EL2252 | BECKHOFF | EtherCAT Terminal 2-Channel Digital Output with Timestamp

Product Overview

The EL2252 is a high-performance 2-channel digital output EtherCAT Terminal designed for applications requiring extreme temporal precision. Operating at 24 V DC, it provides a push-pull output stage capable of driving ohmic, inductive, and lamp loads up to 0.5 A per channel. The standout feature of the EL2252 is its XFC (eXtreme Fast Control) technology, which allows for ultra-precise timestamping. With a terminal-level timestamp precision of 10 ns and a resolution of 1 ns, it enables outputs to be switched at exact, predefined times, independent of the fieldbus cycle time. This makes it an essential component for high-speed synchronized tasks in packaging, printing, and high-end motion control.

Technical Configuration

The EL2252 integrates Distributed Clocks (DC) to synchronize its switching events across the entire EtherCAT network:

• Ultra-Fast Switching: Features an output delay and switching time (TON/TOFF) of typically less than 1 µs, ensuring the physical output matches the high-speed internal timestamping logic.

• Push-Pull Output Stage: The output stage actively drives the signal both high and low, providing clear signal edges and reducing noise susceptibility compared to standard sourcing-only outputs.

• Timestamping Logic: The process image includes a 9-byte timestamp. This allows the controller to "schedule" an output event in the future, which the terminal executes with nanosecond-level accuracy when the Distributed Clock matches the target time.

• 4-Wire Connection: Supports a full 4-wire connection technology for each channel, simplifying wiring for sensors and actuators that require their own power and ground references directly at the terminal.

Technical Specifications

Technical FAQs

How does the "Timestamp" feature improve control performance?

In standard digital outputs, the switching time is jittery because it depends on when the PLC cycle finishes and the EtherCAT frame arrives. With the EL2252, the PLC sends a command saying "Switch at exactly 12:00:00.000000500". The terminal waits for that exact moment based on its internal synchronized clock and switches then, providing jitter-free output timing.

What is the benefit of the Push-Pull output stage?

Standard outputs are often "sourcing" (PNP), where they only provide power. A push-pull stage can both source current (push) and sink current (pull). This results in much faster signal transitions and allows the terminal to better handle loads that might have residual capacitance or require active discharge.

Is this terminal suitable for hazardous environments?

Yes, the EL2252 carries the ATEX Ex marking (II 3 G Ex nA IIC T4 Gc), meaning it is approved for use in Zone 2 hazardous areas, provided it is installed in a suitable enclosure and according to ATEX guidelines.

Engineering & Installation Guide

• Wiring for High Speed: To maintain the nanosecond-level precision of the timestamping, ensure that the wiring to the actuator is as short as possible. Use high-quality stranded or solid conductors (0.08…2.5 mm²) and ensure proper ferrule crimping to prevent signal impedance issues.

• Distributed Clock (DC) Configuration: For the timestamping feature to function, the EL2252 must be configured in the EtherCAT Master (e.g., TwinCAT) with DC enabled. Ensure that the "Reference Clock" in your EtherCAT system is properly synchronized to maintain the << 1 µs network-wide precision.

• Short-Circuit Protection: Each channel is short-circuit proof with a current limitation of typically 1.5 A. If a short circuit occurs, the terminal will limit the current and protect itself. However, the fault should be cleared promptly to avoid excessive heat buildup in the 12 mm compact housing.