PID controller: features, settings
Automatic Process Control
Automatic process control involves measuring the values of certain parameters of the system and adjusting indicators in the necessary direction. For example, controlling the temperature in various heating devices allows automatically regulating the power of the devices to avoid overheating. This interaction is important in many fields of engineering.
PID Controller as a Means of Control
An effective method of regulating system parameters is the PID controller, which receives data from various elements and generates the corresponding control signal. In the case of heat control, the operation of the PID controller looks as follows: the controller receives information about heating from a temperature sensor, based on which it forms and sends a signal to the element responsible for regulating the power of the heating element.
PID controller is an abbreviation that stands for Proportional-Integral-Derivative controller.
Proportional Component
To maintain the required value of the parameter, the controller sends signals that instruct the elements to reach the necessary indicator. However, using only a proportional controller in certain cases may be unreasonable. For example, when the temperature value of the device approaches the set point, the power decreases, and the decrease in power occurs more slowly, resulting in the required temperature may not be reached.
Integral Component
The integral controller attempts to bring the system to the necessary parameter value but does so gradually, causing fluctuations in values near the target indicator, then lowering it again until temperature stability is achieved.
Derivative Component
The speed of the approach of the parameter to the required value is assessed by the derivative controller, which generates a signal to increase the system's response speed.
Tuning the PID Controller
Defining the necessary coefficients of the components in the controller can be carried out in various ways:
- Set the maximum operating power of the regulated device. Increase the value of the proportional controller and observe the behavior of the system. Continue increasing the value until fluctuations caused by over-regulation occur.
- Reduce the value of the proportional controller until system stabilization is achieved (damping of oscillations).
- Reduce the value of the proportional controller by 15% below the level of system stabilization and decrease the operating power of the regulated device.
- Gradually increase the maximum operating power of the regulated device. Increase the value of the integral controller until damped oscillations occur, after which reduce it to a level at which the system reaches the desired value without oscillations.
- If it is necessary to set the value of the derivative controller, gradually increase the speed and accordingly raise the value of this controller until the system reaches a stable state with minimal signal processing time. The value is considered correct when there is one over-regulation in the system.
- Check the accuracy of the system tuning by setting different operating powers of the regulated device.