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An Introduction to Industrial Wireless Networking

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1 An Introduction to Industrial Wireless Networking
Presented by Yokogawa North America Network Solutions Business Unit February 2007

2 RF Wireless Industrial Applications

3 Industrial RF Wireless Technology Applications
Information Layer Information Layer HMI, Computer, Database Server Control Layer Recorder, Data Acquisition I/O, Controller, PLC Device Layer Transmitters, Sensors, Actuators Control Layer Device Layer

4 Industrial RF Wireless Technology Applications
Technology must support the Application Considerations Packet Size Throughput Response Time Network Size Our Focus Info & Control Layers 2.4 GHz Spread Spectrum Technology 802.11 Proprietary SS Bluetooth Zigbee

5 Control Layer Communications Protocols
Requirements More throughput Faster Response Time Large Networks More data Typical Protocols Modbus RTU RS232, RS422, RS485 Modbus TCP Ethernet Proprietary TCP Standard Ethernet FTP SMTP SNTP HTTP

6 Wireless – A Money Saving Solution
$0 $5,000 $10,000 $15,000 $20,000 $25,000 $30,000 25' 50' 100' 250' 500' 1000' Wireless - 1st Node Wireless -2nd Node Wireless - 3rd Node Wire $20/ft Wire $30/ft Wire $50/ft Wireless cost savings increase with distance & number of nodes

7 Wireless for Hazardous Locations
Wiring costs increase for tougher environments Reduced operator costs Clean rooms too! UL Class I Div 2 approved radios

8 History of Wireless LANs
Wireless Networks were first developed by the Military Eventually Moved to Private Sector High Cost, Low Data Rate and Complexity prevented the widespread use Used when other options weren’t possible ALOHAnet developed at the University of Hawaii, was one of the first private wireless data networks Turning Point - Late 1990s IEEE ratified B Data Rates Increased Hardware Cost & Availability Performance similar to Wired Ethernet

9 RF Radio Frequency & Power

10 Radio frequency spectrum is assigned by governments
Radio Frequencies Radio frequency spectrum is assigned by governments CB radio: MHz FM radio: MHz WiFi for PC’s: 2.4 GHZ Licensed vs. Unlicensed bands Licensed provides more power! Two licensed frequency bands 400 MHz 900 MHz 3 unlicensed frequency bands in U.S. ISM bands (Industrial, Scientific, Medical) MHz 2.4 to GHz 5.725 to GHz (U-NII*) *Unlicensed National Information Infrastructure

11 Lower Frequencies (i.e. 900 MHz have greater distance)
RF Propagation Higher frequencies have higher data rates (bandwidth) There is 1000 times more spectrum between 1-2 GHz as there is between 1-2 MHz. RF waves lose power as they travel in the air Higher frequencies lose power (attenuate) faster RF waves attenuate as they pass through objects Higher frequencies attenuate faster Lower Frequencies (i.e. 900 MHz have greater distance)

12 Understanding Power in Radios
RF transmitter and receiver power is expressed in watts. RF power can also be expressed in dBm (decibels relative to milliwatts) dBm for RF power is useful when calculating radio system gains (since other gains and losses from cables & Antennas are in dB’s) The relation between dBm and watts can be expressed as follows: Power(dBm) = 10 x Log10 Power(mW) 1 Watt = 1000 mW; PdBm = 10 x Log10(1000) = 30 dBm 100 mW; PdBm = 10 x Log10 (100) = 20 dBm 1mW: PdBm = 10 x Log10 (1) = 0 dBm Power(mW) = 10(Power(dBm)/10) 15 dBm = 10 (15/10) = 10 (1.5) = 32 mW

13 A Table of mW to dBm

14 Understanding Gain Measurements
Antenna performance is primarily established by its gain. There are three common references used when defining gain in radios: Gain referenced to a dipole antennae: dBd Gain referenced to an isotropic source: dBi Gain referenced to power in milliwatts: dBm

