When does Proportional (P) Integral (I) Derivative (D) Controllers are Used

When Proportional (P) Controller is Used:

Proportional (P) 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:

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:

Proportional and Integral action is employed when

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

When Proportional and Derivative (PD) controller is used:

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PD action is employed when:

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

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

PID controller is used when system requires:

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