JPH1065726A - Distributed control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a distributed control system where efficiency in a processing to perform access to process data with various kinds of communication lines is improved. SOLUTION: An application executing means 101 generates an address with a process data identifier at the time of performing access to process data. A correspondence data storing means 111 stores an address conversion table at the time of executing communication among the application executing means, an inter-PLT control station and field equipment 4. A converting means 112 converts the addresses transmitted by communication through the use of a table stored in the correspondence data storing means 11 when communication is executed among the application executing means, the control station and the field equipment. A distribution change-over means 113 sorts the addresses converted by the converting means to the application executing means, the control station and the field equipment. In another case, a virtual control station for virtually constituting the control station is provided and the address conversion table concerning the virtual control station is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control system for controlling a plant while communicating with control stations and field devices using various communication lines. More specifically, the present invention relates to a distributed control system improved to realize integration of communication in various communication lines.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a configuration example of a conventional distributed control system. In FIG. 3, PLT is a plant to be controlled. 1 is a monitoring station (hereinafter, referred to as OPS) for monitoring the plant PLT, 2 is a control station (hereinafter, referred to as FCS) that is distributed and arranged in the plant PLT and controls the plant PLT under the control of the OPS1, and 3 is an OPS1 And LA to which FCS2 is connected
N and 4 are field devices that are installed in the plant PLT and control the plant PLT, and 5 is a field device communication bus to which the OPS 1 and the field device 4 are connected. The LAN 3 and the field device communication bus 5 use different communication systems. LAN3 is, for example, ML
-Bus or the like. The field device communication bus 5 is, for example, RS-232-C, Ethernet, or the like.

In such a system, when it is desired to monitor how the process data existing in the plant is changing, the process data is accessed based on the address with the identifier of the process data. .
Generally, when high reliability or advanced control is required,
Access via redundant FCS2. OPS
1 and FCS2 perform communication unique to PA (process automation). However, this access increases the unit price of data. On the other hand, when it is desired to obtain a large number of points of process data at a low cost rather than reliability or performance, communication with the field device 4 is performed. Communication specific to FA (Factory Automation) is performed between the OPS 1 and the field device 4. The field device 4 is, for example, a PLC (programmable logic controller). In recent years, a PLC is required to have a process control process in addition to an original sequence control process. Therefore, a field device may be installed in a plant and the field device may be connected to the OPS via a communication line. In the conventional example of FIG. 3, access to the FCS 2 and access to the field device 4 have different communication formats.
The OPS1 needs to access in consideration of the difference in the communication format, and there is a problem that access processing becomes inefficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and integrates various types of communication lines connected to the OPS to thereby establish various types of communication lines. It is an object of the present invention to realize a distributed control system in which the efficiency of processing for accessing process data via a computer is improved.

[0005]

SUMMARY OF THE INVENTION The present invention is a distributed control system having the following configuration. (1) a monitoring station for monitoring a plant, a control station distributed in the plant and controlling the plant under the control of the monitoring station, a LAN to which the monitoring station and the control station are connected, A field device for performing control processing of a plant; a field device communication bus to which a monitoring station and a field device are connected;
And a field device communication bus, wherein the monitoring station executes an application program and generates an address with a process data identifier when accessing the process data. An execution unit, a table in which an address generated by the application execution unit is associated with an address assigned to process data handled by the control station, and the generation address is associated with an address assigned to process data handled by the field device. When communication is performed between the correspondence data storage means storing the table and the application execution means, the control station and the field device, an address transmitted by communication is determined by using the table stored in the correspondence data storage means. Distributed control system comprising conversion means for address translation, the application executing means the converted address this converter, the distribution switching means for distributing the control station and the field device, by comprising a. (2) The monitoring station has a virtual control station that virtually configures the control station, and the corresponding data storage unit associates the generated address with an address assigned to process data handled by the virtual control station. (1) The distributed control system according to (1), wherein the stored table is stored.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention.
1 that are the same as those in FIG. 3 are given the same reference numerals. In FIG.
10 is an OPS. In the OPS 10, reference numeral 101 denotes an application execution unit which executes an application program and generates an address with an identifier of the process data when accessing the process data existing in the plant. Reference numeral 102 denotes a conversion server that converts a logical address generated by the application execution unit 101 into a physical address. A communication unit 103 converts the logical address received from the application execution unit 101 into the conversion server 10.
2 and sends the physical address converted by the conversion server 102 to the conversion unit 104. The conversion unit 104 is a feature of the present invention. The physical address includes the name and type (TAG and ITEM) of the process data. For example, the physical address “ABC.SV” is the name of the process data in which “ABC” exists in the plant, and is the type of the “SV” process data (here, the set value). 105, a LAN driver connected to the LAN 3; 106, a field device communication driver connected to the field device communication bus 5;
Is a virtual FC that virtually configures the control station FCS
S. The virtual FCS 107 is a memory that stores, for example, process data.

