Chapter 12 Description of Parameter SettingsCP2000 
 
 
12.1-08-6 
  PID control output frequency is filtered with a primary low pass function. This function can filter a 
mix frequency. A long primary low pass time means the filter degree is high and a short primary 
low pass time means the filter degree is low.   
  Inappropriate delay time setting may cause system error.   
  PI Control:   
Controlled only by the P action, so the deviation cannot be entirely eliminated. In general, to 
eliminate residual deviations, use the P + I control. When you use the PI control, it eliminates the 
deviation  caused  by  the  targeted  value  changes  and  the  constant  external  interferences. 
However, if the I action is too powerful, it delays the response when there is rapid variation. You 
can use the P action by itself to control the loading system with the integral components. 
  PD Control:   
When deviation occurs, the system immediately generates an operation load that is greater than 
the load generated only by the D action to restrain the deviation increment. If the deviation is 
small,  the  effectiveness  of  the  P  action  decreases  as  well.  The  control  objects  include 
applications  with  integral  component  loads,  which  are  controlled  by  the  P  action  only. 
Sometimes, if the integral component is functioning, the whole system may vibrate. In this case, 
use the PD control to reduce the P action’s vibration and stabilize the system. In other words, 
this control is useful with no brake function’s loading over the processes. 
  PID Control:   
Use the I action to eliminate the deviation and the D action to reduce vibration; then combine 
this with the P action for the PID control. Use the PID method for a control process with no 
deviations, high accuracies and a stable system. 
  Serial connection 
 
  Parallel connection