15-04-2017, 03:17 PM
A control system manages, orders, directs or regulates the behavior of other devices or systems. It can range from a domestic heating controller using a thermostat that controls a domestic boiler to large industrial control systems that are used to control processes or machines.
In the most common form, the feedback control system is desired to control a process, called the plant, so that its output follows a control signal, which can be a fixed or changing value. The control system compares the output of the plant with the control signal and applies the difference as an error signal to bring the output of the plant to the control signal.
The term "control system" can be applied to essentially manual controls which enable an operator, for example, to close and open a hydraulic press, perhaps including the logic so that it can not be moved unless there are safety guards .
An automatic sequential control system can activate a series of mechanical actuators in the correct sequence to perform a task. For example, several electric and pneumatic transducers can fold and paste a carton, fill it with product and then seal it in an automatic packaging machine. Programmable logic controllers are used in many cases like this, but there are several alternative technologies.
In the case of linear feedback systems, a control loop, which includes sensors, control algorithms and actuators, is arranged in such a way that it tries to regulate a variable to a setpoint or reference value. An example of this can increase the fuel supply to an oven when a measured temperature falls. PID controllers are common and effective in cases like this. Control systems that include a certain detection of the results they are trying to achieve are making use of feedback and thus can, to some extent, adapt to different circumstances. Open loop control systems do not make use of feedback, and are executed only in preset ways.
In the most common form, the feedback control system is desired to control a process, called the plant, so that its output follows a control signal, which can be a fixed or changing value. The control system compares the output of the plant with the control signal and applies the difference as an error signal to bring the output of the plant to the control signal.
The term "control system" can be applied to essentially manual controls which enable an operator, for example, to close and open a hydraulic press, perhaps including the logic so that it can not be moved unless there are safety guards .
An automatic sequential control system can activate a series of mechanical actuators in the correct sequence to perform a task. For example, several electric and pneumatic transducers can fold and paste a carton, fill it with product and then seal it in an automatic packaging machine. Programmable logic controllers are used in many cases like this, but there are several alternative technologies.
In the case of linear feedback systems, a control loop, which includes sensors, control algorithms and actuators, is arranged in such a way that it tries to regulate a variable to a setpoint or reference value. An example of this can increase the fuel supply to an oven when a measured temperature falls. PID controllers are common and effective in cases like this. Control systems that include a certain detection of the results they are trying to achieve are making use of feedback and thus can, to some extent, adapt to different circumstances. Open loop control systems do not make use of feedback, and are executed only in preset ways.
