Gain a strong understanding of the fundamentals of 4-20 mA current loops, and be better equipped to decide when, where, or if a 4-20 mA current loop solution is right for your application.

In industrial process control, analog 4–20 mA current loops are commonly used for electronic signalling, with the two values of 4 and 20 mA representing 0–100% of the range of measurement or control.

Let’s explore the fundamentals that underpin the 4-20 mA current loop, including Ohm’s Law, key components of the loop, the pros and cons of using this system, and more.

4-20mA overview 4mA represents 0% input level Allows up to 4mA to power external input circuitry 4mA zero level allows under-scale settings and fault detection 20mA represents 100% input level Over …

4-20mA Current loops are widely used to transmit process variable data such as temperature, pressure, flow rate, level, consistency, speed, etc between the process controllers and the field devices. …

Jul 18, 2025 · The 4-20 mA current loop remains one of the most dominant types of analog output in the industry today. In this article I will look at the history of the 4-20 mA loop, why it is widely used in …

Feb 3, 2025 · Learn about 4-20 mA current loop fundamentals, system design, and setup for the purposes of process monitoring and control.

A single loop can carry both measurement and health information (e.g., out-of-range currents to flag faults), which is exactly why 4–20 mA remains the default in process plants.

📏 What Is a 4–20mA Signal Loop? A 4–20mA loop is a method of transmitting an analog signal from a sensor (like a temperature or pressure transmitter) to a control system like a PLC or DCS.