6-36
 
6-8 Improved Response Characteristics 
The Server provides gain switching function and position loop feed forward gains to improve 
system response. Attention! These two functions must be used correctly to improve the response 
characteristics, otherwise the response will deteriorate. Description as follows: 
 
  Gain Switching Function   
The Gain Switching Function of this Device can be divided into two types of Speed Loop Gain 
PI/P Switching and Two Stage Gain Switching. The purpose of this function is as follows: 
(1) In Speed Control, suppress the Acceleration / Deceleration overshoot. 
(2) In Position Control, suppress the amplitude of oscillations caused by positioning and shortens 
the settling time. 
(3) Can reduce the use of the Servo Lock function that causes a harsh noise. 
Please refer to “6-7 Gain Switching Function” for detailed description. 
 
  Position Loop Feed Forward Gain   
The use of Position Loop Feed Forward Gain can reduce the Position Control following error and 
speed up the reaction speed. If the Position Loop Gain is large enough, the effect of this function is not 
significant, therefore, it is suitable to be used in the system that it cannot adjust the Position Loop 
Gain high enough and wants to increase the response speed. 
Adjust Steps are as follows: 
Step 1: 
Adjust Speed and Position Loop in accordance with the steps specified in”6-6 Manual 
Gain Adjustment”. 
Step 2:
 Slowly increase 
Pn312
 (Position Loop Feed Forward Gain), and observe the Output 
Contact 
INP
 (Positioning Completion Signal) at the same time to enable rapid output 
and shorten the settling time. Make sure the Position Loop Feed Forward Gain is not be 
too high. Excessive Feed Forward Gain can cause speed overshoot and the digital 
Output Contact 
INP
 (Positioning Completion Signal) turns on and off repeatedly.