A pressure transmitter is a device used to measure pressure, which can convert the pressure signal into an electrical signal or a digital signal for monitoring and control. The two most common types of measurement are absolute pressure and gauge pressure.
Absolute pressure refers to the absolute pressure of the measured medium at a certain temperature, which does not change with the change of the external environment, and is usually used to measure the pressure of the gas. Gauge pressure, on the other hand, refers to the atmospheric pressure of the measured medium relative to the surrounding environment, which will change with the change of atmospheric pressure, and is usually used to measure the pressure of liquids.
In practical applications, the measurement of absolute pressure and gauge pressure has different application scenarios and characteristics. Absolute pressure measurement is usually used for pressure measurement of gases, such as compressed air, natural gas, etc., because the distance between gas molecules is large and not disturbed by atmospheric pressure, so the use of absolute pressure measurement can more accurately reflect the actual pressure of gases. Gauge pressure measurement is usually used to measure the pressure of liquids, such as water and oil, because the distance between liquid molecules is smaller, and the interference of atmospheric pressure is greater, so the use of gauge pressure measurement can more accurately reflect the actual pressure of liquids.
In addition to the different application scenarios, the measuring principles of absolute pressure and gauge pressure are also different. Absolute pressure measurement is usually done in isolation, where the medium to be measured is isolated from the atmosphere and then the absolute pressure of the medium is measured. Gauge pressure measurement, on the other hand, usually uses a reference measurement method, that is, the measured medium is connected to the atmosphere, and then the relative pressure of the medium is measured.
In actual use, the measurement of absolute pressure and gauge pressure also needs to pay attention to different precautions. Since absolute pressure measurement involves the measurement of absolute pressure, the influence of temperature, gas composition and other factors needs to be considered to ensure the accuracy of the measurement. Gauge pressure measurement, on the other hand, needs to take into account the effect of changes in atmospheric pressure on the measurement, so it is necessary to calibrate the equipment regularly to ensure the accuracy of the measurement.