www.baldormotion.comB-4 Control System MN1919B.1.3 Position (Step and Direction) controlSetting the control mode to Position Control (Step and Direction) configures the MicroFlex as apositioning system, as shown in Figure 53, capable of following a position command signal.The up down counter and gearing interpret the step and direction signals and use them togenerate a position demand signal.The position demand signal is fed into a position controller and used, together with the positionmeasured from the feedback device, to generate a suitable speed demand signal. If theposition controller is tuned correctly, the measured position will accurately track the positiondemand.The speed demand signal from the position controller is fed into the speed controller and used,together with the speed measured from the feedback device, to generate a torque demandsignal. If the speed controller is tuned correctly, the measured speed will accurately track thespeed demand.Finally, the torque demand signal is fed into a torque controller, which determines theappropriate amount of current to apply to the windings of the motor. This demand current iscompared with the actual winding current measured from sensors, and a suitable pulse widthmodulation (PWM) signal is generated. This PWM signal is fed to the power electronics in thedrive.Positioncontroller Speedcontroller Torquecontroller Power stage+ motorSpeeddemand Torquedemand PWMPositionPositionStepMeasured currentMeasured speedMeasured positionDirection GearingPulsecountUp/downCounterreferenceFigure 53 - Control structure in Position control (Step and Direction)
