Process Instrumentation & Automation

A process Indicator or Controller is a device or system that measures, indicates and regulates a process such as temperature, pressure, flow rate, or level, to ensure that the system operates within a desired range or reference band. The principle of a process controller involves the use of feedback control, where the controller continuously measures the process variable (PV), compares it to the desired setpoint value (SV), and adjusts the control output (CO) accordingly. The principle of a closed-loop controller is based on the following steps: Measurement, Error Calculation, Control Action and Feedback. The closed-loop controller is widely used in industrial control systems, such as temperature control, pressure control, and speed control.