JP4305221B2 - Gateway device - Google Patents

Description

  In the present invention, data acquired from another system is reflected in a memory via an OPC (OLE for Process Control) interface disclosed as a common interface for process data reference, and the functional block of the control means accesses this memory. The present invention relates to a gateway device.

  FIG. 4 is a functional block diagram showing an example of a conventional gateway device. Reference numeral 1 denotes an operation monitoring device of its own system (distributed control system), and 2 denotes a control device that executes control of a field device (not shown), which are connected to a control bus 3 and communicate with each other.

  Reference numeral 4 denotes a general-purpose communication bus represented by Ethernet (registered trademark). Reference numeral 5 denotes an OPC server, which is connected to the general-purpose communication bus 4 and communicates with another system 6 to refer to and acquire process data of another system that supports the OPC server.

  Reference numeral 7 denotes a gateway device, which is connected between the control bus 2 and the general-purpose communication bus 4 and accesses the process data of the other system 6 so that it can be managed by the own system and the control using the other system data by itself. Have means.

In the gateway device 7, 71 is an OPC client, which communicates with the OPC server 5 via the general-purpose communication bus 4, collects process data acquired from the other system 6 by the OPC server 5, and is realized by implemented memory resources. The other system data image 72 is reflected. The other system data image 72 is a memory.

  Reference numeral 73 denotes a control means having one or a plurality of control blocks 73a. Each control block accesses the process data of the other system data image 72 on the basis of the set function and executes a predetermined control. The result is written in the other system data image 72 and is reflected in the other system 6 through the OPC interface at regular intervals.

  A communication driver 74 is connected to the control bus 3 to interface the operation monitoring device 1 and the control device 2 of the own system with the control unit 73, and passes a data acquisition request from these higher-level devices to the function block 73a of the control unit. And relaying the acquired data to the host device.

Japanese Patent Laid-Open No. 9-259055

(1) Since the connection destination of the conventional gateway device is a small-scale PLC and requires a high-speed response, it is necessary to specify all the target data in advance and reflect it in the other system data image for updating. . Therefore, regardless of whether or not these data are used, all data is acquired and held at a fixed period. However, since the memory resources of the gateway device are limited, the area size of other system data images is limited, and the number of data that can be handled is limited.

(2) When the connection destination is expanded from a small-scale PLC to a large-scale process control system to improve the versatility of the gateway device, the number of data handled by the process control system generally ranges from 100,000 to 1 million. . When such huge data is to be reflected in another system data image of the conventional configuration, it requires huge memory resources and is difficult to realize in terms of cost. Even if this problem is solved and the area size of the other system data image is expanded, it takes a lot of time to read all the data, so that it has no practical meaning.

  Therefore, the problem to be solved by the present invention is to realize a gateway device that can handle a large amount of other system data while retaining the advantages of the conventional configuration for generating the other system data image.

In order to achieve such an object, the configuration of the present invention is as follows.
(1) It has another system data image reflecting data acquired from another system via the OPC interface, and a functional block for accessing this other system data image, and writes the control result to the other system data image. In a gateway device having a control means for reflecting to the other system via the OPC interface ,
OPC item access processing means for acquiring data from the other system via the OPC interface based on the OPC item ID and passing the data to a host device ;
An access path selection unit that allocates a data acquisition destination to the control unit or the OPC item access processing unit depending on whether the data acquisition request from the host device is the functional block name or the OPC item ID;
A gateway device comprising:

(2) The sub-system connection gateway device according to (1), wherein the access path selection unit executes the distribution with reference to an OPC tag list reflecting the OPC item ID.

(3) The gateway apparatus according to (1) or (2), wherein the OPC item access processing means includes a cache data management means that refers to and uses cache data formed in the OPC interface. .

(4) The gateway device according to any one of (1) to (3), wherein the other system is a PLC.

(5) The gateway device according to any one of (1) to (3), wherein the other system is a distributed control system.

(6) The gateway device according to any one of (1) to (5), wherein the data of the other system is alarm or event data.

As is apparent from the above description, the present invention has the following effects.
(1) The advantage (high-speed path) of the conventional gateway device that collects data via the OPC server at high speed at a constant cycle and generates another system data image can be used as it is. That is, the collected data can be used in function blocks (control operation function block, sequence control block, etc.), and when the other system to be connected is a PLC, the conventional high-speed response environment can be continued.

(2) According to the added gateway function (medium-speed path) of a large amount of data, the response is slower than the high-speed path, but access is performed for each data in synchronization with the access request. Generation is not necessary and consumption of memory resources is zero. Furthermore, even when there is a large amount of data to be accessed, the response time is almost the same, so the response time does not depend on the number of data.

(3) Engineering work can be simplified. That is, since it is not necessary to consider memory resources, all data existing in other systems can be allocated, and the complicated determination work of selecting data to be accessed at the engineering stage is eliminated.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing an embodiment of a gateway device to which the present invention is applied. The same elements as those of the conventional apparatus described with reference to FIG. Hereinafter, the characteristic part of the present invention will be described.

  In FIG. 1, reference numeral 100 denotes a gateway device to which the present invention is applied. In this gateway apparatus, the elements of the OPC client 101, other system data image 102, control means 103, function block 103a, and communication driver 104 are the OPC client 71, other system data image 72, control means 73, function described in FIG. The block 73a has the same function as the communication driver 74, and forms a high-speed path for the medium-speed path element added in the present invention.

  The element of the medium speed path added in the present invention is the OPC item access processing processing means 105. An access path selection unit 106 has a function of selecting and distributing a high-speed path according to a conventional configuration or a medium-speed path added in the present invention in response to a data acquisition request from a host device. Prepare.

