compliance for the use, storage, and transport of hazardouschemicals.

y Integrated technologies: Wireless sensor networks, or Mesh Networks, represent anemerging technology that has great potential for widespread applications. These networksconsist of a large number of simple nodes with limited power sources and functionality,but they offer greater utility than the sum of those individual nodes. Greater flexibilityand connectivity may be achieved by integrating these networks with other wireless

technologies.

Summary

Information is power. As such, the ability to gather time-critical information, digest it, and reactupon it is the key to continuously adapting to change with increasing reliability and profitability.No one type of wireless technology solves all problems. Therefore, it becomes very importantthat the necessary monitoring, management, and security capabilities be evaluated to ensure thewireless architecture selected maximizes limited resources, while at the same time allowing thedisparate applications to share the spectrum within the context of their importance, timesensitivity, and mission criticality.


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Wireless Horizons

-- 1 October 2010

Madanmohan Rao provides a comprehensive round-up of developments in thedynamic world of industrial wireless technology.

In my annual wireless review column two years ago, we

identified key emerging issues such as industrial LANs,

standards, green wireless, vendor M&A and learnings from

sectors like energy. This year, we revisit these themes and

explore some new ones, such as wireless robotics in

industrial plants, and convergence between traditionalcorporate office IT roles and plant networking practitioners.


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Key features for industrial wireless solutions will continue to be ultra low

power consumption, robustness against physical and electrical interference,

self-configuration, openness to WAN and complementary wireless

technologies, configuration in tree, star and mesh network topologies, design

for multiple network co-existence, and developer APIs with productdevelopment toolkits.

The wireless machine-to-machine (M2M) world is also evolving rapidly with a

growing number of devices connected to each other in various types of

industrial and domestic networks. Using scalable wireless mesh networking,

wireless products should be able to handle configurations scalable up to any

size.

M2M wireless (including industrial applications) is sometimes regarded as the

third wave of wireless, after office-based (Wi-Fi) and consumer based

(mobile) communications.

Sometime soon, the five billionth device will connect to the Internet, according

to IMS Research. And the overall number of connected devices will quadruple

over the next 10 years.The research firm projects that in 10 years, there will be six billion cell

phones, most of them with internet connectivity. An estimated 2.5 billion

televisions today will largely be replaced by TV sets that are internet capable,

either directly or through a set-top box. Yet, the greatest growth potential is in

machine-to-machine, according to IMS president Ian Weightman.


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Demand for wireless sensor networks (WSN) is showing significant growth

following a period in which adoption was impacted by the economic

downturn. In 2009, 802.15.4 chipset shipments were down almost 30 percent

compared with the previous year, according to a recent ABI research report

on the WSN market.Because they are based on emerging technology, wireless sensor network

adoption suffered during 2009 as pilots and early projects were scaled back or

put on hold. However, 2010 has seen a significant rebound and strong

shipment growth, according to ABI research principal analyst Jonathan

Collins. Indeed, a strong uplift in shipments in 2010 will help drive growth

from a little more than 10 million chipsets in 2009 to 645 million in 2015,

which equates to a CAGR of 99.6 percent.

Ethernet everywhere

Ethernet is now being increasingly used for industrial applications, in linewith standards IEEE 802.3 (Ethernet) and 802.11 (wireless LAN). Flexible and

efficient communication networks with a wide range can be installed via

Ethernet.

And it is also making inroads into the domains of other industrial networking

products, thanks to its stability, speed, bandwidth, flexibility and

communication management. ARC Advisory Group has pegged the market for

industrial Ethernet at more than three million nodes by 2012.

When industrial heavyweights take M2M seriously, practitioners can expect

economies of scale to kick in (and some amount of vendor lock in as well!),

according to Pike Research industry briefs.

For instance, Cisco and Itron are collaborating on standardized IP-based end-

to-end platforms for smart meter hardware, leveraging IPv6 for interoperable

RF mesh field area networks. The IETF is also working on an IP-based ZigBee

stack version as part of its Smart Energy Profile 2.0 feature. Smart grids will

soon make their way to industrial plants as well.

The next-generation IEEE 802.11n wireless communication standard is more

reliable and supports greater bandwidth and speed, recommends BillWotruba, director of networking and connectivity products for Belden. It

helps to minimize common connectivity and throughput problems, such as

when an antenna is partially obstructed by moving objects.

IEEE 802.11 has new security enhancements, such as AES encryption and WEP

authentication, which alleviates some concerns. A single wireless system can

support multiple devices and protocols with common security.


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Green IT

Wireless industrial applications are a cutting edge of the green IT

movement. From data centers and desktops to mobiles and mesh networks,

the green movement is on the radar and balance sheets for IT and

communications professionals.

The fastest-growing and arguably most attractive segment in alternative

energy and energy efficiency lies in hardware, software and networking

equipment, according to Silicon Investor magazine.

Industry heavyweights such as Honeywell and Johnson Controls are now

joined by start-ups such asD

aintree Networks, Adura Technologies andEchoFlex in pushing the frontiers of M2M applications in areas like integrated

solutions and smart energy.

Given the potential ubiquity of such wireless nodes in industrial spaces, low

battery cost and maintenance costs are critical for network planners hence

the importance of ultra low power wireless networks. The biggest technical

challenge for developing these ultra low power sensor networks is managing

the energy consumption without reducing range or functionality, like speed

and standards compliance, according to Greenpeak Technologys CEO Cees

Links.


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By using a hardware based scheduler and synchronizer within the chip itself,

the radio only wakes up as needed to see if there is any data that needs to be

sent. If not, it returns to sleep. If there is data to be sent, the controller then

wakes up the microcontroller. The chip then communicates the information

and then goes back to sleep until the next time it is scheduled to wake, heexplains.

Robotics... unplugged

Robotic applications in industry reached the peak of the hype cycle in the

1990s, but are making a quiet come back now. Strong manufacturing is one of

the keys to global economic recovery, and manufacturing agility and

rationalization on all aspects of technology will be a modest part of this

recovery. Robotics rejoins wireless control engineering as one of the frontiers

of industrial plant revitalization.

For instance, by installing remote maintenance and diagnostics software on an

industrial robot welding machine, companies like Sims are able to remotely

monitor and control it using secure wireless connections.

This solution is based on eWON's Talk2M (Talk to Machines), an internet-

based remote maintenance and diagnostics service ramped up to meet the

security, reliability and traceability levels required by industrial applications.

The eWON range of industrial routers complies with a range of serial andEthernet-based modules including Siemens, Rockwell Automation, Schneider

Electric and Omron.


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ABB has introduced a robot controller for robot cell applications, with

interactive displays and unified development environment for configuration,

debugging and visualization. ABB Robotics is active in metal fabrication,

foundry and electronics industries, and claims to have installed more than

175,000 robots worldwide.After the past couple years serious sales slump, the industrial robotics

industry is beginning to rebound, according to data from the Robotic

Industries Association (RIA). Recent installations provide examples of the

many ways in which automation is being employed to increase efficiency and

productivity, reduce costs, and improve product quality.

