Electric eddy current pick-up of turbine flow sensor and CPLD nonlinearity correction

摘要

The force due to electromagnetic pick-up can affect the performance of small pipeline turbine flow sensor. Based on electric eddy current, a new pick-up was designed for eliminating the effect of reluctance torque in traditional pick-up. The range ability of DN4mm, DN6mm and DN10mm turbine flow sensor were expanded to 10∶1. The reliability of nonlinearity correction by software is not fully guaranteed as it was applied in bad work condition. In order to solve the problem, a method of nonlinearity correction by hardware, is that Complex Programmable Logic Device (CPLD), was put forward. It was shown by turbine flow sensor prototype experiment with electric eddy current pick-up combining CPLD hardware nonlinearity correction. DN4mm, DN6mm and DN10mm turbine flow sensor obtain the linearity 0.32%, 0.26%and 0.32% respectively in the range ability of 10∶1.