Weighing in with process gains
29 Jan 2007
Welsh cheese manufacturer Aeron Valley Cheese has significantly enhanced the accuracy and efficiency of its production operations through the installation of a new process weighing system.
AVC manufactures and pre-packs a large variety of Welsh-branded cheese products at its facilities in Lampeter, Ceredigion with cheese taken up into towers and cut into blocks. The previous weighing system was unreliable so that the cheese sliced in the towers was coming out in varying weights. The problem was linked to the original weight controller being unable to communicate back to the PLC to make the necessary corrections.
To address these issues, AVC opted for a solution from Applied Weighing to replace the existing load cells and weight instrumentation for the tower weighing systems with a closed system in a feedback loop. This can get within 7g accuracy of the 25kg in the towers for greater consistency in the company's cheese production.
Each tower weighing system works in conjunction with a load cell junction box, which facilitates monitoring of the load cell performance. The load cells were used with special weighing assemblies. A single weight controller, the Model 920i, shows a graphic weight display for each tower and a single Profibus output was provided to communicate with the PLC.
Alongside the three towers is a conveyor line, which comes back on itself in a loop. A checkweigher on the conveyor belt checks the weights of the cheese coming out of the towers. The original checkweigher was upgraded by using another Model 920i weight controller to perform a dynamic weighing programme.
This weight controller notices changes in weight from each tower individually and has a single Profibus output to communicate with the existing PLC. Operators can therefore correct any changes in weight by altering the cheese cutter settings in the towers.
The checkweigher can be used as a standalone unit, but information can also be sent to and from it via LAN/Profibus/RS232. Information about many different products can be stored in an internal databank, as can information about product routing and belt speeds. The checkweigher is therefore suitable not only for 'in-weight' checks but also for classification and sorting for a wide variety of different weights and sizes.
AVC manufactures and pre-packs a large variety of Welsh-branded cheese products at its facilities in Lampeter, Ceredigion with cheese taken up into towers and cut into blocks. The previous weighing system was unreliable so that the cheese sliced in the towers was coming out in varying weights. The problem was linked to the original weight controller being unable to communicate back to the PLC to make the necessary corrections.
To address these issues, AVC opted for a solution from Applied Weighing to replace the existing load cells and weight instrumentation for the tower weighing systems with a closed system in a feedback loop. This can get within 7g accuracy of the 25kg in the towers for greater consistency in the company's cheese production.
Each tower weighing system works in conjunction with a load cell junction box, which facilitates monitoring of the load cell performance. The load cells were used with special weighing assemblies. A single weight controller, the Model 920i, shows a graphic weight display for each tower and a single Profibus output was provided to communicate with the PLC.
Alongside the three towers is a conveyor line, which comes back on itself in a loop. A checkweigher on the conveyor belt checks the weights of the cheese coming out of the towers. The original checkweigher was upgraded by using another Model 920i weight controller to perform a dynamic weighing programme.
This weight controller notices changes in weight from each tower individually and has a single Profibus output to communicate with the existing PLC. Operators can therefore correct any changes in weight by altering the cheese cutter settings in the towers.
The checkweigher can be used as a standalone unit, but information can also be sent to and from it via LAN/Profibus/RS232. Information about many different products can be stored in an internal databank, as can information about product routing and belt speeds. The checkweigher is therefore suitable not only for 'in-weight' checks but also for classification and sorting for a wide variety of different weights and sizes.
