The advantage offered by these units lies in the combination of several functions within a common housing. These sensors are widely used in the through passageway of automatic doors. The radar motion detector activates the door opening cycle. The light curtain delays the closing cycle as long as someone is located in the access area. European standards demand that two safety sensors be located immediately in front of and behind the door panel/leaf.
For sliding doors in emergency exits and escape routes, a special radar motion detector is required for the escape direction. Consequently, a distinction is made between models used for standard applications and models used for the escape direction.

Where the requirement is exclusively one of safety without additional door activation, a safety light curtain is a viable choice. This device type is more frequently found on the secondary closing edge to monitor the opening cycle. If someone is located within the detection range, the opening cycle is stopped.
A safety light curtain is appropriate in the through passageway of a door where activation to open the door is performed, for example, by means of a manual pushbutton.