Introduction of photoelectric switch detection scheme

Detection is to use physical methods to identify the number of measurement parameters in a certain range to determine whether the measurement parameters are qualified or whether there is a number of measurement parameters. During the measurement process, the unknown quantity to be measured is compared with the standard quantity of the same quality, the multiple of the standard quantity to be measured is determined, and the multiple is expressed in numbers. In the field of automation and testing, the task of testing is not only to test and measure finished or semi-finished products, but also to inspect, supervise and control a certain production process or moving object to make it in a better state selected by people. This kind of real-time detection and measurement technology of production process and moving target is also called engineering detection technology.

There are two measurement methods: direct measurement and indirect measurement

Direct measurement is to measure the measured object, the meter reading does not do any operation, directly from the measured value, such as: use a thermometer to measure temperature, use a multimeter to measure voltage. Indirect measurement is to measure several physical quantities related to the measurement, and calculate the measured value through functional relationships. For example, power p is related to voltage v and current i, that is, p=vi. Power can be calculated by measuring voltage and current.

The direct measurement method is simple and easy to implement, and is often used in practice. However, in cases where direct measurement cannot be used, inconvenient or large errors, indirect measurement can be used.