Beckhoff EL3124 Analog Input EtherCAT Terminal for 4 to 20 mA Signals

The Beckhoff EL3124 is a 4-channel analog input terminal for the EtherCAT industrial Ethernet system. It measures input currents from 4 to 20 mA, the standard industrial range for transmitting process variables such as pressure, temperature, flow, and level. The significantly faster conversion time and support for distributed clocks enable use in time-critical applications and set them apart from the EL30xx series. The EL3124 is suitable for high-speed measurement tasks and precise process monitoring in automation systems.

Analog Input Specifications

Each of the 4 differential channels measures 4 to 20 mA current inputs. The 16-bit resolution ensures accurate signal acquisition. The GND connection points of the terminal are not connected internally directly but via EMC protection components; each analog encoder must be connected separately with 2 wires, even if the connection diagram indicates a common ground (GND). The maximum permitted current on signal-relevant terminal points (inputs, GND) is 40 mA. The current inputs are protected against overcurrent by internal current limitation. In the event of a fault, the current limiter must not be overloaded by a voltage greater than 30V from the source device.

Diagnostic and Status Indication

The RUN LED indicates the terminal's operating state with defined modes: off indicates INIT initialization or BOOTSTRAP, flashing indicates PREOP for mailbox communication, single flash indicates SAFEOP verification, and on indicates OP normal operating state with process data communication. The ERROR LED provides fault indication in the event of undershooting or overshooting of the measuring range. Overcurrent in the process image is displayed as "Overrange". After occurrence, the error condition must be stopped immediately; the source device must be switched off or disconnected from the input terminal. If the error condition persists, the internal current limitation reduces the absorbed signal current depending on ambient conditions.

Distributed Clock and Synchronization

The EL3124 supports distributed clocks for synchronized data acquisition across multiple EtherCAT terminals. This feature is critical for high-precision applications where input data from several terminals must be sampled simultaneously with precise time stamps. The high-speed conversion time enables use in applications requiring fast acquisition of rapidly changing process signals.

Physical Design and Power Contacts

The terminal housing is standard Beckhoff EtherCAT design for DIN rail mounting. In the EL3124, the common reference ground is connected to the 0V power contact. The terminal communicates with the EtherCAT network via the E-Bus, which also powers the terminal's electronics. Screw-type or spring-type terminal connectors are available depending on the model variant. The terminal width is 12mm for high-density installation.

TwinSAFE SC Option

The EL3124-0090 variant supports TwinSAFE SC (Single Channel) technology, allowing the use of standard analog input signals in safety applications up to SIL 2 in conjunction with a TwinSAFE logic component. This option expands the application range to include safety-related analog monitoring without requiring dedicated safety analog modules.

Applications and Industries

The EL3124 is used in analog signal acquisition from 4 to 20 mA sensors and transmitters in process automation, machine condition monitoring, packaging machinery, test stands, building automation, and water and wastewater treatment.

Conclusion

The Beckhoff EL3124 4-channel analog input terminal provides 4 to 20 mA measurement with 16-bit resolution for EtherCAT systems. Its fast conversion time, distributed clocks support, and optional TwinSAFE SC functionality make it suitable for high-speed and safety-related analog acquisition in industrial automation.