Vendor advances

A number of vendors are rolling out modular offerings in M2M wireless. For

instance, Radiocrafts has expanded its IEEE 802.15.4 product line with two

new modules, the low cost RC2400 and RC2400HP. They are designed forZigBee PRO, 6LoWPAN and other protocols based on IEEE 802.15.4. Typical

applications include smart meter reading, automation, and sensor grids.

Wireless applications are being rolled out not just for industry environments

with high temperature and toxic fumes but also those in the open and exposed

to rains. For instance, RFID provider IDTronic has developed Gen 2 RFID chip

solutions that are completely waterproof.

Zebra Technologies has announced a new RFID printer-encoder; RFID tag

manufacturer Xerafy, headquartered in HongKong, has new tagging solutions

as well. UbiU, an RFID solutions provider in South Korea, is also focusing on

data management and integration solutions. As the RFID market is growing,

so is the demand for middleware in various industries," says UbiU manager

Brian Son.

Companies such as PCN Technology - active in industrial automation, control

and energy systems have products that allow the multiplexing of a variety of

communication protocols. This helps customers quickly leverage installed

infrastructure for multiplexed controls, automation, and Internet networks,

according to Venkat Shastri, PCNs CEO.While much M2M attention has focused on short-range communications,

companies like AvaLAN Wireless are also addressing long range industrial

wireless radio technology for robotics, industrial automation, access control

and smart grid markets. There are always good niches in areas like high

interference indoor applications and long distance outdoor applications.


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Tyco Thermal Controls TraceTek technology enables wireless monitoring of

valves, which the company claims can result in up to 60 percent total system

cost savings thanks to features like leak detection. And Wavenis from Clarke &

Severn Electronics offers an optimized ultra low power and long-range

wireless solution for M2M applications.On the mergers and acquisitions front, distributed enterprise network

solutions provider Aruba Networks has recently acquired Azalea Networks, a

supplier of outdoor mesh networks. The acquisition includes an operations

center in Beijing which will complement Aruba's existing R&D centers in

Bangalore and Silicon Valley. Azalea Networks offers mesh products for

critical industrial applications in the oil and gas, manufacturing and smart

grid sectors.

Some of these vendor advances are finding practical implementation across

Asia as well. For instance, Mahindra Vehicle Manufacturers greenfield plant inPune, India, includes a wireless solution based on Rockwell Automations

industrial Ethernet protocol and ProSoft Technologys wireless

communication systems for real-time control and synchronization

capabilities.

In central Asia, plant wireless specialist Emerson Process Management is

expanding its presence in countries such as Azerbaijan, via a partnership with

Russian company Balteks; future countries targeted will be Belarus, Ukraine

and Kazakhstan. In the same sector, another regional player, Yokogawa

Electric Asia, recently clinched the Manufacturing Excellence Award (MAXA),

the most prestigious manufacturing accolade in Singapore.

RFID renewal

Another entry into industrial and logistics wireless applications is via RFID, as

in a number of Asian airports. For instance, the Asia Airfreight Terminal at the

Hong Kong International Airport has deployed RFID for cargo handling,

documentation processing and other services.

Australian technology firm Wi Protect offers tracking technology which is a

mix of active RFID

and ZigBee for wireless data transfers. Real-time trackingsystems can reduce data error and improve process efficiency, according to Wi

Protect general manager Jonathan Elcombe.


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ThinkMagic CEO Tom Grant cautions that RFID uptake has been uneven and

subject to marketing hype and a series of false starts. The realization of that

vision was dependent on the availability of a family of embeddable RFID

radios, he observed in a trade press interview. Multi-scale radio

communication devices should co-exist along with the need to link RFID withother modes such as GPS, Wi-Fi and Bluetooth.

New members are also signing up to join the RFID Consortium, a group of RFID

vendors that hold patents essential to the development and use of ultra high-

frequency (UHF) RFID products that leverage standards defined by EPCglobal

and the International Organisation for Standardization (ISO). Members

recently signed up include the Electronics and Telecommunication Research

Institute (ETRI).

ZigBee buzz

The ZigBee Alliance now has close to 350 institutional members around theworld, and industry enthusiasts even call ZigBee a global wireless language!

ZigBee vendor Ember Technologies has now made it to the Inc 5000 list of Inc

magazine for emerging companies, thanks to its offerings in security

monitoring and automation. Boston-based Ember also has an office in Hong

Kong. In May 2010, Ember announced that it had shipped 10 million

ZigBee chips, the first company to achieve the milestone. And the companys

revenue is on track to grow by more than 300 percent this year compared to

2009, according to CEO Robert LeFort. Ember also has 50 million energy

meters in the US under contract to put ZigBee in them, according to Skip

Ashton, senior vice president of engineering at Ember.

Meanwhile, Atlantik Elektronik now has a new line of XBee and XBee-PRO ZB

embedded ZigBee modules based on the EM357 System on Chip. Such

additions can facilitate integration with embedded microcontrollers lowering

cost of development and shortening time to market.

Freescale Semiconductor, a leading supplier of IEEE 802.15.4 chipsets,

recently announced the MC1323x system-on-chip device family for ZigBee

RF4CE electronics. RezaK

azerounian, senior vice president and generalmanager of Freescale's Microcontroller Solutions Group, expects ZigBee

wireless applications to continue their rapid growth.

Other niche players emerging in areas like ZigBee-based realtime location

systems (RTLS) are Skytron and Awarepoint.

Standards spotlight


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In the in-plant wireless arena, the ISA100 Wireless Compliance Institute (WCI)

recently announced certifications of six ISA100.11a wireless devices

conducted for National Technical Systems. They cover pressure transmitters

and temperature transmitters. Such certification can facilitate broad market

adoption, according to Andre Ristaino, managing director of WCI.The ISA100 Wireless Compliance Institute (WCI) is a nonprofit industry

organization providing users and developers with market awareness,

educational information, technical support, and compliance for the ISA100

family of universal industrial wireless standards.

The ISA100.11a industrial wireless networking standard is the first in the

ISA100 family of standards. It helps supplier companies build interoperable

wireless automation control products. As a result, manufacturing sites are

able to create, modify, optimize, and scale a wireless network quickly, cost-

effectively, and seamlessly. Planned additions to the ISA100 a family ofstandards include support for backhaul functionality and factory automation.

Institute members include end users, technology suppliers, research and

development professionals, academia, and other industry consortia and

standards bodies. Early members include Chongqing University of Posts and

Telecommunications, Fuji Electric, Apprion, Honeywell, Nivis, Shengyang

Institute of Automation, Yamatake and Yokogawa.

