GB923609A - Automatic control arrangement - Google Patents

Abstract

923,609. Timed control of electric circuits.. PYE Ltd. July 15, 1960 [July 17, 1959], No. 24639/59. Class 139. In an arrangement for automatically controlling a sequence of operations that are to be carried out at predetermined times, there is a timing device which compares the time, at which a recorded instruction is to be carried out, with actual time and when the times are in coincidence initiates the carrying out of tne instruction. The instructions and the time at which they should occur are recorded on a punched tape which is then placed into a tape reader 1. The code system used for the tape is such that the first horizontal row of holes indicates that the following rows of holes will be figures (e.g. hours, minutes, seconds), following which is a row indicating that letters are to follow. Two rows of holes are used for the letters (13 different letters in each) which form the basis of a two-letter code capable of representing 169 different instructions. In response to decoder 2 identifying a " figure " code, bi-stable circuit 5 operates to switch the signals from the decoder into a time store 6. The first operating time is stored here and is also shown on a time display unit 17 on the instrument panel R. When the complete time code is stored, the " letters " code appears on tape reader 1, which causes the latter to be stopped and the decoder to be switched through to an instruction store and decoder 3. A master clock 7, fed from a one pulse per second source 11, drives a time display unit 16 and passes a signal into coincidence detector 8. When the times on the master clock and the time store 6 coincide, tape reader 1 is restarted, the two letter instruction is decoded at 3 and the corresponding relay 10 is actuated. More than one set of instructions can be given at one time but decoder 3 is cleared once per second by means actuated from pulse source 11. The master clock and time store 6 may both be cold cathode tube stores. The instructions can be put into operation earlier than at the time shown in display unit 17 by pressing start-reader button 12 or they can be delayed by pressing hold-off button 14 which opens the circuit between detector 8 and the reader 1. If interval clock-start button 25 is operated, switch 26 causes, control of the apparatus to be transferred from master clock 7 to an interval clock 19, and the last three digits in time store 6 to be set up on the interval clock by means of transfer store 21. Clock 19 thus starts running from this time and hence the " first " instruction is put into operation immediately. If a midnight, i.e. zero, time code appears on the punched tape then a midnight detector 22 operates to light two cue lamps 23, 24. Depression of button 25 now extinguishes lamp 23 and initiates the operation of the equipment for a predetermined interval, the following instructions having been recorded with reference to zero time. At the end of the interval, master clock-start button 27 must be operated, to allow normal running of the equipment and to reset clock 19. An indicator 28, 29 indicates the discrepancy between actual time MC and the time shown on the interval clock IC.