The paper touches upon the application of logic with vector semantics for the development of expert systems (ES). As an example, the ES is used for setting up industrial frequency converters. The system was created with the help of a software tool environment using -logic – a special case of logic with vector semantics, in which the truth is described by a vector with components of “True”; “False”. The values of the components can be interval. The issues of formalization of uncertainty and contradictions in such systems and some peculiarities of the output machine are considered.

expert system, logic with vector semantic, frequency converters.