As for WirelessHart, an estimated 30 million devices around the world use the

wireless based Hart protocol in process applications, according to industry

observers. This has been ratified as an international standard (IEC 62591) and

at least at the moment, there appear to be two competing standards for

process industry applications, i.e. ISA100.11a and WirelessHart.

One of the networks leading proponents, Emerson Process Management, has

introduced a WirelessHart vibrating fork liquid level switch, which reportedly

allows level detection to be made in locations previously inaccessible or too

costly for wired devices. Emerson claims the switch will not be disrupted by

the usual factors of flow, bubbles, turbulence, foam, vibration, solids content,

coating, liquid properties and product variations.


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Typical applications include overfill protection, high and low level alarms,

pump control (limit detection) and pump protection or empty pipe detection.The Rosemount 2160 switch is a component of the companys PlantWeb

digital architecture solution.

In some implementations, WirelessHart self-organizing mesh networks have

enabled switches to automatically find the best communication path, with

greater than 99 percent data reliability.

Emerson offers a range of IEC 62591 (WirelessHart) certified wireless field

instrumentation and plant wireless network hardware. These include MPM

(machine position monitoring) and MHM (machinery health management)

devices and wireless interfaces.

Practitioner checklists

When it comes to M2M, practitioners should make sure that new modules of

any vendor offerings offer backward compatible with existing hardware and

software, allowing them to leverage their existing deployments.

Advanced metering infrastructure (AMI) has tremendous and far-ranging

potential, according to Bob Heile, who is a member of the IEEEs 802.15

Working Group on Wireless Personal Area Networks, P2030 Work Group Task

Force 3 and chairman of the ZigBee Alliance.

However, the quantity of data being generated, collected and analyzed in the

M2M world will be orders of magnitude greater than before, he cautions. Not

surprisingly then, there are a whole range of start-ups and analytics services

emerging in areas like meter data management (MDM).


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AMI is of no value to the utility or its customers unless it develops into

something much more than an interesting IT challenge, Heile urges. The

higher-level strategic concern of MDM is converting high-quality data into

timely business intelligence that companies can actually use to make good

decisions in operations management.MDM could fuel a range of valuable capabilities such as more cost-effective

planning, anticipating and averting system outages, and identifying particular

systems that are at risk of failure.

M2M practitioners entering into agreements with wireless solutions vendors

should ensure that their arrangements cover upgrades to existing facilities,

renewal options, quality of service, measurement instrumentation, and asset

management solutions.

Many industrial M2M solutions are built in conjunction with plant expansions

and alterations, hence the challenge in dealing with multiple vendors andversions of technologies. Cost factors may also come in the way of migrating

whole-scale to newer versions of products, though the newer ones may be

more effective or easier to maintain.

How long do you want your wireless devices to be self-powered? How many

devices and applications do you want your network to handle now and in the

future? How many application interfaces will need the wireless data, and how

often? How important is standards compliance for these platforms? These are

other questions for M2M practitioners to address when assessing new plans

and corresponding solutions.

Network and traffic planning is important in this regard, so are convenience

and system performance. Noise and interference can be challenges for

wireless in industrial environments, but application engineers now have

many creative solutions. Latency and delay factors due to dropped or blocked

data will remain a challenge in wireless environments, cautionsDan Payerle,

business unit manager for the DataComm Test division at Ideal Industries.

Useful checklists for such practitioners can be found in Guidelines for

Industrial Ethernet Infrastructure Implementation, developed jointly byRockwell Automation and Cisco Systems. Network designers tend to overlook

the physical infrastructure; about 70 percent of network problems are tied to

the physical infrastructure, and the rest originate on the logical side, like

errors in bandwidth calculations, according to report.


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Standards-based evolution is expected to compensate for the plug-and-play

approach that inadvertently sets up real risks and lifecycle costs. Each

wireless technology has its own advantages. IEEE 802.11 frequently is used in

the plants because of the large amount of data exchanged between systems.

Cellular is popular with machine builders to enable remote troubleshooting atthe customers location, adds Jim Weikert, strategic product manager for

wireless at ProSoft Technology.

Trends Ahead

An interesting trend to watch in the world of industrial wireless is the

increasing collaboration between traditional IT departments in the corporate

office and the process engineers on the plant floors, thanks to the penetration

of Ethernet in both; this spills over into areas like network monitoring,

performance analysis and optimization. As plants expand, the demand for

wireless increases. Todays wireless allows a robust architecture that is cost-competitive, observes Hesh Kagan, director of technology innovation for

Invensys.

In sum, wireless is continuing to grow in the industrial space as some of the

newer technologies are more capable and secure. Choice does not always have

to be accompanied by complexity in this case, especially when future-proofing

is concerned.

Madanmohan Rao is the editor of Asia Unplugged: The Wireless & Mobile Media

Boom in Asia Pacific (http://twitter.com/MadanRao)

------------------------------------

Next Generation Wireless LANs

Faster, more reliable, less interference - that's the new IEEE 802.11n standard

for wireless localareanetworks. ByMoxa.


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Although 802.11a/b/g networks continue to be popular today, the next

generation of wireless applications, such as real-time voice and video streams

for remote monitoring, will require more bandwidth and reliability. To meet

the growing needs of these bandwidth-hungry applications, the latest IEEE

802.11n standard (published in 2009) offers blazing data rates of up to 300Mbps. In contrast, 802.11b only supports a mere 11 Mbps, while 802.11a and

802.11g top out at 54 Mbps each. If you're looking to deploy a reliable and

secure wireless network for high-bandwidth applications, IEEE 802.11n is for

you.

IEEE did more than just boost the bit rates supported by 802.11a/b/g when

they developed 802.11n. By dramatically changing the basic frame format

802.11 devices use to communicate with each other, 802.11n offers WLANs

increased channel size, higher modulation rates, and reduced overhead.

802.11n can operate in either the 2.4 or 5 GHz bands and is backwards-compatible with existing 802.11a/b/g deployments to future-proof wireless

investments.

MIMO technology

The key technique behind enhanced data rates in 802.11n networks, called

Multiple Input Multiple Output (MIMO), refers to a link where the transmitting

end and the receiving end are both equipped with multiple antennas.


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Radio signals reflect off objects, creating multiple paths. In conventional

transmission this causes interference and fading, but MIMO leverages the

multipath phenomenon. On the transmission side, MIMO uses spatial

multiplexing to send multiple parallel data streams simultaneously over the

same channel, thereby increasing the data rate and transmission power Onthe receiving end, MIMO allows multiple signals to be combined into a single

signal, eliminating the effects of multipath fading. MIMO actually takes

advantage of radio reflection to improve wireless range and reliability.

Channel bonding

The amount of data that can be delivered relies on the channel width used in

data transmission. By bonding two or more channels together, more

bandwidth is available for data transfer. 802.11n uses channel bonding to

combine two adjacent 20 MHz channels into a single 40 MHz channel in both

the 2.4 and 5 GHz bands to provide increased channel width and the ability totransmit more data.

