Instrument calibration Definition: Instrument used for measurement alone or in conjunction with auxiliary equipment (also known as measuring instrument) Instrument calibration is a technical tool or device used to measure and obtain the value of the object being measured. Its main features are :1, used for calibration; 2, itself is a technical tool or device. In China's relevant metrological laws and regulations, measuring instruments are called measuring instruments, that is, measuring instruments are synonymous with instrument calibration. Classification: Measuring instruments are divided into measuring instruments, physical measuring instruments, standard substances and measuring systems (or devices) according to their structural characteristics and measuring purposes. 1, physical measuring instruments: in a fixed form to copy or provide one or more known values of quantitative instruments. 2, measuring instruments: from different angles can have different naming methods, usually: named in the name of the measurement, named in the name of the measurement principle involved, named in the name of the inventor of the instrument, named in the name of the manufacturer or the name of the product chosen by the manufacturer. There are many kinds of measuring instruments, but judging whether it is a measuring instrument or whether the main judgment of the instrument is used for measurement mainly depends on whether the measurement is converted on the instrument. Generally speaking, measuring instruments are divided into display, recording, accumulation, integration, analog and digital. (3) Standard material: having one or more materials or materials that are uniform and deterministic enough to calibrate measurement devices, evaluate measurement methods or give value to materials. It can be pure or mixed gas, liquid or solid and falls under the category of physical measurement. 4, measurement system: Assemble a complete set of measuring instruments and other equipment for specific measurements. For specific or multiple measurement tasks.