KR20200139521A - Method for unidirectional data communication based on opc standard and apparatus for the same - Google Patents

Abstract

A unidirectional data transmission method based on an OLE for process control (OPC) standard is disclosed. According to the present invention, a unidirectional data transmission method based on an OPC standard comprises the steps of: comparing the maximum data throughput of a reception proxy with the data throughput per second of a transmission proxy; comparing the sum of a request period of historical data, a request range of historical data, and an update factor if the data throughput per second of the transmission proxy is greater than or equal to the maximum data throughput of the reception proxy; increasing the request period of the historical data by the update factor if the request range of the historical data is greater than or equal to the sum of the request period of the historical data and the update factor; and if the request range of the historical data is less than the sum of the request period of the historical data and the update factor, increasing the request range and the request period of the historical data by the update factor.

Description

One-way data communication method and device based on OPC standard {METHOD FOR UNIDIRECTIONAL DATA COMMUNICATION BASED ON OPC STANDARD AND APPARATUS FOR THE SAME}

The present invention relates to a data communication method and apparatus, and more particularly, to a method and apparatus for reliably transmitting data while maintaining security during one-way data transmission from an OPC server to an OPC client in OPC standard-based data communication.

In the case of major national infrastructure such as power plants, military information networks, and public institutions, security is strengthened by fundamentally blocking access to the control system of the facility from outside.

One-way data transmission technology using a one-way data transmission device is being used as a way to enhance security. A typical communication network in which a one-way data transmission device is used is a control network operated in a major infrastructure. Most of the control networks are in the form of monitoring the data of the segregated closed network (safe area) in the external network, and are performed through the control protocol of various application layers suitable for the control network.

When a single "??*" data transmission technology is introduced into a separate closed network (safe area) such as a control network, it can be very effective against external security threats. One-way data transmission is performed only in one-way transmission path between data sender and receiver Because it allows and does not allow transmission from the opposite direction, system access from the outside is fundamentally blocked An example of one-way data transmission is a physical single link that fundamentally blocks access to the safety area from outside to protect the safety area. A base unidirectional data transmission technology, a unidirectional data transmission/reception technology based on a dedicated protocol for securing the security of transmission data, and a forward error correction technology to ensure the reliability of transmission data.

On the other hand, OPC (OLE for process control), which connects production equipment and facilities through a network and collects data from the production equipment and facilities, increases the efficiency of equipment and facility management, and automates the implementation of a smart factory. It is attracting a lot of attention.

In addition, in order to apply new 4th industrial revolution-based technologies such as artificial intelligence and cloud to the production site, it is important to secure compatibility between factories of the same or different types, between equipment, between objects, and between control system providers, and improve productivity and reduce defect rates. It is important to secure such compatibility in the implementation of a smart factory that aims to secure price and quality competitiveness.

As such, OPC is a protocol for interoperability between interfaces (including between factories, between equipment, and between objects) of different control system providers, and is a standard interface abstracting a specific protocol for a programmable logic controller (PLC). In the use of control protocols of various application layers in OPC, as various control communication protocols of various control system suppliers are used, an OPC standard for interoperability between interfaces of different suppliers has been introduced.

Among the OPC standards, the OPC classic standard has been successfully applied to thousands of products, and has been subdivided into OPC DA (data access), OPC HDA (historical data access), and OPC AE (alarm & event) functions.

In the era of the Internet of Things, the application of OPC is expected to expand to secure the compatibility of data communication between production equipment and facilities of the same or different types, and a technology that blocks external access to important facilities and equipment through IoT equipment, etc. Needs to be applied to the standards of OPC.

Meanwhile, if data is lost during one-way data transmission based on the OPC standard, retransmission of some data is difficult. Therefore, there is a need for a method to prevent data loss in unidirectional data transmission based on the OPC standard.

An object of the present invention for satisfying the above needs is a one-way data transmission method for effectively transmitting OPC standard-based data of a safe area to a non-secure area while fundamentally blocking external intrusion into a safe area, which is a separated closed network, and To provide the device.

Another object of the present invention is to provide a method and apparatus for preventing data loss during unidirectional data transmission based on OPC standards.