15 EIRP (Effective Isotropic Radiated Power)
EIRP is the effective power transmitted from the antenna. EIRP = (power at transmitter) - (cable attenuation) + antenna gain EIRP = Pout - Ct - Gt Pout = output power of transmitter in dBm Ct = transmitter cable attenuation in dB Gt = transmitting antenna gain in dBi Take the following example: transmitter power out = Pout = 50mW cable loss (attenuation) = Ct = 4dB transmitting antenna gain = Gt = 6 dBi convert transmitter power from mW to dBm 10 x log (50/10) = 17 dBm EIRP = 17dBm - 4 dBm + 6 dBm = 19 dBm

16 A Quick Comparison: Office vs. Industrial
32 mW 200 feet indoors 0 C to 40 C Plastic Power Distance Operating Temp Construction Mounting 500 mW 20 miles outdoor -30 C to 60 C Aluminum

17 Performance of 2.4 GHZ vs. 900 MHz
Typical Outdoors with Line of Sight 2.4GHz, 1W plus 6dB gain antennas 5 – 15 miles 900MHz, 1W plus 6dB gain antennas 15 – 25 miles 2.4GHz, 100mW plus 16dB antennas 10 – 40 miles 900MHz, 100mW plus 16dB antennas 20 – 60 miles Typical Indoors in Congested Environment 2.4GHz, 1W 100 – 600 feet 900MHz, 1W 500 – 5000 feet

18 Spread Spectrum & IEEE Spread Spectrum & IEEE Standards

19 Introduction to Spread Spectrum
Spread spectrum – a class of modulation techniques that spreads a signal’s power over a wider band of frequencies than is necessary for the information being transmitted Benefits of spreading the signal: signal is immune to unwanted noise / interference coding and decoding allow simultaneous transmission of multiple signals within the same frequency band provides inherent data encryption / security

20 Spread Spectrum Introduction - 2
Two main classes: Frequency Hopping Spread Spectrum (FHSS) Random Hops to difference frequency. 1 MHZ band. More Secure proprietary interface. Direct Sequence Spread Spectrum (DSSS) Hot Spot WIFI 22 MHZ band b, 11 Megabit New modulation technique for higher data rates: Orthogonal Frequency Division Multiplexing (OFDM) achieves 54MBPS 802.11g and a – Split byte and transmit pieces simultaneous.

21 Frequency Hopping Spread Spectrum

22 Spread Spectrum vs. Narrow Band
Wide bandwidth of spread spectrum make more immune to interference vs. narrow band signal shown in the center of the graph (Older Radios use narrow band)

23 IEEE Standards “Soup” HomeRF 2.0 Wi-Fi5 802.11g 802.11a HomeRF 802.11b
Bluetooth IEEE specifies wired connection between radios and devices IEEE specifies an over-the-air interface between a wireless LAN client and a base station or between two wireless LAN clients.

24 802.11x WLAN “S-p-e-l-l-e-d Out”
1 or 2 Mbps transmission in the 2.4 GHz band frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS) Wi-Fi Wireless Ethernet Compatibility Alliance (WECA) certification for b devices 802.11b (Current Offering) 11 Mbps transmission in the 2.4 GHz band Only DSSS Vendor access points not compatible

25 802.11x WLAN “S-p-e-l-l-e-d Out” - 2
Up to 54 Mbps in the 5GHz U-NII band 300 MHz bandwidth indoor, OFDM Orthogonal frequency division multiplexing (OFDM) 50m range at 11 Mbps 802.11g 54 Mbps speed extension of b in the 2.4 GHz band with OFDM Backward compatible with b for <11 Mbps Wi-Fi5 (Newer Technology) Wireless Ethernet Compatibility Alliance (WECA) certification for a devices

26 802.11x WLAN “S-p-e-l-l-e-d Out” - 3
802.11i (Incorporated into WIFI Standard) Security Enhancements to Encryption & Authentication TKIP – Temporal Key Integrity Protocol – interim solution AES – Advanced Encryption Algorithm – new hardware 802.1x Authentication Framework included in i Authentication protocol (EAP-TTLS, LEAP) Dynamic encryption key distribution method Supported in Windows XP

