The Beckhoff KL2904 is a 4-channel digital output Bus Terminal from the TwinSAFE safety product line, designed to provide reliable and secure switching of actuators in safety-related applications. With its integrated functional safety features, robust output capability, and compliance with the highest safety standards, the KL2904 is a cornerstone component for implementing modern, decentralised safety systems in industrial automation.

Each of the four outputs delivers 24 V DC with a maximum current of 0.5 A per channel, allowing direct control of actuators such as contactors, relays, signal lamps, or other safety-relevant devices. Built with 2-wire connection technology, the module provides a straightforward wiring solution that simplifies installation while maintaining secure connectivity.

The KL2904 is built around Beckhoff’s TwinSAFE concept, supporting the Safety over EtherCAT (FSoE) protocol. This allows it to be integrated into distributed safety architectures with ease, enabling communication of safety data across the standard EtherCAT network. By eliminating the need for separate safety wiring, TwinSAFE reduces system complexity and costs, while offering the flexibility to configure safety functions entirely in software.

One of the key strengths of the KL2904 is its adherence to internationally recognised safety standards. Certified to DIN EN ISO 13849-1:2008 (Category 4, Performance Level e) and EN 61508:2010 (SIL 3), it provides the highest level of protection for personnel and machinery. This certification ensures that the terminal can be deployed confidently in critical applications where functional safety is mandatory, such as robotics, packaging machinery, presses, or automated material handling systems.

Fault response is another critical capability of the KL2904. The terminal features a parameterisable watchdog, ensuring that the system can react appropriately to faults within the defined time frame. In the event of a communication failure or system error, the outputs are reliably switched off, guaranteeing that connected actuators are placed into a safe state. This configurability allows system designers to tailor the fault-handling strategy to their specific safety application.

Power is supplied through the power contacts, with consumption dependent on the connected load, while the K-bus itself draws a typical current of 250 mA. This efficient design ensures that the KL2904 integrates seamlessly into Beckhoff’s modular I/O ecosystem. It is typically installed in a horizontal position within the terminal row, aligning with standard cabinet layouts and simplifying deployment.

In summary, the Beckhoff KL2904 TwinSAFE Bus Terminal combines high-performance digital outputs with integrated safety functionality in a compact, modular format. With its four 24 V DC outputs, TwinSAFE/FSoE communication, adherence to SIL 3 and PL e standards, and configurable watchdog fault response, it provides a reliable solution for implementing functional safety in decentralised automation systems. Designed to meet the needs of advanced safety applications, the KL2904 delivers both flexibility and assurance for industries where safe and efficient operation is essential.