Which Allen Bradley light curtain solution is the best fit for my application?

The majority of people I interact with are typically not comfortable selecting and configuring Allen Bradley light curtains. In order for us to properly pick out a light curtain, there are some terms we need to be familiar with first:

POC (Point of Control): Required for applications where an operator must regularly reach into a machine hazard as part of the process at the point of operation. POC is also referred to as partial-body access.

PAC (Perimeter Access Control): Requirement for a person to be standing or walking in (or have access to) the hazardous area around a machine that does not require frequent interaction between personnel and the hazard during regular operation. Generally used for maintenance and troubleshooting. PAC is also referred to as full-body access.

Resolution: This refers to the amount of space between beams. Resolution determines the size of body part the safety device can accurately and reliably detect (finger , hand, limb, full body).

Muting: The temporary automatic suspension of a safety function during the non-hazardous portion of the process/machine cycle. Muting a light curtain would completely ignore the light curtain safety function. Some typical muting applications include:

  • Muting a light curtain during entry/exit of pallets on a palletizing machine.
  • Muting a light curtain on a hydraulic press during the up stroke.
  • Muting light curtains on load/unload stations of a robot cell during the non-hazardous state.

Blanking: Bypassing a portion of the sensing field. Note that this is just a portion of the sensing field, not the entire field. A common application is to blank out a small gap in the light curtain to allow feeding of material through it to a punch press while still protecting the operator. Care must be taken not to create an unsafe gap that a person could reach through.

Cascading: Light curtain feature that allows you to wire light curtain pairs in series with other light curtain pairs to reduce wiring/installation costs.


As you know, there are many different AB light curtain families to choose from, making product selection confusing. To make the light curtain selection process as simple and painless as possible, we will lead with our Bulletin 450L light curtain in every light curtain application except:

  • Washdown-rated applications (Micro 400)
  • PAC applications (440L or 445L)

See below for the different 450L Light Curtain Types:

  • 450L-B (Basic Version)
  • 450L-E (Enhanced Version)
  • 450L-E (CIP Safety Version……….Future Release)

If a customer just needs on/off light curtain functionality (is something breaking the beam or not), then we would lead with the 450L-B. However, if the customer needed any additional functionality (muting, blanking, cascading), we would go with the 450L-E. Eventually, there will also be a CIP Safety light curtain option (scheduled to be released Q3 FY20). The 450L light curtains provide a flexible and cost-effective safety solution for almost all possible light curtain applications. Below is the link to the 450L product webpage.

https://ab.rockwellautomation.com/Sensors-Switches/Operator-Safety/POC/450L-B