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

9 Adjustments9.4.8 Speed Feedback Compensation(1) Adjustment ProcedureThe following procedure explains how to adjust when the speed loop gain cannot be increased due to vibrationsin the mechanical system. When adding a speed feedback compensation, observe the position error and torquereference with the analog monitor while adjusting the servo gain. Refer to 9.5 Analog Monitor on monitoring theposition error and torque reference.1. Set parameter Pn110 to “0002” so that the following conditions are satisfied.• To use the speed feedback compensation• Not to use the online autotuning function2. With PI control, gradually increase the Speed Loop Gain in Pn100 and reduce the Speed Loop IntegralTime Constant Pn101, so that the setting the Position Loop Gain in Pn102 to the same value as that of theSpeed Loop Gain in Pn100.Use the result from the following equation as an initial estimate when setting the Speed Loop IntegralTime Constant in Pn101.Speed loop integral time constant (Pn101)40002 Pn100Speed loop gain units: HzCheck the units when setting the Speed Loop Integral Time Constant in Pn101. The value in Pn101 is setin units of 0.01 ms.Set the same value for the speed loop gain and position loop gain even though the speed loop gain units(Hz) are different form the position loop gain units (1/s).3. Repeat step 2 to increase the speed loop gain while monitoring the settling time with the analog monitor’sposition error and checking whether vibration occurs in the torque reference. If there is any vibratingnoise or noticeable vibration, gradually increase the Torque Reference Filter Time Constant in Pn401.4. Gradually increase only the position loop gain. When it has been increased about as far as possible, thendecrease the Speed Feedback Compensation in Pn111 from 100% to 90%. Then repeat steps 2 and 3.5. Decrease the speed feedback compensation to a value lower than 90%. Then repeat steps 2 through 4 toshorten the settling time. If the speed feedback compensation is too low, however, the response waveformwill oscillate.6. Find the parameter settings that yield the shortest settling time without causing vibration or instability inthe position error or torque reference waveform being observed with the analog monitor.7. The servo gain adjustment procedure is complete when the positioning time cannot be reduced any more.IMPORTANTThe speed feedback compensation usually makes it possible to increase the speed loop gain and positionloop gain. Once the speed loop gain and position loop gain have been increased, the machine may vibratesignificantly and may even be damaged if the compensation value is changed significantly or Pn110.1 is setto “1” (i.e., speed feedback compensation disabled).9-24