Motion control is the heart of today’s industrial automation. It’s everywhere right from a simple conveyor system to a complex 9 axis CNC machine or an industrial robot. Systems can be configured for either accurate positioning within tolerances of a few microns, speed of motion or torque. Traditional motion controllers use a direction signal and a pulse train to control servo motors but due to this architecture a lot of latency is introduced in multi axis motion control applications which are time critical. These systems often require real time control due to which fast real time communication protocols become a necessity. [1] This thesis focuses on using an open real time ethernet based communication protocol called EtherCAT in order to improve the performance of multi axis time critical motion controllers. An industrial development kit was used to program the EtherCAT master to function as a 3 axis CNC controller. The controller was responsible to communicate with the servo motors mounted on a CNC machine and demonstrate the improvement of motion performance in terms of speed and acceleration. [2] The result of this thesis clearly showed that the EtherCAT based CNC controller was able to attain full RPM of the servo motors used to travel from one extremity to the other whereas the traditional CNC controller could not. The project also showed that due to the use of industrial communication protocols to control motion, the speed of motion is not dependent on the technical specification such as the clock frequency of the main processor of the controller. This method frees up the main processor to carryout other time critical tasks since motion control is completely offloaded to the EtherCAT network resulting in higher time critical performance. ; Rörelsekontroll är hjärtat i dagens industriella automation. Det är överallt, från ett enkelt transportsystem till en komplex 9 -axlig CNC -maskin eller en industriell robot. System kan konfigureras för antingen exakt positionering inom toleranser av några mikron, ...