27 2.4 GHz Direct Sequence Spread Spectrum (DSSS) Channels
802.11b Wireless LAN 2.4 GHz Direct Sequence Spread Spectrum (DSSS) Channels 11 US, Canada 13 Europe 14 Japan Data rates: 1, 2, 5.5, 11 Mbps (auto) Signal level can cause lower data rate. Access points, clients, bridges (Example Hardware) Other notes: Vendor Access Points do not generally communicate 802.11b and g clients will communicate 802.11a will not communicate with b/g

28 802.11b Channels 1 1 2 3 4 5 6 6 7 8 10 9 11 11 12 13

29 802.11 Access Points, Bridges and Clients
Wired Network Access Point Client (Station) Coverage Area Access Point – Root Mode Access Point – Repeater Mode Ad hoc – no AP Bridge or Access Point in Bridge Mode Bridge – Repeater Mode

30 Security Security

31 Keep intruders out of your network
Wireless Security Keep intruders out of your network Authenticate users Stop others from “sniffing” your data Data encryption – proprietary or Wi-Fi Protected Access (WPA) Minimize detection of your network Turn off identifiers in beacon Appropriate coverage area Detect “rogue” access points Wireless network maintenance software

32 802.11 Wireless Security Data Encryption 1
WEP (Wired Equivalent Privacy) RC4 based 40/128/256 bit keys Key scheduling algorithm weaknesses Wi-Fi Protected Access (WPA) Solves weakness in WEP Temporal Key Integrity Protocol - TKIP Message Integrity Checking (MIC) Extensible Authentication Protocol (EAP) / RADIUS Authentication, authorization & accounting system

33 802.11 Wireless Security Data Encryption 2
AES (Advanced Encryption System) 802.11i & new hardware Symmetric 128 bit block data encryption Will be supported in a few months. Other Steps – remove SSID from beacon MAC ID white list (Limit MAC Addresses) Must Enable to Be Effective

34 Wireless Network Planning

35 Wireless Network Planning Overview
What questions should I ask to qualify the application? How can I predict link performance? How do I test it? Which antenna cables? How high do the antennas need to be installed to clear this hill? Which antennas? What’s a dBi? Radio What about interference? Where can / should the antenna go? Radio How do I get terrain data? X kilometers Can this distance be covered? What is meant by line of sight and why is the Fresnel Zone important

36 Throughput and latency considerations
# bits of data x frequency sent Add I/Os, PLC messaging, etc. Repeater / master must be able to handle sum of remotes Radio technology must fit or slow update rate / report by exception Similar analysis to specifying PLCs Throughput will determine update rate Seconds to poll vs. hours

37 Radio coverage area

38 Radio Network Architectures: Point-to-Point
Point A Point B Point-to-point, stationary network easiest to design Use directional antennas on both sides Maximize signal strength Minimize noise pickup Must have line-of-sight between points ….but plan ahead if network will be expanded in the future If Site A will be hub for additional sites, may need an omni or sector antenna With less directional antennas, low noise at Site A – test Can Site A “see” the future sites – or need additional height Plan for bandwidth too – can radio at Site A handle 100’s of remotes?

39 Radio Network Architectures: Point-to-Multipoint
Hub site can be omni-directional or sectorized with multiple directional antennas – e.g. like slice of pie Use sectors when more bandwidth is needed Each sector antenna attached to radio on different hopping pattern or different b channel Line-of-site more important – site survey Hub site Sector 1 (Ch. 1) Coverage Ares Sector 1 (Ch. 11) Sector 2 (Ch. 6) Coverage Area

40 Use of Wireless Repeaters
Use repeaters to: Extend range of the wireless network Avoid obstacles For YLinx RLX-FH series Use of repeater reduces bandwidth by factor of two - but does not decrease more for additional repeaters For some radios bandwidth reduced by 1/# repeaters Repeater on top of hill or on one side to go Around the hill RLX Link too long for Repeater on top of hill RLX RLX RLX

