The position of the machine is identified by an absolute rotary encoder, which transfers an absolute angle or path dimension to the cam controller, depending upon the machine position. A significant advantage of the devices EPR, EPC is the possibility of optimising switching points in operating machines and compensating delay times of connected actuators, depending upon the speed (downtime compensation). Other important advantages of all variants are the significantly high speeds as compared to the PLC, the exact switching points, multiple programmes in one device, simple programme designing and modification as well as accurate downtime compensation to precisely 1 ms.