Hands on with "PID Controllers"

In the most simplistic terms, the?controller?calculates the P, I and D actions and multiplies each parameter by the error or E, which is equal to SP-PV in direct acting, Then, all parameter calculations are added up to produce the Control Variable.

PID Tuning- Proportional term

The proportional term (Proportional Gain) is a ratio. This parameter can also be called?Proportional Band?and measured in the unit of percent.

The parameter KP, determines how fast the system responds. Higher the gain, higher the sensitivity, less stable loops and vice versa.

PID?Tuning-?Integral term

The Integral term or?I?Constant often called?Reset?can be expressed repeats per second, This parameter determines how fast the?steady-state error?is removed.

PID?Tuning-?Derivative?term

The purpose of the?Derivative constant is for predicting change. The Derivative action acts of the rate of change measured in the Process Variable.

The value of this parameter basically means how far in the future you want to predict the rate of change. This parameter can help to create a faster response in your loop and a better performing loop as well. Derivative terms are not often used in controls.

PID Algorithms and?Parameters

The most commonly used controller is the PI. Most processes can be well served with this type of control. P and PID controllers are occasionally used while PD controllers are rarely used.

PID tuning methods

There are multiple theoretical methods of determining stability however most widely used tuning method is?trial and error.