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‘Demonstrates the need for calibrating test and monitoring equipment. Shows how the US Navy’s calibration program is organized.’
US Navy Training Film MN-10105
Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
Calibration is process of finding a relationship between two unknown (when the measurable quantities are not given a particular value for the amount considered or found a standard for the quantity) quantities. When one of quantity is known, which is made or set with one device, another measurement is made as similar way as possible with the first device using a second device.The measurable quantities may differ in two devices which are equivalent. The device with the known or assigned correctness is called the standard. The second device is the unit under test, test instrument, or any of several other names for the device being calibrated.
The formal definition of calibration by the International Bureau of Weights and Measures is the following: “Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or secondary standard) and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication.”…
History
Origins
The words “calibrate” and “calibration” entered the English language as recent as the American Civil War, in descriptions of artillery. Some of the earliest known systems of measurement and calibration seem to have been created between the ancient civilizations of Egypt, Mesopotamia and the Indus Valley, with excavations revealing the use of angular gradations for construction. The term “calibration” was likely first associated with the precise division of linear distance and angles using a dividing engine and the measurement of gravitational mass using a weighing scale. These two forms of measurement alone and their direct derivatives supported nearly all commerce and technology development from the earliest civilizations until about AD 1800…
Modern metrology calibration targets different types of industrial instruments that can be categorized based on the physical quantities they are designed to measure. Exact categorizations vary internationally, e.g., NIST 150-2G in the U.S. and NABL-141 in India. Together, these standards cover instruments that measure various physical quantities such as electromagnetic radiation (RF probes), time and frequency (intervalometer), ionizing radiation (Geiger counter), light (light meter), mechanical quantities (limit switch, pressure gauge, pressure switch), and, thermodynamic or thermal properties (thermometer, temperature controller). The standard instrument for each test device varies accordingly, e.g., a dead weight tester for pressure gauge calibration and a dry block temperature tester for temperature gauge calibration.
Calibration methods for modern devices can be both manual and automatic, depending on what kind of device is being calibrated. The picture on the left shows a U.S. Navy Airman performing a manual calibration procedure on a pressure test gauge. The procedure is complex, but overall it involves the following: (i) depressurizing the system, and turning the screw, if necessary, to ensure that the needle reads zero, (ii) fully pressurizing the system and ensuring that the needle reads maximum, within acceptable tolerances, (iii) replacing the gauge if the error in the calibration process is beyond tolerance, as this may indicate signs of failure such as corrosion or material fatigue…
Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement.
Metrology is defined by the International Bureau of Weights and Measures (BIPM) as “the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology.” The ontology and international vocabulary of metrology (VIM) is maintained by the Joint Committee for Guides in Metrology (JCGM), a group made up of eight international organisations – BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML and ILAC…
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