The most difficult problem in analysing man-machine systems is the assessment of the operator's work load. The methodological difficulties are evident because of the human complexity and the necessity of avoiding any interference in the work situation. These problems, especially the great number of data needed, necessitate now concepts in ergonomics measurements. By Using an actual problem, the analysis of the task and work load of radar controllers, the application of multichannel automatic data acquisition and processing is demonstrated. For assessing strain, advantage is taken of the physiological variables: electro-cardiogram (ECG), electro-oculogram (EOG) in both directions, electro-myogram (EMG) of a back muscle and respiration. To correlate these variables with factors of stress and strain a coding is described, which renders the evaluation of a multi-dimensional work process study automatically and synchronously with the physiological data.