Security of robot with light screens

Safe working in confined machines


  • One conveyor
  • Two robot palletising cells
  • The machine is fully protected by a fence with three entrances. One input for each robot cell and one input to the rear of the conveyor belt. All doors are equipped with a safety switch.

If the input of a robot cell is opened, for example by an incoming fork-lift truck, the robot stops. If the input to the conveyor belt is opened, the entire system stops. The loaded pallets are removed by a forklift through the entrance at the front of each robot cell. Both openings are protected by a safety light curtain. When the interruption of a light curtain stops the associated robot. The reset button is mounted near each light screen.

Used products

  • 2 safety light curtains
  • 2 reset buttons for the safety light curtains
  • 3 door switches
  • 4 emergency stop buttons

Solution with programmable safety relay Mosaic

If we apply safety relay, it is necessary to use a minimum of six relays for the desired functionality:

  • 2 safety relays for the light curtains
  • 3 safety relay for door switches
  • 1 safety relays for the emergency stop button

Applying the Reer Mosaic is sufficient for the following hardware, consisting of only two two programmable safety controllers:

  • 1 base unit M1
  • 1 expansion module MI802

As the picture on the right shows, the software with which the safety controller is programmed with a clear overview of the situation. Features are easy to add or adapt to it.