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.

Comparison of Safe Link and conventional coupling

Conventional coupling: floating contacts

  • High wiring effort
  • Confusing and error-prone

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

Other safe Ethernet systems

  • Safe communication over the respective fieldbus via Ethernet
  • Additional safety PLC (e.g. F-CPU) required
  • Pure direct communication between safe PLC and each gateway
  • Generally higher device costs
  • Separate network

Safe Link

  • 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 cost effective 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.

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

Safe communication via...

... diagnostic interface

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

... optical data transmission / WLAN *

  • 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


* Optical data transceivers and industrial WLAN have to be ordered directly from the respective manufacturer. Devices with Safe Link from Bihl+Wiedemann are compatible with all commonly available brands and suppliers.

... fieldbus interface

  • 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

Safe Link can be used flexibly in small installations or via the fieldbus interface of the gateways of subsystems. Via the safe coupling, the subsystems can be combined into an overall system and be accessed without barriers.

Safe coupling of machines

Safe information exchange is possible between different system parts and also diverse field bus protocols via diagnostic interface.

Safe Link at a glance: the simplest way to safely couple many signals

31 devices can be coupled with each other

  • Connections between the devices via Ethernet are usually already available
  • Coupling via Ethernet-based fieldbus interface
  • Coupling via Ethernet diagnostic interface
  • Safe Link conforms to SIL3/Kat4/PLe
  • Signals can be provided per device
  • 31 x SIL3/Kat4/PLe
  • “Each one hears all” principle
  • Up to 1922 safety signals

Most simple

  • 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

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