【正文】 nts (eg , linear , expontial , parabolic , etc ) can be chosen by the setup puter , as well as the required gap adjustment velocity and stroke length . Accurate tracking of the approach of the head and tail end is essential . This is achieved by special hot metal detectors coupled with bar speed measurement . Inbar width control has two modes : BISRA gagemeter , and feedforward . Although the potential for the former mode of control ( which relies on the accurate sensing of instantaneous roll force to reduce mill stretch ) was always considered limited , due to the high frictional forces relative to the low rolling loads , it was , nevertheless , investigated . It 大學(xué)畢業(yè)設(shè)計(jì) — 外文翻譯 6 was found to be unsatisfactory for the reason stated . The feedforward mode , utilizing ining width error variations detected by a widthmeter after stand E3/R3 , was successful . It resulted in exit width variations , measured after stand E4/R4 , within + mm for 95% of the bar length , as measured by the new widthmeter in this location . This instrument is used to give bar to bar width updating to maintain system calibration . However , it is not used for in bar monitor feedback , because the transport distances involved are a significant proportion of the bar length . ? Hydraulic AGCThe operational features included in the hydraulic AGC system can be divided into those that can be considered as conventional and those that have a novel element . Conventional AGC features include : absolute and lockon BISRA gagementer modes for each hydraulic stand 。s desk contromechanical system, depending on which system was selected. The AWC system prises shortstroke, singleacting cylinders (four in total )engineered between the ends of the horizontal screwa and the vertical roll chocks . These cylinders are servocontrolled, with a stroke speed of 100 mm/s (4 ips) to provide in bar width control. (With the bar being typically 50 mm thick at this stage, only a limited 大學(xué)畢業(yè)設(shè)計(jì) — 外文翻譯 2 amount of correction was expected.) A new widthmeter after roughing stand R3 is used to give feed forward control signals to the edger E4 AWC with the existing widthmeter after rougher R4 providing bar to bar updating . The AGC system on the last four finishing stands has shortstroke, singleacting cylinders located between the top chocks and the acrewdown thrust bearing/load cell cylinders have excetionally high dynamic performance (28 Hz ,10 mm/s velocity ). Becayse of the physlcal distance between the edger E4 and the finishing stands F4 to F7 ,separate pump sets serve each atra ,The hydraulic pressure is 275 bars, mineral oil,with a filtration level of 3 microns . The new puter configuration pries a work of seven PDP 11/73 microprocessors linked by an Ether highway . An unusual feature of the system was the need to tap into the existing 64way parallel munications link between the existing supervisory control puter (SCC) and the melplac plc39。大學(xué)畢業(yè)設(shè)計(jì) — 外文翻譯 1 ? Appication of hydraulic AGC and width control to a hot strip mill Davies,Project Sale Manager,Engineering and Construction Div. Davy Mckee (Sheffie id)Lid, Sheffieid, U. K. THE Pohang Iron amp。s which perform the screwdown AGC, The tap had to be transparent to existing munication and of a high integrity . (Hence a warm spare stand by puter was included in the system .) The required data for the AGC/AWC was extracted , serialized and municated to the new system along the Ether , highway , This had the advantage of opening up the puter system to easier munications in the future , as new systems could be attached easily to the Ether .(A few months later , a further contract for ENCO heat retention panels and interstand water curtains was retention panels and interstand water curtains was received which required a further 11/73 miceoprocessor .) ? Mechanical/hydraulic design features AGC cylinders Various ponents of the AGC cylinders and their assembly are illustrated in Fig . 4,5 and 6. The cylinder design incorporates a single , low friction seal that constests of a Teflon band mounted on the piston below a bronze , side trust ring . The base of the piston is chamfered to give a rocking surface when the cylinder is used in a collapsed state .It gives the necessary degree of freedom to absorb the normal deflections in the mill . 大學(xué)畢業(yè)設(shè)計(jì) — 外文翻譯 3 A hydraulic manifold is mounted to the front of each cylinder that includes the of the position transducers is slightly discernible behind the small accumulator .Another position transducer is fitted diametrically opposite . The two signals from the transducers are averaged to provide a mean stroke signal . The transducer package is shown in .The Sonymagnescale transducers with 1 mic