The OPC standard-based one-way data transmission method according to an embodiment of the present invention for achieving the above object includes: comparing a maximum data throughput of a receiving proxy and a data throughput per second of a sending proxy, and receiving the data throughput per second of the sending proxy. If greater than or equal to the maximum data throughput of the proxy, comparing the request period of historical data with the sum of the request range of the historical data and the update factor, the request range of the historical data is the request period of the historical data and the If it is greater than or equal to the sum of the update factors, increasing the request period of the historical data by the update factor, and if the request range of the historical data is less than the sum of the request period of the historical data and the update factor, the history And increasing the request range and request period of curl data by the update factor.

According to the present invention, in the OPC standard-based one-way data transmission, the reliability of one-way data transmission by controlling the request period and request range of historical data based on the data throughput of the sending proxy and the receiving proxy to prevent data loss during transmission. Can improve.

1 is a conceptual diagram of an OPC standard-based one-way data transmission apparatus according to an embodiment of the present invention.
2 is a flowchart illustrating a procedure for building an OPC server proxy according to an embodiment of the present invention.
3 is a flowchart illustrating an OPC standard-based one-way data transmission method according to an embodiment of the present invention.
4 is a flowchart illustrating a method of updating historical data in an OPC standard-based unidirectional data transmission apparatus according to an embodiment of the present invention.
5 is a flowchart illustrating a method of preventing data loss in a one-way data transmission method based on an OPC standard according to an embodiment of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and some embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, and the scope of the present invention should be understood as including all changes, modifications, equivalents or substitutes belonging to the technical idea of the present invention conceived from the embodiments. do.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. It should be understood that there is no other component in the middle only when it is stated that a component is "directly connected" or "directly connected" to another component.

The terms used in the present application are only used to describe the examples presented, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the existence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and other features, numbers, and steps. It is to be understood that it does not preclude the possibility of the presence or addition of, operations, components, parts, or combinations thereof.

All terms used in this specification, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs, and are ideal or excessively reduced formal It should not be interpreted as a meaning, and when defining the meaning of a term in this specification, the term should be interpreted as defined.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

The aforementioned one-way data transmission is performed by a one-way data transmission device. Data in the safe area corresponding to the separated closed network is transferred to the non-secure area such as the external network by the one-way data transmission/reception device. Such unidirectional data transmission is a kind of network separation technology, and has a characteristic of enhancing security, but there is a problem in that the convenience of use is deteriorated because data exchange between the internal network and the external network is impossible. That is, there are many limitations in maintaining session information and supporting operation of the application layer, which are necessary to support most of the TCP/IP-based bidirectional services.

These limitations are gradually being overcome through continuous research and development, but there may be additional limitations such as changes in existing network information due to the increase of supported protocols and reliability problems of data transmission due to blocking of physical penetration paths. have.

For example, when a unidirectional data transmission device is located at the boundary of existing networks, difficulties such as a situation in which existing network information is required to be changed for interworking with the unidirectional data transmission device while existing network information is lost may occur. have. Therefore, an effective technique for performing one-way data transfer while maintaining existing network information is required.

On the other hand, there are several versions of the aforementioned OPC standard depending on the time when it was enacted and functions introduced. OPC Classic, which is an early OPC standard, was applied to several systems. OPC UA (unified architecture) was also established to provide new functions and integrate detailed OPC functions to solve the problem of platform independence and data modeling limitations to overcome the high dependence on specific OS products of OPC Classic. Due to the relatively long period of time, many systems with OPC Classic are still in operation in industrial sites.

Next, an OPC standard-based one-way data transmission method and apparatus according to an embodiment of the present invention will be described.

1 is a conceptual diagram of an OPC standard-based one-way data transmission apparatus according to an embodiment of the present invention.

The OPC standard in the one-way data transmission device 120 based on the OPC standard according to an embodiment of the present invention shown in FIG. 1 refers to an OPC-related standard including OPC Classic and OPC UA.

The OPC standard-based one-way data transmission apparatus 120 according to an embodiment of the present invention is based on the OPC server 110 and the OPC client 150. The OPC server 110 collects and stores information through an interface with field devices such as PLC, IED, and RTU inside the control network operated in the form of a separate closed network, and the OPC client 150 receives the corresponding information according to the OPC standard. Will be monitored.

