EL3104 by Beckhoff

The EL3104 is a four-channel analog input terminal produced by Beckhoff as part of the EL EtherCAT Terminals series. Installed on a standard DIN rail, it links field-level sensors to an EtherCAT network so that a controller can sample low-level process variables in real time. By converting differential voltage signals into a digital process image, the module provides precise data acquisition for industrial automation tasks such as closed-loop control or data logging.

This terminal accepts 4 single-ended or differential inputs over a signal span of ±10 V. Each channel has a native resolution of 16 bits, providing 65,536 discrete codes for fine measurement granularity. A maximum common-mode tolerance of 35 V protects the inputs against ground offsets frequently encountered with remote sensors. Analog values pass through an internal filter that tracks changes up to 5 kHz, while a multiplexed sampling scheme sequences the channels without additional wiring. The differential ground reference suppresses noise picked up along the cable pairs, and the process image is organized as four 16-bit values plus four 8-bit status bytes so that control software can read raw data and diagnostic flags in one cycle.

The terminal draws a typical backplane supply current of 130 mA through the E-bus, minimizing the load on the power supply when multiple modules share a segment. The enclosure provides IP20 protection, including finger-safe openings suitable for cabinet installation. Each input has an internal resistance of greater than 200 k?, ensuring negligible loading on high-impedance sensors, and the permissible input contact current remains limited to 40 mA. The housing clips onto a 35 mm mounting rail, allowing quick addition or removal during panel maintenance. Distributed Clocks support enables sub-microsecond synchronization with other EtherCAT nodes so that sampled values align accurately with drive or motion events.