Safety device for a processing bench with local loading and unloading

Situation sketch

The employee is obliged to load and unload the objects. The machine is protected by two horizontal safety light curtains. In this scenario, the safety light curtain must be equipped with a muting function to allow access to the hazardous areas. Unsafe situations mainly occur in the area where the objects are processed. If the employee takes the produced object from the workbench, one of the two safety light screens is "muted / muted" while the other light screens are active. This way the employee can safely load and unload the item. Read more about safety light curtains with muting function.

Double muting

In the event that the employee has to adapt to the machine, a reverse operation takes place. The light screens detect the employee and the machine is muted / muted. The entire technical installation is protected by a gate with an access gate, equipped with a safety switch. When the gate with the safety switch is open, the machine stops. The corresponding manual restart operation is located near every safety light screen. The system is equipped with three emergency push buttons that, if activated, stop the machine.

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If conventional safety relays are used to set up this safety circuit, 4 safety relays would be required. 2 safety modules for the safety light curtains, 1 for the switch on the gate for access to the machine and 1 safety relay for the emergency stop.

Solution with programmable safety relay - Mosaic

When applying the ReeR programmable safety relay Mosiac, the following 2 modules are required to install the safety circuit.

• Main module Mosaic M1
• MI8 expansion module

The reset buttons are not included in the diagram because they are directly connected to the feedback from the OSSD safety outputs. The 3 e-stop buttons are included in the diagram as a single block. The diagram also shows 2 indicator lights used to display the active status of the muting safety light screen.

The Mosaic programmable safety relay from ReeR Safety can be easily configured using drag & drop software. This enables you to set up your own safety system that fully meets your wishes and requirements. The software provides a clear overview of the situation, making functions easy to add. 

Read more about programmable safety PLC - Safety system