154Manual Gain Tuning (Basic)Adjustment in Full-Closed Control ModeFull-closed control of MINAS-A4P series is described in Block diagram of P.225 of Full-Closed Control.Adjustment in full-closed control is almost same as that in position control described in P.153 “Adjustment inPosition Control Mode”, and make adjustments of parameters per the procedures except cautions of P.140,“Outline of Full-Closed Control”.Here we explain the setup of external scale ratio, hybrid deviation excess and hybrid control at initial setupof full-closed control.1) Setup of external scale ratioSetup the external scale ratio using the numerator of external scale division (SV.Pr78), the multiplierfor numerator of external scale division (SV.Pr79) and denominator of external scale division (SV.Pr7A).• Check the encoder pulse counts per one motor revolution and the external scale pulse counts per onemotor revolution, then set up the numerator of external scale division (SV.Pr78), the multiplier for nu-merator of external scale division (SV.Pr79) and denominator of external scale division so that the fol-lowing formula can be established.• If this ratio is incorrect, a gap between the position calculated from the encoder pulse counts and that ofcalculated from the external scale pulse counts will be enlarged and hybrid deviation excess (Err.25) willbe triggered when the work or load travels a long distance.• When you set up SV.Pr78 to 0, the encoder pulse counts will be automatically set up.2) Setup of hybrid deviation excessSet up the minimum value of hybrid deviation excess (SV.Pr78) within the range where the gap betweenthe motor (encoder) position and the load (external scale) position will be considered to be an excess.• Note that the hybrid deviation excess (Error code No.25) may be generated under other conditions than theabove 1), such as reversed connection of the external scale or loose connection of the motor and the load.Caution(1) Enter the position command based on the external scale reference.(2) The external scales to used for full-closed control are as follows.• AT500 series by Mitutoyo (Resolution 0.05[μm], max. speed 2[m/s])• ST771 by Mitutoyo (Resolution 0.5[μm], max. speed 2[m/s])(3) To prevent the runaway and damage of the machine due to the setup of the external scale, setup thehybrid deviation excess (SV.Pr7B) to the appropriate value, in the unit of external scale resolution.(4) We recommend the external scale as 1/20 <= external scale ratio <= 20.If you setup the external scale ratio to smaller value than 50/position loop gain (SV.Pr10 and 18), youmay not be able to control by one pulse unit. If you set up too large external scale ratio, you may expectlarger noise in movement.SV.Pr78 1 x 2SV.Pr7A 5000 =SV.Pr79 17 Number of encoder pulses per motor rotation Number of external scale pulses per motor rotation
