PLC independent safety technology

Our ASi systems are wired using a simple two-wire cable. It is easy to handle, avoids wiring mistakes and can be extended without difficulty. When it comes to higher-level systems, our safety and wiring technology can be used with any system and manufacturer and enables simple, fast and thus cost-effective commissioning.

The right protocol for any controller

One of the easiest installation concepts worldwide

With conventional parallel wiring, at least four lines per E-STOP are necessary to achieve PLe, plus additional two lines for the lighting. In case of other safety sensors even more lines might be needed.


Bihl+Wiedemann devices, on the other hand, can send up to 62 safe signals plus the supply voltage over just one 2-conductor cable.

The result:

  • Simplified wiring – cost savings
  • Makes pre-assembly possible
  • Much less error-prone than conventional parallel wiring


Wiring advantages

  • Unshielded 2-conductor cable
  • Data and power on the same cable
  • Piercing technology makes installation simple
  • Up to 62 safety devices


Free choice of topology

  • Ring, star or linear structures
  • Simple expansion

Simple installation technology

  • AS-Interface features a clever piercing technology using a profiled cable. Simply insert the cable, tighten down – finished. Contact pins always penetrate the profiled cable vertically to guarantee perfect contacting.
  • Optimal contacting provided by:
    • Vertical contacting – contact security
    • 4 or 6 pins per cable and 2 or 3 pins per conductor

Relieves the fieldbus

PLC independent safety technology relieves the higher level controller: instead of many individual fieldbus slaves only the Safety Gateway is connected to the fieldbus. It collects the safe sensors and actuators directly in the field and controls the actuators.

The use of Bihl+Wiedemann devices enables compact machinery design, since for example the space for decentralized control cabinet can be saved. Therefore the wiring effort required for doors with interlocks for example is significantly reduced. The piercing technology greatly reduces time and effort compared with expensive and cumbersome connector assembly. 


  • The field installation concept is always the same and reduces the fieldbus nodes – greater overview
  • Safety Gateways eliminate the need for expensive measuring instruments thanks to the integrated measuring technology
  • Increased performance of the fieldbus and simple expansion of the field modules

Free selection of sensors and actuators

If for example multiple light barriers from manufacturer X are used for OSSDs in combination with safety doors with interlocks from manufacturer Y, conventional installation requires that all the components be wired in the control cabinet.


With the active distributors from Bihl+Wiedemann all sensors and actuators can be easily integrated into the network regardless of manufacturer:


  • Safety switches
  • Safety sensors
  • Guard doors
  • OSSDs

The active distributors from Bihl+Wiedemann allow sensors and actuators to be connected in the field directly where they are used. Such flexible use offers many advantages from the construction site to the continuous flow production.

Simple control – commissioning regardless of the controller

The safety system can be commissioned regardless of the higher level controller:

  • No connector assembly – Plug and Play down to the sensor
  • Physical and logical diagnostics integrated
  • No additional measuring devices required

Active Distributors Safety

Safe input modules

  • 1 × 2 channel safe input (SIL3, PLe) – manufacturer-neutral
    • OSSDs or
    • Floating contacts

With variable cable lengths

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Speed monitoring

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Do you have questions about our products and solutions?

ASi – A resource-saving technology

Thanks to the greatly reduced wiring effort with AS-Interface, you save assembly and material costs. This saves valuable resources.


More information!