What is the variation of instrument fittings

What is the variation of instrument fittings
The variation of instrument pipe fittings refers to the difference between the indicated values of the instrument when the measured variables reach the same value from different directions for many times, or the degree of inconsistency between the measured parameters changing from small to large (positive characteristic) and the measured parameters changing from large to small (negative characteristic) when the external conditions of the instrument remain unchanged. The difference between the two is the variation of the instrument.
The variation is taken as the percentage of the ratio between the error and the scale range of the instrument: the main causes of variation are the clearance of the moving mechanism of the instrument, the friction of the moving parts, the lag of the elastic elements, etc. With the continuous improvement of instrument manufacturing technology, especially the introduction of microelectronics technology, many instruments are fully electronic and have no movable parts, so the variation index is not so important and prominent in intelligent instruments.