ABB drives help achieve precise control

A crosslapper accepts a light weight fibre web from a carding machine and uses it to build up a heavier web in layers (known as a batt). The crosslapper overlaps the layers by means of a complex arrangement of conveyors and reversing mobile carriages that turn the material through 90 degrees. Typical end-products include automotive textiles, bedding, industry felts and filtration media. Tatham's latest TSX control system utilises ABB high performance machinery drives and servomotors. Several panel combinations are available depending on the existing crosslapper configuration. The system is linked to the master process control using Profibus, an ABB AC500 PLC provides positioning data to the drives which convert it into control signals to maintain the speed of the servomotors. "We chose ABB drives because of their versatility and power", says Jim Kelly, Senior electrical engineer at Tatham, "together with ABB we developed a control software based on the ABB drives' programmable function blocks which mean we had a system that provided precise positioning that is repeatable resulting in total control of the batt profile. The heaviness of the batt is a function of the speed it is laid down at and using the ABB PLC, drives and servomotors allows us to vary this precisely, giving a much more accurate and controllable build up of the layers. We can adjust the speed of the carriage at the edges of the batt to avoid distortions and maintain the correct thickness across the entire width." The accuracy of the ABB high performance machinery drives mean the TSX system can provide precise control of web delivery to achieve the required batt profile.