[0007] In the conversion unit 104, 108, 109, 110
Is the LAN connected to the LAN driver 105, the field device communication driver 106, and the virtual FCS 107, respectively.
Adapter, field device communication adapter, and virtual FCS adapter. Reference numeral 111 denotes a corresponding data storage unit that stores a table for performing address conversion. The following table is stored in the correspondence data storage unit 111. Using the address given to conversion section 104 as a key, L
Table for extracting an address on the AN 3 Table for extracting an address on the field device communication bus 5 using the address given to the conversion unit 104 as a key Table for extracting an address for accessing the virtual FCS 107 using the address given to the conversion unit 104 as a key 112 Is a conversion unit, and the application execution unit 10
1, FCS 2, field device 4, and virtual FCS 107
When the communication is performed, the address transmitted by the communication is converted using the table stored in the corresponding data storage unit 111. Reference numeral 113 denotes a distribution switching unit which converts the address converted by the conversion unit 112 into the application execution unit 101, the FCS2, the field device 4, and the virtual FCS1.
Assign to 07. The distribution is performed when the address is transmitted from the application execution unit 101 side and when the FCS is
2, both when the address is sent from the field device 4 and the virtual FCS 107 side. 20 is another OP
S. The OPS 20 has the same configuration as the OPS 10.

The operation of the system shown in FIG. 1 will be described. An operation of accessing the FCS 2, the field device 4, and the virtual FCS 107 from the application execution unit 101 will be described. When the application execution unit 101 generates a logical address, the communication unit 103 sends the logical address to the conversion server 102, and the conversion server 102 converts the logical address into a physical address. The communication unit 103 sends the physical address to the distribution switching unit 113. The distribution switching unit 113 gives the transmitted physical address to the conversion unit 112. The conversion unit 112 determines whether the given physical address is an address for identifying process data handled by the FCS 2, the field device 4, or the virtual FCS 107, and uses the table stored in the corresponding data storage unit 111 to determine the address. Convert. The translated address is returned to the distribution switching means 113. The distribution switching unit 113 stores the returned address in the LA
N adapter 108, field device communication adapter 10
9. Distribute to any of the virtual FCS adapters 110. As a result, FCS2 using the address as an identifier,
The process data accessed by any of the field device 4 and the virtual FCS 107 is accessed. Access to the process data is performed, for example, when the application execution unit 101 monitors a trend of the process data.

An operation in which the field device 4 accesses the FCS 2 or the virtual FCS 107 will be described. When the field device 4 generates an access destination address, the address is stored in the field device communication bus 5, field device communication driver 106, field device communication adapter 10
9 to the distribution switching unit 113. Distribution switching unit 1
13 causes the conversion server 102 and the corresponding data storage unit 111 to perform address conversion in the same manner as when there is access from the application execution unit 101. When the converted address is returned, the distribution switching unit 113
The LAN adapter 108 and the virtual FCS adapter 11
Assign to any of 0. As a result, the process data handled by either the FCS 2 or the virtual FCS 107 is accessed using the address as an identifier. When it is necessary to return the access result to the transmission source of the process data, the distribution switching unit 113 accesses the FCS 2 or the virtual FCS 107 again.

The operation in which the OPS 20 accesses the field device 4 or the virtual FCS 107 will be described. OPS2
0 obtains the OPS holding the field device 4 and the virtual FCS 107 from the data described in the corresponding data storage unit 111 of the device itself. The obtained OPS is set to 10. O
PS20 is LAN3, LAN driver 105, LAN
The access destination address is sent to the distribution switching unit 113 via the adapter 108. The distribution switching unit 113 causes the conversion server 102 and the corresponding data storage unit 111 to perform address conversion in the same manner as described above, and distributes the converted address to either the field device 4 or the virtual FCS 107. As a result, the process data accessed by either the field device 4 or the virtual FCS 107 is accessed using the address as an identifier.

In this manner, OPS10, OPS2
0, FCS 2, field device 4, and virtual FCS 107 can access process data in an integrated manner. Thereby, as shown in FIG. 2, the OPS 10, OPS 20, FCS 2, field device 4, and virtual FCS 107 are placed on one communication bus B on one communication bus BS.
Communication can be performed in the same manner as when connecting on S.

[0012]

According to the present invention, the address conversion between the various communication lines connected to the OPS is performed by the conversion unit in the OPS. This makes it possible to integrate communications on various communication lines connected to the OPS, thereby improving the efficiency of processing for accessing process data via the various communication lines.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an image of a connection configuration of the system of FIG. 1;

FIG. 3 is a diagram showing a configuration example of a conventional distributed control system.

[Explanation of symbols]

 2 FCS 3 LAN 4 Field device 5 Field device communication bus 10, 20 OPS 101 Application execution unit 102 Conversion server 104 Conversion unit 107 Virtual FCS 111 Corresponding data storage unit 112 Conversion unit 113 Distribution switching unit

Claims (2)

[Claims] 1. A monitoring station for monitoring a plant, a control station distributed in the plant and controlling the plant under the control of the monitoring station, and an L connected to the monitoring station and the control station.
An AN, a field device installed in the plant for controlling the plant, and a field device communication bus to which the monitoring station and the field device are connected, wherein the LAN and the field device communication bus have different communication systems. In the distributed control system, the monitoring station executes an application program and, when accessing the process data, generates an address with an identifier of the process data, and an address generated by the application executing means. And a table that associates addresses assigned to process data handled by the control station, and a table that associates the generated addresses with addresses assigned to process data handled by the field device. Conversion means for performing an address conversion of an address transmitted by communication using a table stored in the corresponding data storage means when performing communication between the application execution means, the control station and the field device; And a distribution switching unit for distributing the address converted in step 1 to the application execution unit, the control station, and the field device. 2. The monitoring station has a virtual control station virtually configuring the control station, and the corresponding data storage means stores the generated address and an address assigned to process data handled by the virtual control station. 2. The distributed control system according to claim 1, wherein a corresponding table is stored.