EL3022 BECKHOFF 2-Channel Analog Input Terminal 4–20 mA Differential

Product Overview

The EL3022 (EL3022) is a professional-grade 2-channel analog input terminal designed for the EtherCAT I/O system. It is specifically engineered to process 4 to 20 mA current signals using differential input technology. Unlike single-ended modules, the EL3022’s differential inputs provide superior noise rejection and eliminate ground loop interference, making it the ideal B2B solution for high-precision measurements in electrically noisy industrial environments. With a 12-bit resolution and integrated signal filtering, this terminal is a staple for critical process monitoring, including pressure, flow, and level sensing in chemical, energy, and manufacturing sectors.

Hardware Architecture and Differential Advantage

The EL3022 architecture centers on its two independent differential inputs. By measuring the voltage difference between two signal lines rather than referencing a common ground, the module can effectively cancel out common-mode noise that often plagues long cable runs in industrial facilities. It supports a Common-mode voltage ($U_{CM}$) of up to 10 V, providing significant flexibility in various field wiring topologies.

The terminal features a 1 kHz hardware filter and software-activatable FIR/IIR filters to ensure signal stability. Data is converted via a multiplexing process with a default time of 0.625 ms, ensuring a steady stream of high-quality data to the EtherCAT master. The module is housed in a standard 12 mm polycarbonate casing, featuring 500 V electrical isolation to protect the E-bus backplane from field-side surges.

Technical Specifications

Technical FAQs

Why choose the EL3022 differential input over a single-ended model?

Differential inputs are essential when sensors are located far from the controller or when the sensors and the PLC operate on different ground potentials. The EL3022 ignores the noise that appears on both signal wires equally, ensuring that only the actual sensor data is processed by the 12-bit converter.

Does this terminal require an external power supply?

The logic and communication of the EL3022 are powered via the E-bus. However, the 4–20 mA current loop for the sensors typically requires an external 24 V DC supply, which can be distributed via separate power feed terminals in the EtherCAT segment.

Can I monitor for sensor failure?

Yes. Since the signal uses the "live zero" 4 mA standard, any reading of 0 mA (or significantly below 4 mA) indicates a wire break or sensor malfunction. The EL3022 supports limit value monitoring to automate these diagnostic alerts in the TwinCAT environment.

Engineering & Installation Guide

• Wiring for Maximum Precision: Use shielded twisted-pair cables for all differential connections. To maximize the noise-rejection capabilities of the EL3022, the shield should be connected to the functional earth (FE) at the terminal side using a low-impedance shield clamp.

• Filter Configuration: For slow-moving process variables (like temperature or tank levels), activate the FIR filter via the CoE (CanOpen over EtherCAT) settings to achieve a highly smoothed signal. For more dynamic processes, the IIR filter provides a faster response with effective noise suppression.

• Maintenance and Replacement: The EL3022 features pluggable wiring level (ES series). This allows for the removal of the terminal block without disconnecting individual wires, facilitating rapid servicing and minimizing the risk of wiring errors during module replacement.

Engineering Advantages

The EL3022 is a robust "problem-solver" for analog signal integrity. Its 12-bit resolution provides ample precision for standard industrial applications, while its ATEX certification allows for safe deployment in Zone 2 hazardous areas. Compliance with EN 61000-6-2/4 ensures that the terminal remains operational in environments with heavy electromagnetic interference. For B2B machine builders and system integrators, the EL3022 offers a reliable, globally-certified interface that simplifies the integration of sophisticated analog instrumentation into the EtherCAT ecosystem.