Copyright© 2013 Adaptive Wireless Solutions Ltd Wireless Sensor Networks Nick Baker Walter Woods...

Copyright© 2013 Adaptive Wireless Solutions Ltd

Wireless Sensor Networks

Nick BakerWalter Woods

Adaptive Wireless Solutions Ltd


Adaptive Wireless Solutions• Specialists in monitoring and control solutions using wireless mesh sensor

networks for over 8 years

• Offer systems integration and equipment supply for numerous wireless and wired technologies driven by customer requirements

• Distributor for ECOMM and Wireless Sensors in UK and Europe • Certified System Partner for HMS Industrial Networks (Netbiter) in UK

• Can help you integrate and manage your data gathering, monitoring and control activities – Complete solution design, supply and support– Wireless technology consulting and advice– Programme and project management– Technical and wireless architecture design – Equipment and software supply from multiple vendors– Integration with other systems– Installation and commissioning– Maintenance and Support


Customers and Projects

• Mesh Wireless projects in BMS extension, energy management, industrial plants, IT environments, commercial offices, universities and colleges, hotels and apartment complexes, warehousing, recycling plants, food companies and national utilities.

• Customers in UK, Ireland, Italy, Netherlands, Belgium, Hungary, Israel, Saudi Arabia

BOMBARDIER

http://www.philips.com/global/index.html

http://en.wikipedia.org/wiki/File:Saudi_Aramco.svg

http://en.wikipedia.org/wiki/File:ABB_logo.svg

http://honeywell.com/Pages/Home.aspx

http://www.johnsoncontrols.co.uk/publish/gb/en.html

http://www.irf.com/

http://www.evolveenergy.com/index.html

http://www.countrystylegroup.co.uk/

http://www.central-systems.co.uk/

http://www.marshsystems.co.uk/


Business Advantages of Mesh Radio

Economic and operational advantages vs. wired sensors

• Up to 90% lower installed costs– Lower cost of required equipment and supplies– Much quicker installation = less on-site time and less disruption

• Monitor and control in:– harsh environments (lots of metal and interference)– “wire unfriendly” situations where wires are difficult or undesirable

• Low cost and speedy retrofit to existing buildings, equipment and processes

• Monitors mobile or rotating equipment• Easy optimisation of sensor position in process for a better result• Cost-effective diagnostics in uncertain or temporary situations • Multiple sensor types with standard wireless nodes on a single network• Remote, ‘PC-less’, monitoring from anywhere on the internet


Wireless Network Types

Direct Connection– Wire replacement– Point to point, highly specific– Engineered to suit application

Star– One central routing and control point– Single-hop - point to multi-point– All data flows through central point

Mesh– Multiple data paths– Multi-hop– Can operate as star or hybrid star/mesh– Self configuring, self healing– Highly flexible, highly reliable

Gateway

Mesh node

Sensing

node

Older, less flexible, less reliable technologies

Newer, more flexible, more reliable technology


Operational Advantages of Mesh

• Multiple Pathways– Stronger connectivity – Self-Healing, Self-Managing

• Transmit Around Equipment– More robust– More flexible

• Extend Network Range– More robust– More capable

Primary

Secondary

Out of Range

Primary


Core Mesh Wireless Product Ranges

System Monitor/Inputs

Control/ Outputs

Key Strengths

ECOMM Yes Yes Large scale networks, multi-channel I/O, direct equipment/meter integration

Wireless Sensors

Yes No External TRH sensors, RTD’s, battery operation, device packaging


ECOMM direct integration with Modbus meters

• The following electricity meter types are currently supported by direct integration via Modbus RS485 connection to the ECOMM WC21 radio unit– Schneider E 5600– Schneider ION 8600– Schneider PM 710/750– Schneider PM 9C– Schneider ION 6200– Carlo Gavazzi EM24– Veris H 8036– EIG Shark 100– Continental Controls Wattnode

• Other meter types can be added as needed (at a modest cost)


