3202 Rev A Module Specifications - Advanced Micro Controls Inc

Chapter 2: Calculating Move Profiles3202 Rev A Module SpecificationsTwo Channel ControlLogix Stepper ModuleRevision 4.0Before starting a move operation, the 3202 module completely calculates each portion of the moveprofile. That is, it calculates how many steps of the move profile will be required for acceleration andhow many steps will be required for deceleration. Depending on the data used to define the move profile,this can result in two types of velocity profiles, either a Trapezoidal Profile or a Triangular Profile.A Trapezoidal Profile jumps from rest to the Starting Speed, accelerates to the Programmed Velocity atthe commanded acceleration rate, continues at the Programmed Velocity to a predetermined point, andthen decelerates to the target position at the commanded deceleration rate to the starting speed and stops.VelocityStartingSpeedTrapezoidal ProfileHowever, if the length of a commanded move is not long enough to attain the programmed velocitybefore the deceleration point is reached, a Triangular Velocity profile will be generated.TimeVelocityStartingSpeedTriangular ProfileRegardless of the type of Velocity Profile that is being run, the following equations can be used todetermine both the time to accelerate and the number of steps needed to accelerate. These formulas canalso be used to calculate the time and distance to decelerate.TimeTa = (Vs – Vo)/aDa = Ta * (Vo + Vs)/2VelocityVsVo = Starting Speed (steps/second)Vs = Programmed Speed (steps/second)Ta = Time to accelerate (seconds)Da = Distance to accelerate (steps)a = Acceleration rate (steps/second/second)VoTime20 Gear Drive, Plymouth Industrial Park, Terryville, CT 06786 page: 11Tel: (860) 585-1254 Fax: (860)584-1973 E-mail: Sales @amci.com