Why 4-20 ma only using on control signal?

Question

Accepted Answer

4-20 mA is commonly used as a control signal due to its advantages in terms of noise immunity, long-distance transmission, and compatibility with various devices.

4-20 mA signal provides a wide dynamic range for precise control.
It is less susceptible to noise interference compared to other signal types.
The current loop configuration allows for long-distance transmission without significant signal degradation.
Many devices and instruments are designed to work with 4-20 mA signals, ensuring compatibility.
It is easy to convert the current signal to other forms, such as voltage, if required.
Example: 4-20 mA signal is commonly used in industrial process control systems to regulate the flow rate of a liquid or control the position of a valve.