In this book design and synthesis of microprocessor controlled DC drive system in start-stop working mode is presented. The motor is fed from three - phase thyristor converter without circulating current. The design of position control is based on cascade principle with optimal speed control adjusted by means of modulus optimization method. Synthesis of the system is based on Z-transformation and bi-linear conform copying from Z-plane to W-plane of complex pseudo frequency. Velocity is measured with incremental encoder using M/T method. Software realization of digital speed and position controller is obtained, using direct realization of the recursive algorithm. The results of synthesis, using module and symmetrical optimization method are compared with the results obtained by simulation of the control system. The speed and position control are realized digitally by means of a microcomputer EPAC 68008, a real time operating system, RTOS, and the PEARL language.By directly implementing the recursive algorithm, a simple practical implementation of an adaptive PI-speed controller and PD-position controller is presented.