5 Adjustments5.2.1 Calculating the Moment of Inertia5-105.2 Advanced Autotuning (Fn201)With advanced tuning for the multi-winding drive system, adjustment is performed only for moment of inertiacalculation.5.2.1 Calculating the Moment of InertiaTo calculate the load moment of inertia, the multi-winding drive unit and SERVOPACKs perform automaticoperation (reciprocal forward and reverse operation) and the moment of inertia is calculated during operation.The parameter that sets the moment of inertia ratio (ratio of the load moment of inertia to the motor moment ofinertia) forms a standard for adjusting the gain, and therefore must be set as accurately as possible.The load moment of inertia can be calculated from the mass and composition of the mechanical section, butdoing so is troublesome and accurate calculation has become difficult with the complexity of current mechan-ical compositions. You can use this calculation function to get a highly accurate load moment of inertia simplyby driving the actual motor in forward and reverse a few times.The following automatic operation specifications apply.• Maximum speed: Rated motor speed × 2/3• Acceleration torque: Approximately 100% of rated motor torqueThe acceleration torque varies with the influence of the moment of inertia ratio(Pn103), machine friction, and external disturbance.• Travel distance: The travel distance can be set freely. The distance is factory-set to a value equivalent to 3motor rotations.(1) PreparationCheck the following settings before performing advanced autotuning.The message “NO-OP” indicating that the settings are not appropriate will be displayed, if all of the followingconditions are not met.• The main circuit power supply must be ON.• There must be no overtravel.• The servomotor power must be OFF.• The control method must not be set to torque control.• The gain selection switch must be in manual switching mode (Pn139.0 = 0).• Gain setting 1 must be selected.• All alarms and warning must be cleared.• The hardwire baseblock (HWBB) must be disabled.• The write prohibited setting parameter (Fn010) must be set to Write permitted (P.0000).Travel distanceSERVOPACKMovementspeedReferenceResponseExecute advanced autotuningafter a JOG operation to movethe position to ensure a suitablemovement range.Multi-windingdrive unitt: timet: timeRated motorspeed × 2/3Rated motorspeed × 2/3Rated motortorque Approx. 100%Rated motortorque Approx. 100% Automatic operationCAUTION• Because advanced autotuning adjusts the multi-winding drive unit during automatic operation, vibration orovershooting may occur. To ensure safety, make sure that an emergency stop can be applied at any time.
