JP2000268016A - Distributed control system and its constituting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To share allocation changing information with a logical name and a physical address with all the computers by updating tag data based on information from a controller holding allocation data of the physical address and its logical name. SOLUTION: Computers 8a and 8b hold tag databases(TDB) 10a and 10b showing an allocating relation between the physical address on an input/output signal handled by controllers 7a to 7c respectively through an FA network 9 and its logical name. Middlewares 11a and 11b as access supporting means accesses to the input/output signal after converting the logical name to the physical address by referring to the TDBs 10a, 10b and update the TDB 10a and 10b based on local data bases 12a to 12c sucked from the controllers 7a to 7c. Consequently, when allocation change between the logical name and the physical address is executed concerning one of the controllers, its changing information can immediately be shared with all the computers.

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 suitable for use as, for example, a programmable logic controller (PLC) system and the components thereof, and more particularly to an input / output signal by designating a logical name on a host computer. The present invention relates to a distributed control system capable of monitoring and the like and components thereof.

[0002]

2. Description of the Related Art In the field of factory automation (FA), one or more control devices (for example, PL
C, a temperature control controller, etc.) and a plurality of computers located above the control devices via a FA network.

Each of the plurality of computers has a physical address of an input / output signal handled by each control device (a physical address of a data area storing an analog value such as ON / OFF of a contact or a temperature) and a logical name thereof. And a middleware as an access support means having a function of converting a logical name to a physical address with reference to the tag database and then accessing an input / output signal.

[0004] When a data access request specifying a logical name is issued in an application (for example, SCADA or simple monitoring software) incorporated in each computer, the middleware as the access support means intervenes. Data access to the corresponding physical address is automatically performed.

An example of such a distributed control system is shown in FIG.
9 is shown in the block diagram. As shown in FIG. 1, the distributed control system 1 includes three control devices (in this example, PLCs) 2a, 2b, and 2c, and two control devices 2a, 2b, and 2c located above the control devices 2a, 2b, and 2c. It is configured by connecting the computers 3a and 3b via the FA network 4.

In each of these two computers 3a, 3b, a physical address of an input / output signal handled by each of the controllers 2a, 2b, 2c (data storing analog values such as ON / OFF of a contact and temperature) is stored. Area physical address)
Tag database 5 showing the allocation relationship between the logical names
a, 5b, and middleware (not shown) as an access support means having a function of accessing a I / O signal after converting a logical name into a physical address with reference to the tag databases 5a, 5b. .

[0007] When a data access request specifying a logical name is issued in an application (for example, SCADA or simple monitoring software) incorporated in each of the computers 3a and 3b, middleware as access support means intervenes. By the data access to the corresponding physical address (read and / or
Write) is performed automatically.

In this type of distributed control system, the assignment relationship between a physical address and a logical name is changed in order to add or change equipment to be controlled in one of the control devices 2a, 2b, and 2c. There are times when it is inevitable. In such a case, regarding the same physical address,
Since it is necessary to guarantee the use of unified logical names in the two computers 3a and 3b, it is necessary to modify both tag databases 5a and 5b according to the new assignment relationship.

[0009] Such a correction work is performed on the OA network O assuming that the FA network 4 uses Ethernet (registered trademark) (TCP / IP protocol).
It is easy to automate by sharing the tag database using S and distributed database.

[0010]

However, in the field of FA where importance is placed on environmental resistance and noise resistance of the network, etc., a network OS for OA based on the use of Ethernet (TCP / IP protocol), Because of the rare use of distributed databases, it has been practically difficult for multiple computers in a factory to share the same tag database with multiple computers. Therefore, at present, designers or maintenance personnel have to re-enter the database for each computer or manually copy files between computers, and as a result, input data confirmation work and database There were problems such as requiring many man-hours to ensure consistency.

The present invention has been made in view of the above-mentioned problems, and has as its object to provide an OA based on the use of Ethernet (TCP / IP protocol).
If the assignment of logical names to physical addresses is changed for any control device without using a network OS or distributed database for distribution, the change information can be shared by all computers. It is to provide a control system and its components.

[0012]

In order to achieve the above object, a distributed control system according to the present invention connects one or more control devices and one or more higher-level devices via a network, The host device accesses the signal after converting the logical name to a physical address by referring to the tag data storage unit, which indicates the assignment relationship between the physical address of the signal handled by the control device and its logical name, and referring to the tag data storage unit. In the case where a data access request specifying a logical name is issued in an application incorporated in a higher-level device,
In a distributed control system in which data access to a corresponding physical address is automatically performed by the intervention of the access support means, the control device includes a physical address of a signal handled by the own device and a logical name thereof. Along with holding a local tag data storage unit indicating the assignment relationship, each of the access support means is provided with a function of updating tag data based on information of local tag data from the control device, and has a logical name, a physical address, In the case where the assignment change of any of the control devices is performed, the change information can be shared by all the higher-level devices.

According to such a configuration, the local tag database held in each control device becomes common to all the high-level computers, and even in a normal FA network, each high-level computer is Since local tag data can be freely downloaded from the control device, the assignment of logical names and physical addresses can be performed without using a network OS for OA or a distributed database on the premise of using Ethernet (TCP / IP protocol). If a change is made to any of the control units, the change information can be shared immediately between all computers, and the designer or maintenance person can re-enter the database for each computer as before. Or manually copying files between computers Sloppy work is not required, as a result,
There is no need to take a lot of man-hours to check input data and to ensure database consistency.

