To keep military equipment fit for use, carry out maintenance activities, an important and integral part of which is metrological service. The effectiveness of metrological services depends on the completeness of the coverage of the monitored parameters, frequency and reliability of their measuring control. The most common, at present, when controlling the parameters of military equipment are electromechanical measuring equipment. The main metrological characteristic of electromechanical measuring instruments in a static measurement mode is the nominal calibration characteristic. During operation, the calibration characteristic of electromechanical measuring instruments, under the influence of various factors, has deviations from the nominal, which leads to an instrumental static error. The article deals with the applied aspects of assessing the static error of electromechanical measuring equipment, which is expressed through the sensitivity or static transmission coefficients of measuring transducers. Based on the results of the analysis, a generalized mathematical model of the relative static error of electromechanical measuring equipment for various structural schemes of connecting measuring transducers was obtained. It is proposed to apply a generalized mathematical model to assess the relative static error of electromechanical measuring instruments (with various structural schemes) during their operation. The use of an updated static error will allow to refine the calibration characteristics of electromechanical measuring instruments, which in turn will lead to obtaining reliable information about the state of military equipment during metrological maintenance and immediately before use.