Single signal conditioning multi electrode for ECVT data acquisition system

Data acquisition system with single signal conditioning for multi-electrode on electrical capacitance volume tomography (ECVT) was described. ECVT is a method in 3D process imaging based on electrical capacitance. The ECVT hardware is employed to measure capacitance signal from 32 electrodes as sensory module. In this investigation, one signal conditioning was used for all electrodes hence hardware construction is simplified and power consumption is relatively low. In order to achieve that, switch configuration which could form analog multiplexer with small resistance and capacitance is required. Each electrode needs 4 analog switches, so that for 32 electrodes 128 analog switches are needed. The electrode is selectable according to desired function as excitation or detection. Experiment result has shown that this ECVT system is able to accomplish capacitance measurement with resolution 0.42 fF.