A high frequency digital induction system for condutive flow level measurements

• Demonstration of real time monitoring of low conductivity flow levels based on inductive principle in a non-contact manner.
• Development of a FPGA-based system capable of delivering 1000 data per second.
• Established relationships between flow parameters and phase angle of inductive measurements.

A highly integrated, Field Programmable Gate Array (FPGA) based induction measurement system for conductive flow level measurement is presented. Exploiting under-sampling and digital I/Q demodulation techniques, the system use direct digital sampling and can operate at multiple frequencies (from 100 kHz to over 10 MHz). Details are discussed in both hardware and software aspects. Simulations and experiments at 2.6 MHz and 8.3 MHz are carried out using saline solutions with conductivities of 1.8 S/m and 4.3 S/m to verify the performance of the system. Application of the system for saline level monitoring is implemented and studied, which further proves the applicability of the system in low conductivity object measurements.