High performance, high accuracy, 4–20mA current loop transmitter for industrial needs

The 4–20mA current loop is widely used as an analog communication interface in the industrial field. It can easily transmit remote sensor data to the programmable logic controller (PLC) in the control center through twisted pair wires. This interface is simple, can achieve reliable long-distance transmission of data, has good noise immunity, and has low implementation cost. It is very suitable for long-term industrial process control and remote automatic monitoring.

There is no doubt that industrial development, like all electronic applications today, requires strong demand for higher precision, lower power consumption, reliable operation in the extended industrial temperature range of -40°C to +105°C, and higher performance. Security and system protection also require support for the High Speed ​​Addressable Remote Sensor (HART ^® ) protocol. Taken together, these requirements make today's 4–20mA current loop designs challenging.

This article describes how to develop and perform performance analysis of a 4–20mA current loop transmitter, and how to select components that meet stringent industrial requirements. Provide error analysis test data, thermal characteristic data, schematic diagrams and analysis software.