Gas Safety System for Oil Drilling Sites using Wireless Sensor

Network

Proposed by:Farouq Muhammad Aliyu (g201303650)Mohammed Al-shabouti (g201305830)

Submitted to :Dr. Abdulaziz Barnawi 1

Outline• Statement of Problem

• Aim

• Literature Review

• Introduction

• MODBUS

• Zigbee

• GPS

• Proposed GAS Safety System

• System Requirements

• Results & discussion

• Experiences

• References2

Statement of Problem

• 64% of accidents that happen in the oil fields are due to

Combustibles and/or Toxic gases [1].

• Combustibles and/or Toxic gases detectors are expensive and

difficult to implement.

• Present systems provide a central warning point.

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Aim

The aim of the project is to development of safety system that is

capable of remotely monitoring presence of Hydrogen Sulfide

(H2S) gas in oil drilling site with the help of standard industrial

sensors and wireless sensor networks.

4

Literature Review

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MODBUS• Transmission in two modes:

Remote terminal Unit(RTU) and ASCII.

• Modbus RTU uses RS-485 or RS-232. Modbus TCP uses Ethernet.

• The types of registers referenced in Modbus devices include the following:• Coil (Discrete Output)• Discrete Input• Input Register• Holding Register

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MODBUS Cont’d• Advantages:• It offers data transmission speeds of 35 Mbit/s up to 10 m and

100 kbit/s at 1200 m• Can connect up to 32 masters, but communicates with one at a

time.• It is highly resistant to noise. • It is cheap (free).

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Zigbee• Developed by Zigbee Alliance based on IEEE 802.15.4

MAC/PHY for low-power consumption• Zigbee stack is scalable and can be co-existed with other

technology use ISM band • Data rate is 250Kbps and ISM band is 2.4 GHz

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Zigbee (Highly Reliable Operation)

• Data Coding • QPSK modulation with conversion of 4-bit data symbols to 32-bit

chip sequences so probability that a message will get through to its destination intact is high.

• Listen before send (CSMA-CA)• Next hop acknowledgements • Scan best channel• Route repair

• So it is suitable for gas safety system

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GPS• Satellite based system provide receiver

with location and time information.[5]• 24 satellites cover the earth• Four Satellites must be line of sight to

get accurate data.• Each position on earth has unique• Longitude • Latitude

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Gas safety system

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System Requirements

• Should be cheap to encourage customers to buy it. • Should be distributed, flexible and independent

of any other system. • Response time of the system should not exceed

120s [7]• Node lifetime should be greater than one shift (8

hours)

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Network nodes

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Hardware • Industrial Sensor & controller • Function:

Sense the gas and send reading to the controller

• Arduino platform + Xbee + Modbus circuit• Function:

Read sensing data from industrial controller. Sends alarm and receives GPS data to and from end nodes.

• Arduino platform + Xbee• Function:

Relay node14

Hardware cont.• Arduino platform + Xbee + GPS (EM406A)• Function:

• Receives alarm and alerts worker• Sends GPS location if required• Aggregates GPS data• Sleep most of the time

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Software …• End node flowchart

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Software…• Coordinator

flowchart

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Aggregation Method• GPS can makes error with 10m• End node will not send new GPS data unless

new GPS location differs from old one by more than 10m• Distance between (lat1,long1) (lat2,long2) is computed as[6]

• Processing power consumption!!• Instead we used:

(abs(oldLat-newLat)>0.0001 || abs(oldLong-newLong)>0.0001) 18

Experiment Setup

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Scenario example• This experiment took place at KFUPM upper soccer field

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Response Time• Response time : Time from sending alarm till, start receiving

GPS position.

• Figure show the average response time.

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End node (Current consumed-Sleeping/Rx)

• Current consumed

• Is = 33.33mA• Itx/rx = 100mA

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End node (Current Consumption Sleeping/GPS ON)

• Is = 33.33mA• Igps = 100mA

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Conclusion• The system has a latency of 5 seconds (which is very

acceptable compared to the 120 second bench mark in [4])• Atmega alone (without the arduino board) consumes

extremely less energy.• Tarduino = Ahr/I = 6 days Tatmega = Ahr/I = 10 months

• Therefore WSN can be used for gas safety system.

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Experiences

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DLINE problem• Shield

An extenction for the arduino for

• UART switch to communicate via USB• DLINE switch to communicate with shield

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Programming…• Bluetooth com ports conflict with both xbee and arduino

programming applications (IDEs).• Solution: Always turn off bluetooth/wifi

• Rejoining• If NJ < 0xFF, joining will be enabled only for a numberof seconds,

based on the NJ parameter• Sleep pin

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References

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[5] http://en.wikipedia.org/wiki/Global_Positioning_System[6] http://www.movable-type.co.uk/scripts/latlong.html[7] Standard EN. 50194.2000, Electrical apparatus for the detection of combustible gases in domestic premises. Test methods and performance requirements, September 15, 2000