The data of the OPC server 110 includes real-time data and historical data. Real-time data includes OPC DA (OPC data access) data and OPC alert and event data, OPC AE data. The historical data refers to OPC historical data access (HDA) data.

The OPC standard-based one-way data transmission device 120 according to an embodiment of the present invention transmits real-time data and historical data monitored and managed by the OPC server 110 in the safe area to the OPC client 150 in the non-secure area. To do this, a send proxy 130 and a receive proxy 140 are used. The transmission proxy 130 communicates with the OPC server 110, and the reception proxy 140 communicates with the OPC client 150.

The transmission proxy 130 receives server information managed and provided by the OPC server 110 and delivers it to the reception proxy 140, and the reception proxy 140 constructs an OPC server proxy that performs the same function as the OPC server. . The transmission proxy 130 accesses the OPC server 110 in the safe area in the same manner as the OPC client 150 in the non-secure area, requests server information provided to the OPC client 150, and sends it from the OPC server 110. After receiving, it is transmitted to the receiving proxy 140. Through this method, the receiving proxy 140 establishes an OPC server proxy.

In this way, the receiving proxy 140, in which the OPC server proxy is built, uses the same IP address as the OPC server 110 in the safe area, so that the OPC client 150 in the non-secure area establishes a connection to the receiving proxy 140. Through this, it is as if it is directly connected to the OPC server 110 in the safe area, and a separate setting change is not required.

In this state, the transmission proxy 130 requests and receives real-time data and historical data from the OPC server 110 in the safe area based on the server information received from the OPC server, and then transmits the request to the reception proxy 140. .

The receiving proxy 140 continuously updates real-time data and historical data of the OPC server 110 based on the received data and provides data suitable for the request of the OPC client 150 in the non-secure area.

Real-time data such as OPC DA data and OPC AE data are automatically generated whenever the data to be monitored changes and transmitted to the receiving proxy 140, and the historical data is included in the request information (including the request period and the request range). It is delivered to the receiving proxy 140 on the basis. Next, a method of constructing an OPC server proxy in the receiving proxy 140 according to an embodiment of the present invention will be described.

2 is a flowchart illustrating a procedure for building an OPC server proxy according to an embodiment of the present invention.

The OPC server proxy construction method in the receiving proxy 140 according to the embodiment of the present invention of FIG. 2 is a problem of loss of synchronization with the OPC server in the safe area when the transmitting proxy or the receiving proxy is restarted due to system maintenance or the like. This is the way to solve the problem.

First, the receiving proxy checks the settings related to the establishment of the OPC proxy server while running (S210). The receiving proxy receives information (referred to as server information) for building the OPC server proxy from the sending proxy and records it in the storage in the form of a file or the like. Through the verification process, it is checked whether or not the pre-established OPC server proxy construction information exists (S220), and if pre-established OPC server proxy construction information exists (example of S220), an OPC server proxy is constructed based on this (S260). .

If the previously established proxy server construction information does not exist (No in S220), server information is requested from the transmitting proxy and data is received (S230). The receiving proxy checks whether server information is included in the received data (S240), and if it does not have it (No in S240), it requests server information from the OPC server through the sending proxy (S250). In this case, the sending proxy can be restarted if necessary. If server information is held (YES in S240), an OPC server proxy is constructed based on the information (S260). When the OPC server proxy is established, real-time data or historical data is received from the transmission proxy (S270) and related processing is performed.

It is determined whether new server information is included in the data received from the sending proxy (S280), and if the new server information is included (example in S280), the OPC server proxy is updated and constructed using the server information, and the new server information is included. If not (No in S280), the data (data of the OPC server) is updated (S290).

On the other hand, even if the receiving proxy is driven based on the previously received information, if it receives new server information related to OPC server proxy construction due to restarting of the transmitting proxy, etc., the OPC server proxy is rebuilt based on this. In this way, the same configuration as the OPC server in the real safe zone is built into the server proxy.

