MAXREFDES15#: 4 ~ 20mA, Loop Current Sensor

The 4–20mA current loop is widely used as an analog communication interface in industrial applications for transmitting the data from remote sensors to a programmable logic controller (PLC) in a central control center over a twisted pair cable. Here, 4mA represents the lowest temperature value, and 20mA represents the highest measured temperature.

There are four main advantages of the current loop. First, the accuracy of the signal is not affected by the voltage drop in the loop, as long as the power supply voltage is greater than the total voltage drop across the loop. Secondly, it uses two wires for power as well as data communication over the entire loop. Thirdly, it is more immune to noise. And lastly, it is offered at a low cost and easy installation.

The Monterey design is based on a complete Maxim solution which combines ultra-low power, high accuracy, and high precision.

This loop-powered sensor transmitter is targeted for industrial sensors, industrial automation, and process control, but it can be used in any application requiring high-accuracy conversion.

Simplicity, reliability, good noise immunity, long distance, and low cost make the Monterey MAXREFDES15#) (Figure 1) interface well suited for industrial process control and automation of remote objects.