1. Calibration Calibration is the process of checking and adjusting the accuracy of a measuring instrument by comparing it with a standard / benchmark. Calibration is necessary to ensure that the measurement results taken are accurate and consistent with other instruments.

  2. Calibration Scope The calibration process begins with designing the measuring instrument you want to calibrate. The design must be able to “withstand calibration” at the calibration interval. In other words, the design must be able to measure to a certain tolerance when used under certain environmental conditions for a reasonable period of time. Designs having these characteristics increase the likelihood of the instrument measuring according to the initial estimate (initial prediction). Basically, the purpose of calibration is to maintain the quality of the measurements in order to ensure proper work of the instrument. The other calibration objectives are as follows:

    • Achieve measurement traceability. Measurement results can be linked or traced to a higher / more rigorous standard (national and / international primary standards), through an unbroken series of comparisons.

    • Determine the deviation (storage) of the correct conventional value designation of a measuring instrument.

    • Guarantee the measurement results are in accordance with national and international standards.

    The benefits of calibration from measuring instruments are as follows:

    • Maintain the condition of measuring instruments and measuring materials in accordance with specifications.
    • To support the quality system applied in various industries in the laboratory and production equipment owned.
    • Can tell the difference between the true value and the value indicated by the measuring instrument
    • Can know the true price deviation from the price shown by the measuring instrument.

  3. Standard Calibration One of the steps in the calibration process is choosing a calibration standard, because a calibration standard is one of the most visible parts of the calibration process. Ideally a standard that has an uncertainty of less than 1⁄4 of the tool you want to calibrate. If this is achieved, the measurement uncertainty of the standard is said to be insignificant because the final measurement ratio is 4: 1.

  4. International Units International Units (abbreviated SI) is the most commonly used modern metric. SI has coherent units based on seven basic units, namely amperes, kelvin, second, meter, kilogram, candela and mole. From the seven standards, 22 derivative units can be derived such as lumens, watts and others. All basic SI units (except for the kilogram) can be derived from natural constants such as the speed of light and the three-point change in the form of water, which can now be measured with excellent accuracy.

    Figure 1. Platinum and iridium cylinders used for a standard mass of 1 kilogram. These cylinders are stored in three-layer glass which has been stored in France since 1889.

    The kilogram standard is a special base unit because it cannot be derived from constants in nature. However, this unit standard is taken from a platinum iridium cylinder certified in 1889 which has the same mass as a liter of water at its freezing point. The following are the other SI base units:

    • Meter. This unit is denoted by the letter “m” with the dimension symbol is denoted by the letter “L”. This quantity represents the distance from one point to another on a straight line. Interestingly, when this unit was first used in 1793, the standard was 1/10000000 of the meridian of the city of Paris in France between the north pole and the equator. Now, this unit was standardized in 1983 by taking the distance that light travels in the vacuum in 1/299792458 seconds.
    • Kilogram. this unit is denoted by the letter “kg” with the dimension symbol “M” in this unit describes the mass, which is the characteristic of an object if the object is attracted to each other in accordance with its gravitational force. As stated earlier, the mass of 1 kg is the mass of a platinum-iridium cylinder stored in France.
    • Second. This unit is denoted by the letter “s” with the dimension symbol “T” this unit represents time. Time is the progress of existence and events that occur in an irreversible order from the past, present to future. The interesting thing is that time is generally referred to as the fourth dimension of the 3- spatial dimension. Seconds were standardized in 1967 as the duration for the cesium-133 atom to transition during the 9191631770 period between the Hyperfine level and the base level.
    • Ampere. This unit is denoted by the letter “A” with the dimension symbol I this unit describes is an electric current. Electric current is the amount of charge at any given time. In 1946 the current constant was standardized by keeping two conductors parallel at this minimum length with a distance of 1 m if the resulting force on the two conductors was equal to 2E (-7) newtons per meter.
    • Kelvin. This unit is denoted by the letters K and given a symbol Θ in the dimension symbol. It describes the temperature thermodynamics where the standard in 1967 with 1 / 273.16 temperature at three water points (triple point water). A mole unit is a unit which describes the number of atoms in 0.012 kilograms of carbon-12. This unit is denoted by the word “mole” with the dimension symbol N.
    • Candela. In 1979 the light intensity was in the vector direction from a source that produces monochromatic radiation with a frequency of 5.4E14 hertz and having a mean intensity in the direction of 1/683 watt per steradian. This unit is denoted by the word “cd” with the letter “J” as a symbol of the dimension.

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