Basic SCADA Communication Design

Transcription

1 Gas Well De-Liquification Workshop February 28 - March 2, 2005 Basic SCADA Communication Design Jim Gardner Business Development Manager FreeWave Technologies

2 Defining the System: 6 Key Questions Volume of Data Frequency of Polling Location of Master Location of Slaves How Many Slaves What are You Willing to Spend 2

3 Volume of Data? How Much Data per Poll? What is Baud Rate? How long Will it Take to Poll Each Site Quick Equation Sample Equations 40,000 bytes of data 1200 baud = 33 seconds per poll 40,000 bytes of data Kbaud = less than 1 second per poll 3

4 Frequency of Polling? How often should you poll? Once an hour? Once a day 4 times per day? 17 seconds per site, times 200 sites = 57 minutes per polling cycle (1per hour) What is best fit Best Fit? 4

5 Location of Master? 5 miles from wells? 50 miles from wells? 500 miles from wells Hybrid Solution combining radio and back haul technology? Best fit 5

6 Location of Slaves? How large is coverage area? What are the characteristics of the terrain? Hills, Valleys, Mountains How dense is the foliage? How tall is the foliage? Do we need repeaters? How many repeater? 6

7 How Many Remote Sites? 400 sites 5,000 bytes per site 2 million bytes of data If each poll takes 17 seconds 2 hours per poll cycle 7

8 What Does it Cost? Hardware cost (Fixed) Monthly charges (Recurring) Tower Rental Usage fees CDPD, Cell Phone Bill Land Line Bill Satellite fee s Life Cycle Costs Repairs Warrantees Service 8

9 Communication Choices Licensed Radio Spread Spectrum Radio CDPD, GSM, Land Line, Telephone Satellite Microwave Hybrid Systems What is the Best Fit? The answers to Questions 1 through 6 are going to determine your need, combine this with a knowledge of communication devices, you will be able to answer which is the Best Fit for you 9

10 Licensed Radio User purchases a channel License from the FCC. (Annual Renewal fee s) Typically 50 mile radius of base station Strong on range Weak on interference Limited to one repeater Line of Sight Slow Throughput 10

11 Spread Spectrum Radio Multiple Repeaters Each Radio Can Be: Slave/Repeater Master Repeater 32 Bit CRC Check Sum Low Power Consumption 6 mills Faster Throughput (115.2 Kbaud) Selectable 232/485 Board Level (Low Cost) Ethernet Shorter Range (25 miles) 11

12 CDPD Operates on Cell Network No Infrastructure Required Web Access Recurring Expense (Monthly Fee) Not Universal Coverage User losses Control Service? Going Away (Soon) 12

13 Land Lines Unlimited Long Haul Allows Web Access Combines well with other technologies for Hybrid Solution Monthly Expense Not Available everywhere Service Interruptions 13

14 Satellite Coverage Everywhere Large Band Width High Throughput Combines well for Hybrid Solution Very Expensive Very, Very Expensive Extremely Expensive 14

15 Microwave Large Band Width High Throughput VoIP Hybrid Solutions Backbone Expensive Hardware Tower Rental Unforgiving Line of Sight 15

16 System Design Two Most Widely used Comm. Devices Licensed Radio Spread Spectrum Radio Path Study First (Always) Provided by integrator Provided by radio contractor Provided by radio manufacturer 16

17 Radio Equipment Antennas Omni Yagi Cables Surge Protectors Filters Towers or Masts 17

18 Antennas Omni 360 degree coverage Master Repeaters Yagi Single direction Slave sites 18

19 Signal Strength Radio output power Licensed 4 watts Spread Spectrum 1 watt Line loss (Cable) LMR db per 25 ft Gain from antenna 3 db 6 db 10db 19

20 Signal Strength Spread Spectrum 1 watt Line Loss: LMR db per 25 ft LMR db per 50 ft Surge Protector ½ dbm Connectors ½ dbm Antenna Gain 6 dbm 1 Watt equals 30dBm Minus 2 dbm 25ft LMR 400 cable Surge protector, & 1 connector Plus 6 dbm Antenna Equals 34 dbm (Roughly 3 Watts of output Power) 20

21 Filters Cone Notch Band Pass 21

22 Antennas/Towers Commercial Towers Rental per foot of elevation User Owned Towers 100 foot Free Standing $12, Guyed Towers $9, Antenna Placement No horizontal duplication Vertical Polarization 22

23 Conclusion Understand Objective FreeWave Slave Radios How much data, how often. Whitworth Best Fit Technology FreeWave Slave Radios CP10 FreeWave Slave Radios Radio FreeWave Slave Radios Hybrid Shurley 99-7 Fields Tower CP13 System Design Sonora Office West DC FreeWave Slave Radios Path Study Installation Kits Wilson FreeWave Slave Radios Accommodate growth Support Cry-out Fawcett Tower Cedar Ranch FreeWave Slave Radios Brown \Whitehead FreeWave Slave Radios FreeWave Slave Radios FreeWave Slave Radios FreeWave Slave Radios Glasscock McMullan Ranch 374 Primal 23

24 Conclusion! Overcome obstacles with proper design! Build scalable, cost effective solutions Good planning creates good systems Good systems communicate, every time, all the time! 24

25 Thank You 25