The instrumentation of a 14-inch experimental rolling mill

The paper describes the comprehensive instrumentation scheme recently developed and applied on the new 14 in experimental rolling mill in the British Iron and Steel Research Association (B.I.S.R.A.) Sheffield Laboratories. Roll force on each side of the mill, front and back tensions and strip gauge, using the B.I.S.R.A. gaugemeter principle, are continuously indicated on high-speed servo-operated potentiometric indicators fitted with large pointers and dials. The supply voltage to all measuring elements and transducers in the system is at a frequency of 400 c/s and a rational system of electronic units has been worked out which enables identical amplifiers to be used for all channels. Some of these amplifiers are already in quantity production for other purposes. In the a.c. gaugemeter system used the normal gauge-setting control is situated on the main control desk, and a device is included for automatically setting the zero of the gauge-deviation indicator. Also the mill-screw setting data are fed into the gaugemeter system by Magslip transmission from the screw top. The five indicating dials are mounted in one unit on the mill housing. The whole instrumentation scheme is designed and laid out as a model system for industrial mills of this class. Facilities are provided for experiments with various systems of automatic gauge control previously developed by the B.I.S.R.A.1 A simple method of on/off control of the existing a.c. screw motors according to the gauge deviation has been successfully operated with a tolerance zone of only ? 0.0005 in. Facilities have also been provided for switching to automatic tension control based on measured tensions as an alternative to the present method of control of coiler-motor current with correction for radius of build-up. The accuracy of the various measuring systems is discussed in the light of experience gained so far, and attention is drawn to possible sources of error, particularly in the gaugemeter system.