## Introduction: PID (Proportional–Integral–Derivative) Controller

A proportional–integral–derivative controller (PID controller) is a control loop feedback mechanism (controller) commonly used in industrial control systems

## Step 1:

A proportional–integral–derivative controller (PID controller) is a control loop feedback mechanism (controller) commonly used in industrial control systems. A PIDcontroller continuously calculates an error value as the difference between a measured process variable and a desired setpoint .

The controller attempts to minimize the error over time by adjustment of a control variable, such as the position of a control valve, a damper, or the power supplied to a heating element, to a new value determined by a weighted sum:

Eq is shown obve .

where Kp,Ki and Kd, all non-negative, denote the coefficients for the proportional, integral, and derivative terms, respectively (sometimes denoted P, I, and D). In this model,
P accounts for present values of the error (e.g. if the error is large and positive, the control variable will be large and negative),I accounts for past values of the error (e.g. if the output is not sufficient to reduce the size of the error, the control variable will accumulate over time, causing the controller to apply a stronger action), andD accounts for possible future values of the error, based on its current rate of change

As a PID controller relies only on the measured process variable, not on knowledge of the underlying process, it is broadly applicable.By tuning the three parameters of the model, a PID controller can deal with specific process requirements. The response of the controller can be described in terms of its responsiveness to an error, the degree to which the system overshoots a setpoint, and the degree of any system oscillation. The use of the PID algorithm does not guarantee optimal control of the system or even itsstability.
Some applications may require using only one or two terms to provide the appropriate system control. This is achieved by setting the other parameters to zero. A PID controller will be called a PI, PD, P or I controller in the absence of the respective control actions. PI controllers are fairly common, since derivative action is sensitive to measurement noise, whereas the absence of an integral term may prevent the system from reaching its target value.

## Step 2: Proteus File

Components Required:-

2 ics >> lm358 & lm324. resistors >> 10k,100k and variable Resistor 1M ohm. Capcitors >> 1 micro Farad and 22 Micro Farad. some jummpers

in this sktech
first one is Set point
2nd there are 3 op amp in which
1st Proportional, 2nd Integral and 3rd Derivative . which are connected in top, center and bottom orders.
last one is Error

## Step 4:

After Soldering it should look like that