Composition and function of photoelectric detection system

The basic composition of photoelectric detection system and the main functions of each part.

Its basic components can be divided into: light source, formation of detected objects and optical signals, matching processing of optical signals, photoelectric conversion, amplification and processing of electrical signals, microcomputer, control system and display.

Light source The light beam emitted by the light source is a substance that carries the detected information. The formation of the detected object and optical signal utilizes various optical effects, such as reflection, absorption, interference, diffraction, polarization and so on. The light beam carries the characteristic information of the object to be measured to form the signal to be measured, and the information to be measured can be better obtained by matching the light signal. In order to meet the needs of photoelectric conversion, photoelectric conversion converts optical signals into electrical signals, and the amplification and processing of electrical signals use circuits with different functions to achieve various detection purposes. Microcomputer, control system and display display the processed electrical signal to be measured directly through the display system.

2 Direct measurement, indirect measurement, true value, specified value and practical value

For direct measurement, the to-be-measured is directly compared with another known quantity of the same kind; For indirect measurement, the measured quantity is indirectly compared with another known quantity of the same kind. The theoretical or defined values of physical quantities are stipulated by various physical standards or standard devices established by the state and remain unchanged as much as possible. The practical value is transmitted to all levels of metering stations and specific testing instruments step by step through the transmission of metering standards. When comparing and measuring, metering stations or testing instruments at all levels regard the values of the previous standard as approximate true values, which are all called practical values, reference values or transfer values. 3. Check the balance with a standard weight, weigh the object with the balance, measure the nightglow strength with an illuminance meter, and measure the workpiece size with a caliper. What are the practical values of the above?

Standard checkweigher is not used to weigh objects. It is not used to measure the strength of nightglow with an illuminance meter, but to measure the size of the workpiece with a caliper.

What are systematic errors and random errors, and what are their causes?

System error produces a constant error in the detection process, which is called constant error or error that changes according to a certain law, which is called variation. The causes of system error include tool error, equipment error, method error, external error and personal error.