The article examines the problem of developing the methodological foundations of the influence of various parameters on the measurement accuracy, as well as the adoption of a technical solution that allowed describing the function of converting an informative parameter in an electric field and the function of influencing the accuracy of the instrument readings of the main informative and uninformative parameters of the measurement process. The influence of the physical and mechanical properties of raw cotton and the behavior of the material under study in a high-frequency electromagnetic field is considered. The principle of operation of high-frequency measuring systems is described, based on the presence of a relationship between the dielectric constant of the controlled material and its humidity in the electromagnetic field. The state of moisture control of raw cotton and products of their industrial processing of local varieties grown in the Republic of Uzbekistan is analyzed. The issues of the error of the thermogravimetric method of measuring humidity (informative parameter) are discussed as the main direct model method, as well as a number of sources of measurement errors (uninformative parameters), including moisture absorption properties, drying criterion, sample weighing, raw cotton composition, as well as the degree of influence of various interfering factors on the accuracy of determination and measurement of the value of the mass moisture ratio of raw cotton and its primary processing products. The application of humidity control devices at the enterprises of the agro-industrial complex is described, which will allow to stabilize technological processes, improve the quality and quantity of products, as well as improve working conditions in industrial premises. An assessment of the thermogravimetric method for measuring humidity and recommendations for the use of indirect measurement methods based on the implementation of the method and the selection of the optimal number of measured parameters of the object of study, ensuring maximum accuracy of determining the desired value, are given.