An experimental rig capable of automatically sequencing and collecting data from a dead-end pressure filter is described, The computer-controlled apparatus uses electrical impedance measurements in multiple vertical scanning planes to determine the status of a filter cake during either the cake formation, gas dewatering or displacement washing phases of a filter cycle, The data acquired are displayed in real time during a test in conjunction with liquor flow rates, Initial results from an experimental programme are presented, which show the filtration and dewatering characteristics of aqueous-based calcium carbonate suspensions, The importance of data acquisition and system control are discussed, and an outline of future developments is given.