Frame aggregation

Every frame transmitted by an 802.11 device has fixed overhead that limits

the effective throughput. To reduce this overhead, 802.11n introduces frame

aggregation, which is the process of packing multiple frames in a single

transmission. With this mechanism, instead of several sets of overhead for

different frames, only one set of overhead is used, which greatly reduces the

average delay and increases the throughput performance of the 802.11 WLAN.

What's in it for you?

Thanks to improvements such as MIMO, 802.11n achieves greater SNR (signal-

to-noise ratio) on the radio link, as well as more efficient MAC protocol and

radio transmissions. These improvements translate into benefits in three

areas: reliability, predictable coverage, and throughput.

Reliability: Higher SNR means that more interference is needed to corrupt a

transmission, which translates directly into more reliable communication and

higher data rates.

Low interference: Thanks to MIMO technology, areas that previouslysuffered from destructive multipath interference now make use of that same

multipath effect to provide robust communication.

High throughput: Since 802.11n is backwards-compatible, legacy 802.11

devices will be able to take advantage of higher throughput rates when

deployed on an 802.11n network.

Case in point


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For train video surveillance, if each carriage has six cameras installed, and

each camera runs in full D1 mode with a 2 Mbps data rate, then two carriers

will use a total data rate of 24 Mbps. This poses obvious challenges for

802.11a/b/g networks that only support up to 20 Mbps of throughput. Moxa

offers 802.11n products with up to 120 Mbps throughput that can deliverdemanding video streaming applications on trains. Additionally, MIMO

technology and frame aggregation can transmit superior quality video

streams. MIMO enables higher bandwidth, reduced interference, and

enhanced connectivity, while frame aggregation ensures that content is

combined to support streaming video.

Moxa is a supplier of industrialnetworkingproducts (www.moxa.com).

------------------------------------

Getting Smart for Steel

How replacing traditional wired network with a wireless solution for processcontrol enhanced operations and worker safety in a traditionally harsh

environment.

Boosted production by as much as one batch per day. Cut maintenance costs

by US$200,000 annually. And improved worker safety. Thats industrial

wireless technology, which has helped Northstar Bluescope Steel improve

furnace control at its mini-mill in Delta, Ohio, USA.

At the plant, a self-organizing wireless network from Emerson Process

Management, and which is based on the IEC 62591 (WirelessHart) standard,

collects data used to control the temperature of cooling panels and water-

cooled burners on the mills electric arc furnace.

This data is critical to safe furnace operation. Overheating cooling panels can

lead to major furnace damage, with a blown-out panel costing as much as

$20,000 to repair. Production time is also lost when the furnace must be shut

down during maintenance or repairs.

Better temperature control through wireless has allowed us to add up to one

additional batch per day, said RobKearney, maintenance supervisor for

Northstar Bluescope Steel. "With each batch worth as much as $200,000, that'sa significant advantage."


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Improve SCADA operations using wireless

instrumentation

yBy Hany Fouda on 1 November 2010

y 0 commentsyy

Australia's extensive mining operations, water projects, water and waste water treatment plantsand pipelines all lend themselves to using wireless to connect remote monitoring systems withcentralised SCADA systems and control rooms. But not everyone is convinced.

The last ten years have seen a dramatic change not only in the radio technology but moreimportantly in how we use it as instrument and control engineers. As more consumers line up toacquire the latest Smart Phones with embedded Wi-Fi, Bluetooth and broad band capabilities, theprice of radio modules have plummeted. This has made it easy on industrial vendors to integrateradio modules into a long list of devices and sensors.

The business case behind deploying wireless instrumentation is compelling. By eliminatingcabling and trenching, you can reduce the cost of deployment by as much as 70 per cent. Sincewireless instrumentation is battery powered, they are much easier to deploy in the field. Wiredsystems can take days or weeks to be properly installed, whereas wireless instruments requireonly the sensor to be installed in the process, saving hours or days and valuable resources. Otherinstruments can be added as needed. If the business case is strong and the return on investment issolid, why are some still reluctant to deploy wireless instrumenta tion in their facilities?

There are three main reasons: Reliability, Adaptability, Integration.


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Reliability: In industrial applications, reliability is a major concern. Wireless instrumentationmust be as reliable as conventional wired units. Even in simple applications like remotemonitoring, users come to expect a certain level of reliability and network availability.

For example, the controls and communications for a wastewater pump station, often located far

from the central control room, have to be reliable. If something goes wrong, maintenance peoplehave to be dispatched immedi ately. South East Water Company in Melbourne had that problem.Their dual submersible pump control (Figure 1) required the local controller to cycle betweentwo pumps, ensuring that both pumps were used approximately equally.

The local controller also had to report critical system data, such as flow totals and pump runningtimes to the central SCADA system. Grundys Electrics, a systems integrator in Melbourne,installed Control Microsystems SCADAPack controllers, local display panels, and DNP3 optimised radios at each pump station.

Radio signals are subject to reflection as a result of structure, trees, water bodies and buildings.

Furthermore, interference from near-by wireless systems such as cell towers adds morechallenges. RF design is getting better in addressing many of these issues. By designing highlysensitive radio receivers, and using the transmit power more effi ciently with high gain antennas,engi neers can establish highly reliable RF point-to-multipoint links.

Adaptability: Wireless instrumentation networks are required to adapt to the existingenvironment. It is not practical to move a well head, a compressor, tank or a separator just tocreate a reliable wireless link. It is sometimes difficult to find a location for an access point orbase radio that provides reliable commu nication with the wireless instru ments. Relocating theaccess point or base radio to improve the RF link with one sensor could result in degrading thelinks with other sensors in the same network. Adaptability can be addressed by using lower

frequency bands, such as the license-free 900 MHz, which tend to provide better coverage,longer range and better propagation characteristics allowing the signal to penetrate obsta cles.Also, high gain external antennas that can be mounted as high as possible on a structure allowaccess to hard-to- reach sensors which could be located at the bottom of a tank. Improved receivesensitivity of radio modules also plays a crucial role in ensuring network adapt ability to variousindustrial environ ments. For example, the Beypazari water system in Turkey is spread out over700 sq km of mountainous terrain. They had problems with the distant locations of their alarmsystems, so maintenance staff had to visit each pumping station three times a day to check onsystem opera tion. Because of the high cliffs, a wireless system appeared to be impractical.

Beypazari installed Control Microsystems SCADAPack controllers at each of the nine remotesites. Wireless radios at each site and two wireless data concentrators one on a hill overlooking the town transmit critical data to the central SCADA/HIM system. Thecommunication network is a mixture of 2.4 GHz radio modems and conventional UHF radio andline modems that are ideally suited to the mountainous locale in which they operate. Also, GSM(a digital mobile telephone standard) was implemented at the central location to provide ShortMessage Service (SMS) that sends alarms to operator cell phones.


