Programmable controller with function chart interpreter
AssigneeAllen-Bradley Company, Inc.
InventorsDavid R. Rohn, Terry L. Dauterman, Ronald E. Schultz
Life of this patent
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Abstract
A programmable controller stores a user control program which is comprised of a plurality of conventional ladder programs and a structure chart program. A microprocessor executes a structure chart interpreter routine to interpret the structure chart program and to thereby create an active state list which indicates the ladder programs that are to be executed. The same microprocessor with the assistance of a bit processor also executes the ladder programs which are indicated on the active state list to control a machine connected to the programmable controller.
Claims9
A programmable controller for operating a machine to carry out a plurality of programmed functions, which comprises:
- a memory which stores a user control program comprised of a plurality of ladder programs that each include a plurality of instructions which direct the programmable controller to operate the machine to perform a specific function, and a structure chart program that determines the sequence in which the plurality of ladder programs are to be executed to thereby control a machine connected to the programmable controller;
- processor means coupled to the memory and being operable to execute the use control program and to thereby perform the functions indicated by the ladder programs, said processor means including:
- means coupled to the memory for interpreting the structure chart program to produce an active state list which is stored in said memory and which indicates the order in which the ladder programs are to be executed;
- and
- means coupled to the memory for reading the stored active state list and for executing the ladder programs indicated by the active state list by reading the ladder program instructions from the memory and carrying out the functions indicated thereby to operate the machine.
In a programmable controller which includes a memory for storing a user control program and a processor for executing the user control program to direct the operation of a machine connected to the programmable controller through a sequence of states, the method comprising:
- storing a structure chart program in the memory which defines the sequence of states;
- storing the user control program in the memory as a plurality of ladder programs, each of which ladder program includes a set of ladder program instructions that indicate the functions which the machine is to perform when the instructions are executed by the processor, and another ladder program instruction that indicates that the machine is to change to another of its states when said another ladder program instruction is executed by the processor;
- processing the stored structure chart program, the steps comprising:
- (a) selecting a stored ladder program which is associated with the indicated current state of the machine;
- (b) processing the selected ladder program to operate the machine by reading the ladder program instructions therein from the memory and executing them with the processor;
- (c) indicating a change in the current state of the machine and de-selecting the selected ladder program when a state change is indicated by said another ladder program instruction during its processing;
- and
- (d) repeating steps (a), (b) and (c).
Dependencies are inferred from the claim text.