The Beckhoff KL6904 is a TwinSAFE logic Bus Terminal designed to integrate safety-related control functions directly into the standard Beckhoff Bus Terminal system. It serves as a communication interface and features four safe digital local outputs (24 V DC, 0.5 A), allowing decentralized safety applications to be built with minimal hardware components (such as pairing it directly with a KL1904 safe input terminal).

• Logic Processing: Programmed using certified safety function blocks (e.g., Emergency Stop, safety door monitoring, two-hand control) linked via Boolean operators (AND, OR). 
• Network Capacities: Supports up to 15 TwinSAFE connections, 48 function blocks, and 8 TwinSAFE groups per terminal. Multiple terminals can be cascadable across a network. 
• Configuration: Entirely configured via the standard TwinCAT System Manager and downloaded to the module through the existing fieldbus network. 
• Safety Certifications: Meets high functional safety criteria, achieving up to SIL 3 (IEC 61508) and PL e (ISO 13849-1).