Abstract: There is provided a multi-parameter, self-contained, programmable, microcomputer-controlled monitoring system for the measurement of physical and chemical properties of water and other fluids. Data are stored within a sensor packge according to a chosen format and schedule. Oceanographic and limnological data are thus gathered without need of umbilical power and/or data links to external devices. A programming and interpreting device provides analytic interface with the sensor packge for logic input and data readout. Program-controlled analog/digital conversion yields constants for calibration of sensors which leads to freedom from measurement drift as well as great versatility and accuracy.