- •Standard function blocks
- •FF signal status
- •Function block modes
- •Device commissioning
- •Calibration and ranging
- •H1 FF segment troubleshooting
- •Cable resistance
- •Signal strength
- •Electrical noise
- •Using an oscilloscope on H1 segments
- •Review of fundamental principles
- •Wireless instrumentation
- •Radio systems
- •Antennas
- •Decibels
- •Antenna radiation patterns
- •Antenna gain calculations
- •RF link budget
- •Link budget graph
- •Fresnel zones
- •WirelessHART
- •Review of fundamental principles
- •Instrument calibration
- •Zero and span adjustments (analog instruments)
- •Calibration errors and testing
- •Typical calibration errors
- •Automated calibration
- •Damping adjustments
- •LRV and URV settings, digital trim (digital transmitters)
- •An analogy for calibration versus ranging
- •Calibration procedures
- •Linear instruments
- •Nonlinear instruments
- •Discrete instruments
- •Instrument turndown
- •NIST traceability
- •Practical calibration standards
- •Electrical standards
- •Temperature standards
- •Pressure standards
- •Flow standards
- •Analytical standards
- •Review of fundamental principles
- •Continuous pressure measurement
- •Manometers
- •Mechanical pressure elements
- •Electrical pressure elements
- •Piezoresistive (strain gauge) sensors
- •Resonant element sensors
- •Mechanical adaptations
- •Differential pressure transmitters
- •DP transmitter construction and behavior
- •DP transmitter applications
- •Inferential measurement applications
- •Pressure sensor accessories
- •Valve manifolds
- •Pressure pulsation damping
1310 |
CHAPTER 18. INSTRUMENT CALIBRATION |
18.11Review of fundamental principles
Shown here is a partial listing of principles applied in the subject matter of this chapter, given for the purpose of expanding the reader’s view of this chapter’s concepts and of their general interrelationships with concepts elsewhere in the book. Your abilities as a problem-solver and as a life-long learner will be greatly enhanced by mastering the applications of these principles to a wide variety of topics, the more varied the better.
•Linear equations: any function represented by a straight line on a graph may be represented symbolically by the slope-intercept formula y = mx + b. Relevant to instrument input/output scaling.
•Zero shift: any shift in the o set of an instrument is fundamentally additive, being represented by the “intercept” (b) variable of the slope-intercept linear formula y = mx + b. Relevant to instrument calibration: adjusting the “zero” of an instrument always adds to or subtracts from its response.
•Span shift: any shift in the gain of an instrument is fundamentally multiplicative, being represented by the “slope” (m) variable of the slope-intercept linear formula y = mx + b. Relevant to instrument calibration: adjusting the “span” of an instrument always multiplies or divides its response.
•Deadband and hysteresis: the di erence in response with the independent variable increasing versus decreasing. Usually caused by friction in a mechanism. Relevant to the calibration testing of instruments, both analog and discrete. For continuous measurement devices, the response of a sensor at some stimulus value (increasing) will not be the exactly the same as the response of that same sensor at that same value when decreasing. For process switches, the “trip” the value at which a switch changes state when its stimulus increases is not the same value it changes state when its stimulus decreases.
References
Agy, D. et al., Calibration: Philosophy In Practice, Second Edition, Fluke Corporation, Everett, WA, 1994.
Lipt´ak, B´ela G. et al., Instrument Engineers’ Handbook – Process Measurement and Analysis Volume I, Fourth Edition, CRC Press, New York, NY, 2003.
“Micro Motion ELITE Coriolis Flow and Density Meters”, product data sheet DS-00374 revision L, Micro Motion, Inc., June 2009.