APPLICATION STORY

          

          



The Rider Roll Control System
ensures highly accurate control



RRS microPOS, announced by Nobel Systems Ltd., is a digital, closed-loop system for controlling nip pressure applied by the rider roll on paper manufacturing and processing machines. This system provides uniform hardness and even tension distribution throughout the reel, thus ensuring consistent quality. Highly accurate control also reduces the number of web breaks as well as reducing wrinkling. Prior to applying to the reel to be wound, the rider roll is positioned in displacement mode to ensure a parallel and rapid switchover. The roll application is carried out very gently at a reduced speed to eliminate the risk of damage to the reel. After applying, the system reverts to force control and will then also monitor any vibrations and counteract reel ejection tendencies. In the RRS microPOS system, there are six freely programmable force control curves. The force control curves can also be generated in the PLC and transferred to the RRS microPOS in analogue form or via Modbus. The main part of the parameters are entered prior to delivery and the entire parameter set-up can be stored on a disk. The RRS microPOS is programmed with a Windows programme on a standard PC via RS232. The parameters are shown in a menu system for simple and clear handling. The servo system comprises servo valves and servo cylinders, position transducers for position control and load cells supporting the rider roll to control the line force. One or two parallel control position transducers continuously measure the position of the rider roll. The rider roll is moved at maximum speed until it approaches close to the paper core when its speed is reduced. The force control mode then commences using the rider roll force measuring load cells as feedback. The programme also contains six different core diameters. During the reeling phase, required line force (nip loading) is controlled by one of six selectable force curves or by an externally generated desired value from the PC/PLC. The curves are a function of the roll diameter and the parameters already entered and can be selected on the basis of paper quality and other factors. The closed force control means that the load cells measure the actual roll force and any deviations from the force curves are continually corrected. After reeling is completed, the system switches to position control and goes to the waiting mode and remains in position control while waiting for the next command. Options available include combinations of one or two axle force and positioning control. The system is supplied complete in an integral 1P65 waterproof enclosure with internal screw terminal connections. _____________________________________________ For more information, please contact:- Nobel Systems - Murdock Road, Bedford MK41 7PQ. United Kingdom Tel: +44(0) 1234 220800 Fax: +44(0) 1234 325387 January 2000 - Ref: MicroPOS/N2322
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