EL3068 by Beckhoff

The EL3068 analog input terminal is produced by Beckhoff as part of the EL EtherCAT Terminals series. Designed for industrial automation, it digitizes low-level voltage signals from field sensors and forwards them to an EtherCAT controller through the backplane. By consolidating multiple voltage channels in a 12 mm slice, the component reduces panel space while providing straightforward DIN-rail mounting inside an IP20 cabinet. Its single-ended architecture suits applications where all transducers share a common reference, such as temperature probes, potentiometers, or PLC expansion racks.

Each of the 8 analog inputs is referenced to a shared ground and measures a unipolar voltage against the bus supply. An internal track-and-hold circuit with a cutoff frequency of 1 kHz attenuates higher-frequency noise before conversion. The input stage presents an impedance of >130 k?, minimizing sensor loading across extended wiring. Conversion accuracy is set by a 12-bit successive-approximation ADC, providing 4,096 discrete codes per channel. The module does not implement the EtherCAT distributed clocks feature, so sampling is synchronized by the host controller instead. With a protection rating of IP20, the electronics must be installed in an enclosed control panel.

Channel isolation toward adjacent terminals is verified for a dielectric strength of 30 V, suitable for common low-voltage instrumentation loops. Signal acquisition employs a multiplex sequence, so the internal converter is time-shared among channels while deterministic update timing is preserved. The module locks onto a 35 mm DIN rail and maps a fixed process image of 2 bytes status + 2 bytes value/ch to the controller. The module does not support CoE storage for retaining configuration parameters through power cycles.