EL2258 BECKHOFF 8-Channel Multi-Timestamp Digital Output Terminal

Product Overview

The EL2258 (EL 2258) is a high-performance 8-channel digital output terminal designed for ultra-precise synchronization and high-speed switching within an EtherCAT network. Operating at 24 V DC with a 0.5 A capacity per channel, the EL2258 stands out due to its multi-timestamping functionality and integrated Distributed Clocks (DC). This terminal is engineered for applications where standard cycle times are insufficient, such as high-speed sorting systems, laser control, and precision electronic assembly. By allowing multiple switching commands to be executed within a single communication cycle, the EL2258 achieves temporal precision significantly below 1 microsecond, ensuring that output edges are placed exactly when required by the process.

Technical Configuration

The EL2258 utilizes a high-density (HD) housing to provide 8 channels in a slim 12 mm width using 2-wire connection technology. Its core strength lies in its "Multi-Timestamp" capability: it can store and execute up to 10 switching events per channel (depending on configuration) relative to the Distributed Clock. The output stage uses a push-type design, optimized for ohmic, inductive, and lamp loads with integrated short-circuit protection and reverse voltage protection. With internal execution times ranging from 10 to 40 microseconds, the terminal can detect and process between 100 and 25,000 edges per second. Electrical safety is maintained via 500 V isolation between the E-bus logic and the field potential.

Technical Specifications

Technical FAQs

What exactly is "Multi-Timestamping" and how does it differ from standard outputs?

Standard digital outputs update once per PLC cycle. Multi-timestamping allows the EL2258 to receive a buffer of multiple timestamps from the controller. The terminal then autonomously switches the output at those exact times, independent of when the next EtherCAT telegram arrives. This allows for switching frequencies much higher than the fieldbus cycle frequency.

Does this terminal support Distributed Clocks (DC)?

Yes, Distributed Clocks are essential for the EL2258. They synchronize the local clocks of all EtherCAT devices to a common reference time. This synchronization is what allows the terminal to execute its timestamped commands with a precision far better than 1 microsecond.

Can I use the EL2258 for inductive loads?

Yes. The EL2258 is rated for inductive loads with a maximum breaking energy of 150 mJ per channel. However, for very large inductive loads or high-frequency switching of solenoids, it is always recommended to verify the energy dissipation to prevent premature wear of the output stage.

Engineering & Installation Guide

Wiring in HD (High Density) Housings:

The EL2258 uses the HD terminal design, which features 16 connection points in a 12 mm housing. Due to the compact nature, ensure you are using the correct wire cross-sections: solid conductors up to 1.5 mm² or flexible conductors with ferrules up to 0.75 mm². Use a small screwdriver to actuate the spring terminals. The 2-wire technology means both the signal and the associated ground/reference can be terminated directly on the module for some configurations, simplifying cabinet wiring.

TwinCAT Configuration and Auto-Activation:

When integrating the EL2258 into TwinCAT, ensure the "DC" (Distributed Clock) tab is configured for "DC-Synchronous" mode. The "Auto-activation" feature helps the terminal automatically start the output sequence as soon as the first valid timestamp is received. You will need to map the 9-byte timestamp process image to your PLC variables to take full advantage of the precision timing.

Thermal Considerations:

While the terminal is rated for 0.5 A per channel, a fully loaded module (8 x 0.5 A = 4 A total field current) generates internal heat. Ensure the installation environment maintains 95% non-condensing humidity and an ambient temperature below 55°C. If mounting multiple EL2258 units side-by-side in a small enclosure with high-frequency switching, consider adding a fan or spacing modules to prevent thermal derating.