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Integration: Managing and debugging dispersed wireless networks presents a new level ofcomplexity to field opera tors that could deter them from adopting wireless instrumentationdespite the exceptional savings. The wireless network integration dilemma is more apparent inSCADA systems. Since wireless instrumentation networks are supposed to tie into the sameSCADA infrastructure available at site to relay valuable operating data to the SCADA host,

having the ability to manage the complete infrastructure as one network becomes essential.

Ensuring data integration is still a major problem. Some SCADA systems even have a separatehistorian module that must be purchased as an add-on to handle the flood of data as a result ofadding wireless instrumentation networks. A coal seam gas (CSG) opera tion in Queensland hadthat problem. CSG, abundant in Queensland, is the same as natural gas and is collected frommore than 700 well sites scattered across the state. Parasyn Controls, based in Tingalpa,Queensland, is installing Control Microsystems SCADAPack controllers at each site (Figure 2)to collect data, provide local and remote control, report events, and communicate with centralSCADA systems via radio links. Standardising SCADA and wire less hardware from a singlevendor made it simple to connect the remote sites to the central SCADA systems.

A new breed of advanced wireless instrumentation base station radios or gateways is nowemerging in the market place. This new generation of gateways integrates both a wirelessinstrumenta tion base radio and a long range indus trial radio in the same device.

The integrated long range remote radio is configured as a remote device relaying information toa Master radio at the main SCADA centre. The available two serial ports on the radio are configured to tunnel Modbus polling and diagnostic data simultaneously to the wireless instrumentationbase radio. This allows operators to manage and diagnose the wireless instrumentation networkthrough the existing long range SCADA infrastructure. Live data and status infor mation for allfield units are displayed in a separate view or integrated in the SCADA host.

On the data integration front, modern SCADA host software offers a fully integratedenvironment that includes an integrated and scalable histo rian to handle more additional datawithout going through expensive and sometimes lengthy upgrades. Developing the SCADAscreens based on templates allow engineers to add data points easily and rapidly in their systems.


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Holding industrial wireless vendors to

account

Online: www.elprotech.com

Phone: 07 3352 8600

While wireless technology has moved well beyond simple point-to-point connectivity, the

fundamental tenets of the technology remain the same. However, one shouldnt be put off, and

we dont all need to be certified RF engineers to start making informed choices. This articlelooks to highlight the fundamental tenets of RF technology and empower more informeddecision-making in relation to which wireless technology to deploy relative to application need.

There can be little doubt that wireless technology is omnipresent in our professional lives atpresent. From the touting of standards such as ISA100, WirelessHART and IEEE 802.11, towireless sensor-based networks (WSN) and mesh technology, wireless systems are becomingincreasingly accepted and integrated into greenfield and legacy plants and applications globally.

However, as with much in life, a trade-off exists when deploying wireless. Informed decision-making means looking at the criticality and latency of the PV in the process, the volume of

information needing to be transferred and the required communication distance and terrain - andall of this should be relative to the frequency waveform properties, modulation scheme andAustralian Communication and Media Authority (ACMA) guidelines.

The wireless spectrum and

terminology

Informed choices on wirelesstechnology begin with theunderstanding that wirelessequipment manufacturers have

only a subset of the variables thatthey can control and even these aresubject to regulatory compliance.The balance of factors areapplication or site specific and aredecision variables for the siteengineer.

Figure 1: The Fresnel zone between two antennas.


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In design, manufacturers can control the amount of RF power emitted (to regulatory standards),the amount of modulation (also, by default, a function of the regulatory body) and the receiversensitivity (the lowest RF signal that the receiver can reliably detect). Other decision variablesare application specific (Do I need 4-20 mA or live video feed?) or site-specific (such as, Howfar do I want to communicate and over what terrain?). These variables are pivotal and go to the

heart of good wireless technology decision-making.

A summary of how wireless works.

Wireless communication involves modulating binary data onto a carrier waveform andpropagating it via the Fresnel zone (elliptical path of RF) between transmitting and receivingantennas. The data is then removed (or demodulated) from the carrier wave for interpretation bythe receiving device. It is the obstruction of the Fresnel zone relative to the frequency waveformproperties, regulatory compliance, receiver sensitivity and modulation that will impact onreliable communications over a given distance.

Talking

and comp

aring RF

Radio frequency (RF) signals are often characterised by two common measurements - frequencyand power. Frequency is measured in Hertz (Hz) and RF signal strength is often specified inmilliwatts (mW) or decibels (dB). When working with radio-based systems, its useful tounderstand both and convert between them, as they will often be used interchangeably betweenvendors. Moreover, conversion will be required to understand and comply with wirelessregulatory approvals (for example, when deciding on overall antenna gain).

The relationship between milliwatts and decibels is defined by the following equation:

dBm = 10 log10(RF power in mW)

The above equation shows radio signal strength expressed in decibels with reference to 1 mW ofRF power. Therefore, 1 mW of RF power = 0 dBm. Given that its a logarithmic scale, adoubling of RF power adds another 3 dB.

Understanding waveform properties

The question is often asked, how far will my radio signal reliably go? This is a function of anumber of factors beginning with waveform properties.

From your technical training you should remember that wavelength is inversely proportional tofrequency. Waveform diffraction (the ability of the waveform to bend around objects), reflection(the ability to bounce off objects) and general object penetration is better at longer wavelengths,and therefore lower frequencies, than it is at higher frequencies. Moreover, higher frequencies,with their smaller wavelength, are more prone to scattering upon meeting obstructions (known asmultipath fading). This, and the modulation technique (discussed later), is the reason higherfrequency devices often have two or more antennas compared with a low frequency device.


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In summary, the general rule is that obstacles, and their location relative to the Fresnel zone,decrease the overall reliability and operating distance. Any blockage impeding the Fresnel zonefrom opening will decrease reliable communications distance, depending on the properties of thetransmitted waveform.

RF powerand dist

ance

Irrespective of frequency, increasing a transmitters RF power and antenna gain will increase thecommunication range. This is due to the higher power mitigating the signal attenuation thatoccurs as the signal passes through, and reflects or bends around, obstructions. In effect, RFsignals attenuate proportionally (through a constant medium) to the square of the distance. Whatthis means, practically, is that to double your reliable distance, you need to increase your RFpower level by four times (ie, add 6 dB). One way to do this is by using a higher gain (moredirectional) antenna. The benefit of a directional antenna is that it achieves greater power (anddistance) in one direction while reducing spill (and sensitivity) to the sides and back, givinggreater control over interference.