  The access path selection means 106 selects a high-speed path when the data acquisition request from the host is a function block name, and the data acquisition request is defined by the OPC item ID (defined by the tag name and variable name of other systems). If it is, the medium speed path is selected and the data access route is distributed.

  Data access using the high-speed path is the same as conventional data access. That is, the process data of other systems is collected in advance at regular intervals via the OPC interface and held as the subsystem data image 102. In the high-speed path processing, reading / writing of this data image is performed via the function block 103a. Do.

  When the data acquisition request is an OPC item ID, the OPC item access processing unit 105 in the medium-speed path accesses the other system 6 via the OPC interface based on the OPC item ID passed from the access path selection unit 106. And the acquired data is passed to the host device via the communication driver 104.

  The OPC item access processing means 105 has a data access function for the other system 6 based on the OPC item ID and a converter function for performing protocol conversion between the own system and the other system.

  According to the present invention, by additionally introducing the OPC item access processing unit 105 having a gateway function (medium speed path) for a large amount of data, the response becomes slower than the high speed path, but one data is synchronized with the access request. Since access is performed every time, it is not necessary to generate another system data image, and consumption of memory resources is zero.

  Data access via the medium-speed path eliminates the need to consider memory resources, making it possible to allocate all the data that exists in other systems and eliminates the need to select data to be accessed in the engineering stage. Work can be simplified. Furthermore, even when there is a large amount of data to be accessed, the response time is almost the same, so the response time does not depend on the number of data.

  FIG. 2 is a functional block diagram showing another embodiment of the present invention, and the difference in configuration from FIG. 1 is that an OPC tag list 107 is introduced. The access path selection unit 106 refers to the OPC tag list 107 that reflects the OPC item ID in response to a data acquisition request from the host device, and executes high-speed path or medium-speed path distribution.

  Since the OPC item ID is composed of tag names of other systems and arguments such as variables, the data name is often longer than the function block name. When there is a restriction on the length of data names that can be handled by the operation monitoring device 1 and the control device 2 which are host devices, a case where a data acquisition request cannot be transmitted directly with an OPC item ID name occurs.

  Therefore, all the OPC item ID names to be accessed are defined as short data names that can be supported by the host device, and stored in the table of the OPC tag list 107. The host device issues a data acquisition request with a defined short data name.

  The access path selection means refers to the OPC tag list 107, and if the defined data name is in the list, selects the medium speed path and passes the data name to the OPC item access processing means 105. If the data name passed from the host device is not in the list (in this case, the data name is a function block name), a high-speed path is selected.

  The OPC item access processing means 105 can acquire the OPC item ID name corresponding to the data name passed with reference to the OPC tag list 107 and access the data of the other system 6.

  FIG. 3 is a functional block diagram showing another embodiment of the present invention. The structural difference from FIG. 2 is that a cache management unit 105 a is provided in the OPC item access processing unit 105.

  If the requested data is in the cache data holding unit 5a supported by the OPC server 5 as a standard function, the cache management unit 105a acquires the cache data and returns it to the host device.

  The OPC server 5 registers a predetermined number of data that has been accessed by the other system 6 in the cache data holding means 5a once, and acquires and updates the data from the other system 6 at regular intervals. If this cache data is used, the latest data can be returned to the host device at a higher speed in response to the second and subsequent acquisition requests for the same data than when accessing the other system 6 each time, and the response speed of the medium speed path can be increased. Can be improved.

In the embodiment described above, it is intended for process data acquisition of other systems.
In addition to process data, alarms or event messages generated from other process control systems can be integrated into the local system using the OPC A & E interface supported by the standard.

  In the embodiment described above, OPC that has been disclosed and popularized as a common interface for process data reference has been exemplified as means for acquiring data from other systems. However, standardized interfaces such as XML (eXtensible Markup Language) and WebSOAP are used. If used, the same configuration as the OPC interface is possible.

It is a functional block diagram which shows one Embodiment of the gateway apparatus to which this invention is applied. It is a functional block diagram which shows other embodiment of this invention. It is a functional block diagram which shows other embodiment of this invention. It is a functional block diagram which shows an example of the conventional gateway apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Operation monitoring apparatus 2 Control apparatus 3 Control bus 4 General-purpose communication bus 5 OPC server 6 Other system 100 Gateway apparatus 101 OPC client 102 Other system data image (memory)
DESCRIPTION OF SYMBOLS 103 Control means 103a Function block 104 Communication driver 105 OPC item access processing means 106 Access path selection means

Claims (6)

Another system data image reflecting data acquired from another system via the OPC interface, and a functional block for accessing the other system data image, and writing the control result in the other system data image, the OPC interface. In the gateway device having a control means to be reflected in the other system via
OPC item access processing means for acquiring data from the other system via the OPC interface based on the OPC item ID and passing the data to a host device ;
An access path selection unit that allocates a data acquisition destination to the control unit or the OPC item access processing unit depending on whether the data acquisition request from the host device is the functional block name or the OPC item ID;
A gateway device comprising: The subsystem connection gateway apparatus according to claim 1, wherein the access path selection unit performs the distribution with reference to an OPC tag list reflecting the OPC item ID. The gateway apparatus according to claim 1 or 2, wherein the OPC item access processing means includes a cache data management means that refers to and uses cache data formed in the OPC interface. The gateway device according to claim 1, wherein the other system is a PLC. The gateway device according to claim 1, wherein the other system is a distributed control system. 6. The gateway device according to claim 1, wherein the data of the other system is alarm or event data.

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