EL4021 by Beckhoff

The EL4021 analog output terminal belongs to the EL EtherCAT Terminals series produced by Beckhoff for distributed I/O systems in industrial automation. It is installed on a DIN-rail alongside other EtherCAT modules and converts internal process data into a standardized current signal that can directly drive actuators such as proportional valves or signal isolators. By extending the fieldbus with analog functionality, the terminal eliminates separate wiring runs and allows tight synchronization of analog control points with the deterministic EtherCAT cycle.

Its electrical interface draws 24 V DC from the upstream power contacts, distributing energy to the output stage without an additional supply. The channel delivers a controller-selectable 4-20 mA signal, a format widely used for noise-immune transmission of process variables over long cable lengths. Digital conversion granularity is 12 bit, giving 4096 discrete steps across the programmed range, which supports fine set-point resolution for actuators. Power demand on the terminal side is moderate; the power-contact rail requires only 50 mA typically, while EtherCAT communication and internal logic absorb about 140 mA from the E-bus. These low currents minimize heat rise inside compact control cabinets and permit dense terminal groupings without derating.

The analog section is short-circuit protected; it tolerates load impedances down to < 500 ?, so loop wiring faults do not damage the electronics. With only 1 output channel, commissioning parameters are limited to a single process variable, simplifying configuration in TwinCAT mapping tables. The housing carries an IP20 rating, matching typical IP-protected control enclosures and indicating finger-safe terminals without sealing against moisture. This compact profile lets system designers from Beckhoff maintain uniform mechanical spacing across the EL family, ensuring that mixed digital and analog slices lock onto the same 12 mm width and pass identical power-contact currents for straightforward modular assembly.