Palletsafe: 'L' Self-Muting Light Curtain Simulation
To ensure correct operation of the safety system both mute beams must be blocked by a loaded pallet within approximately 2 seconds of each other and both must remained blocked during the entire period the palletized load is transferring through the light curtain.
Once both cross beams are blocked (and remained blocked) the system will become muted.
There is a short period of time when the trailing edge of the pallet load 'clears' the detection field of both mute sensors but is still blocking the vertical light curtain. A timer is incorporated within the safety control system that allows a period of 2 seconds between the pallet load 'Clearing' the mute sensors and 'Clearing the vertical light curtain. If the 2 second period is exceeded the safety system will trip.
Position the light curtain to ensure that the pallet load does not stop after clearing the mute beams yet still block the vertical light curtain.
For increased safety integrity a third mute input is available at the light curtain safety controller. This 3rd signal is normally taken from the conveyor transport system (mute enable). Inclusion of this signal indicates to the safety control that the conveyor is transferring products towards the light curtain detection field, thus instructing the controller to activate a MUTE ON condition during the pallets transfer through the light curtain.
Once both cross beams are blocked (and remained blocked) the system will become muted.
There is a short period of time when the trailing edge of the pallet load 'clears' the detection field of both mute sensors but is still blocking the vertical light curtain. A timer is incorporated within the safety control system that allows a period of 2 seconds between the pallet load 'Clearing' the mute sensors and 'Clearing the vertical light curtain. If the 2 second period is exceeded the safety system will trip.
Position the light curtain to ensure that the pallet load does not stop after clearing the mute beams yet still block the vertical light curtain.
For increased safety integrity a third mute input is available at the light curtain safety controller. This 3rd signal is normally taken from the conveyor transport system (mute enable). Inclusion of this signal indicates to the safety control that the conveyor is transferring products towards the light curtain detection field, thus instructing the controller to activate a MUTE ON condition during the pallets transfer through the light curtain.
L type (exit) light curtains are normally used to safe guard an "Out feed" zone. When a loaded pallet (or other recognized component) travels out from the danger area, the cross-beam intersection point is positioned inside the danger area.
STAGE1: The product approaches the cross-beam sensors of the L type light curtain from the danger area.
STAGE2: Once the product blocks both of the cross-beams, the light curtain goes into the mute mode. The light curtain will remain muted as long as the product is blocking the sensing unit and the mute enable signal is applied.
STAGE 3: One the product clears the cross beam the L type light curtains safety function of the light curtain will reactivate after a delay.
STAGE1: The product approaches the cross-beam sensors of the L type light curtain from the danger area.
STAGE2: Once the product blocks both of the cross-beams, the light curtain goes into the mute mode. The light curtain will remain muted as long as the product is blocking the sensing unit and the mute enable signal is applied.
STAGE 3: One the product clears the cross beam the L type light curtains safety function of the light curtain will reactivate after a delay.