When the sending proxy is restarted, the OPC server proxy of the receiving proxy is unconditionally rebuilt. On the contrary, when only the receiving proxy is restarted, it is possible to selectively rebuild the OPC server proxy based on previously stored configuration information. Next, an OPC standard-based one-way data transmission method according to an embodiment of the present invention will be described.

3 is a flowchart illustrating an OPC standard-based one-way data transmission method according to an embodiment of the present invention.

The OPC standard-based one-way data transmission method according to an embodiment of the present invention of FIG. 3 is an OPC standard-based one-way data transmission apparatus according to an embodiment of the present invention of FIG. 1 and a reception according to an embodiment of the present invention of FIG. It is about a method of unidirectional data transmission based on OPC standard based on proxy construction method.

First, the transmission proxy 130 of the one-way data transmission device 120 requests server information to establish a connection with the OPC server 110 (S310), and receives server information from the OPC server 110 (S315). . The transmission proxy 120 may access the OPC server 110 in the safe area, request server information, and receive server information from the OPC server 110 in the same manner as the OPC client in the non-secure area.

Then, the transmission proxy 130 transmits the server information received from the OPC server 110 to the reception proxy 220 (S320), and the reception proxy 140 constructs an OPC server proxy using this (S325). At this time, as described above, the OPC server proxy 140 built in the receiving proxy 140 uses the same IP address as the OPC server 110 in the safe area, so that the OPC client 150 in the non-secure area It may have the same effect as accessing the OPC server 110, and a separate setting change procedure may be omitted.

After performing the OPC server proxy construction process in the above procedure, the transmission proxy 110 of the one-way data transmission device 120 transmits real-time data (OPC DA) to the OPC server 100 in the safe area based on the previously received server information. Data can be received by requesting data and OPC AE data) and historical data (HDA data).

Specifically, the transmission proxy 130 of the one-way data transmission device 120 requests real-time data from the OPC server 110 (S330), receives real-time data from the OPC server 110 (S335), and Real-time data is transmitted to the receiving proxy 140 (S340). In addition, the reception proxy 140 that has received the real-time data may update the real-time data (S345).

And the transmission proxy 130 of the one-way data transmission device 120 requests historical data to the OPC server 110 (S350), receives the historical data from the OPC server 110 (S355), received history The curl data is transmitted to the reception proxy 140 (S360). Also, the reception proxy 140, which has received the historical data, updates the historical data (S365).

In the process of updating historical data, the transmission proxy 130 may repeatedly perform a request for historical data and transmit the received historical data to the reception proxy 140. In addition, the receiving proxy 140, which has performed an update of real-time data and historical data, is connected to the OPC client 150 and may transmit data corresponding to the request of the OPC client 150 (S370).

In this way, since the OPC server in the safe area and the receiving proxy on which the OPC server proxy is built can be synchronized, additional configuration changes of the OPC server and OPC client according to the prior art are not required, and historical data is not required. It is possible to improve the reliability of one-way data transmission. In addition, data can be stably monitored through this.

That is, the OPC standard-based one-way data transmission device 120 according to an embodiment of the present invention operates appropriately for the transmitting side and the receiving side according to the characteristics of the data transmitted by the OPC server 110 to the OPC client 150. By arranging a proxy for performing the process, it is possible to effectively transmit data (real-time data and historical data) of the safe area to the non-secure area, while blocking external intrusion to the safe area. Next, a method of updating historical data in an OPC standard-based unidirectional data transmission apparatus according to an embodiment of the present invention will be described.

4 is a flowchart illustrating a method of updating historical data in an OPC standard-based unidirectional data transmission apparatus according to an embodiment of the present invention.

The method for updating historical data in the OPC standard-based unidirectional data transmission apparatus according to an embodiment of the present invention of FIG. 4 is shown in FIG. 3. It's about how to update.

OPC DA data and OPC AE data, which are real-time data, are transmitted at the same time as the data requested to the OPC server is changed, but in the case of OPC HAD data, which is historical data, data is transmitted based on the request period and the request range. Accordingly, the transmission proxy 130, which is an OPC client proxy, needs to set a request period to request historical data from the OPC server in the safe area.

