What is the zero point transfer of a pressure transmitter

A change in the value of an output due to some influence when the input is at the lower limit of the range.When the current limit value is not zero, it is also called the starting point migration (offset).

Take the input signal (measured) of the instrument relative to the range as the abscissa, and the output signal relative to the signal range as the ordinate, then the input/output characteristic curve of the instrument can be drawn, and set it as the linear relationship.When the characteristic curve shifts and the slope of the curve remains the same, it is called a zero point migration.

The measuring range of the transmitter is equal to the range + migration, that is, the measuring range = the range + migration.The positive migration moves to the positive direction, and the negative migration moves to the negative direction, and the distance of movement is the migration quantity. Therefore, the essence of positive and negative migration is to change the upper and lower limits of the range by adjusting the transmitter, while the size of the range remains unchanged.It can also be remembered as follows: when the input pressure is zero (0%), the output current signal is also zero (0%), indicating no migration;When the input pressure is zero (0%), the output current signal is positive and negative.When the input pressure is zero (0%), the output current signal is negative, less than the working zero, is positive migration;



When the differential pressure transmitter is used to measure the liquid level, if the positive and negative pressure Chambers of the differential pressure transmitter are on the same level as the pressure point of the container, migration is not necessary.However, in practical application, due to the consideration of equipment installation location and easy maintenance, the measuring instrument may not be on the same level with the pressure point.If the medium under test is highly corrosive or heavy viscosity of the liquid, can not directly put the medium into the pressure gauge, must be installed isolation liquid tank, with the isolation liquid to transmit the pressure signal, in order to prevent the instrument under test by corrosion.The effect of the column of media and spacer on the reading of the pressure gauge must be considered.

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