Chapter 7 Motion Control ASDA-M7-30 Revision December, 20147.10 The Description of E-Cam FunctionE-Cam is a virtual cam which is implemented by software. It includes Master axis and Slaveaxis. The illustration is as the following:In PT mode, the position command (slave) is issued by the external pulse input (master).The two is merely the linear scaling relation (its scaling equals to e-gear ratio). However,instead of linear scaling, E-Cam is defined by cyclic curve profile, just like the cam shape. Inphysical machine cam, slave axis can operate as variable speed motion, alternating motion,intermittent motion, etc by master axis with the constant speed motion. It is very extensivein application. Using E-Cam could have similar effect. The following table describes thedifferences between E-Cam and Machine Cam.Machine Cam E-CamStructure Return to the original positionafter rotating a cycle.It might not return to the originalposition after rotating a cycle. Thestructure could be in spiral shape likemosquito coil incense.Machine Cam E-CamSmoothPerformance It is determined by the finenessof the real process.It is interpolated by cubic curve viasoftwarePositionAccuracy Very precise (when it has novibration)The command is very precise, but theactual position might have deviationdue to the servo delay.Long DistanceMotion The longer the slave axis is,the bigger the cam will be. It isnot easy to make.Change the value of the table will do. Itis easy to realize.
