Kinco CD420 User Manual

Also see for CD420: Manual

Contents

Kinco CD420 User Manual Manual pdf 89 page image

89however, the bandwidth F of the feedback filter of velocity loop must be at least three times of the bandwidthof velocity loop; otherwise oscillation may occur. The formula for calculating the bandwidth of feedback filterof velocity loop is F = Speed_Fb_N*20+100 (Hz).2. Parameters for position loopTable 8-2 Parameters for position loopNumericDisplayVariable Name Meaning DefaultValueRanged2.07 Kpp Indicates the proportional gain of theposition loop Kpp1000 0~16384d2.08 K_Velocity_FF 0 indicates no feedforward, and 256indicates 100% feedforward256 0~256d2.09 K_Acc_FF The value is inversely proportional tothe feedforward7FF.F 32767~10d0.05 Pc_Loop_BW Sets the bandwidth of the positionloops in Hz0 N/AProportional gain of the position loop Kpp: If the proportional gain of the position loop increases, thebandwidth of the position loop is improved, thus reducing both the positioning time and following errors.However, too great bandwidth may cause noise or even oscillation. Therefore, this parameter must be setproperly according to loading conditions. In the formula Kpp=103* Pc_Loop_BW, Pc_Loop_BW indicatesthe bandwidth of the position loop. The bandwidth of a position loop is less than or equal to that of a velocityloop. It is recommended that Pc_Loop_BW be less than Vc_Loop_BW /4 (Vc_Loop_BW indicates thebandwidth of a velocity loop).Velocity feedforward of the position loop K_Velocity_FF: the velocity feedforward of a position loop can beincreased to reduce position following errors. When position signals are not smooth, if the velocityfeedforward of a position loop is reduced, motor oscillation during running can be reduced.Acceleration feedback of the position loop K_Acc_FF (adjustment is not recommended for this parameter): Ifgreat gains of position rings are required, the acceleration feedback K_Acc_FF can be properly adjusted toimprove performance.* * _K_Acc_FF 250000* 2 * *p ttI K Encoder RJ Note: K_Acc_FF is inversely proportional to theacceleration feedforward.Adjustment steps:Step 1: Adjust the proportional gain of a position loop.After adjusting the bandwidth of the velocity loop, it is recommended to adjust Kpp according to actualrequirements (or directly fill in the required bandwidth in Pc_Loop_BW, and the driver will automaticallycalculate the corresponding Kpp). In the formula Kpp = 103*Pc_Loop_BW, the bandwidth of the position loopis less than or equal to that of the velocity loop. For a common system, Pc_Loop_BW is less thanVc_Loop_BW /2; for the CNC system, it is recommended that Pc_Loop_BW is less than Vc_Loop_BW /4.Step 2: Adjust velocity feedforward parameters of the position loop.Velocity feedforward parameters (such as K_Velocity_FF) of the position loop are adjusted according toposition errors and coupling intensities accepted by the machine. The number 0 represents 0% feedforward,and 256 represents 100% feedforward.3. Parameters for pulse filtering coefficient