Remote Monitoring and Control


Solution Architecture – Netbiter remote monitoring

Typical Sensors and I/O devicesBattery and/or line poweredTemperature sensorTemperature and humidityOccupancy, door contactLightPulse countingDry contact inputsUp to 32 inputs per radio: contact, NTC, 0-5V, 0-20mARelay and analogue outputsMulti-stage thermostat controllerModbus RTU bridge

Wireless mesh Gateway

Netbiter is Modbus TCP proxy

Wireless range to cover large sites, highly reliable digital mesh radio, not affected by interference. Scales from 1 to 100’s of points. Netbiter transfers data off-site to Netbiter Argos remote monitoring portal. Web API available to integrate data to other applications

Remote off-site monitoring using Netbiter Argos

http://docs.netbiter.net/files/2011/11/Netbiter_EC150.jpg


Although we specialise in mesh radio we also use

GSM/GPRS and Narrowband radio systems

when needed to meet customer requirements


Typical Solution Architecture Overview (1)


Typical Solution Architecture Overview (2)


Example ProjectsIntegration type Sector DescriptionOPC / Remote Asset

ManagementSupermarket refrigerator, freezer temperature monitoring, HVAC and outside temperature monitoring. Expansion of trial site to 10 further stores

Modbus TCP / Remote Energy Electricity consumption monitoring on 7 floors of Dept. Health, London office, 8 meters per floor in risers. Wireless installed and commissioned in 2 days.

Modbus TCP into BMS Asset Management

Electricity feeder pillar status and generator status monitoring and control with battery UPS-protected wireless network across 100 acre government laboratory site.

Modbus TCP Building Management

Temperature and Humidity monitoring across 5 warehouses in large warehouse complex for Nestle

Modbus TCP/ BMS Building Management

Wireless temperature monitoring and window damper, heating valve and air recirculation damper controls. Historic university building. Demonstration project for Irish government.

BMS Energy Wireless boundary gas meters pulse transfer to BMS outstations on hospital site

Modbus TCP / SCADA Pharma Laboratory refrigerator, freezer and warehouse monitoring at Johnson & Johnson facility. Validated environment.

Direct I/O Asset Management

Remote generator status monitoring into site SCADA system


Application example – Westfield Shopping Mall BMS integration for temperature control

55,000 Sq Metres on two floors with Atrium

49 Air handling units on

roof

1 Wireless network

18 Mesh repeaters

30 Sensing nodes

Ambient Temperature input to HVAC zone controls via Modbus

TCP

Installed in 2 days to resolve critical

operating requirement

£6,100 equipment cost


Application example – Large Data Centre Monitoring Solution

Primary Server

Secondary Server

Remote Disaster Recovery Centre

Remote Business

Continuity Centre

Basement

Floor 1

Floor 2

Floor 3

Console

Control Room Viewers

OtherViewers

Secondary Console

CommonEthernet Network

Main Mission Critical Data Centre

7,500 Sq Metres

4 Floors

Phase 1 - 20086 Wireless Sub-

networks22 Mesh repeaters178 Sensing nodes

Ambient TRH

Phase 2 - 2009100 additional TRH

sensors on two floors

4 more wireless sub-networks

Phase 3 - 2010 Being planned now

Electrical PowerChilled water


BMS / SCADA Integration

• We have supplied systems to clients providing integration to existing BMS’ and SCADA / software systems via:– Modbus TCP and RTU– Direct analogue and digital connection– ODBC, OPC and SQL connection

• BMS’ that have been integrated with our systems include:– Trend– Siemens– Schneider– Andover Controls/TAC– Honeywell– Priva

• Numerous SCADA systems have also been integrated


Network Performance and Reliability


Industrial Wireless Sensor Networks

Industrial WSN OEM Adoption Inhibitors

92%

67%

58%

53%

43%

20%

10%

0% 20% 40% 60% 80% 100%

Reliability

Standards

Ease of Use

Battery

Dev Cycles

Education

Node Size

Source: ON World, Inc.


