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Automation Totalflow Measurement & Control Systems AGA3 Equations & Data

Automation Totalflow Measurement & Control Systems AGA3 Equations & Data. Summary - Totalflow’s AGA-3 Implementation. A portion of the equation is calculated once per second and the rest is calculated once per Vol Calc Period

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Automation Totalflow Measurement & Control Systems AGA3 Equations & Data

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  1. Automation Totalflow Measurement & Control Systems AGA3 Equations & Data

  2. Summary - Totalflow’s AGA-3 Implementation • A portion of the equation is calculated once per second and the rest is calculated once per Vol Calc Period • The Extension is integrated once per second • Also on a one second basis, update “flow-dependent” accumulators for Hw, Pf, and Tf in order to construct averages for use in Vol Calc Period calculations. • Additional set of timed averages (independent of flow) are maintained to provide Pf and Tf averages for complete periods without flow.

  3. Summary - Totalflow’s AGA-3 Implementation • Once Per Volume Calculation Period • These accumulators and the flowtime are used to calculate Vol Period averages for Hw, Pf, and Tf. • These Vol Period averages are then used to compute the Integral Multiplier (C’). • This Integral Multiplier is then multiplied with the Integrated Extension to compute Volume. • User Can Select either AGA3-85 or AGA3-92 • Adjustable Vol Calc Period of 1, 2, 5, 10, 30, or 60 minutes. • Supercompressibility computed using • NX19, various method • AGA8-92 Gross Method • AGA8-92 Detail Method (up to 23 composition variables)

  4. Summary - Totalflow’s AGA-3 Implementation • Either Linear or Square Root averages (user selectable) based on one second samples taken during times of flow. • Extrapolation of live inputs during transducer calibration • Selectable Static Pressure Tap Location • Selectable Differential Pressure Tap Type(Pipe Taps require AGA3-85)

  5. Summary - Totalflow’s AGA-3 Implementation • Equations are explicit implementations, not table driven approximations • Participated in API round robin for AGA-3-92 • API sought +/- 50 ppm deviation tolerance • 10,080 calculation sets were tested • Our deviations were within +/- 5 ppm • Along with whole flow computer, algorithms subjected to flow laboratory testing (CEESI)

  6. Calculation Method Calculation Units Reporting Units Fpv Method Contract Hour Pressure Tap Location Tap Type Temperature Base Pressure Base Ratio of Specific Heats Viscosity Ft and Fp for one form of NX19 Barometric Pressure Faux - Auxiliary Factory Factor Selects Hi/Lo Limits for Pf, DP, TF, Rate RTD Enable RTD Zero Bias Fixed Temperature Fb (AGA3-85) Use Fixed or Calced Cd? (AGA3-92) Fixed Cd (AGA3-92) DP Zero Cutoff AGA-3 Configuration Data Summary

  7. Fixed Composition (Events) Live Composition (No Events) Diameter Data for AGA3 92 Orifice Reference Diam Orifice Reference Temperature Orifice Coef. of Thermal Expansion Pipe Reference Diam Pipe Reference Temperature Pipe Coef. of Thermal Expansion Diameter Data for AGA3 85 Orifice Diameter Orifice Material Pipe Diameter DP Calibration Points (3 or 5) Pf Calibration Points (3 or 5) Device ID (10 characters) Calculation Period Log Period Averaging Technique(Linear or Square Root) Database Size Parameters Number of Events Number of Log Period Records Number of Day Period Records AGA-3 Configuration Data Summary

  8. Log Period is programmable (Default=60 min) Number of Log Period Records is programmable(Default = 970 records, or 40 days of hours + 10 skips) Record Size = 36 bytes Log Period Data Items Date/Time Sequence Number Average Dp Average Pf Average Tf Integrated Extension Quantity Volume Quantity Energy Flowtime Period time Discrete Alarms (24) Verification Code AGA-3 Log Period Data Summary

  9. Number of Day Period Records is programmable (Default = 50 Day records, 40 Days + 10 Day Skips) Record Size = 100 bytes Day Period Data Items Date/Time Sequence Number Event Sequence # Starting Log Period Sequence # Ending Log Period Sequence # Contract Hour Day Period Data Items cont Extension Volume Energy Flow Time Backflow Time Period Time Discrete Alarms (24) Min, Max & Avg Pf %PF Hi, %PF Lo Min, Max & Avg DP %DP Hi, %DP Lo Min, Max & Avg Tf %Tf Hi, %Tf Lo Verification Code AGA-3 Day Period Data Summary

  10. AGA Calculation Error NX19 Used Methane-Gravity Alternate Analysis Used Low Lithium Battery Low Charger DP Measurement Error Pf Measurement Error Tf Measurement Error DO #1 Tripped DI #1 Detected Backflow Detected Zeroflow Detected DP Below Low Limit DP Above Hi Limit Pf Below Low Limit Pf Above Hi Limit DO #2 Tripped DI #2 Detected Tf Below Low Limit Tf Above Hi Limit AGA-3 Log Period & Day PeriodDiscrete Alarms

  11. Number of Event Records is programmable (Default = 200 Events) Record Size = 12 bytes Event Record Data Items Date Time Event Flags (dayskip) Sequence # Event Code Old Value New Value Verification Code AGA-3 Event Log

  12. Compatibility with on-site/off-site Calculation Methods • Our Flow computers Are Compatible With Either • Off-Site Calculations • Integrated Extension, hourly or faster • Flowtime based averages for Live Inputs, hourly or faster(Averages must be in synch with extension) • Fixed Inputs for each Calculation available via Config and Events File • On-Site Calculations • High priority to pre-empt other tasks • Ability to accept Live inputs for Pf, Tf, DP • Ability to accept either real-time or periodic fixed composition • Adequate facilities to review necessary data at site

  13. Program/Config For Basic Operations • Can Be Configured using • On-site PC laptop software w/ user friendly interface • On-site ruggedized hand-held w/user friendly interface • On-site terminal with interactive command line interface or batch file upload/download capability (Tech Bulletin #44). • On-Site VT-52 compatible terminal with interactive menu driven from Flow Computer • Various Remote Communications Protocols • No permanently mounted keyboard or switches • Environmental Concerns • More economic to amortize cost over several flow computers. • Trend toward remote configuration

  14. Example Data Capacities 256K RAM = 262144 bytes System = 81920 200 Events = 2400 50 Day Recs = 5000 3850 Log Recs = 138600 Free = 34224 128K RAM = 262144 bytes System = 81920 200 Events = 2400 50 Day Recs = 5000 970 Log Recs = 34920 Free = 6832 (40 days of 60 min recs or 10 days of 15 min recs or 3 days of 5 min recs or <1 day of 1 min recs + 10 dayskips) (160 days of 60 min recs or 40 days of 15 min recs or 13 days of 5 min recs or 2+ days of 1 min recs + 10 dayskips)

  15. Example Data Capacities 512K RAM = 524288 bytes System = 81920 200 Events = 2400 50 Day Recs = 5000 11530 Log Recs = 415080 Free = 19888 (480 days of 60 min recs or 120 days of 15 min recs or 40 days of 5 min recs or 2 days of 1 min recs +10 dayskips)

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