The ECVT DAS is an Electrical Capacitance Tomography Data Acquisition box.Â ItÂ is designedÂ to monitor Â industrial processes and produceÂ images ofÂ multi-phase flow. The DAS measures the capacitance between all plate pairsÂ of the sensor. It provides 276 distinct plate pair combinations with a resolution higher than 1 femtofarad.
The DAS dynamically balances out the standing capacitance of the cells (Â typically in the order of picofard) and the effect of cable capacitance (typically 500 picofarads). It operates at a rate of 50 frames per second when all 24 channels are used, and provides real time digitization of the flow. The mixed signal design uses a Virtex-5 FPGA which interfaces to DAC’s, ADC’s, multiplexer banks and programmable gain amplifiers.