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

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 non linearity 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.