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ACADs (08-006) Covered Keywords

Advanced Process & Measurement Control. ACADs (08-006) Covered Keywords Process measurement, control, zero error, angular error, units of weight, units of measurement, SI Measurements, range, span, upper range, lower range, accuracy, precision. Description Supporting Material.

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ACADs (08-006) Covered Keywords

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  1. Advanced Process & Measurement Control ACADs (08-006) Covered Keywords Process measurement, control, zero error, angular error, units of weight, units of measurement, SI Measurements, range, span, upper range, lower range, accuracy, precision. Description Supporting Material

  2. NIA97ADVANCED PROCESS AND MEASUREMENT CONTROL Any sufficiently advanced technology is virtually indistinguishable from magic. Arthur Clark

  3. Path to becoming an I&C Techat Palo Verde Plant Systems Advanced Process NIA97 GPI I&C Tech In Field (OJT) Loop Calibration The ‘100’ card Loops NIA02 Foxboro NIA98 Other required training: Site Access Training RWP & Dress out Respirator training & fit test Conduct of Maintenance Prints & Plant Drawings Tagging Electrical Safe Work Practices Industry Events I&C Select Training: PPS, Excore BOP/NSSS ESFAS SESS/RK RRS/SBCS QSPDS CEDMCS DAFAS VLPMS Technical Skills NIB43 Seismic DFWCS Fire Protection PPC/PLC GR EHC/TSI Gas Turbine

  4. NIA97 Lessons • Measurement Fundamentals • Pressure instrumentation • Level instrumentation • Flow instrumentation • Temperature instrumentation • Pneumatic instrumentation • Calibrating & maintaining flow control valves

  5. Terminal Objective • From memory the I&C Technician will define concepts and terminology related to the process measurement and control industry. Mastery will be demonstrated by successful completion of Lab Performance Exercises and written Exam.

  6. Enabling Objectives • Define the term "measurement“ • List two common engineering measurement systems • Define the following terms as they relate to process measurement and control: • a. Range • b. Span • c. Linearity • d. Dead band • e. Hysteresis • f. Sensitivity • g. Conformity • h. Accuracy • i. Resolution • Differentiate between "Zero Error" and "Angular Error"

  7. Measurement is • the determination of the size or magnitude of something. • An observation that reduces the amount of uncertainty about the value of a quantity. • A comparison of a quantity to some standard, called a unit Who decides which units we will use?

  8. Imperial or English Customary Weights & Measurements 1 inch = the length of 3 barleycorns (the word ‘inch’ comes from the word ‘thumb’ in some languages) 1 yard = the distance from the nose to the fingertip of Henry I 1 mile = the length of 1000 paces of a Roman legion 1 acre = a field of a size that a farmer can plow in a single day 1 grain = the weight of 1 barleycorn 1 pound = 7000 grains (The Latin word for pound is Libra, hence the abbreviation LB) 1 gallon = the volume of 8 pounds of wheat

  9. U.S. Customary Units • Similar to the old Imperial system • Based on many old local units derived over centuries, often based on old Anglo-Saxon and Roman units • Length: The inch, foot, yard, and mile are declared units based on historical customs • Volume: The ounce, quart, cup, pint, gallon, and barrel are declared units based on custom • Weight: The ounce, pound, and ton are Avoirdupois weights based on custom • Temperature: Degrees Fahrenheit based on historical custom.

  10. The SI System 1 meter = the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second 1 second = the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom 1 Kelvin = The Kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water." 1 kilogram = the mass of the international prototype of the kilogram

  11. The Second • Same unit in nearly every system • Originally 1/86,400 of a mean solar day • Earth’s rotation is not sufficiently uniform • With the development of atomic clocks, the second was redefined in terms of atomic time. • the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom

  12. Unit systems we do not use • MKS-Meter/Kilogram/Second • CGS-Centimeter/Gram/Second • Both were replaced by the SI system in 1960

  13. Bureau International des Poids et Mesures The BIPM at Le Pavillon de Breteuil in Sevres, France

  14. SI base units Base quantity Name Symbol length meter m mass kilogram kg time second s electric current ampere A thermodynamic temperature kelvin K amount of substance mole mol luminous intensity candela cd

  15. KPa • 1 Pascal = 1 Newton x 1 meter2 • 1 Newton = 1 kilogram x 1meter/sec2 • 1000 Pascal x 1 meter2 = 1 KPa • 1 Kilopascal = 0.145 psi • 1000 Kilopascal = 145 psi

  16. Range Vs. Span What is the range of the output of a Rosemont transmitter? What is the span?

  17. Range: The region between the limits within which a quantity is measured Span: The algebraic difference between the upper and lower limits of a range expressed in the same units as the range.

  18. URV – Upper Range Value – the highest quantity a device is adjusted to measure • LRV – Lower Range Value – the lowest quantity a device is adjusted to measure

  19. Terms • Accuracy • Precision • Resolution • Inaccuracy • Linearity • Scale • Total loop uncertainty • Repeatability • Tracability • Sensitivity • Conformity

  20. Accuracy vs. Precision measure with a micrometer, mark with chalk cut with an ax

  21. Precision: How much you care to say about a particular itemAccuracy: How correct you are when you say something about that itemResolution: The resolving power of a system, the smallest increment in a measurement

  22. Zero, Span, Angularity & Gain Static Calibration Errors

  23. Input Ideal Output (psig) (ma) (ma) 0 4 4 25 8 8 50 12 12 75 16 16 100 20 20

  24. Span Adjustment Zero Adjustment

  25. Input Output (psig) (ma) 0 4 25 8.25 50 12.5 75 16.75 100 21.0 Angular or Span Error

  26. Input Ideal Output (psig) (ma) (ma) 0 4 4 25 8 7.75 50 12 11.5 75 16 15.25 100 20 19 Would you adjust zero or span?

  27. Input Ideal Output (psig) (ma) (ma) 0 4 3 25 8 7 50 12 11 75 16 15 100 20 19 Would you adjust zero or span?

  28. Input Ideal Output (psig) (ma) (ma) 0 4 5 25 8 9 50 12 13 75 16 17 100 20 21 Would you adjust zero or span?

  29. Zero Based Linearity

  30. Linearity-a behavior of a system in which the output varies in direct proportion with the input. In a linear circuit the output/input ratio is always the same • Sensitivity-The ratio of the change in output magnitude to the change in input that caused it

  31. Conformity-(used when output is not linear from input) the closeness to which the output curve approximates a specified curve, such as a parabolic or logarithmic. Conformity is specified as independent, terminal-based, or zero based • Repeatability Repeatability is the closeness of agreement among a number of consecutive measurements of the output for the same value of the input under the same operating conditions, approaching from the same direction. It does not include hysteresis.

  32. Hysteresis

  33. I2V Uncertainty Transmitter +/- 0.5% Converter +/- 0.25% Indicator +/- 0.75% Total Loop Uncertainty = 0.935%

  34. On to Measuring Pressure

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