In addition, real-time data is data that is continuously updated, whereas historical data is data that is continuously accumulated, so if it is lost during transmission/reception, it is difficult to retrieve data of the corresponding time again. Therefore, in unidirectional transmission of historical data, it is necessary to ensure reliability of transmission/reception data by adjusting the request period and the request range.

To meet this need, the transmission proxy 130 of the one-way data transmission device 120 based on the OPC standard according to an embodiment of the present invention requests historical data (HAD data) from the OPC server 110 (S410 ), the OPC server 110 transmits historical data to the transmission proxy 130 (S415).

차 요청)을 수신하여, 송신 프록시(130)로 히스토리컬 데이터를 전송할 때, OPC 서버(110)는 OPC 서버 전송 히스토리컬 데이터(1~13) 중에서 히스토리컬 데이터를 전송하는 시점까지의 데이터인 히스토리컬 데이터 1 내지 5를 송신 프록시(130)로 전송한다.For example, the OPC server 110 requests historical data (

Tea request), and when transmitting the historical data to the transmission proxy 130, the OPC server 110 is the data from the OPC server transmission historical data (1 to 13) up to the time of transmitting the historical data. The curl data 1 to 5 are transmitted to the transmission proxy 130.

The transmission proxy 130 receiving the historical data from the OPC server 110 transmits the received historical data to the reception proxy 140 (S420). Also, the reception proxy 140 that has received the historical data performs first historical data update (S425).

For example, the reception proxy 140 may receive historical data of data 1 to 5 from the transmission proxy 130, and may perform a first historical data update (S425) using the received historical data. . At this time, the historical data 1 to 5 are the first received historical data.

,T)을 요청한다(S430). 이 때 요청되는 히스토리컬 데이터는 히스토리컬 데이터(

, T)로 표시될 수 있다. 이는 데이터 범위 T를 갖는

차 요청이라는 의미를 나타낸다. 전송범위 T가 표시되지 않은 경우는 사전 설정된 기본 범위를 갖도록 구현될 수 있다.When the time corresponding to the preset request period (P) has elapsed after the initial request for historical data, the transmission proxy 130 transmits the historical data to the OPC server 110 (

,T) is requested (S430). The historical data requested at this time is historical data (

, T). It has a data range T

Indicates the meaning of a tea request. When the transmission range T is not indicated, it may be implemented to have a preset basic range.

The OPC server 110 transmits historical data to the transmission proxy 130 (S435). The transmission proxy 130 receiving the historical data from the OPC server 110 transmits the corresponding historical data to the reception proxy 140 (S440), and the reception proxy 140 updates the second historical data. It can be done (S445).

, T)를 요청하면, OPC 서버(110)는 요청 범위(T) 내의 히스토리컬 데이터인 히스토리컬 데이터 2 내지 8을 송신 프록시(130)로 전송할 수 있다. 이 경우 수신 프록시(140)는 송신 프록시(130)로부터 히스토리컬 데이터 2 내지 8의 히스토리컬 데이터를 수신하여, 제2 히스토리컬 데이터 갱신를 수행한다(S445).For example, the transmission proxy 130 to the OPC server 110 historical data (

, T), the OPC server 110 may transmit historical data 2 to 8, which are historical data within the request range T, to the transmission proxy 130. In this case, the reception proxy 140 receives the historical data of the historical data 2 to 8 from the transmission proxy 130 and performs second historical data update (S445).

In this case, historical data 1 in the reception proxy 140 is previously received historical data, historical data 2 to 4 are redundant reception historical data, and historical data 5 to 8 are new reception historical data.

, T)를 요청하고(S450), OPC 서버(110)로부터 히스토리컬 데이터를 수신(S455)한다. 송신 프록시(130)은 수신한 히스토리컬 데이터를 수신 프록시(140)로 전달(S460)하고, 송신 프록시(130)로부터 히스토리컬 데이터를 수신한 수신 프록시(140)는 제3 히스토리컬 데이터 갱신을 수행한다(S465).When a time corresponding to the request period (P) elapses after the transmission proxy 130 requests historical data, the transmission proxy 130 receives the historical data (

, T) is requested (S450), and historical data is received from the OPC server 110 (S455). The transmission proxy 130 forwards the received historical data to the reception proxy 140 (S460), and the reception proxy 140, which receives the historical data from the transmission proxy 130, performs a third historical data update. Do (S465).

