JPH1049203A - Value equalization device for constant-period gathered data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten the load by facilitating the data equalization of a control system having duplexed process data bases. SOLUTION: An absent data counter is provided for a file of process data with time which are transmitted at a constant period and this counter is updated sequentially unless process data can be received (steps S11 and S17); when the update of the absent data counter is detected (steps S13 and S14), equalization to data in a master-side data base is performed to eliminate the need to monitor the system state, thereby lightening the load of the equalization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an apparatus for equalizing data collected at regular intervals in a process control system for monitoring and controlling a plant or a process.

[0002]

2. Description of the Related Art Conventionally, in this type of process control system, process data during plant operation is stored in a database station in a time series, and the data (trend data) is displayed to monitor the plant. The database station is duplicated to improve reliability. Thus, storing the process data in each database station,
Due to an abnormality in the network line or the database station, for example, the process data of the two may be different.
Therefore, it is necessary to equalize (copy all data) the process data stored in each database station in order to centrally manage the process data in the process control system. In this regard, conventionally, it is common practice to monitor the system state of the partner station using a network line between stations that have been duplicated, and detect occurrence of an abnormality to perform equalization.

[0003]

However, according to the above method, it is necessary to monitor the system state of the partner station, copy process data, and the like.
There is a problem that the load increases. Therefore, an object of the present invention is to eliminate the necessity of monitoring the system state of the partner station, reduce the load for equalization, and increase the reliability.

[0004]

In order to solve such a problem, according to the first aspect of the present invention, the process data with time, which is collected and stored at regular intervals by the duplex system, is adjusted to one data. In converting to a value, a missing data counter that counts the number of times when the process data is not sent, and monitors the update count of the missing data counter, and when the data has been updated, responds to the update count. An equalizing means for equalizing the process data with the process data stored in another system is provided.

[0005] In the first aspect of the present invention, the continuous update count of the missing data counter is set in advance, and when the update count does not continuously exceed the set value, the missing data counter is cleared. Process data can be equalized only when the update count continuously exceeds a set value (the invention of claim 2), or the update count of the missing data counter is set in advance and updated. The process data can be equalized only when the count number becomes equal to or larger than the set value (the third aspect of the present invention).

[0006] In the first aspect of the present invention,
The data position when the missing data counter is updated first is stored, and the range of the latest data position can be equalized from this position (the invention of claim 4), or the missing data can be equalized. Each time the counter is updated, the data position at that time is stored, and only the data at that position can be equalized (the invention of claim 5).

[0007]

FIG. 1 is a flowchart for explaining an embodiment of the present invention, FIG. 2 is a system configuration diagram to which the present invention is applied, and FIG. 3 is a diagram illustrating an example of an equalization processing method according to FIG. FIG. As shown in FIG. 2, this type of process control system includes a process control station 1, process database stations 2A and 2B, and a LAN.
The process control station 1 transmits process data to the database stations 2A and 2B at regular intervals.

The database station 2A is always used as a master and the database station 2B is used as a slave. When the database station 2A is abnormal, the database station 2B is used as a master. Each database is provided with a storage file FL, a missing data counter CT, and the like, as shown in FIG.

Referring to FIG. First, after initializing the missing data counter CT, it is determined whether process data of a fixed period has been sent from the process control device 1 (see step S11), and if there is process data, it is stored in the storage file FL (see step S11). See step S12). Next, it is determined whether or not the missing data counter CT has been updated (see step S13), and if it has not been updated, the process shifts to a fixed period wait process (step S1).
6). This state corresponds to the case of FIG.

On the other hand, if there is no process data sent, after updating (incrementing) the missing data counter CT (see step S17), the process shifts to a fixed period wait process (see step S16). This state corresponds to the case of FIG. If the process data has been sent and the missing data counter CT has been updated, the equalization process is started (see step S14).
This state corresponds to the case of FIG. 3, in which the process data corresponding to the count of the missing data counter CT is brought from the database on the master side and equalized. In this example, the count of the missing data counter CT is “1”.
Therefore, the data at the shaded positions shown in FIG.

By the way, process data collected at regular intervals can be obtained by prediction even if data for a certain period is lost. This is explained in FIG.
Thus, the data “△” at time 4 in FIG. 4A can be predicted from the data before and after it. However, FIG.
If the data is missing for a long time, as in In other words, although the method shown in FIG. 1 can reliably perform equalization, in some cases, the frequency of activation of the equalization processing increases, and the load increases. FIG. 5 is a flowchart showing a second embodiment of the present invention based on such a viewpoint, and FIG. 6 is an explanatory diagram of an example of an equalization processing method according to FIG.

FIG. 5 is a modification of the detection unit (step S13) shown in FIG. 1 as shown in the drawing. It is determined in advance as a continuous set number how many data are to be equalized when they are continuously lost. To keep. Here, for example, as shown in FIG. And in the detection unit of FIG.
At step S21, it is determined whether or not the missing data counter CT has been updated. If the missing data counter CT has not been updated, the process directly proceeds from step S21 to the fixed-cycle waiting process. Is compared with the continuous set number (see step S22), and if the count number exceeds the continuous set number, the process proceeds to a step of activating the equalization process. This state corresponds to the case of FIG. If the counted number does not exceed the continuous set number, the lost data counter CT is cleared (see step S23), and the process proceeds to a fixed period wait process. This state corresponds to the case of FIG. As a result, the data to be subjected to the equalization processing is reduced, and the burden is reduced.

