Computer control arrangements

Claim 2

Electrical circuit means for use in controlling a computer having a memory address register, upon receipt of a predetermined input signal, comprising: first input means for receiving the predetermined input signal; output means for loading an address into the memory address register of the computer; storage means for storing the start address of a predetermined computer program; and a sequence signal generator means connected to said first input means, output means and storage means for generating a series of output signals when the predetermined input signal is received by said first input means for sequentially (1) stopping the coMputer in the event that it is already operating in accordance with another program, (2) causing said stored start address to be fed from said storing means to said output means, and (3) causing the computer to begin operating in accordance with said predetermined program.

Claim 3

Electrical circuit means as claimed in claim 1, wherein the sequence signal generator means generates a first output signal for stopping the computer, a second output signal which is applied to said output means for enabling the memory address register in the computer to accept said start address and is also applied to said storing means to cause said start address to be fed to said output means, and a third output signal for causing the computer to begin operating in accordance with said predetermined program.

Claim 4

Electrical circuit means as claimed in claim 2, wherein said second output signal is generated shortly after the first output signal and said third signal is generated an interval of time after said first output signal which is at least equal to the longest instruction time of the computer.

Claim 5

Electrical circuit means as claimed in claim 1, further including a logic circuit means, connected between said sequence signal generator means and said first input means, for preventing the generation of said output signals if said predetermined input signal is applied to the said input means for less than a predetermined interval of time.

Claim 6

Electrical circuit means as claimed in claim 1, further including a logic circuit means including a second input means connected, in use, to the computer or to a unit associated therewith, for preventing the generation of said output signals unless a check signal, representing that the computer or associated unit is in a condition suitable for loading said start address, has been applied thereto, said logic circuit means being connected between said first input means and said sequence signal generator means.

Claim 7

Electrical circuit means as claimed in claim 1, wherein said sequence signal generator means includes means for generating a train of pulses, a counter for counting the pulses generated by said generating means, and decoder means coupling the counter to the said output means for providing said output signals at said output means when the count reaches predetermined values respectively associated with said output signals.

Claim 8

A computer system utilizing the electrical circuit means of claim 1 comprising a computer, first switch means for coupling said computer to a chemical plant or the like which is to be controlled thereby, a first external store for a control program for controlling operation of the plant, said electrical circuit means, the output means of said electrical circuit means being connected to said computer, and a second store for said predetermined program, said predetermined program serving as a loading program for initiating the loading of said control program into said computer from said external store; whereby application of said predetermined signal to said electrical circuit means causes said sequence signal generator to generate said output signals, whereupon said computer operates according to said loading program, the control program is loaded into the computer, and the computer is then able to control the plant or the like according to said control program upon operation of said first switch means to couple said computer to the plant or the like.

Claim 9

A computer system utilizing the electrical circuit means in claim 1 comprising two computers, first switch means for selectively coupling the computers to a chemical plant or the like which is to be controlled thereby, one of the computers being normally on-line and coupled to the plant and the other being normally off-line, a common store for a program for controlling the plant and for up-to-date information concerning the plant which is fed to said common store from said on-line computer, second switch means for selectively coupling said computers to said common store, said electrical circuit means, the output means of said electrical circuit means being connected to said off-line computer, a first malfunction detector having an input connected to said on-line computer, an output connected to said first input means of said electrical circuit means for providing said predetermined input signal at said first input means of said electrical circuit means when there is a malfunction of said on-line computer, a store for said predetermined program, said store being connected to said off-line computer and said predetermined program serving as a loading program for initiating the loading of said control program and said up-to-date information concerning the plant from said external store into said off-line computer; whereby a malfunction of said on-line computer causes said predetermined input signal to be applied to said off-line computer from said first malfunction detector, said sequence signal generator means to generate said output signals, and said loading program to be loaded into said off-line computer, whereupon the operation of said loading program causes the operation of said first switch means to couple said off-line computer to said external store, loading of said control program and said up-to-date information into said off-line computer, and said second switch means are then operated to couple the off-line computer to the system.

Claim 10

A computer system as claimed in claim 8, wherein said on-line computer is also provided with said electrical circuit means and an external store, and a second malfunction detector connecting said off-line computer to said first input means of said electrical circuit means associated with said on-line computer, whereby malfunction of said normally off-line computer, after it has been switched into control of the plant, causes return switching of said normally on-line computer into control of the plant.

Claim 11

A computer system as claimed in claim 8, wherein said common store contains a load-from-common store program, whereby operation of said loading program causes said load-from-common store program to be loaded into said normally off-line computer, and operation of said load-from-common store program causes said control program and up-to-date information to be loaded into said off-line computer.

Claim 12

A computer system as claimed in claim 8, wherein said external store is a read-only memory unit.

Claim 13

A computer system as claimed in claim 8, wherein said common store is a disc store.