Data acquisition refers to the automatic collection of data from various data sources into a device. The collected data is a variety of physical quantities that have been converted into telecommunications, such as temperature, water level, wind speed, pressure, etc. It can be analog or digital. Generally, the collection method is sampling, that is, the data of the same point is collected repeatedly at certain intervals (called sampling period). Most of the collected data are instantaneous values, but also an eigenvalue in a certain period of time. Accurate data measurement is the basis of data acquisition.