The paper brings some authors´ results in the field of autotuning research. Autotuners represent a combination of a relay feedback experiment and a suitable control design method. The contribution deals with SISO systems where symmetrical or asymmetrical relay can be used. Asymmetric relay with hysteresis feedback experiments enable to estimate three parameters for aperiodic first or second order transfer functions. After the identification experiment, controller parameters are derived through a linear diophantine equation in two different rings. The first ring is a set of proper and stable rational functions RPS. The second ring RMS represents a set of RQ-meromorphic functions suitable for delay systems. Moreover, a final controller can be tuned by a scalar real parameter m>0. Many of designed controllers have the PI or PID form. A Matlab-Simulink program implementation was developed for simulation and verification of the studied approach. The emphasis is laid on the user-friendly program system for control design and simulation. Naturally, also higher order systems can be controlled by the approach. Illustrative examples support simplicity and efficiency of the proposed methodology in simulation and real-time control.