As an example, the OPC server 110 receiving a request for historical data from the transmission proxy 130 transmits the historical data 6 to 12, which are data within the request range T, from the time when the request is received. Can be transferred to. In addition, the transmission proxy 130 transmits historical data 6 to 12 to the reception proxy 140, and the reception proxy 140 may perform a third historical data update (S465 ).

At this time, historical data 1 to 5 are previously received historical data, historical data 6 to 8 are redundant received historical data, and historical data 9 to 12 are new received historical data.

, T)를 요청하는 과정(S470)을 수행하여, 일정한 요청 주기(P)마다 요청 범위(T)에 상응하는 히스토리컬 데이터를 요청 및 수신할 수 있다. 히스토리컬 데이터를 요청하는 시간(

)은 히스토리컬 데이터의 전송을 요청하는 현재 시간을 의미하며, 바로 직전 주기에서 히스토리컬 데이터를 요청한 시간(

)로부터 요청 주기(P)만큼의 경과한 시간을 의미한다.After that, the transmission proxy 130 transmits historical data to the OPC server 110 (

, T) by performing the process of requesting (S470), it is possible to request and receive historical data corresponding to the request range (T) every predetermined request period (P). Time to request historical data (

) Means the current time that the historical data is requested to be transmitted, and the time the historical data is requested in the immediately preceding cycle (

It means the time elapsed as much as the request period (P) from ).

)과 요청 범위(T)를 지정함으로써, 현재 시간(

)을 기준으로 이전 T 시간만큼의 히스토리컬 데이터를 수신할 수 있다. 한편, 히스토리컬 데이터의 중복 수신을 위하여 요청 범위(T)는 요청 주기(P)보다 항상 크거나 같아야 하며, 더 바람직하게는 요청 범위(T)는 요청 주기(P)보다 항상 커야 한다.That is, the transmission proxy 130 requests the OPC server 110 in the safe area to transmit historical data for each request period P, and the current time (

) And the request range (T), the current time (

), historical data of the previous T time can be received. Meanwhile, in order to receive duplicate historical data, the request range T must always be greater than or equal to the request period P, and more preferably, the request range T must always be greater than the request period P.

The OPC standard-based one-way data transmission apparatus 120 according to an embodiment of the present invention transmits the received historical data to the OPC client 150. Thereafter, the reception proxy 140 of the OPC standard-based one-way data transmission device 120 may receive a data request from the OPC client 150 and transmit data suitable for the request to the OPC client 150.

As described above, the OPC standard-based one-way data transmission device 120 according to an embodiment of the present invention can set the request period (P) and the request range (T) according to the network environment and the importance of the data, and through this It is possible to improve the reliability of unidirectional data transmission of curl data. That is, the reception proxy 140 adjusts the request range (T) and the request period (P) according to the network environment and the importance of the data (T≥P) in order to prevent data loss, thereby unidirectional data transmission reliability for historical data. Can increase.

Meanwhile, data loss in unidirectional data transmission can be prevented through the historical data update control according to the above-described embodiment of the present invention. Next, a method of preventing data loss in a one-way data transmission method based on an OPC standard according to an embodiment of the present invention for preventing data loss based on the adjustment of historical data update will be described.

5 is a flowchart illustrating a method of preventing data loss in a one-way data transmission method based on an OPC standard according to an embodiment of the present invention.

In general, data loss in a one-way data transmission device is caused by an overload of the receiving proxy, and thus the loss of transmitted data is prevented by appropriately adjusting the receiving capacity of the receiving proxy (this is referred to as guaranteeing reliability of the transmitted data).

5 is an automatic adjustment of historical data (HAD data) request period (P) and request range (T) in the method for preventing loss of historical data in the OPC standard-based one-way data transmission method according to an embodiment of the present invention. Data loss is prevented.

Specifically, the request period of historical data (P) by comparing the maximum data throughput (M) of the receiving proxy 140 of the one-way data transmission device 120 and the data throughput per second (C) of the transmitting proxy 130 And request range (T) are automatically adjusted to prevent data loss.