However, government regulations on the amount of emitted RF power are enforced to ensurecoexistence and management of the radio spectrum. These allowable limits are known aseffective isotropic radiated power (EIRP) or effective radiated power (ERP) and are referencedto an isotropic or dipole antenna respectively. As a result, an antenna with higher gain (such as adish or array) will increase the EIRP in the direction the antenna is facing. To work out theeffective power, you add the gain of the antenna in dBi to the transmitter power in dBm to get aneffective dB power emitted, after allowing for insertion losses such as cable and surge arrestors.

Radio licenses

It is timely that we introduce what are termed licensed and licence-free bands. In general,licensed systems are those that the ACMA grants for a given geographic area, given channel sizeand level of RF power. Licence-free or industrial, scientific and medical (ISM) use does notrequire a licence to be granted, but users need to query vendors on the ability of their equipmentto mitigate interference on the same band.

Effect of receiver sensitivity

Communication distance is also a function of radio receiver sensitivity levels, which are oftenspecified at a particular bit error (BER) or frame error rate (FER), such as -108 dB @ 1x10-6BER. For a given frequency, radio products with an ability to receive at lower levels willoutperform those with poorer levels of receiver sensitivity. Put simply, they can detect anddemodulate more successfully over longer distances.

However, receiver sensitivity by itself does not ensure reliable communications. There is also theeffect of fade margin, which represents the difference between the dBm level of the receivedsignal relative to the dBm level of RF background noise of the same, or similar, frequencies.


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A system with a poor fade margin, even with superior receiver sensitivity, will not performreliably when compared with a system of lesser receiver sensitivity but strong fade margin. Thisis particularly relevant where environmental factors can be transient (inclement weather) and addto the problem. Intermittent communications is a telltale sign in this situation.

So, good receiver sensitivity along with a good fade margin will have a high impact on reliablecommunications distance.

Wide versus narrow channels, band size and modulation.

Up to this point you could be forgiven for thinking that lower frequencies are the panacea. Well,that depends on the application and the required data throughput - there are always trade-offs inwireless physics!

While lower frequencies offer greater range, it is also the case that these frequencies are made upof either a single narrow channel or multiple smaller channels within a band. However, higher

frequency systems have wider bands and the channels are wider.

More numerous and wider channels allow for greater modulation and potential data throughput.Why cant we modulate more at lower frequencies? For each increase in modulation (and datarate) the spread of the frequency lobe (the size and number of sidebands) increases, potentiallyspilling into adjacent channels, creating potential interference.

In general, it is beneficial to know which modulation technique is being deployed as it will helpachieve a more informed choice. There are three types commonly used.

Figure 2: Frequency shift keying (FSK).

Digital frequency shift keying (FSK) modulates data on a given carrier waveform and is typicallythe domain of lower frequencies with narrow channels. It is, therefore, limited in its datathroughput capabilities. The limitation of FSK can be its susceptibility to interference on thatfrequency which can (not always) be a reason to use a licensed frequency.

Frequency hopping spread spectrum (FHSS) is a scheme using narrow channels within a band,scanning and hopping through available channels when communicating or experiencing


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interference. Again, channels are smaller in size and are typically in the range of 19.2 Kbps at900 MHz and toward 250 Kbps for FHSS at 2.4 GHz (depending on channel size).

Figure 3: Frequency hopping spread spectrum (FHSS).

Direct sequence spread spectrum is a wideband modulation technique spreading the data acrossmuch of the band using differing variants of differential phase shift keying (DPSK). Theconcurrent spreading and even multidimensional sending of data streams (eg, multiplein/multiple out spatial multiplexing of 802.11n) allows for data throughputs to 108 Mbps andbeyond.

Overall, 802.11 devices are not able to communicate as far but offer greater data throughput than

lower frequency devices.

Figure 4: Direct sequence spread spectrum (DSSS) in 802.11.

Repeatability and wireless mesh

Understandably, if repeating or wireless mesh technologies (by default repeating) are viableoptions, then greater communications distances may be achieved. Repeating of wireless


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communications has been available for some time but practical considerations include budgeting(including the cost of holding redundant spares for repeater-only units), site accessconsiderations and associated infrastructure (such as antenna masts, power supply, etc).

The most common mesh architectures are those using a coordinator, a gateway or independent

coordination and feature high or low RF power. Both coordinator and gateway networkstypically feature low RF power and rely on redundant coordinators or gateways to managenetwork communications. When there are obstructions or long distances involved, low RF powerwill require the insertion of additional network nodes. Coupled with the addition of redundantcoordinators or gateways, this adds to the cost of network infrastructure. Independentcoordination networks, however, can be much different. Independent networks offer no singlepoint of failure when a coordinator or gateway fails, and they typically provide higher RF power,promoting more reliable communication over distance.

Figure 5: Types of mesh architecture.

Site-specific questions

When thinking about deploying wireless, the application and site specific questions you shouldbe asking are:

What are the data throughput and connectivity requirements of my application?

Do you really need 108 Mbps or is it really just a want? Perhaps you might want a mixed

system of I/O, VoIP and IP cameras - then the answer is not at lower frequencies but athigher frequencies. What are the data communication requirements of my equipment? Is itI/O, RS232 or RJ45? Do I need to communicate at different speeds (Modbus RTU to TCP)or are differing protocols at play? Put simply, but for cost, if you could cable between thetwo devices, would they interoperate? If so, and the data rate is low, then maybe thefunctionality and simplicity of a wireless modem will suffice. If not, then a gateway styleof product may be applicable.


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Plant safety engineers take aim at a wireless

future20 September 2010

Author: Dr.Patrick Hogan, vicepresident ofmarketing for HoneywellAnalytics

Equipping the mobile worker with a personal gas monitor that not only can

monitor a range of hazardous gases, but also report the workers exact location,

continuously, in real timeover a wireless communications gridrepresents one

small step forward for todays control room operator, yet one giant leap forward

for plant safety.

The not-so-distant future is likely to see a convergence of wireless technologies such as GPS,Bluetooth, WiFi and voice communication for location management and operator ID tracking aswell as personal gas monitoring and other personal protective equipment (PPE) use.

Because there is no need to run wires or conduit in a wireless system, information from bothprocess and safety instruments used in a refinery, petrochemical plant, wastewater treatmentfacility and various other manufacturing environments can now be obtained more costeffectively. This is particularly advantageous for monitoring in hard-to-reach or remote areaapplications.

We are on the cusp of a new era in plant operations characterized by a galaxy of sensorsobtaining and transmitting information on a multitude of changing dynamics e.g. temperature,pressure, transportation, tank levels, vibration, corrosion, gas concentration levels over awireless grid. The transmitters will be installed using different wiring schemes, and connected toa variety of control systems using PLCs, SCADA or DCS as well as stand-alone control systems.

