Safety Light Curtain: Muting vs Blanking

So you want to know the difference between the muting function and blanking function for a safety light curtain? This is a very commonly misunderstood functional difference that I asked about often. No reason to feel ashamed, let us see if we can straighten out the differences.

Fixed blanking is a teachable function available on some safety light curtains (memorized and saved to onboard memory). This function allows grouped light beams to be "taught" to ignore intrusion from an object of a taught size (i.e. a conveyor protruding through a light curtain) maintaining safety outputs. This intrusion will shut down the process as it is supposed to be present in the detection area.

Floating blanking allows the same teach function as described under fixed above but this taught a set of beams can travel up or down the light beam face. A good example of when this function would be used is for a brake press machine where the bending metal interrupts beams as it travels.

Muting is a completely different animal in comparison to fixed or floating blanking. Muting is the temporary suspension of the safety function (i.e. ignore interruptions to all beams to allow material through the protective field). This temporary suspension of the safety function is very common in the industrial world, allowing the material (i.e. a loaded pallet) to travel into and from areas that have dangerous motion (i.e. robot (de)palletizer. This suspension is activated and deactivated by a couple of suitable sensors (typically optical) which are meant to differentiate between the material and a person. A good example of an application using muting is the conveyance of a loaded pallet into a shrink wrapping area. In this application, both the entrance and exit would utilize muting safety light curtains to allow material through but keep personnel out.

See the Leuze MLC530 safety light curtain video as a detailed example of muting and blanking along with other light curtain functions for your reference: https://youtu.be/5-tqlMzDhK8

These are fairly straightforward examples of the difference between muting and blanking, I hope that they are helpful to your understanding. If you are interested in additional information, please feel free to contact me as there are many resources (i.e. standards, videos) that can be helpful.