Data processing: database and file management or data structures – Database design – Data structure types
Utility Patent
1993-12-09
2001-01-02
Amsbury, Wayne (Department: 2771)
Data processing: database and file management or data structures
Database design
Data structure types
Utility Patent
active
06169991
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a client server system, and more particularly to a client server system and a control method thereof which processes data collected from control apparatus and outputs the processed data to a server.
BACKGROUND OF THE INVENTION
FIG. 17
is a block diagram illustrating the general configuration of a conventional client server system
601
, and in this figure, this client server system
601
comprises a server
96
, and client machine devices
501
a
to
501
c
, all of which are interconnected by a communication line (PC-LAN)
5
. PLCs
86
a
to
86
c
are programmable controllers connected to the client server system
601
. Each of the client machine devices
501
a
to
501
c
collects data from the PLCs
86
a
to
86
c
, processes the data by function A and function B (such as quality control and availability analysis in factory automation-FA), and transfers the result to the server
96
. The server
96
has a database
96
a
which stores data from the client machine devices
501
a
to
501
c.
FIG. 18
is a block diagram illustrating a task configuration in the client machine device
501
a
. Herein the term “task” is defined as a minimum execution unit for a program, which is an object for scheduling required to decide an execution sequence. In this figure, the reference numeral
91
indicates a data collection task for collecting data from the PLCs
86
a
to
86
c
, the reference numeral
92
indicates a common memory in which the data collected by the data collection task
91
is written, and the reference numeral
93
AB indicates a data generation task for a database for an integrated function A (data used in quality control)/function B (data used in availability analysis) database.
Also the reference numeral
94
indicates a network database communication task for communicating with a database
96
a
in the server
96
, the reference numeral
97
AB indicates a database data processing task for a database for an integrated function A/function B database for output of a processing request to the database
96
a
(such as generation, renewal, and insertion) to a network database communication task
94
, and the reference numeral
98
indicates a man/machine CRT display processing task for executing processing according to an operator instruction (i.e., instruction for screen display) from a console device
99
.
It should be noted that the client machine device
501
b
has almost the same configuration as the client machine device
501
a
. However it also has a function C database data generation task for a database (generation of data used in collecting facility maintenance information) and a function C database data processing task in place of the integrated function A/function B database data generation task
93
AB for and the integrated function A/function B database data processing task
97
AB. Also it should be noted that the client machine device
501
c
has a function D database data generation task (generation of data used in collecting tool life information) and a function D database data processing task.
Now description is made hereinafter of the operations of the system. It should be noted that, as operations of the client machine devices
501
b
and
501
c
are almost the same as those of the client machine device
501
a
(Only the functions served by each are different), description is made for only operations of the client machine device
501
a
. At first, the data collection task
91
collects data from the PLCs
86
a
to
86
c
at a specified interval and writes the data to be stored data in a common memory
92
.
FIG. 19
is a drawing illustrating configuration of the common memory
92
, and the common memory
92
comprises a storage area for bit signals and a storage area for numerical data.
FIG. 20A
shows 1 record of stored data
151
in the storage area for bit signals, and
FIG. 20B
shows 1 record of stored data
152
in the storage area for numerical data. The 1 record of storage area
151
stores an “instantaneous value” sent as a bit signal, “data of generation” (month, day, hour, minute), “ON time” and “Number of ON times”. Furthermore, the 1 record stores “status”, namely “1” for inversion of a bit signal or “0” for non-inversion thereof as compared to that collected previously. 1 record of stored data
152
stores a “instantaneous value” sent as numerical data, an “average value” of each instantaneous value, a “MAXIMUM value”, a “MINIMUM” value, a “data count value”, “normalized data”, and “raw data”. Furthermore the 1 record stores “status”, namely “0” for numerical data and “1” for less than a specified lower limit.
Then, the function A/function B database data generation task
93
AB reads stored data
151
and
152
in the common memory
92
, and then sends a processing request (i.e., generation, renewal, and insertion) to the database
96
a
to the network database communication task
94
. Then, a console
99
sends a processing request via the man/machine CRT display processing task to the function A/function B database data processing task
97
AB when a screen display request is entered by an operator.
The function A/function B database data processing task
97
AB causes the database
96
a
of the server
96
to execute processing to retrieve data and transfers the result of retrieval to the man/machine CRT display processing task
98
. The man/machine CRT display processing task
98
displays the transferred result of retrieval on a CRT of the console device
99
.
In addition, technological documents relating to the present invention include the Japanese Patent Laid Open Publication No.19325/1992 disclosing a “multi-host connection control system”, the Japanese Patent Laid Open Publication No.150358/1992 disclosing a “communication control device”, and the Japanese Patent Laid Open Publication No.147151/1991 disclosing a “portable resource-sharing file server with transplantation using common routines”.
In the conventional type of client server system as described above, a number of tasks exists in each client machine device, and the function A/function B database data generation task
93
AB is an integrated one, so that, if a processing speed of any client machine device is slower than a processing speed of the entire system, it is necessary to adjust the work load to the client machine device by, for instance, reducing a number of tasks or minimizing a size of the program for each task, which means an increase of work load to each programmer and lower work efficiency. Also in a database data generation task for database, collected data is read into a common memory, which requires a long time, and furthermore in a data collection task a change in data is determined by comparing collected data to previous data, which makes the processing efficiency lower. In addition, in a client server system based on the conventional art, if any client machine device fails, a spare client machine device is used, and for this reason sometimes some data is lost, or the system cost increases.
SUMMARY OF THE INVENTION
It is object of the invention to provide a client server system and a control method thereof which can make it easier to adjust a work load and improve the work efficiency as well as the processing efficiency by reducing the time required for data transaction and to prevent data from being lost and system cost from increasing by eliminating the necessity for a spare client machine device.
According to the invention, the master task controls each database data processing task and database data generation task each comprising a plurality of functional tasks each corresponding to a different function in a first client machine device. When a work load concentration state or abnormal state in a second client machine device is detected, the first client machine device is caused to additionally execute a function that originally was the responsibility of the client machine device in the work load concentration state or abnormal state.
And, according to the invention, the individual function database data
Amsbury Wayne
Mitsubishi Denki & Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
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