EL1872 by Beckhoff

The EL1872 is a 16-channel digital input terminal manufactured by Beckhoff within the EL EtherCAT Terminals series. It clips onto a standard DIN rail and converts 24 V sensor signals into EtherCAT process data so that a PLC can read each input in real time. Every channel has a dedicated LED that shows its current state, providing immediate visual feedback when signals and wiring are checked. The compact terminal is intended for machine control systems that require multiple digital sensors to be connected through a space-saving EtherCAT I/O station.

The input side operates at 24 VDC, and each channel draws only 3 mA while the terminal takes 4 mA from the supply. Communication electronics are powered through the EtherCAT backplane, with a segment current rating of 100 mA. The housing measures just 12 mm across when neighboring terminals are latched together, conserving space inside the control cabinet. Sensor wires are collected on a flat-ribbon cable that terminates at a pair of 2 × 10-pin male headers. This connection arrangement allows the complete group of input wires to be attached through a compact interface rather than through individual front terminals. During each cyclic bus update, the process image maps every physical input to its corresponding EtherCAT data bit.

The mounting foot locks onto a 35 mm rail, ensuring alignment with other Beckhoff I/O terminals and maintaining an orderly installation within the cabinet. Each channel meets the switching thresholds established by EN 61131-2 Type 1/3, supporting compatible industrial digital sensors. A built-in hardware filter of 10 µs suppresses brief transients so that contact bounce or electrical noise does not cause false state changes. The housing has an IP20 protection rating, which provides protection against accidental finger contact with internal electrical parts. Because the enclosure does not protect against water or fine contaminants, the terminal must be installed inside a suitable control panel. The dedicated status indicators remain visible from the front, allowing input conditions to be checked without disconnecting the ribbon cable or removing the terminal from the rail.