System description
EL2904 17Version: 3.2.2
The new ELx9xx series Bus Terminals only include three basic functionalities: digital inputs EL19xx, digital
outputs EL29xx and a logic unit EL6900. For a large number of applications, all sensors and actuators can
be wired on these Bus Terminals. The required logical link of the inputs and the outputs is handled by the
EL6900. For small to medium-sized configurations, the tasks of a fail-safe PLC can thus be handled within
the Bus Terminal system.
3.2.2 Safety concept
TwinSAFE: Safety and I/O technology in one system
• Extension of the familiar Beckhoff I/O system with TwinSAFE terminals
• Freely selectable mix of safe and standard signals
• Logical link of the I/Os in the EL6900 TwinSAFE logic terminal
• Safety-relevant networking of machines via bus systems
TwinSAFE protocol (FSoE)
• Transfer of safety-relevant data via any media (“genuine black channel”)
• TwinSAFE communication via fieldbus systems such as EtherCAT, Lightbus, PROFIBUS or Ethernet
• IEC 61508:2010 SIL 3 compliant
Configuring instead of wiring: the TwinSAFE configurator
• Configuration of the TwinSAFE system via the TwinCAT System Manager
• System Manager for editing and displaying all bus parameters
• Certified function blocks such as emergency stop, operation mode, etc.
• Simple handling
• Typical function blocks for machine safety
• any bus connection with the EL6900 TwinSAFE logic terminal
TwinSAFE logic Bus Terminal EL6900
• Link unit between TwinSAFE input and output terminals
• Configuration of a simple, flexible, cost-effective, decentralized safety controller
• No safety requirements for higher-level control system
• TwinSAFE enables networks with up to 65535 TwinSAFE devices.
• TwinSAFE Logic Terminal can establish up to 128 connections (TwinSAFE connections).
• Several TwinSAFE Logic Terminals are cascadable in a network
• Safety functions such as emergency stop, protective door, etc. are already included
• Suitable for applications up to SIL 3 according to IEC 61508:2010 and
DINENISO13849-1:2015(Cat4, PLe).
TwinSAFE digital input (EL1904) and output terminal (EL2904)
• All current safety sensors can be connected
• Operation with a TwinSAFE logic terminal
• EL1904 with 4 fail-safe inputs for sensors (24VDC) with potential-free contacts
• EL2904 with four safe channels for actuators (24VDC, 0.5A per channel)
• Conforming to IEC 61508:2010 SIL 3 and ENISO13849-1:2015(Cat4, PLe) requirements.