PID Controllers Pros & Cons


#1

When does Proportional (p.) Integral (I) Derivative (D) Controllers are Used ?

When Proportional § Controller is Used during the following conditions:

  • Load Changes are small
  • Offset (error exist due to difference between steady state value and desired value) can be tolerated
  • The process reaction rate is such as to permit a narrow proportional band. Since this reduces the amount of the offset

When Integral (I) Controller is Used during:

  • When the offset must be eliminated
  • Integral saturation due to sustained deviation is not objectionable

When Derivative (D) Controller is used:

  • Large transfer or distance velocity lags are present
  • It is necessary to minimize the amount of deviation caused by the system changes

When Proportional plus Integral (PI) Controller is used when:

  • System changes is small
  • Offset must be eliminated
  • No objection on the recovery duration

When Proportional and Derivative (PD) controller is used:

  • When the system changes are small
  • Improve the recovery time
  • When system lags are high

When Proportional, Integral and Derivative (PID) Controller is used when :

  • System changes are small
  • Offset must be eliminated
  • Fast recovery time

Closed-loop controllers