Method of programming industrial controllers with highly distributed processing

• US 5,530,643 A
• Filed: 12/21/1994
• Issued: 06/25/1996
• Est. Priority Date: 08/24/1993
• Status: Expired due to Term

• Current Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Original Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Inventors: Hodorowski, John
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US08/360,862
• Time in Patent Office: 552 Days
• Field of Search: 364/131-136, 364/146, 364/147, 364/185, 364/188-192, 364/488, 364/491, 364/578, 395/155, 395/159, 395/161, 395/500, 395/700
• US Class Current: 700/86
• CPC Class Codes: G05B 19/0421 Multiprocessor system
• CPC Class Codes: G05B 19/0426 Programming the control sequence
• CPC Class Codes: G05B 2219/21053 Each unit, module has unique identification code, set during manufacturing, fMAC address
• CPC Class Codes: G05B 2219/23258 GUI graphical user interface, icon, function bloc editor, labview
• CPC Class Codes: G05B 2219/23276 Use of virtual, logical connections
• CPC Class Codes: G05B 2219/23406 Programmer device, portable, handheld detachable programmer
• CPC Class Codes: G05B 2219/25032 CAN, canbus, controller area network bus
• CPC Class Codes: G05B 2219/25067 Graphic configuration control system
• CPC Class Codes: G05B 2219/25075 Select interconnection of a combination of processor links to form network
• CPC Class Codes: G05B 2219/25086 Assign functions to group of complete or partial cells, modules
• CPC Class Codes: G05B 2219/25194 Twin core, twisted cable
• CPC Class Codes: G05B 2219/25232 DCS, distributed control system, decentralised control unit
• CPC Class Codes: G05B 2219/25314 Modular structure, modules
• CPC Class Codes: G05B 2219/25324 Modules connected to serial bus
• CPC Class Codes: G05B 2219/2621 Conveyor, transfert line

Abstract

A highly distributed industrial control system employs a number of separate control modules communicating together on a shared communications medium. Each module emulates one or more basic electrical parts having electrical terminals, such as switches and relays, and transmits production messages indicating the state of the parts, such as conducting current or not. A connection list for each part in each control module defines message identifiers of other parts whose production messages are received by the control module and interpreted as current flow to one or more of its parts. The control system is programmed by generating a schematic on a programming terminal showing connections of terminals on symbols of the parts such as would represent actual wiring of the emulated parts. A parts layout diagram is used in conjunction with the schematic to identify each part to a physical module. In this way the program is divided to run concurrently on the various modules without explicit instructions by the programmer.

Claims

1. A method of programming a highly distributed industrial controller comprised of a plurality of physically distinct modules communicating along a shared communications link, the modules transmitting and receiving messages on the communications link, the method of programming comprising the steps of:

(a) generating a logical diagram depicting the industrial controller in the form of an electrical schematic of electrical symbols on an electronic display screen,

the electrical symbols representing elemental electrical functions and having at least one input terminal and at least one output terminal,

the terminals representing points between which current flows according to the elemental function, each terminal having a state indicating current flow,

the terminals connected by lines representing wires to terminals of other electrical symbols and

wherein

one such electrical symbol is connected to a power source symbol;

(b) generating a physical diagram, on the electronic display screen, showing outlines representing the modules surrounding physical symbols representing the elemental functions to be performed by the modules;

(c) programming the modules to emulate the elemental function of the physical symbols associated with the module by the physical diagram; and

(d) compiling the physical and logical diagrams to generate a communications table establishing communications between the modules on the communications link so that the elemental functions executed by a given module may communicate the state of their terminals with other elemental functions in other modules as if the electrical symbols of those elemental functions were wired together according to the logical diagram.

2. The method of claim 1 wherein each module has a unique address on the shared communications link and wherein the compilation of step (d) produces an address list indicating for each given elemental function performed by a given module, the address of other modules having other elemental functions whose electrical symbols are connected to the electrical symbol of the given elemental function by the logical diagram.

3. The method of claim 1 wherein the physical symbols depict the appearance of a physical equivalent to the elemental function.

4. The method of claim 1 wherein the physical diagram indicates the interconnection of the modules by the shared link by means of a line connecting the outlines.

5. The method of claim 1 wherein step (d) comprises:

(i) reviewing the physical diagram to assign each terminal of the electrical symbols with an address formed of an address of the module to which its elemental function is allocated and a unique sub-address within that module;

(ii) reviewing the logical diagram to determine the interconnections between each electrical symbol; and

(iii) relating the interconnection to the assigned addresses to produce the communications table.

6. The method of claim 1 wherein each module has a capability index indicating those elemental functions that can be performed by that module and wherein the compiling of step (d) reviews the physical diagram and the capability index of the modules to verify that the elemental functions assigned to each module can be performed by the module and if not provides an indication to an operator.

7. The method of claim 1 wherein each module has a capability index indicating those elemental functions that can be efficiently performed by that module and wherein the compiling of step (d) also reviews the physical diagram and alters the assignment of elemental functions to the physical modules if the allocation of elemental functions indicated by the physical diagram allocates elemental functions to modules that cannot efficiently perform those elemental functions.

8. The method of claim 7 including the step of:

(e) identifying each elemental function as either module dependent and thus not freely movable to another module or module independent, and reallocating the module independent elemental functions to modules other than those indicated by the physical diagram to ensure the module independent functions are allocated to modules that can efficiently perform the elemental functions.

9. The method of claim 7 wherein the capability index is a function of the module hardware and of the number of elemental functions assigned to the module.

10. The method of claim 1 including the step of:

(e) identifying each elemental function as either module dependent and thus not freely movable to another module or module independent, and reallocating the module independent elemental functions to modules other than those indicated by the physical diagram to reduce the need for communications between modules on the shared communications link.

11. The method of claim 1 including the additional step of:

(e) loading at least a portion of the communication table into each module so that it may initiate messages to other modules to communicate the state of the terminals of the electrical symbols of its elemental functions to the elemental functions of the other modules.

12. The method of claim 1 wherein the physical diagram of step (b) is generated by selecting among a menu of module types having predefined construction electrical symbols.

13. A method of programming a highly distributed industrial controller comprised of a plurality of physically distinct modules communicating along a shared communications link, the modules transmitting and receiving messages on the communications link, the method of programming comprising the steps of:

(a) writing a logical program indicating a logical operation of the industrial controller, the logical operation comprised of a purality of elemental functions;

(b) writing a physical program indicating an allocation of the elemental functions to modules;

(c) programming the modules to emulate the elemental functions indicated by the physical program;

(d) compiling the physical and logical programs to generate a communications table establishing the communications between the modules on the communications link so that the elemental functions executed by a given module may communicate with other elemental functions in other modules to execute the logical program;

wherein each module has a capability index indicating those elemental functions that can be efficiently performed by that module and wherein the compiling of step (d) reviews the physical program and the capability index of the modules to verify that the elemental functions assigned to each module can be efficiently performed by the module and if not provides an indication to an operator.

14. The method of claim 13 wherein the compiling of step (d) also reviews the physical program and alters the assignment of elemental functions to the physical modules if the allocation of elemental functions indicated by the physical diagram allocates elemental functions to modules that cannot efficiently perform those elemental functions.

15. The method of claim 13 including the step of:

(e) identifying each elemental function as either module dependant and thus not freely movable to another module or module independent, and reallocating the module independent elemental functions to modules other than those indicated by the physical program to reduce the need for communications between modules on the shared communications link.