Abstract: A method for monitoring plants, in particular complex plants in the iron and steel industry, having the steps of recording at least two channels of measurement data of a plant, if appropriate storing the measurement data, defining a target channel from the measurement data, preprocessing the measurement data, preparing at least one model of the target channel on the basis of the measurement data, and using the model thus generated and currently determined measurement data to detect fault conditions of the plant. This is to monitor industrial plants to improve the quality of the recorded measurement data of the plant, and reduce the volume of the measurement data, without a significant loss of information. Preprocessing the measurement data are subjected to the method steps of 1) detecting and eliminating “zero channels”, 2) detecting and eliminating outliers, 3) filtering, and 4) downsampling.