EL3042-0017 by Beckhoff

The EL3042-0017 is a two-channel analog input terminal developed by Beckhoff for the EL EtherCAT Terminals series. As a modular I/O slice, it digitizes low-level voltage signals and streams the data onto the EtherCAT network so a controller can monitor machine sensors in real time. The unit installs on a DIN rail beside other terminals to expand process-control topologies without requiring field devices to be rewired.

Each channel accepts a maximum of 30 V, providing protection for downstream electronics against differential overvoltage. The module has two analog inputs that are scanned sequentially through a multiplexing scheme; this technique lowers crosstalk while allowing the channels to share the internal converter. Raw data are quantized at a 12-bit resolution, so 4,096 discrete codes represent the full signal span. After conversion, the reading is packed into a 16-bit presentation width, leaving room for the status and sign bits required by the EtherCAT protocol. An internal low-pass stage with a 1 kHz cutoff frequency attenuates higher-frequency noise before sampling, which improves measurement repeatability in servo and motion applications.

The electronics are supplied via the E-bus, eliminating separate 24 V wiring and allowing power to pass through adjacent terminals. Ground is referenced in a single-ended manner to the 0 V power contact. Distributed clocks are not implemented, so the terminal relies on the EtherCAT cycle for timing. Installation uses a standard 35 mm DIN rail commonly found in control cabinets. The enclosure has an IP20 protection rating for installation in closed panels that prevent direct exposure to moisture and excessive dust. Data transfer uses one value byte and one status byte for each channel, resulting in two bytes per channel and keeping the network load predictable during operation.