The recent progress of microelectronics enables the creation of intelligent sensors as integrated units including both a sensor and a microcontroller capable of performing many decentralized monitoring and/or control system functions. This paper shows how the robustness of such a device applied for the PID—control can be substantially increased by the gnostical filter. The high filtering efficiency of such an algorithm enables the use of fixed optimum digital operators for estimation of signal derivatives according to the method of ‘static programming’ and yields considerable savings in operation time and memory requirements, so that the task is manageable by a single—chip computer. An example demonstrates practical realizability of this approach by currently available technology.