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

9.4 Servo Gain Adjustment Functions9.4.5 Using the Mode Switch (P/PI Switching)Use the mode switch (P/PI switching) function in the following cases:• To suppress overshooting during acceleration or deceleration (for speed control)• To suppress undershooting during positioning and reduce the settling time (for position control)SpeedOvershootReferenceActual motor operationTimeUndershootSettling timeThe mode switch function automatically switches the speed control mode from PI control mode to P control 1mode based on a comparison between the servo’s internal value and a user-set detection level.IMPORTANT1. The mode switch function is used in very high-speed positioning when it is necessary to use theservodrive near the limits of its capabilities. The speed response waveform must be observed to adjustthe mode switch.2. For normal use, the speed loop gain and position loop gain set by autotuning provide sufficient speed/position control. Even if overshooting or undershooting occur, they can be suppressed by setting the hostcontroller’s acceleration/deceleration time constant, the SERVOPACK’s Soft Start Acceleration/DecelerationTime (Pn305, Pn306), or Position Reference Acceleration/Deceleration Time Constant (Pn204).(1) Selecting the Mode Switch SettingThe SERVOPACK provides the following four mode switch settings (0 to 3). Select the appropriate mode switchsetting with parameter Pn10B.0.ParameterMode Switch SelectionParameterContainingDetectionSetting UnitPoint SettingPn10B n.0 Use a torque reference level forPercentage to the rated torquedetection point.Pn10C(Factory Setting)n.1 Use a speed reference level fordetection point.Pn10D Servomotor speed: min -1n.2 Use an acceleration level for detectionpoint.Pn10E Servomotor acceleration: 10 min -1 /sn.3 Use a position error pulse for detectionpoint.Reference unitPn10Fn.4 Do not use the mode switch function. − −Select a condition to execute the mode switch (P/PI switching). (Setting is validated immediately.)9TERMS1From PI control to P controlPI control means proportional/integral control and P control means proportional control. In short, switching “from PIcontrol to P control” reduces effective servo gain, making the SERVOPACK more stable.9-19