APPLICATIONS OVERVIEW 7 8 APPLICATIONS OVERVIEW

Safeguarding End-of-Line Packaging machinery The following section provides a guide to the application of 8000 Series safety light curtains when used in conjunction with end-of-line packaging machinery.Light curtains mounted across pallet conveyors have special control features that enable pallet loads to pass through the light curtain without interruption to the machine operation but, would shut-down the machine immediately should a person attempt to pass through the intangible barrier. This control function is called muting , which means, disabling operation of the safety light curtain output switches for a limited period, while a pallet load passes through. Obviously when light curtains are used at the pallet entry / exit zones of these machines muting the light curtain during the pallet transfer is essential if automatic operation is to be maintained. Muting conditions for safety light barriers at pallet entry/exit zones as defined in European Standard EN 415-4 Safety of Machinery Palletisers & de-palletisers state:1.Muting may only occur during the period of the operating cycle when a loaded pallet obstructs access to the hazardous zone.2.Muting shall be automatic.3.Muting shall not be dependant upon a single electrical signal.4.Muting signals shall not depend entirely on software signals5.The muting signals, if they occur in an invalid combination, shall not allow muting, or they shall ensure the machine goes to lock-out.6.The muted condition must be cancelled immediately following the passage of a pallet through the detection zone of the protective device.Note: In some applications pallet loads can stop within the muted light curtain detection field for undefined periods of time. To ensure the light curtain does not remain in a muted condition a mute cancel timer is normally installed. If the mute period exceeds 15 minutes the light curtain control will initiate a machine shut-down.All of the above requirements as defined in the Standard are met when using a Smartscan 8000 Series light curtain with the on-board mute control system.Signals used for muting the light curtain during a pallet transfer are normally derived from photo-electric sensors, strategically positioned to enable differentiation between a pallet load and a person. European Standard EN 415-1 recommends two specific muting configurations:1) Cross-beam sensors. 2 ) Parallel-beam sensors operating in pre-defined and timed sequence).The Smartscan 8000 system can be simply configured to provide both the cross-beam and parallel-beam mute configurations. Additionally the 8000 system incorporates the cross-beam / parallel beam sensors as an integral part of the light curtain. In some applications it may be more desirable to use separate sensing devices to enable them to be mounted in configurations to suit unusual applications. Smartscan provide the photo-electric sensors for these applications. They just plug-in to the mute input connector sockets mounted on the light curtain transmitter and receiver columns. 8000 SERIES8000 SERIES