GB1350367A - System for machine control and tape for use therein - Google Patents

Abstract

1350367 Programmed control RACAL-THERMIONIC Ltd 5 July 1972 Addition to 1254947 31496/72 Heading G3N The system disclosed in parent Specification 1254947 is modified in that the reading means, reading each alternate data from the tape, stops the tape before the next block of data to be read, the length of a block and the inter-block gap being known, the tap being devoid of the tag characters previously provided to ensure the reading of alternate data blocks. As shown, information on open ended magnetic tape having one of the forms (T 1 - T 4 ), Figs. 1-4 (not shown) having data blocks (DB) read alternately, in sequence (1#n), the tape reversing at the approximate mid point of the reading, passes via buffer store 44 to core memory 45 controlled by counter units 46 and 47, determining the addresses of the incoming data, and those addresses whence data is to be extracted for circular knitting machine KM respectively, unit 47 being controlled, via the character request signal, provided by an incremental encoder (not shown) on the machine. Difference unit 48 contains the difference in the counts of units 47, 48, its contents representing the amount of unused data in store 45, and when such falls to a predetermined value, a data block request signal to controller 52 causes the reader 42 to read a data block DB, traverse the next data block on the tape, intended for reading in the reverse tape direction, and stop with the reading head in the gap between the last block traversed, and the next block to be read. The core memory 45, see Fig. 6 (not shown), in addition to data store locations (1-20...) stores, in locations (CL1-CL4), the counts of units 46, 47, and a count identifying that interblock gap of the tape under the reading head. The information from the core store, in character assembler 49 containing route gates 50 and memory 51, is assembled into a pair of 36 bit data rows, Fig. 7 (not shown), for use in machine (KM). Tape information format. Data is recorded in groups of nine bits, one bit being the odd party of the other eight, which are divided into four information bits, with each of the remaining four bits being the odd party of a group of three of the information bits, thus enabling a one bit error to be detected and corrected, or a two bit error to be detected.