Accuracy is an important indicator of measuring instruments. In the flow measurement of ultrasonic flowmeters with time difference method, the error sources mainly come from the following aspects: 1. Effect of machining accuracy and temperature variation on mechanical size. The machining accuracy of mechanical parameters such as acoustic path Angle, pipe diameter, acoustic path, and temperature stability have a direct impact on the measurement of which glass is. In the measurement process, they will change with the change of temperature. This error can be minimized by precision machining, reasonable material selection and reasonable structural design. The propagation speed of ultrasonic wave increases with the increase of fluid temperature, so the measurement error will be brought. The influence of fluid temperature change on the accuracy can be automatically compensated by temperature compensation method through the measurement of fluid temperature and the calculation of temperature compensation digital model. 3. The electrical characteristics of the error device is unstable, the low precision of the counting circuit makes the flow measurement error, in order to reduce the error, we choose high-precision and high-stability quartz crystal oscillator as the base signal, the selection of large-scale high-speed programmable logic devices to achieve complex logic control and high-precision timing functions, in order to achieve the stability and reliability of the system. 4. Echo waveform change and amplitude change bring error The change will make the timing comparison point of the ultrasonic flowmeter binary circuit change, resulting in waveform error, which is difficult to overcome with hardware methods, must be solved by software method to introduce intelligent analysis algorithm.
Post time: Nov-03-2024