FIG. 7 is a flowchart showing a third embodiment of the present invention, and FIG. 8 is an explanatory diagram of an example of an equalization processing method according to FIG. FIG. 7 shows the detection unit of FIG. 1 (step S13).
Is changed as shown in the figure, and the number of missing data items to be subjected to the equalization processing is determined in advance as a maximum set number. Here, for example, as shown in FIG. Then, the detecting unit in FIG. 7 determines whether or not the missing data counter has been updated in step S31. If the missing data counter has not been updated, the process directly proceeds to the fixed-cycle waiting process. The count number of the CT is compared with the maximum set number (see step S32). If the count number exceeds the maximum set number, the process proceeds to a step of activating the equalization process. This state corresponds to the case of FIG. If the count number does not exceed the continuous set number, the process shifts to a fixed period wait process. This state corresponds to the case of FIG. As a result, the data to be subjected to the equalization processing is the data at the shaded position in FIG. 8, and the number of equalizations is limited, and the load is reduced.

FIG. 9 is a flowchart showing a fourth embodiment of the present invention, and FIG. 10 is an explanatory diagram of an example of an equalization processing method according to FIG. FIG. 9 shows an example of a method of changing the missing data storage unit (step S17) of FIG. 1 as shown and determining which process data is to be equalized.
If there is no process data transmitted, first, after updating the missing data counter CT (see step S41), it is determined whether or not the missing data counter CT has been updated for the first time (see step S42), and the updated data has been updated for the first time. In this case, the storage location of the storage file FL is stored in the missing data head position file FF (see step S43).
This state corresponds to the case of FIG. If it is not the first update, the process shifts to a fixed period wait process. This state corresponds to the case of FIG. In this way, the position of the data requiring equalization is stored in the file FF, and when the equalization is started, the equalization processing is performed from that position. In FIG. 10, the file F shown in
The shaded portion of L is subjected to equalization processing.

In the method shown in FIG. 9, there is a possibility that the data size (data amount) to be subjected to the equalization processing becomes large. FIG.
Is a flowchart showing a fifth embodiment of the present invention for avoiding this, and FIG. 12 is an explanatory diagram of an example of an equalization processing method according to FIG. FIG. 11 changes the missing data storage unit (step S17) of FIG. 1 as shown in the figure, and when there is no process data sent, first updates the missing data counter CT (see step S51). Specify the storage location where data should be saved in file FH
(See step S52). This state is shown in FIG.
2 corresponds to the case of. In this way, the position of the data requiring equalization is stored, and when the equalization is activated, the equalization processing is performed from that position. In FIG. 12, the shaded portion is the target data. That is, a total of four data of 3, 5, 6, and 7 at the storage file position are subjected to equalization. This makes it possible to reduce the size of the equalization target data as compared with the method of FIG.

[0016]

According to the present invention, when equalizing process data, it is not necessary to monitor a station connected to a network line, and the burden of equalization processing is reduced. There is an advantage that it is possible to improve the reliability of collected / stored data while maintaining the performance of the system, without imposing an extra load on the system.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a system to which the present invention is applied.

FIG. 3 is an explanatory diagram of the contents of a storage file corresponding to the case of FIG. 1;

FIG. 4 is an explanatory diagram of predictability of process data.

FIG. 5 is a flowchart showing a first modified example of FIG. 1;

FIG. 6 is an explanatory diagram of the contents of a storage file corresponding to the case of FIG. 5;

FIG. 7 is a flowchart showing a second partial modification of FIG. 1;

FIG. 8 is an explanatory diagram of the contents of a storage file corresponding to the case of FIG. 7;

FIG. 9 is a flowchart showing a third partial modification of FIG. 1;

FIG. 10 is an explanatory diagram of the contents of a storage file corresponding to the case of FIG. 9;

FIG. 11 is a flowchart showing a fourth modified example of FIG. 1;

FIG. 12 is an explanatory diagram of the contents of a storage file corresponding to the case of FIG. 11;

[Explanation of symbols]

1 Process control station, 2A, 2B database station, 3 LAN (local area network), FL storage file, CT loss data counter, FF loss data head position file, FH loss data position file.

Claims (5)

[Claims] 1. Equalization of time-added process data collected and stored by a duplexing system at regular intervals to match one of the data, a defect that counts the number of times the process data is not sent. Monitors the data counter and the update count of the missing data counter, and when updated, equalizes the process data corresponding to the update count with the process data stored in another system. And an equalizing device for fixed-cycle collected data. 2. A continuous update count of the missing data counter is set in advance, and when the update count does not continuously exceed a set value, the missing data counter is cleared, and the update count continues. 2. The equalization apparatus for periodic data collection according to claim 1, wherein the process data is equalized only when the set value is exceeded. 3. The process according to claim 1, wherein an update count of the missing data counter is set in advance, and the process data is equalized only when the update count exceeds a set value. An equalizer for periodic data collection. 4. The method according to claim 1, wherein a data position when the missing data counter is updated first is stored, and a range of a latest data position is equalized from this position. An equalizer for periodic collection data. 5. The fixed-cycle collection data according to claim 1, wherein each time the missing data counter is updated, the data position at that time is stored, and only the data at that position is equalized. Equalizer.