Measurement

Measurement

Introduction

Measurement is the process of collecting and processing information in order to obtain the numerical values of the existing units. Different requirements of production practice and a huge amount of measurements and determine the various methods for measuring the actual dimensions. Method of measurement include a collection of tools and measurement conditions, making it possible to obtain complete information on the accuracy of a given parameter product under optimal technical and economic parameters of the measurement process (Douglas, 2007).

Discussion

The development history of science shows a tendency to unify the systems of units and achieve simplification of their conversions. It is now almost universally accepted the International System of Units, which from seven magnitudes, known fundamental derives the known set of units, expressing the values of all variables used to characterize the properties of objects and phenomena nature. This derivation is based on relationships established by arbitrarily or responds to physical laws (angelfire.com, 2013). By expressing the value of a measurement is not enough to determine the measured value as a timely determination, since it does not indicate how close or far you are to the true value. It is necessary to express the range of uncertainty in the measurement, i.e., express it as a confidence interval, only then will you know how accurate and precise measurement is performed.

Basic metrological performance measuring tools and instruments

Metrology is the science of measurement and means to implement them. Technical measurements in engineering are an organic part of the whole process. In the repair production machinery industry as a sector, to technical measurements impose substantially the same requirements. However, remember that in the repair production measurement used for the purpose of defect ration and test specifications for the assembly, and this requires a different approach to the selection of measuring tools, measuring instruments and tools (Douglas, 2007). Basic metrological performance measurement tools are:

Scale value unit - measured value corresponding to the movement of the pointer on one scale.

Interval scale values (scale line) - the distance between the axes of symmetry of the two close lying lines (expressed in lineyn.'s or in angular units). For example, the caliper ShTs type-1 (accurate reading of 0.1 mm) primary scale on the bar has a range of division and division value equal to 1 mm, and a vernier same interval division amounts to 1.9 mm, and the price division - 0.1 mm.

Scale Reading device - measured value corresponding to the full scale and equal to the product of the price of dividing by the number of stops.

Measurement limits on the scale of the instrument - the measured value corresponding to, the movement pointer to the total number of stops.

Limits of measurement instrument as a whole - the largest and smallest values of dimensions that can be measured with this instrument (Pedhazur, et al. 1991).

Methods of Measurement

There are two main methods of measurement: absolute and relative. Absolute (direct) method gives the value of all the measured values e.g., the entire length or the entire diameter ...