K-Bus; Power Contacts; Twinsafe; The I/O Construction Kit Is Extended Safely - Beckhoff KL2904 Operating Instructions Manual

System description
3.1.3

K-bus

The K-bus is the data path within a terminal strip. The K-bus is led through from the bus coupler through all
the terminals via six contacts on the terminals' side walls. The end terminal terminates the K-bus.
3.1.4

Power contacts

The operating voltage is passed on to following terminals via three power contacts. Terminal strip can be
split into galvanically isolated groups by means of potential feed terminals as required. The power feed
terminals play no part in the control of the terminals and can be inserted at any locations within the terminal
strip.
3.2

TwinSAFE

3.2.1

The I/O construction kit is extended safely

With the TwinSAFE Terminals, Beckhoff offers the option of simply expanding the proven bus terminal
system, and to transfer the complete cabling for the safety circuit into the already existing fieldbus cable.
Safe signals can be mixed with standard signals without restriction. This saves design effort, installation and
material. Maintenance is simplified significantly through faster diagnosis and simple replacement of only a
few components.
The new KLx9xx series Bus Terminals only include three basic functionalities: digital KL19xx inputs, digital
KL29xx outputs and a KL6904 link unit. For a large number of applications, all sensors and actuators can be
wired on these bus terminals. The required logic link of the inputs and the outputs is handled by the KL6904.
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
• Logic link of the I/Os in the KL6904 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
• Freely selectable fieldbus connection with the KL6904 TwinSAFE logic terminal
KL6904 TwinSAFE logic Bus Terminal
• Link unit between TwinSAFE input and output terminals
18 Version: 3.1.0 KL2904