Todays plant - The problem of isolation


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In this scenario, hazardous chemicals are either being used in the process or generated as by-products of it. The processes may be managed by thousands of workers in both permanent andmobile locations throughout the plant. By law, workers within the plant must carry single-gasmonitors to alert them of exposure to a poisonous gas such as hydrogen sulphide or lack ofoxygen. Some operators may alternatively need four-gas monitors if they work in confined

spaces such as tunnels, reactor vessels and other areas where a mix of explosive and toxic gasescan build up or diminish breathable oxygen levels.

In todays busy, noisy process environment, when a personal monitor detects a dangerous gaslevel and goes into alarm, it may alert only the operator. Moreover, data logged within theportable unit is accessible only to the plant supervisor at the end of the shift. This happens whenthe operator returns to the instrument shack and places the portable in a docking station torecharge the batteries, automate the data download process and test the detector with freshcalibration gas.

In todays typical plant there are multiple monitoring activities working in isolation and the

overall hazard combination cannot be made readily apparent either to the plant supervisors in thecontrol room, or more significantly, to the technicians working in the plant. Connections betweenthe overall sensor inputs cannot be realized quickly enough and in many cases is not used tocapture a true picture of the overall plant and personnel hazards.

Tomorrows plant Better connected

In tomorrows plant we will see a greater deployment of wireless and hybrid wired /wirelesssystems that share data rapidly across the plant. The data will be aggregated into a moresophisticated assessment of the hazard to the plant and the operators.

T

he next generation of portable gas monitors will be able to connect wirelessly to wireless WiFirouters located around the plant and immediately share and communicate sensor data carried byhundreds of other operators into the plants hazard visualization overview as seen in the controlroom. Another feature of this integrated mesh between mobile and fixed sensor points is that thelocation of the operators will be depicted in a real-time mode at the supervisory level. In otherwords, the plant safety manager will know at all times where the combined dangers are, alongwith the location of all personnel.

Lets describe a few emergency scenarios that demonstrate how much safer the plant andworkers will be in this integrated sensor environment.

Effective emergency response

Should a plant worker in a trench suddenly be exposed to a dangerous level of hydrogen sulfidetoxic gas, that persons monitor will go into immediate alarm and warn the worker to get out ofthe trench. The gas reading, alarm level, operator ID and location will be immediately flagged onthe plant SCADA system in the control room. Immediate action will be taken to alert theemergency response unit, who will go to the scene and assist with recovery or first aid needs.


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Moreover, other personnel in the immediate hazard area also will be alerted automatically on thescreen of their personal gas monitors (with all gas monitors connected to the intelligent plant-wide grid). Using a combination of sensor inputs (hazard levels, wind direction and other dataregarding muster points in the vicinity), control room operators will be able to confidently directworkers where to exit safely. The overall outcome is the direct result of a connected safety

philosophy the person in trouble is not only made aware of the danger, but also has theappropriate support services rolling faster and more effectively. All operators are automaticallyaccounted for by location and operator ID.

This intelligent connection between field operators and plant infrastructure also means thathazards not associated directly with a gas release (e.g. fire, leak, flood, smoke) can also beflagged with evacuation instructions to the same communication portal that the personal gasdetector provides.

In addition to providing more effective hazard mitigation, real-time wireless communicationswill also generate plant efficiencies and cost reductions.As workers travel around the plant, their

monitors will log levels of gas leakage from solvents or other gases that while not initiallydangerous nevertheless are indicators of areas that need preventative maintenance. Serviceteams can be deployed to the exact location to hunt down leaking valves, corroding pipes ordamaged process equipment, and they can make those repairs proactively, thereby avoiding moreexpensive repairs or even catastrophic failures.

Barriers to wireless adoption

Despite the rapid spread of wireless communications for industrial processes, adoption of thewireless format for life safety systems has been slow to gain a foothold. This is understandabledue to the necessarily cautious, universal regard for plant safety. After all, a life safety systemmust be failsafe by design; and the use of wireless communications for this purpose is relativelynew.

However, the life safety system of tomorrow will see a convergence of wireless technologies(WiFi, GPS, and mesh wireless) forming a multi-layered, redundant system design. Also theindustrial WiFi mesh system will be made more robust, with additional levels of security addedto prevent hacking or stray interference. The wireless life safety system of tomorrow will be


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purpose-built to the needs of the plant, putting the plant owner in full control of the system,along with plenty of signal strength and redundant back-ups.

It should also be pointed out that, in the unlikely event that the integrated communicationssystem fails during a gas release, the gas monitor will still raise the local alarm strobe/ buzzer/

vibration so the operator can take evasive action without the need to be dependent on a remoteaction that may or may not be connected due to other environmental issues.

The user experience: A plea for simplicity

In step with the emerging sophistication of the wireless platform, gas monitors have becomeeasier to use and increasingly unlikely to be misused.

Today, many manual tasks previously conducted by workers have become automated. Gasdetector user options have been simplified, prompting the user to respond only to commandsneeded for day-to-day operations. Some examples:

Many critical gas detector operations are now controlled by a personal computer so workerscannot harm themselves or their company.

User interaction with the instrument has been simplified through button presses, includingsingle button operation, turning a complicated device into an on-off one.

With multiple generations of products designed using the same interface, training time has beenminimised or eliminated, further simplifying safety.

One trend likely to gain widespread use is the visual compliance feature, or flashing LED on the

gas monitor.T

aking its cues from the airline, construction and other industries where visualtechnologies have become available to improve safety, users of gas detectors can now determine,from a distance, the compliance status of portable gas detectors. Low power high intensity LEDs(Light Emitting Diodes) constantly flash during normal operation and can be seen from up to 20feet away in sunlight. In less than a second, safety managers and workers can determine correctdetector functionality and its compliance status.

Visual compliance technology is emerging as the simplest, most economical way to ensure thatthe crew is safe, the site is compliant and the job is productive. It is likely to become a mainstayon the wireless gas monitor of the future.

T

o summarise then, we are on the verge of seeing gas detectors use wireless and location basedtelemetry, LED flash technology and other simplified operational features to provide a futureroadmap of a more integrated and intelligent monitoring solution. The goal is to exploitadditional functionality out of the essential gas detector platform to drive greater productivityand prevent downtime at all points in a typical workers shift. The overall impact to the businessis a smarter, safer and more cost effective working environment and a boost to efficiency andbottom-line profitability.


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Wireless gas detection systems in use today

Honeywell Analytics, the gas monitoring instrumentation arm of Honeywell, has already proventhe viability of wireless communications in life safety, with many installations of multi-pointcarbon monoxide/nitrogen dioxide gas monitoring systems in continuous operation in parking

garages, vehicular structures and other public facilities .T

his gas monitoring system uses a meshwireless topography with smart gas detectors and transmitters operating in a self-organisingdesign. The network automatically adapts as devices are added or removed, obstructions areencountered, or when one monitor loses power; this self-healing characteristic is an essentialfeature of mesh wireless and constitutes a form of redundant safety.

