Safety of palletizing systems

Detection of irregular objects

One of the problems that can be encountered in the protection of palletizing systems, is the handling of irregular objects, like for example, sacks or any type of material not easily stackable, typically with the presence of seams, labels, and protrusions that may randomly change the geometric shape of the pallet and thereby cause false signals from the sensors.

To achieve a high degree of flexibility in the design of a safety system for a plant, ReeR Safety has developed Safegate, a Type 4 Muting Integrated Access Control Barrier, that also allows software configuration and Muting parameters optimization.

The programmable models (SMPO) allow in fact the configuration of Muting logics and additional functional parameters (i.e. Partial Muting) via the Safegate Configuration Software (SCS), allowing the further configuration of specific parameters, ideal to address particular issues in more complicated application scenarios.

This solution allows us to easily adapt the safety system of the plant and guarantees compliance with the regulatory requirements on Muting sensors geometry as well as all other safety-related parameters, as per EN 62046 and other current standards.

SAFEGATE – Muting Logics

One-way openings with pallet exit

Muting sensors are placed on one single side of the vertical light curtain, pointing towards the upcoming pallet.

The Muting function is activated following concurrent interruption of the 2 sensors within a programmable directive-compliant time range. This value can be set through parameter: Sensor time (from 2 sec. to 5 sec.).

The Muting function remains active as long as both sensors remain occupied. When the first of the 2 sensors is cleared, the material has a set (programmed) time to abandon the guarded area delimited by the light curtain. This time can be set through the parameter: End of Muting time (from 2,5 sec. to 6 sec.).

The Muting condition will be disabled as soon as the protected area is cleared. If the light curtain is still occupied, the OSSD outputs are disabled, interrupting the functioning of the machine.

Using the parameter: Blind Time (from 250 msec. to 1 sec.) it is possible to lengthen the time within which the light curtain, even though resulting occupied (detection of labels, seams, etc.), does not go into alarm and stops the machine.

The maximum duration of the Muting condition (timeout) can be set from 10 seconds to infinity, using the parameter: Muting Timeout.

Two-way openings with pallet entrance/exit

Muting sensors are placed on both sides of the vertical light curtain, pointing towards both directions of travel of the pallet.

The Muting function is activated following concurrent interruption of the 2 sensors within a programmable directive-compliant time range. This value can be set through parameter: Sensor time (from 2 sec. to 5 sec.).

The Muting function remains active as long as both sensors remain occupied.

When the first of the two sensors is cleared, the Muting function is disabled.

Also for this system, the maximum duration of the Muting condition can be set from 10 seconds to infinity, using the parameter: Muting Timeout.

The SCS Safegate Configuration Software

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Courtesy of ReeR Academy

Written by G Giovenino, V Casetta, M Paglietta