PROPORTIONAL INTEGRAL DERIVATIVE

                PID or proportional integral derivative is describing how the error term is handled, it van be written by ‘error.

a.        The proportional term

The proportional term make the current error signal multiply with a gain (Kp). The result will be the output signal. In the proportional path , if the input is 0, so is the output. And if the input is negative, so is the output.

Output signal = Kp x error signal

 The integral term

The integral termmake the current error signal value and duration is multiplied with a gain (Ks). The integral signal is the sum of all the error from whenever you started counting unti you stop. The integral term , accelerate the movement of the process towards setpoint and eliminate the residual steady-state error that occur with a proportional only controller.  Above the x axis is the positive area, and the below x axis is negative area. The integral path is used to remove constant error in the control system.

 The derivative term

            Derivative term make the rate of the change of the error signal is multiplied with a gain (Kp). the slower the error moving  in time, the derrivative is small. But if the error is moving faster, the derrivative is become larger. This effect is the most noticeable close to the controller setpoint.

If we sum those 3 terms, we can calculate the controller output. Or we change the value of each term, we can see how sensitive is the system we have. so this is the picture if you combine the three term.

source:                http://www.youtube.com/watch?v=wbmEUi2p-nA

                             http://www.youtube.com/watch?v=UR0hOmjaHp0

Romyah Bighoiri Romy

112110090

TI-35-INT