41 Information required to design wireless network and select accessories
Minimum information required to design all but the simplest systems Number of sites today and planned Location of sites & if indoor / outdoor Drawing of building with scale and site locations and structure information GPS coordinates or location on a drawing / topographic map with distances between sites to link If device will move – show track / area where link is required Structures where antennas can be placed and any rules on antenna structures (e.g. luxury living areas) Protocol of devices to connect Which devices need to communicate Data throughput requirements for each node Country radios will be installed Any other radio systems in-use if known

42 Methods to collect application information
Verbal or electronic description of application from customer Electronic drawings of buildings Topographic maps showing site location and any obstructions or Topo USA type program Electronic path study using digital elevation data and GPS coordinates of sites Site review – visit site and physically inspect links If very clear line of sight should not be an issue High power strobe light for longer links - but visual LOS only Test with RLX IF using same antennas and antenna locations Complete site survey including RF noise analysis at key points

43 Handheld Spectrum Analyzer & 802.11 Analyzers

44 In-Building Site Survey
Building drawings Construction materials Metal interior walls? Ceiling height Equipment / product information Coverage required Fixed vs. mobile If mobile – where? Existing wireless infrastructure Type / channels Conduct site survey – walking plant and taking measurements Signal-to-noise measurements with Ekahau Site Survey Tool

45 Topographical Maps

46 Outdoor – Computerized Path Studies
GPS coordinates Digital terrain data Paths feasible? Antenna height Repeaters? Location Performance prediction Redundant path analysis to support self-healing network capability Blue - primary path Red – back-up path Black – path not available without increased antenna height

47 Example Wireless Outdoor Path

48 Site Survey – The Real World
“Shoot and scoot” For less involved / shorter range installations Bring radios, equipment and test links – if look good, finalize install Formal site survey Identification of all potential interference Environment & radio – spectrum analysis Collection of site data for each potential site Geographical coordinates including elevation Access roads, building code restrictions / solutions Installation considerations – site preparation / building access, etc. Nearby towers / structures for repeaters– access / rent Power availability Corroborate path study data with actual field measurements Signal strength, throughput statistics, etc. Identify man-made / tree height obstacles not evident from USGS data We can provide site surveys ($1000 per day + plus per diam)

49 Selecting Antennas & Cables

50 Antennas (most) are passive – focus radio energy not amplify it
Antennas – The Basics Antennas transform electromagnetic signals from transmission lines into electromagnetic waves (& vice-versa) Antennas (most) are passive – focus radio energy not amplify it Antennas work equally well transmitting or receiving RF energy Electromagnetic waves from antennas have an E field and H field components Polarization describes the orientation of the antennas electric field Compare to narrowing beam of a flash light Nozzle at the end of a hose – can narrow (and send water farther) or spread (cover more area) but total amount the same

51 High Quality, Low RF Loss Cables
Remote antenna placement requires lower loss RF cable to maintain system gain Cable should be 50 ohm for RadioLinx impedance matching Quality connectors, weather proofing, lightning protection PoE and placing radio by antenna

52 Matching connector types
Common types N-type SMA TNC BNC MMCX (PC card) Matching connector types Jack = threads on outside Plug = threads on inside So a jack will connect to a plug (if polarity matches) Polarity Standard polarity – plug has inner conductor pin Reverse polarity – jack has the inner conductor pin MMCX-Male RP-TNC-Female RP-TNC-Male RP-SMA-Female RP-SMA-Male SMA-Female N-Male N-Female-Bulkhead

53 Configuring & Implementing Wireless Networks

54 Wireless Network Design Best Practices
Install antennas as high as possible Avoid high gain omni-directional antennas (Harder to hit the target) Design the system with a margin 10 dB minimum 20 dB if anticipate foliage growth Use industrial routers in-front of wireless industrial Ethernet Prevents LAN broadcast traffic from using RF bandwidth

55 Wireless Network Design Best Practices - 2
Put switch with IGMP snooping in-front of RadioLinx RLX-FH if multicast traffic – e.g. industrial Ethernet I/O messaging After installation, test radio network before automation Verify RF performance Test throughput before & after automation added Ethernet use ping or pathping (latter shows latency for each segment to identify bottlenecks)

