What is calibration?
Calibration in measurement is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Static and dynamic are two classifications of calibration
Static calibration:
A static calibration is a calibration where the physical input does not vary significantly as a function of time; in other words, the frequency of the physical input is 0Hz. An example of a static calibration is a measurement of the output of an accelerometer excited by a constant instantaneous value such as +1g. An example of static calibration is to place a load on wings of an aircraft to calibrate strain gages mounted on the wing.
There are numerous techniques for calibrating devices such as thermocouples and strain gage bridges using electrical simulation and reference junctions. In the field, a known input such as a static pressure should be applied. The engineer should understand and refer to the laboratory and manufacturer’s calibration procedure
Examples of measurements that may require static calibrations include temperatures, flight loads, humidity, and Pitot-static pressure.
Dynamic calibration:
For dynamic calibration, the instantaneous value of the physical input varies as a function of time; in other words, the frequency content is greater than 0Hz. An example of dynamic calibration is the placement of an accelerometer on a hand held shaker calibrator that excites the accelerometer at a frequency of 159Hz and amplitude of 1grms.
Dynamic Data Acquisition and Analysis introduces the subject of the calibration of dynamic measurement systems. End-to-end mechanical calibrations include calibration signal and insertion procedures, random excitation, sinusoidal excitations, step excitations, and reconciliation of calibration discrepancies. Calibrations can be single frequency, frequency sweeps, or random noise calibrations. An understanding of manufacturer and laboratory calibration procedures is essential. When possible, an end-to-end calibration should be accomplished.
In most checking procedures the effort is to produce a condition where no output is expected; if an output is produced, it is declared garbage. Today, testing is expensive and computer power is of relatively low cost. The few tests we can afford must be above reproach and yield provably valid data. Check channels should be used for both self-generating and non-self-generating
In most checking procedures the effort is to produce a condition where no output is expected; if an output is produced, it is declared garbage. Today, testing is expensive and computer power is of relatively low cost. The few tests we can afford must be above reproach and yield provably valid data. Check channels should be used for both self-generating and non-self-generating