Patent GB-968996-A (GB)
Title: Improved electrical sequencing control
IPC: G06F9/32
Filed: 1960-09-27
Abstract: 968,996. Computer sequencers.  MINNEAPOLIS-HONEYWELL REGULATOR CO. Sept. 27,1960[Sept.30 1959],No. 33186/60. Heading G4A.  A computor control sequencer comprises saturable magnetic cores 1 to 20 each capable of being switched to a saturated state by a driver supplying current to all the cores through a line 63 but of which all except one core at any time is threaded by wires carrying the active outputs of flip-flops A FF to E FF and T FF which inhibit the switching of all save the one core. The output of the switched core is picked up by a combination of sense lines S A  to S E  and S 1 , and complements the flip-flops associated with the energized sense lines so as to select the next core to be switched. To start a sequence the flip-flops may be manually set. The output of one core e.g. core 15, may be used to indicate end of operation to initiate another sequence. Flip-flop T FF  is a trace flip-flop under the control of switches 62, 64 used to bring in a subsequence just before the end of any other sequence. The inhibit lines for cores 14 and 15 are the same except for the pair T, T from T FF  which inhibit cores 15, 14 respectively. A typical sequence is started by setting the flip-flops so that lines A, B<SP>1</SP>, C, D<SP>1</SP> and E are energized. This selects core 1 which when switched complements flip-flops A FF  and C  FF  so that core 2 is selected. Core 2 in turn complements flip-flops B FF  and D FF  so that core 3 is selected which in turn selects either core 14 or 15. If the trace flip-flop was initially set to T core 15 is selected and the sequence ends but if the setting was T core 14 is selected which calls in a subsequence to switch in succession cores 4, 5, 6 and 7. The switching of core 14 complements the trace flip-flop and although core 7 when switched selects either core 14 or 15 the setting of the trace flip-flop determines that core 15 is switched. A similar arrangement of alternative selection is shown for cores 18 and 19 which have the same inhibit lines except for the outputs of flip-flop E FF , the switching of either core complementing E  FF , Here a repetitive loop 16, 17, 18, 16, 17, 19 is gone through, the loop being broken by a signal from the computor, as from a balance test. The control signals from the sequencer appear as outputs on lines 0 1 , to O 20  and one line may be associated with more than one core e.g. line 0 1  or one core may have more than one output line e.g. core 20 has output lines O 20  0 20a . Certain cores e.g. 11 to 13 may produce outputs while an independent sequence is occurring. The sequencer is used in a computor organized as shown in Fig. 2, in which registers A to K and U are connected between storage control and display. A and B are general registers; C is a sequence register capable of being incremented by one; D is the arithmetic register, used for addition and subtraction; E is a general register, used also as a memory address register; F, a transfer register; G, the display register; H and J are input registers; I, K and U output registers. Each register consists of flip-flops and stores eighteen bits and corresponding flip-flops are connected by 1 and 0 input buses 54, 56 and 1 and 0 output buses 50, 52 to amplifiers L 1 , L 2 , M 1 ,M 2 . Amplifiers L 1  and L 2  are connected as required by control to either of the amplifiers M 1 , M 2  or to corresponding amplifiers of the adjacent stages (i.e. L 1  only to M 1  of the next stage). Thus by cross connecting the amplifiers the contents of a register are complemented or, by connecting stages, left or right shift is possible. Additionally the contents of a register may be modified by signals interposed between the stage output and input amplifiers, or by combining the outputs of L 1 and L 2  amplifiers as an input to the M 1  amplifier the register can be cleared. The computor is designed for use in process control and a brief description is given of its operation in control is given with reference to Fig. 1 (not shown).