56 RadioLinx Antenna Installation Notes
Avoid attaching antenna too close to buildings, towers, tanks, etc. to avoid reflections Use side mount kits for at least 50 cm distance Outdoor installations should be weatherproofed At each cable splice At antenna connection Cable hangers / ties

57 Maintaining Wireless System Reliability
Changing environment Inside the company – coordinate wireless networks / frequency uses New equipment / infrastructure (metal walls) Joes’s Neighborhood WISP now on your channel Monitor performance for Performance degradation / bottlenecks Increasing throughput requirements Increase ping latency Re-transmit % Monitor security

58 Wireless Network Monitoring Tools

59 Wireless Protocol Analyzer / Security Audit Tools
One differentiator is level of expert analysis to help sort through large number of packets WildPacket AiroPeek, CommView WiFi, Packetyzer, Ethereal (Linux)

60 Application Examples Application Examples

61 YLinx Frequency Hopping Ethernet (2.4GHz)
$1,581 per radio Mobile configuration and data logging without wires! Frequency hopping 2.4 GHz unlicensed (ISM band) Not compatible with wireless (Wi-Fi) Designed for industrial environment (-40 to 158 degF) Up to 16 mile range with line of sight with hi gain antennas Proprietary radio frequency protocol (158 hopping patterns) 40 or 128 bit hardware data encryption

62 YLinx Frequency Hopping Ethernet (2.4 GHz)
Data from Remote DX100’s is Consolidated in PC PC running: DAQStandard (configuration) DAQLogger SCADA/HMI with OPC YLinx -FHE DX104 RS232 MODBUS RTU Slave #1 YLinx -FHE DX104 10BaseT Ethernet YLinx -FHE RS232 MODBUS RTU Slave #2 YLinx -FHE DX104 RS232 MODBUS RTU Slave #3

63 Product Samples: Ethernet Radio Modems
            Product Samples: Ethernet Radio Modems ELPRO 905U-D MDS iNET900 YLinx RadioLinx SCADALINK LANBRIGDE 900 MHz FHSS 900 MHz FHSS 2.4 GHz FHSS 900 MHz FHSS

64 Product Samples: Serial Radio Modems
            Product Samples: Serial Radio Modems Put serial devices on radio SCADALINK SM900 Prosoft RadioLinx 2.4 GHz FHSS 900 MHz FHSS

65 YLinx Frequency Hopping Serial (2.4GHz)
$1,416 per radio Mobile data logging without wires! Frequency hopping 2.4 GHz unlicensed (ISM band) Modbus RTU, Modbus ASCII, DF1, generic ASCII RS232, RS422, or RS485 Flexible set-up modes Point to point Point to multi-point Peer to peer Designed for industrial environment (-40 to 158 degF) Up to 16 mile range with line of sight with hi gain antennas Proprietary radio frequency protocol (158 hopping patterns) 40 or 128 bit hardware data encryption

66 YLinx Frequency Hopping Serial (2.4 GHz)
Data from Remote DX100’s is Consolidated in DX200 YLinx-FHS DX104 RS232 MODBUS RTU Slave #1 10BaseT Ethernet YLinx-FHS DA100 YLinx-FHS RS485 MODBUS RTU Slave #2 RS232 MODBUS RTU DX220 YLinx-FHS UT450 RS485 MODBUS RTU Slave #3

67 YLinx 802.11b Industrial Wireless Radio
$1,755 per radio Mobile configuration and data logging without wires! 802.11b direct sequence spread spectrum radios Can be implemented with a single radio! 2.4 GHz unlicensed (ISM band) Compatible with standard PC wireless cards Designed for industrial environment Up to 20 mile range in outdoor settings

68 UT351 with YLinx 802.11b Hotspot Laptop with 802.11b
“Wi-Fi” wireless ability Laptop with b “Wi-Fi” wireless ability

69 Typical Wireless Network
802.11b wireless 802.11g wireless Linksys G Wireless Router Radiolinx CX1000 UT351 MX100 FA-M3 PLC

70 Wireless Ethernet Organizations
IEEE WLAN Working Groups WECA Wi-Fi Alliance WLANA Bluetooth HiperLAN

71 Thanks! Thanks!

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