The identification methods of the objects are reviewed (active and passive). The method of active identification for closed-loop control system is proposed. The efficiency of using of the regular binary sequence for determining the temporal characteristics of objects is shown. The analysis is made for different constraints: on the output deviation range and on the variance of the output's useful component. The article discusses the use of a priori information about the signal. The estimates of mathematical expectation and variance of process are obtained by changing steam temperature in the upper radiation part of boiler on Ladyzhynskaya State District Power Station (SDPS).