Simple Current-Loop Transmitter Converts PWM To 4-to-20-mA Output

摘要

Over long cable runs, an isolated 4-to-20-mA current loop offers robust noise immunity and tolerance. This characteristic makes it popular for analog data transmission in noisy industrial and process control environments. Unfortunately, the conversion of a digital output to an isolated current-loop signal is a relatively complicated proposition. In addition to the actual signal isolator components, paraphernalia such as multiple floating power supplies and DACs are typically required.