Control system

Details Control system Control system

1999-02-04

2003-07-08

Follansbee, John (Department: 2121)

Data processing: generic control systems or specific application

Generic control system, apparatus or process

Having preparation of program

C717S152000, C706S045000

Reexamination Certificate

active

06591152

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATIONS
The present invention claims priority from Japanese Patent Application No. 10-40638 filed Feb. 23, 1998, No. 10-101438 filed Apr. 13, 1998, and No. 10-146103 filed May 27, 1998, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique for standardizing computer programs used for control. It relates in particular to a technique for standardizing and thereby readily implementing the design, modification and major alteration of such computer programs.
The present invention further relates to a control program of a control system created by combining a plurality of control modules, each of which separately controls at least one of a plurality of controlled elements contained in a single controlled system, and control modules for hierarchically controlling these control modules.
2. Description of Related Art
When a plurality of controlled elements are provided in a single system, it is a widely practiced technique to provide a plurality of control modules for controlling these controlled elements, and to connect these control modules hierarchically so that each of a plurality of first-level control modules controls at least one controlled element, second-level control modules control first-level control modules, and so on, whereby the system as a whole is controlled.
FIG. 2
is a control system diagram schematically representing a single system, and is applicable to both the prior art and embodiments of the present invention. The system depicted in
FIG. 2
comprises a plurality n of controlled elements E(
1
)-E(n) and has the following hierarchical structure. Namely, control module M(
1
) controls controlled elements E(
1
)-E(
3
). Control module M(
2
) controls controlled elements E(
4
), E(
5
), . . . . Control module M(k) controls controlled elements E(i)-E(n). Control module M(k+1) controls control modules M(
1
) and M(
2
), and control module M(k+2) controls a plurality of control modules up to control module M(k). Control module M(k+3) controls these two control modules M(k+1) and M(k+2).
A communications memory COMA is provided and each control module M(
1
)-M(k+3) is configured so that it can access this communications memory COMA by means of a corresponding communications line C(
1
)-C(k+3). Each control module M(
1
)-M(k+3) is configured so that at prescribed intervals it accesses communications memory COMA and reads communications addressed to itself that have been written in an allocated region of the communications memory, and if necessary writes communications addressed to another module in a region of the communications memory which has been allocated to that other module.
This will be explained by way of an illustration in order to make it easier to understand. On the assumption that this system is a semiconductor fabrication system, then controlled element E(
1
) might be the vacuum pump of a first vacuum chamber, controlled element E(
2
) the elevator inside this first vacuum chamber, and controlled element E(
3
) the pressure valve of the first vacuum chamber. Controlled element E(
4
) might be the vacuum pump for a chamber connecting with a second vacuum chamber, and controlled element E(
5
) might be the transfer belt of this connecting chamber. Controlled element E(i) might be a product exit door, controlled element E(n−1) a product exit elevator, and controlled element E(n) a product exit transfer apparatus.
These controlled elements E(
1
)-E(n) are under the overall control of control module M(k+3) and are hierarchically controlled by control modules M(
1
)-M(k+2), whereby a continuous series of semiconductor fabrication steps is carried out. Namely, silicon wafers are transferred into the first vacuum chamber and set in a prescribed position, the degree of vacuum is increased by operation of the vacuum pump, and deposition is carried out. Finally, the product (or semi-finished product) is transferred to the product exit.
Each controlled element has a sensor, and information output from this sensor is sent to the control module which controls the controlled element. Each control module performs servo-control in accordance with the information output from this sensor. Information relating to other control modules is transmitted to and from the other control modules via communications memory COMA.
The present inventor has been working for a long time on the design of control programs for control systems of the sort illustrated in
FIG. 2
, where a plurality of control modules control a plurality of controlled elements. Controlled elements E(
1
)-E(n) may be valves, the switches of motors, or rotating shafts of robot devices. Control modules with different specifications have therefore hitherto been utilized to suit different types of controlled element.
Namely, when designing a control program for a control system of this sort it has been necessary to design control modules which were appropriate to the properties and characteristics of the respective controlled elements E(
1
)-E(n). This has meant that the design of a control program for a control system has taken a large number of man-hours. It has also meant that each time a specification change or modification becomes necessary, it takes a large number of man-hours to change the control program of the control modules. That is to say, if a design change is required for one of the hierarchically combined control modules, this design change will impact on both higher-level control modules and lower-level control modules, so that a large number of control modules have had to have design changes.
Moreover, even if the controlled elements comprising a new controlled system include controlled elements that were used in the past, the designer has to grasp the overall operation of the new controlled system all over again and create a program with reference to the whole series of operations from initial step to final step. Consequently, if a past design is appropriated, the program for the higher-order and lower-order control modules of the new system has to be changed to fit the past design. Accordingly, even if parts of the program for the controlled elements that were used in the past can be transferred to and used in the program for the new controlled system, as a rule the scope for such transfer has been extremely limited.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a program control system and a method of creating a control program thereof, capable of utilizing, without modification, important portions of the program of a previously designed control module. It is a further object of the present invention to provide a control system and a method of creating a control program thereof, capable of considerably reducing the man-hours required to create a control program of a control system comprising a combination of control modules. It is another object of the present invention to provide a control system and a method of creating a control program thereof, capable of rationalizing the process of creating a control program. It is yet another object of the present invention to provide a control system and a method of creating a control program thereof, capable of incorporating the program of previously designed control modules with only slight changes, despite the devices to be controlled and the controlled elements being different. It is a further object of the present invention to provide a control system and a method of creating a control program thereof whereby a small number of man-hours is sufficient to adjust to changes or modifications which have occurred in controlled elements or control conditions. It is yet another object of the present invention to provide a control system and a method of creating a control program thereof whereby a general user without specialist knowledge can deal with changes or modifications which have occurred in controlled elements or contro

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