For over 20 years, BW Technologies by Honeywell has deployed its Rig Rat, a solar-poweredwireless mobile gas alarming device, at many oil and gas production platforms.

In addition, Honeywell has been selling industrial wireless solutions since 2002. Through thecompanys OneWireless platform, hundreds of sites have optimised plant productivity and

reliability, improved safety and security, and ensured regulatory compliance.

Wireless

Designing a Wireless Sensor System for

Storage Monitoring

September 1, 2010 By: N. Venkatesh, Redpine Signals Inc., Rohan Joginpalli, Redpine Signals Inc. Sensors

This article describes the considerations involved when integrating wireless

connectivity based on IEEE 802.11 (Wi-Fi) into a sensor system that monitors a

storage unit.

Storage facilities, especially those that maintain their contents at a controlled temperature andhumidity, require constant and reliable monitoring. Temperature-controlled storage units areused in a variety of environments including hotels, restaurants, hospitals, pharmacies,warehouses, and transporters. Their monitoring mechanisms help verify acceptable temperatureand humidity conditions, reduce costs by preventing overheating or overcooling, avoid lossesdue to freezer failures, improve quality standards, avoid wastage, and even provide historical


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temperature reports for insurance. Monitors also help in planning operations and maintenance,for instance, by logging the number of times that doors open or close.

In this article, we describe the design of a sensor unit for storage monitoring, with emphasis onproviding for universal connectivity through the existing networking infrastructure.

Figure 1 shows the components of the desired system. The sensor unit may be powered from thesame source as the storage unit, or it may be battery powered, enabling more flexible installationand setup. In the following sections, we discuss the general design of the sensor unit, and itsimplementation using a SenSiFi wireless sensor networking module from Redpine Signals Inc.

Figure 1. The sensors at the storage unit are controlled by a sensor unit that is connected to a controller via the enterprise network

Choosing ConnectivitySensor networks have traditionally used a variety of network protocols. Cabling costs anddifficulty in deployment, or redeployment, have resulted in the increasing adoption of wireless asthe chosen physical medium of connectivity, with IEEE 802.15.4 ZigBee and Bluetooth asprominent examples of popular wireless protocols. However, there are significant benefitseasyremote monitoring and control and scalabilityto having sensors on an IP-based network, whichwould already be present in most enterprises. One connectivity choice is the 802.11 wirelessLAN (WLAN) protocol. Apart from seamlessly connecting to the enterprise network, WLANalso stands out among other wireless standards because of its ability to scale up and cater toincreasing densities of wireless nodes. Also, the planning of an organization-wide networkinvolving decisions on frequency reuse, coverage of cells, and security settings, among others

would have already been done, paving the way for quick and flexible installation andcommissioning of equipment and devices. Among 802.11 WLAN variants, the emerging802.11n standard is preferred due to its increased range and throughput and the provision ofenhanced network capacity. The SenSiFi module provides single-stream 802.11n connectivity,while remaining compatible with legacy WLAN networks.


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The Sensor Networking ModuleThe design of the sensor system becomes easier by using an integrated sensor module that offersa few essential features for control and connectivity, as described below.

802.11n wireless communication. The desired core connectivity function is provided by an

integrated 802.11n wireless section that includes a baseband processor, MA

C, analog front end,an RF transceiver and power amplifier, a frequency reference, and optionally an antenna. Acharacterized and, if necessary, calibrated RF section provides uniform performanceconsistentacross all nodesand reduces the validation requirements for the completed system. Most of theWLAN protocol tasks are carried out in software, and the burnt-in embedded firmware takes careof the standards-compliant WLAN connectivity. The software handling the sensor configurationand control, and the packaging of the data collected can therefore be developed independently.The SenSiFi module (Figure 2) provides this facility, with users entering only the networkconfiguration information.

Figure 2. The SenSiFi module contains a wireless LAN section, a sensor interface section, and power management circuitry, with a low power

microcontroller providing control and configuration capability

Ultra-low-power microcontroller. Sensors provide raw data that need to be processed in someway. They also need to be controlled and configured as required by the application; for example,in this case, by setting the frequency of measurement or the frequency of reporting, setting theduration of the warm-up period prior to measurement after powering on, and other parameters.

An Atmel ultra-low-power microcontroller within the SenSiFi module has a multichannel ADCand several peripheral interfaces to connect to a variety of sensors.

When the sensor system operates off a battery, the microcontroller is used to control the system'spower state, dropping the system into an ultra-low-power sleep mode between measurements.The microcontroller is also used to process and package the sensor data for transmission over thenetwork. In this case, we use the SenSiFi module's embedded operating system that supportsstandard networking protocols such as IPv4, IPv6, TCP, and UDP. The communication is two-


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way; sensor data are sent out and system configuration information is sent back from a controllerelsewhere on the network.

Power management. The sensor system works off a single power source, either line power orfrom a battery. Because a battery may produce variable voltages, depending upon its charge

state, the sensor module should generate the various voltage levels required by its internalcomponents, as well as for the sensors attached to it. In the SenSiFi module, this is provided byan internal power management subsystem comprising voltage converters, configurableregulators, and switches. The power management functions also include controlling power tofunction blocks that are placed into standby or power-down modes based on the system'soperational state.

Sensor Interface DesignThe storage monitor application addressed here uses three sensors: temperature, humidity, anddoor actions. Of these, temperature and humidity are both commonly available using a singlesensor, e.g., the Sensiron SHT-75. The sensor's I2C interface can be connected to the SenSiFi

module's I

2

C interface.T

he door opening or closing may be monitored using a contact or infraredsensor connected to one of the digital general-purpose I/O (GPIO) lines of the module. Thissignal is also used as an interrupt to the microcontroller, bringing it out of its sleep state to raisean alarm or to record the activity to provide a history of door opening and closing events, andrelated duration information.

Data ProcessingThe microcontroller's main tasks are to control the sensors and process their data. A statemachine in the application program running on the microcontroller triggers the temperature andhumidity sensor and then collects the sensor data. It also responds to changes in stateexperienced by the door sensor.

The data are put in a format that can be decoded by the software application executed on thecontroller or server. This is a proprietary format and contains details such as the type of databeing transmitted, the length of the data, the raw sensor data, an optional checksum, and a packetsequence number. This is then encapsulated with an IP header using the uIP stack residing in theSenSiFi module's microcontroller. The uIP stack works in both IPv6 and IPv4 networks.

The Ethernet IP packet thus formed is passed to the WLAN stack which then forms a WLANpacket and transmits the packet over the air where it is routed to the server by the Access Point(AP)/router that converts it back into an Ethernet packet. The server decodes the data anddisplays the sensor information (Figure 3). A custom server application gathers the sensor dataand presents it as needed, e.g., as a graph of temperature over time, as illustrated in Figure 4.


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Figure 3. Packet flow from sensor to server

Figure 4. A plot of temperature over time created in a sample server application