The reception proxy maximum data throughput (M) is set by checking the performance value measured in advance by the reception proxy 140 (S510), and the transmission proxy is all data (OPC DA data, OPC AE data, and OPC HAD data) throughput is measured every second to calculate the data throughput per second (C) of the sending proxy.

After confirming the setting, the maximum data throughput (M) in the receiving proxy 140 and the data throughput per second (C) of the transmitting proxy 130 are compared (S520). If the data throughput per second (C) of the transmission proxy 130 is greater than or equal to the maximum data throughput (M) of the reception proxy 140 (example of S520), a request period (P) to reduce data to be transmitted to the reception proxy 140 And request range (T) are changed by a preset update factor (v).

At this time, since the request range (T) must always be greater than or equal to the request period (P), only the request period (P) is adjusted, or both the request period (P) and the request range (T) are adjusted. Specifically, if the request range (T) is greater than or equal to the sum of the request period (P) and the update factor (v) (example in S530), only the request period (P) is increased by the update factor v (S540), and the request range If (T) is less than the sum of the request period (P) and the update factor (v) (No in S530), both the request range (T) and the request period (P) are increased by the update factor v (S550).

On the other hand, if the data throughput per second (C) of the transmitting proxy 130 is less than the maximum data throughput (M) of the receiving proxy 140 (No in S520), the request period (P) and the request range (T) are reset. You will perform a turning adjustment. In this case, the adjusted request period (P) and the request range (T) are not adjusted to be smaller than the initial setting value of the transmission proxy 130. That is, the initial request period (P) and the initial request range (T) are set to suit the system application environment.

Specifically, when the data throughput per second (C) of the transmission proxy 130 is less than the maximum data throughput (M) of the reception proxy 140 (No in S520), the request period P is the same as the initial request period (S560 Example) The configuration check step is performed again, and if not, it is determined whether the request range T is the same as the initial request range (S570).

At this time, if the request range (T) is the same as the initial request range (YES in S570), only the request period (P) is reduced by the update factor v (S580), and if the request range (T) is different from the initial request range (No in S570) Both the request range (T) and the request period (P) are decreased by the update factor v (S590).

In this way, based on the state of the maximum data throughput (M) in the reception proxy 140 of the one-way data transmission device 120 and the data throughput (C) per second of the transmission proxy 130, the request period for historical data (T ) And request range (P), it is possible to minimize data loss due to possible data overflow.

Synchronization between the OPC server 110 and the reception proxy 140 in the safe area is possible through the one-way data transmission method based on the OPC standard according to the embodiments of the present invention described above, so that real-time data ( The reliability of one-way data transmission for OPC DA data and OPC AE data) and possibly lost historical data (OPC HAD data) is improved, and stable data monitoring is possible.

Meanwhile, each of the above-described configurations has been described as a separate device, but this is only an exemplary description for convenience of description and enhancement of understanding, and may be implemented in various forms within the scope of the technical idea of the present invention. Of course. For example, the transmission proxy and the reception proxy may be implemented by being integrated into one module, or may be implemented by dividing into two or more devices.

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as rom, ram, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

The configuration of the present invention has been described in detail above through a preferred embodiment of the present invention. However, the above-described embodiments are for illustrative purposes only, and do not limit the scope of the present invention. Those of ordinary skill in the art of the present invention will be able to make various modifications and changes within the scope of the technical idea of the present invention from the teachings and suggestions of the present specification. Accordingly, the scope of protection of the present invention should be determined by the description of the following claims.

Claims (1)

Comparing the maximum data throughput of the receiving proxy and the data throughput per second of the sending proxy;
Comparing a request period of historical data with a sum of a request range of the historical data and an update factor if the data throughput per second of the transmitting proxy is greater than or equal to the maximum data throughput of the receiving proxy;
If the request range of the historical data is greater than or equal to the sum of the request period of the historical data and the update factor, increasing the request period of the historical data by the update factor; And
If the request range of the historical data is less than the sum of the request period of the historical data and the update factor, increasing the request range and the request period of the historical data by the update factor. Transmission method.

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