Concept representation of the software tool PIDMaster for systems modelling and controllers tuning. The work deals with the representation of the concepts of program package PIDMaster for the signal analysis, system modeling and controller’s synthesis. It is distinguished for the user-friendly interface which enables comfortable work for the less experienced users also. The required user-friendliness was achieved by the use of window interface, completed with some elements of the object oriented user interface management system. Center points of new interface are so-called movable graphical objects and it’s usage in the phase of the system parameter estimation which is explained thoroughly.