The basic components of the control system

The industrial production process control system has a variety of different types, for example, a simple control system, the complex control system, Figure l is a simple example of the control system. Figure, each control system includes a controlled variable, manipulated variable and the corresponding control law. The controlled variable is the need to control the process variable, e.g., heat exchanger outlet temperature of the pump outlet pressure. Make the set value of the controlled variable with the desired consistency, a need for a control means, For example, in FIG. Steam flow, the pump bypass flow. The reason of the controlled variable deviates from the set is the presence of interference in the production process, For example, the steam pressure fluctuations, the pump speed changes. Is usually used to adjust the variable referred to as a manipulated variable.angle seat valve
A simple control system consists of a detector element and transmitter, controller, actuator and controlled object. The detection element and the transmitter (sensorandtransmitter) for detecting the controlled variable, the detection signal is converted to a standard signal. For example, the thermal resistance will be converted to a temperature change resistance variations, temperature transmitter will be the resistance of the signal converted into the standard gas
Voltage or current, voltage signal.pneumatic accessory