Sigma-II Series SGM*H/SGDH USER'S MANUAL - Esco Drives ...

9 Adjustments9.4.5 Using the Mode Switch (P/PI Switching)Using the Torque Reference Level to Switch Modes (Factory Setting)With this setting, the speed loop is switched to P control when thevalue of torque reference input exceeds the torque set in parameterSpeedPn10C. The factory default setting for the torque reference detectionpoint is 200% of the rated torque (Pn10C = 200).Reference speedMotor speed+Pn10CTorquereference 0Torque reference- Pn10CPIPPI controlPPI control• Operating ExampleIf the mode switch function is not being used and the SERVOPACK is always operated with PI control, the speed of themotor may overshoot or undershoot due to torque saturation during acceleration or deceleration. The mode switch functionsuppresses torque saturation and eliminates the overshooting or undershooting of the motor speed.Without Mode SwitchingWith Mode SwitchingOvershootMotorspeedUndershootMotorspeedTimeTimeUsing the Speed Reference Level to Switch ModesWith this setting, the speed loop is switched to P control when the valueof speed reference input exceeds the speed set in parameter Pn10D. SpeedSpeed referenceMotorspeedPn10D• Operating ExampleIn this example, the mode switch is used to reduce the settling time. It is necessary to increase the speed loop gain to reducethe settling time. Using the mode switch suppresses overshooting and undershooting when speed loop gain is increased.PIP controlTimePI controlWithout Mode SwitchingMotorspeedSpeedreferenceMotor speedWith Mode SwitchingIncrease speed loop gain.Long settling timeOvershootMotorspeedUndershootMotorspeedTimeSettling time9-20