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  Speed loop gain 
Because the response of the speed loop is low, it will become the delay factor of the outer position loop, 
so overshoot or vibration of the speed command will occur. Therefore, in the range of no vibration of 
mechanical system, the larger the setting value, the more stable the servo system and the better the 
responsiveness. 
  Integral time constant of speed loop 
In order to respond to small inputs, the speed loop contains integral elements. Because this integral 
factor  is a  delay  factor for  servo system,  when the  time constant  is too  large,  it  will  overshoot  or 
prolong the positioning time, which will make the response worse. 
The relationship between the gain of the speed loop and the integral time constant of the speed loop is 
approximately as follows: 
P1-00 × P1-01 = 636620 
integral time 
constant of speed 
loop 
  Position loop gain 
When the model loop is invalid (P2-47.0=0), the responsiveness of the position loop of the servo unit is 
determined  by  the  gain  of  the  position  loop.  The  higher  the  position  loop  gain  is,  the  higher  the 
responsiveness is and the shorter the positioning time is. Generally speaking, the gain of position loop 
cannot be increased beyond the natural vibration number of mechanical system. Therefore, in order to 
set the position loop gain to a larger value, it is necessary to improve the rigidity of the machine and 
increase the number of inherent vibration of the machine. 
  Filter time constant of torque instruction 
When machine vibration may be caused by servo drive, it is possible to eliminate vibration by adjusting 
the filtering time parameters of the following torque instructions. The smaller the numerical value, the 
better the response control can be, but it is restricted by the machine conditions. When vibration occurs, 
the parameter is generally reduced, and the adjustment range is suggested to be 10-150. 
Filter time constant of 
torque instruction 1 
  Model loop gain 
When the model loop is valid (P2-47.0=1), the response of the servo system is determined by the gain 
of the model loop. If the gain of the model loop is increased, the responsiveness is increased and the 
positioning time is shortened. At this time, the response of the servo system depends on this parameter, 
not P1-02 (position loop gain). The gain of the model loop is only valid in position mode.