Which type of signal is more advantageous for transmission?

Current signals are often considered more advantageous for transmission in various control systems, particularly in industrial environments. There are several reasons for this preference.

One significant advantage of current signals is their ability to remain relatively unaffected by resistance and impedance in the transmission line. When a current signal is transmitted, it maintains consistent characteristics over long distances, which minimizes signal loss or degradation—issues that can often occur with voltage signals.

Additionally, current signals are less susceptible to electrical noise. In a noisy environment, the integrity of a current signal can be preserved because it is based on the flow of electrons in a circuit rather than the potential difference, which may fluctuate due to external interference.

Moreover, current signals can continue to provide a measurable value even if a wire breaks or a connection becomes partially faulty. For example, in a 4-20 mA current loop, a reading below 4 mA can indicate a problem, while the range between 4 to 20 mA can intelligently communicate the variable conditions being measured.

This inherent stability and reliability make current signals a preferred choice for data transmission in many control applications, particularly in situations requiring precise and consistent measurements.