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Description of the measurement dynamic characteristics of the flowmeter

Dynamic characteristics of the flowmeter
When measuring a flow rate for a rapidly changing flow, the flowmeter needs to understand its dynamic characteristics. In the automatic control system of industrial production process, the flowmeter is used as the detector (or sensor) of the process control automation instrument, and its dynamic characteristics have an important influence on the control quality of the system.
The dynamic characteristics of the flow meter can be expressed in a time domain or frequency domain approach.
(I) Time domain representation
The time response characteristic of the flowmeter output value is shown when the input value of the measured object is a step signal. The quality indicator of the time response characteristic can be expressed by a time constant. The number of time bands refers to the time required for the output value to reach a steady state value of 63%.
(2) Frequency domain representation
Figure 3.5 shows the frequency response characteristics of the flowmeter output value when the input value of the measured object changes according to the sine wave frequency. The characteristic that the ratio of the flowmeter output value to the input value varies with frequency is called the frequency response characteristic of the flowmeter. The input value can also be a step signal, and the frequency response characteristic of the flow meter can be obtained through data processing.
A flow meter with good dynamic characteristics should have good frequency response, short response time and small tracking error.

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