GB1354780A - Memory store arrangements - Google Patents

Abstract

1354780 Programmed position control SIEMENS AG 13 July 1971 [14 July 1970] 32688/71 Addition to 1260888 Heading G3N In a memory storage arrangement wherein a stack of plates 10, acting as a data carrier is traversed by write-in and read-out heads 12 mounted on common slide 14, as disclosed in Parent Specification No. 1260888, the slide is moved by an electric actuator 26 comprising a permanent magnet system and a piston within it, carrying a lap winding, with out and return conductors in distinct air gaps, to which current is supplied through fixed brushes, in place of the hydraulic actuator of the Parent. Positional control of heads 12. Slide 14 carries serpentine conductor 76, having position-dependent coupling with a similar conductor 72 supplied by A.C. source 74, and supplying to amplifier 78 an A. C. signal whose envelope is a sinusoidal function of position, and whose zeroes correspond to the track positions on the data carrier. A control device 90 supplies to track difference register 50 a numerical address of the desired position of heads 12, and signals V, R indicating desired direction of head motion. Coarse position control. The output of amplifier 78 is fed to zero detector 82 which provides a pulse to count register 50 towards zero each time a zero of the envelope occurs, and an operational amplifier 17, via d/a converter 54, and decoding circuit 52, providing a constant output to 54 unless the count in 50 is less than a predetermined amount to limit maximum slide speed, receives an input otherwise proportional to the count in 50, and an actual speed signal from speed indicator 20 and, via operational amplifier 18, and powder amplifier 19 excites the actuator 26 such that the actual speed of slide 14 is proprotional to the count in 50, and hence decreases stepwise towards zero, Fig. 2 (not shown). Fine position control. Should the count in 50, as detected by zero detector 15 be non-zero, operational amplifier 16 receives a maximum signal corresponding to a creeping speed of head 14. Upon attainment of zero in register 50, amplifier 16 is controlled in dependence on the output of amplifier 78 and hence the envelope of the A.C. signal, causing the slide to move continuously until a zero of the signal is reached, phase sensitive rectifier 80 receiving a reference signal from source 74. The polarity of the rectifier output may be reversed.