Safe Coupling via Ethernet – Safe Link from Bihl+Wiedemann

Safe Link is a technology in the Gateways with integrated Safety Monitors and the Safety Basic Monitors with Ethernet interface. It allows safety controllers to be connected to each other simply, efficiently and with the greatest possible flexibility. Learn more about it in the following articles.

The video shows the technical properties of Safe Link and the benefits compared with conventional coupling and coupling with other safe Ethernet systems.

Video length: 1:41

Jochen Bihl talks about Safe Link, a safety technology solution by Bihl+Wiedemann. With Safe Link you can link different parts of the system together in a simple and flexible way – even when different controllers are used.

Video length: 2:16

Comparison of Safe Link and conventional coupling

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Conventional coupling: floating contacts

  • High wiring effort
  • Confusing and error-prone

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Safe Link from Bihl+Wiedemann: safe coupling over Ethernet

  • Simple way of safely coupling many signals
  • Each safe signal is available to every device without restriction

Comparison of Safe Link and other safe Ethernet systems

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  • Safe communication over the respective fieldbus via Ethernet
  • Additional safety PLC (e.g. F-CPU) required
  • Pure Master-Slave communication
  • Generally higher device costs
  • Separate network

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  • Safe communication over the respective fieldbus via Ethernet or the already present standard Ethernet (TCP/IP)
  • No additional hardware or safety PLC required
  • Multicast, each device communicates with all other devices
  • Safe Link option at no added cost
  • Existing network can be used

Safety over Ethernet

Both factory and process automation are showing a trend towards ever more complex, branched applications. The most efficient possible coupling of safe networks now becomes one of the special challenges in the area of safety.


A simple and cost-effective solution

Bihl+Wiedemann has met this challenge with a simple and costeffective solution: Safe Link, i.e. safe coupling over the Ethernet interface of the ASi gateways with integrated safety monitor. In the maximum configuration this means up to 1922 safety two-channel input signals can be collected while controlling safety outputs either centrally or locally.

Couple up to 31 gateways

This approach enables up to 31 Safety Basic Monitors or Gateways with integrated Safety Monitor to be coupled to each other – without losing performance at any point and without the use of additional hardware.

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Why safe coupling?


Many safe signals

  • Up to 62 safe signals per safety monitor
  • The more safe signals, the more safety monitors are needed
  • Safety monitors are coupled to each other

Safe couple multiple machines

  • Central E-Shop works on multiple machines
  • E-Stop on one machine works for the neighboring machine

Widely distributed systems

  • Encapsulating of system parts, segmenting
  • Modular system construction
  • Individual modules are coupled to each other

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Safe communication via...

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  • For traditional fieldbus systems
  • Information exchange via Ethernet diagnostics interface

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  • Safe communication over optical data transmission (additionally required)
  • Safe communication over WLAN networks (addional access points required)
  • For example driverless transport systems, storage and retrieval systems and other mobile applications

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  • For industrial Ethernet derivates
  • Couple monitors over the fieldbus interface of the gateways
  • Communication over the already present Ethernet rail
  • Controller-neutral

Safe coupling for any system size

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Safe Link and PROFIsafe or CIP Safety in one unit

Safe Link at a glance


Safety monitors coupled over standard Ethernet

  • Connections between the devices over Ethernet are generally already present
  • Coupling over Ethernet-based fieldbus interface
  • Coupling over Ethernet diagnostics interface
  • Safe Link meets SIL3/Cat4/PLe


 31 devices can be coupled with each other

  • 31 signals per device can be provided
  • 31 x SIL3/Kat4/PLe
  • “Each one hears all” principle
  • Up to 1922 safety signals


Simplest configuration

  • Drag and Drop
  • Familiar environment
  • Concentration on the essentials


Safe coupling regardless of the fieldbus

  • Full compatibility and integration
  • No additional hardware needed
  • One system for all applications


Safe Link – the simplest way to safely couple many signals

Questions about our products and solutions?

We would be happy to assist you.