Process control apparatus
AssigneeInternational Standard Electric Corporation
InventorRaymond T. G. Boute
Life of this patent
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Abstract
Process control apparatus for reading the condition of a selected variable and for generating a next instruction to be implemented based on the observed condition of the selected variable. The next instruction is that of reading one of two possible instructions, one of which causes the state of an output variable to be read and/or set and the other calls for reading the value of another selected input. In this manner, a program cycle is completed so that the values of all output variables can be set and read.
Claims5
A process control apparatus including a memory for storing a program of instructions and a control unit, said control unit including an input circuit having a plurality of inputs for receiving signals representing the condition of said plurality of inputs, said control unit adapted to perform a selected one of said instructions in reading the input condition signal of a selected input to provide a value for a selected one of a plurality of outputs, the output variables each being related to the condition of said inputs of predetermined relationship and said control unit further including an output circuit with a plurality of outputs via which said plurality of output variables can be set and read, wherein said memory comprises storage for a first set of single type instructions, each such instruction correlated with the address of an input to be read and means in said control unit for deriving from the condition of said input read the address of a next following instruction from among at least two instructions of said program.
Dependencies are inferred from the claim text.