Building Automation Wireless Sensor NetworksCommercial Building WSN Adoption Inhibitors

70%

63%

55%

53%

52%

44%

23%

4%

0% 20% 40% 60% 80%

Reliability

Standards

Battery

Education

Dev Cycles

Ease of Use

Node Size

Guest Room

Source: ON World, Inc.


Wireless Sensor Network Reliability

RF Interference

• Common interference sources:– Multipath interference

• Occurs when the RF signal interferes with itself• Reflections off surfaces of all types• Can interfere with original signal and even cancel it out

– Interference with other transmitters• ISM band 2.4 Ghz wireless is increasingly common• Signals can be affected by other sources• Data slows down (more retries) or even stops• A good way to avoid it is to ‘frequency-hop’

• Examples of other transmitters in the 2.4 GHz band can be WiFi nodes, microwaves, cordless phones, Bluetooth devices, RFID, and other wireless sensor networks.

• How can it be avoided?

T R


Wireless Sensor Network Reliability

Interference Avoidance

• Typical methods:– Direct Sequence Spread Spectrum (DSSS) modulation

• Part of the IEEE802.15.4 radio standard• Spreads the signal over a wider bandwidth• Reduces the chance of blocking the whole signal

– Frequency-Hopping Spread Spectrum (FHSS) modulation• NOT part of the IEEE802.15.4 radio standard• Uses a range of base frequencies• Transmitter and receiver periodically hop to a new frequency• Acts more like a narrowband radio for very short intervals• Very unlikely that all channels in the band are interfered

– Dynamic channel hopping• Not a modulation technique• Enhances simple FHSS modulation by dynamically detecting

persistently busy channels and avoiding them

• The best mesh radio systems use all three techniques

TIME

FR

EQ

UE

NC

Y

frequency

Sig

nal s

tren

gth

2.40GHz 2.48GHz

NOISE FLOOR

INTERFERENCE


Wireless Sensor Network Protocols

How do they affect performance?

• Two main options:– Carrier Sense Multiple Access

• Collision-based protocol• Uses collision-avoidance (CA) or collision detection (CD)• Most WSN protocols use CA to avoid network overhead• Network communication is not time-synchronised• Pseudo-random ‘Back-off and re-try’ mechanisms are used• Collisions within the network escalate as networks get larger• ZigBee is based on this CSMA-CA approach

– Time Synchronised Protocols• These minimise or avoid collisions and transmission re-tries• Time synchronisation allows the use of channel-hopping• TDMA (Time Division Multiple Access) is an example• Also called ‘slotted’ protocols because each device has a ‘time slot’

• The benefits of synchronised traffic and channel-hopping are:– Better performance (fewer collisions/retries)– Increased battery life (fewer retries)– Better interference avoidance (channel-hopping)

• The most sophisticated systems use adaptive dynamic channel-hopping


Protocol Standards?

• There are many trade-offs in protocol design• There is room for several feature-specific protocol variants

using the IEEE 802.15.4 base standard• It is important that hardware remains 802.15.4 compliant• ‘Standard protocols’, if they ever become available, will not

mean that proprietary protocols become obsolete or unnecessary.

• ZigBee is not a standard and has serious reliability and performance limitations in industrial and commercial environments. ZigBee equipment from different vendors does not interoperate – one of the key goals of a standard.

IEE 802.15.4

PHY Layer

MAC Layer

MAC Layer

Data Link Layer

Network Layer

Proprietary Application

Application Interface

Application

• 802.15.4-based market offerings are differentiated by proprietary protocol stacks with different design goals

• Network layers of the protocol are not standardised


Contact Details

Adaptive Wireless Solutions Ltd

91 High Street

Prestwood

Great Missenden

HP16 9ER

Tel:+44 (0) 1494 865992

www.adaptive-wireless.co.uk

Nick Baker

Director

Mobile: 07968 352875

[email protected]

Skype: adaptivewireless

http://www.adaptive-wireless.co.uk/

mailto:[email protected]

Copyright© 2013 Adaptive Wireless Solutions Ltd Wireless Sensor Networks Nick Baker Walter Woods...

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