What is Muting?

Muting refers to the momentary bypassing of electro-sensitive protective equipment. This could be, for example, a light barrier or light curtain. The distinction between expected materials and unexpected objects or persons is made using corresponding muting sensors. When arranging the muting sensors, a distinction is made between cross-muting (fig. 1) and sequential muting (fig. 2). ASi as a bus system makes it possible to easily, efficiently and cost-effectively implement the various muting arrangements.

Cross muting

The arrangement of the two sensors with cross muting is crossed. They must both (S1 and S2) be activated simultaneously to initiate the muting cycle.

Sequential muting

With a sequential arrangement, multiple sensors are connected one after the other; they must be activated or deactivated consecutively in a certain sequence.

Muting with Active Distributors

When it comes to muting the important thing is to consider the individual requirements in advance. It doesn't always make sense to bring all the signals to one point – for example when the sensors are too distant from each other. Bihl+Wiedemann also offers appropriate solutions for such applications – for example where active splitters are used. These collect the signals where they arise.

Safe input modules

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

Digital I/O modules

  • 2I/1O module
  • 4I, 4O or 4I/4O module
  • Connection of any sensors and actuators
  • Safety and standard ASi nodes
  • Make standard sensors and actuators ASi capable
  • Up to protection rating IP67
  • Extremely flat design (W × H × D: 60 × 45 × 19 mm)
  • To M12, M8, Push-In terminal or connecting wires
  • ASi cable length: Cable between distributor and components does not have to be taken into account
  • Round cable length: 0,25 m, 0,6 m, 2 m, 5 m, or according to customer requirements

Installation in Cable Duct

Compact design optimized for the cable duct, especially suitable for individual installation paths.

Drag & Drop Makes Configuration Simple

  • First the user needs only to select whether he wants to use cross-muting or sequential muting and then specify the number and arrangement of the desired sensors (2 or 4).
  • Drag & Drop is used to insert and configure sensors, the start condition or override function in the release circuit.
  • The override function allows product to be moved out of the muting area.
  • Many additional settings such as “End of muting after the light barrier becomes free”, “Tolerated interruption time”, “Conveyor stop”, and various timing parameters.

Simple Muting – all Needed Signals in One Single Module

It used to be that multiple modules were often needed to realize a muting application, for example separate modules for safe and non-safe signals. The new ASi Safety I/O Modules from Bihl+Wiedemann  make it possible to connect all the signals needed for muting to just a single module.

Advantages of Bihl+Wiedemann Muting Modules

  • All the signals needed for muting supported by just one module
  • Space-saving solution with many inputs and outputs
  • Simple and highly flexible configuration
  • Muting lamp can be directly controlled
  • Unused inputs and outputs can be used for example to control motors or incorporate pushbutton modules
  • Cost saving solution with a uniform technology (ASi)

The New ASi Safety I/O Modules in Detail


  • Up to 8 two-channel safe inputs (SIL3, PLe)
  • Up to 2 release circuits (2 × fast redundant electronic safety outputs)
  • Connection of periphery using 8 × M12 socket (5-pin)
  • Memory plug for storing configuration data
  • Connection of ASi and AUX using profile cable (BW3490)
  • Safety signal inputs
    • Floating contacts
    • OSSDs
    • Antivalent switch

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Questions about our products and solutions?