Control valves are primarily controlled by receiving a signal from a controller.
Based on the provided information, control valves operate by receiving a signal from a control system. This system is typically a controller, which can be a PLC (Programmable Logic Controller) or a DCS (Distributed Control System).
The Role of the Controller
The controller plays a crucial role in directing the control valve's action. Here's a breakdown based on the reference:
- Monitoring: The controller monitors the actual value of a process variable, such as the flow rate.
- Comparison: It compares this actual value to a desired target value, known as the setpoint.
- Output Generation: If there's a difference between the actual value and the setpoint, the controller calculates the necessary adjustment. It then produces an output signal.
- Valve Operation: This output signal is sent directly to the control valve. The valve receives this signal and moves accordingly (e.g., opens or closes) to adjust the process variable and bring it closer to the setpoint value.
In essence, the controller acts as the brain, processing information and sending instructions via a signal to the control valve, which acts as the muscle to make the necessary adjustments in the process.
