THE Category 4 C4000 entry/exit safety light curtain from SICK can now reliably distinguish between persons and materials thanks to the mobile blanking of objects.
Entry/exit monitoring is advantageous wherever material is automatically transported into the hazardous area of a plant, and the access of persons must simultaneously be reliably prevented.
The system can be parameterised and remotely monitored decentrally via the ProfiSafe field bus.
With ranges of between 0.5m and 19m with a resolution of 20mm, and permissible object speeds of up to 2m/sec, the C4000 entry/exit meets the conditions that are to be found in many industrial transport processes.
The C4000 learns the distances to the target objects autonomously. As a result of these distances, the various transport systems, e.g. skids for differing vehicle types, are automatically accepted and levels of automation and availability for the entire plant are thus increased.
Use of the mobile blanking function has further operational advantages: considerably reduced mounting costs, and lower maintenance and commissioning costs for mechanical and electrical components during plant operation.
Moreover, as the C4000 entry/exit is a compact standard device it is easily retrofitted.
The entry/exit safety equipment of the C4000 is always active. As a result, the system requires no muting sensors, movable barriers, special constructive designs or other secondary sensors - a safety philosophy that has already been implemented on the shell conveyor plant of a major automobile manufacturer.
Among other information, data on the maximum permissible size of an object; protective field entry and exit patterns; and self-taught object distances within the protective field and their changes, are detected and used for differentiating between a worker and a loaded transport system.
The C4000 is parameterised in such a way that it can reliably distinguish between the varying arrangements of the spars of the transport skids and an employee's legs - on the basis of the above-mentioned criteria, and independently of the direction of transport.
The length of the protective field paired with the appropriate height of the structure makes unintentional access impossible.
Just one of the cut-off criteria is sufficient to bring the hazardous movement of a transport system to a stop. A leg that is too wide, or the non-conforming entry to or exit from the protective field, or a leg distance changing unusually, leads to triggering of the safety output - because a person has been identified and not a skid.
The self-monitoring C 4000 safety light curtain is used for safeguarding access. Apart from maximum safety complying with EN 61496, Type 4, the system offers numerous practical functions that can be activated without auxiliary control devices.
The safety light curtain is individually parameterised via the RS232 interface. A further system advantage is its communication capability within control environments based on relays, PLCs or field buses. A decentralised bus module is available for this purpose.
The opportunity for carrying out rapid, reliable, and comprehensive diagnostics in advance and online, leads to correspondingly greater machine and plant availability.