Several measurement methods and applicable scope of sensors

In the process of system detection, various sensors need to be used. The measurement method and performance of the sensor are key factors in whether the detection task can be successfully completed. In the actual operation process, it is necessary to analyze different detection purposes and specific situations, and then find out feasible measurement methods, and then select appropriate detection technology tools according to the measurement method to form a complete detection system for actual measurement. There are three main measurement methods for sensors: direct measurement, indirect measurement and combined measurement. This article compares these three measurement methods to see which detection systems they are suitable for.

Direct measurement

Direct measurement means that when using a sensor instrument for measurement, the instrument reading does not need any calculation to directly represent the required measurement result. For example, using a magnetoelectric ammeter to measure the current of a circuit, using a spring tube pressure gauge to measure the pressure of a boiler, etc., all belong to direct measurement. The advantage of direct measurement is that the measurement process is simple and fast, and the disadvantage is that it is not easy to achieve high measurement accuracy. This measurement method is widely used in engineering.

Indirect measurement

In some measurement situations, the measured quantity cannot or is not convenient to be measured directly. This requires that when using sensors for measurement, several quantities that have a certain functional relationship with the measured physical quantity should be measured first, and then the measured values ​​should be substituted into the functional relationship to obtain the required results through calculation. This method is called indirect measurement. Indirect measurement requires more quantities than direct measurement, and the calculation process is more complicated, and there are more factors that cause errors. However, if the errors are analyzed and the optimized measurement method is selected and determined, and indirect measurement is performed under relatively ideal conditions, the accuracy of the measurement results may not be low, and sometimes higher measurement accuracy can be obtained. Indirect measurement is generally used in situations where direct measurement is inconvenient or there is a lack of direct measurement means.

Combined measurement

When using sensors and instruments for measurement, if the measured physical quantity must be solved by a set of simultaneous equations to obtain the final result, such measurement is called combined measurement. When performing combined measurement, it is generally necessary to change the test conditions to obtain the data required by a set of simultaneous equations. Combined measurement is a special precision measurement method with complex operating procedures and a long time consumption. It is generally suitable for scientific experiments or special occasions.

This article briefly compares the three measurement methods of sensors. Each measurement method has a different scope of application. When choosing, users need to make a comprehensive judgment based on the actual situation of the system.