The Beckhoff EL1904 is a 4-channel digital input terminal designed for safety-related applications within the EtherCAT I/O system. As part of the TwinSAFE family, it enables the acquisition of binary safety signals from sensors such as emergency stop buttons, safety light curtains, or position switches. The EL1904 processes these 24V DC signals and transmits them in a fail-safe manner to a TwinSAFE Logic terminal for further processing. Its compact design and seamless integration into the Beckhoff control platform make it an ideal choice for implementing certified safety functions up to SIL 3 and PL e in modern automation systems.