Computer language structure for process control applications and method of translating same into program code to operate the computer

• US 5,247,693 A
• Filed: 11/17/1992
• Issued: 09/21/1993
• Est. Priority Date: 10/08/1985
• Status: Expired due to Term

• Current Assignee: Invensys Systems Incorporated (Invensys PLC)
• Original Assignee: The Foxboro Company (Schneider Electric SE)
• Inventors: Bristol, Edgar H.
• Primary Examiner(s): Harrell, Robert B.
• Assistant Examiner(s): GECKIL, MEHMET B
• Application Number:
  US07/978,180
• Time in Patent Office: 308 Days
• Field of Search: 395/800, 395/700, 395/140, 364/188, 364/191
• US Class Current: 717/139
• CPC Class Codes: G06F 8/34 Graphical or visual programming

Abstract

A language structure and translator specifically adapted for use in constructing computer programs for controlling chemical and physical processing. The translator converts to compilable code programs written as statements expressing control intentions or results. Each textual function and statement is expressed as a data structure which expresses the function, as configured, and the state and values most recently calculated for the relevant variables. Provision is made for treating the program structure (i.e., control connections, program order and components, etc.) as a part of the dynamic state of the application. Graphical symbols, or icons, are employed to draw the eye to critical features in the control program and to lead the eye through critical interrelationships among the several commands of a complicated control system. At the same time, the translator treats the keystrokes generating these icons as statements (i.e., commands) which define the relationships among other associated program statements (which are usually textual commands), to control the order in which the operations represented by those statements are executed.

Claims

1. A method of operating a computer system to form computer program code from user programmed source statements indicative of process control operations, the source statements including textual statements of process control intentions, wherein a process control intention specifies a control objective without specifying detailed, implementing calculations, each statement of process control intentions comprising (a) a representation of a regulatory function to be implemented in a process control system controlled by the computer system, (b) an identification of a dependent, control variable to be controlled within the process control system and (c) a list of independent, controlling variables to be used by the regulatory function in controlling the dependent variable, the process control system being formed and described in part by a plurality of elements, interconnections between said elements and control variables having time-variant values, and the statements of process control intentions establishing a plurality of control calculations to be performed in a sequence to be determined, such method comprising the steps of:

a. when configuring the system using the source statements, the computer system allocating memory areas in the computer system for receiving and retaining the values of control variables and information describing the interconnections of elements in the process control system;

b. at a run time when the source statements are first encountered, the computer system automatically determining the sequence of control calculations according to a required order of execution of the control calculations needed to carry out the regulatory function and the interconnections between the elements and the control variables; and

c. at a sample time when one of the source statements is active during a process control operation, the computer system executing the plurality of control calculations in the order of execution determined at run time.

2. A method of operating a computer system responsive to user programmed source statements, called IDIOMS, indicative of process control operations, to effectuate interconnection and operation of components of a system to be controlled, each IDIOM including a statement of control intention translatable automatically into context-dependent control instructions, the method comprising the steps of:

(a) at control system configuration time, for each IDIOM, the computer system setting aside in memory any control blocks needed to store adjustments to values of respective control parameters and to establish control connections based on the permanent aspects of system context;

(b) at run time, the computer system automatically configuring control calculations to implement an IDIOM when the IDIOM is to be executed including automatically determining a computation sequence according to a required order of execution of the control calculations needed to carry out the control intention and the control connections established at the control system configuration time;

(c) at system sample time, the computer system executing the control calculations in accordance with the computation sequence determined in the configuring step; and

(d) after execution of the control calculations implementing the IDIOM, the computer system automatically disconnecting the control calculations.

3. A method of operating a computer system to form computer program code from user programmed source statements, comprising the steps of:

providing a set of source statements including textual statements of process control intentions, wherein a process control intention specifies a control objective without specifying detailed, implementing calculations, each statement of process control intentions comprising

(a) a representation of a regulatory function to be implemented in a process control system controlled by the computer system,

(b) an identification of a dependent, control variable to be controlled within the process control system, and

(c) a list of independent controlling variables to be used by the regulatory function in controlling the dependent control variable; and

translating for each occurrence of a textual statement during computer system operation, the source statement into a set of conventional, more-detailed commands that cause the computer to generate control signals usable by the process control system to implement the regulatory function.