The access support device of the present invention can be incorporated in a higher-level device capable of communicating with the control device via a network, and supports input / output signal access from the higher-level device to the control device by designating a logical name. Data acquisition means for acquiring local tag data information indicating an assignment relationship between a physical address of a signal of a designated control device and its logical name; and tag data of the own device based on the acquired local tag data information. Data updating means for updating information.

According to such a configuration, the data download means and the data update means are added to the access support device (which can be realized by middleware) for accessing an input signal by designating a logical name. Even if there is an increase or change in the number, it is possible to continue accurate data access by the logical name without making the application aware of the fact.

A control device according to the present invention is connected to a plurality of host computers via a network and exchanges input / output signals with a controlled device.
Storage means for storing a local tag database indicating an assignment relationship between a physical address of an input / output signal handled by the control device and its logical name, and a response to a data read / write request specifying a physical address from a host computer Data read / write processing means for executing data read / write processing on an input / output signal corresponding to the physical address, and uploading a local tag database stored in the control device to a host computer designated as an upload destination And a tag database upload unit.

According to such a configuration, the control device itself stores the local tag database indicating the assignment relationship between the physical address of the input / output signal handled by the control device and its logical name, and uploads the local tag database. Since uploading is performed to the upper computer specified as the destination, each upper computer only updates its own tag database based on the uploaded local tag database,
An accurate assignment relationship can be maintained.

In a preferred embodiment of the control device of the present invention, the tag database upload means is configured to be started in response to a tag database upload request from a host computer.

According to such a configuration, the tag database upload unit is started in response to the tag database upload request from the host computer, so that the timing of the upload can be controlled by the host computer. Becomes

In a preferred embodiment of the control device according to the present invention, a change notification sending means for sending a change notification to a designated host computer in response to a change in the local tag database in the control device. Is provided.

According to such a configuration, the change notification is sent to the designated host computer in response to the change of the local tag database in the control device. The user is prompted to download and update data at an appropriate timing.

In a preferred embodiment of the control device of the present invention, the designation of a higher-level computer as a change notification destination is configured to be performed by registration in a change notification list provided in the control device.

According to such a configuration, the designation of the higher-level computer as the change notification destination is performed by registration in the change notification list provided in the control device, so that the registered contents are appropriately set. By doing so, it is possible to appropriately select the higher-level computer to be notified of the change,
The operation of the computer irrelevant to the change in the assignment relationship is not bothered.

In a preferred embodiment of the control device of the present invention, in response to a computer registration request from a host computer, a notification destination computer registration means for registering a network address included in the request in a change notification list is provided. Provided.

According to such a configuration, in response to the computer registration request from the host computer, the network address included in the request is registered in the change notification list, so that the tag database is uploaded to the tag database upload destination. The designation of the host computer can be set from the computer.

In a preferred embodiment of the control device of the present invention, a local tag database updating means for updating the contents of the local tag database with the contents of the tag database received from the programming tool is provided.

According to such a configuration, the contents of the local tag database can be updated using a programming tool.

The programming tool according to the present invention is a tag database generating means for generating a tag database indicating an assignment relationship between a logical name and a physical address with respect to an input / output signal included in the control program in accordance with a control program creating operation. And download means for downloading the generated tag database together with the created control program to a designated control device.

According to such a configuration, the creation of the local tag database and the incorporation into the control device can be realized in parallel with the control program creation operation and the incorporation into the control device.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The configuration of a distributed control system to which the present invention is applied is schematically shown in the block diagram of FIG.

As shown in the figure, the distributed control system 6 includes three control devices (in this example, PLCs) 7.
a, 7b, and 7c and two computers 8a and 8b located above the control devices 7a, 7b, and 7c.
It is connected via a network 9.

In each of these two computers 8a and 8b, a physical address of an input / output signal handled by each of the controllers 7a, 7b and 7c (data storing an analog value such as ON / OFF of a contact and temperature) is stored. Area physical address)
Tag database 1 showing the allocation relationship between the logical names
0a, 10b and middleware 11a, 11b (see FIG. 2) as access support means having a function of accessing a I / O signal after converting a logical name into a physical address with reference to the tag databases 10a, 10b. Have been. The tag databases 10a and 10b are stored on, for example, the hard disks of the computers 8a and 8b.

When a data access request specifying a logical name is issued in an application (for example, SCADA or simple monitoring software) incorporated in each of the computers 8a and 8b, the middleware 11a as an access support means is issued. The data access (read and / or write) to the corresponding physical address is automatically performed with the intervention of 11b.

In addition to the above configuration, the control devices 7a, 7b,
Each of 7c holds a local tag database 12a, 12b, 12c indicating an assignment relationship between a physical address of an input / output signal handled by the own device and its logical name. Further, as will be described in detail later, each of the middlewares 11a and 11b constituting the access support means includes:
A function of updating the tag databases 10a, 10b based on the local tag databases 12a, 12b, 12c downloaded from the respective control devices 7a, 7b, 7c is added. In FIG. 2, reference numeral 13 denotes a programming tool used for creating a control program and a tag database and downloading them to the control devices 7a, 7b, 7c.

PL constituting control devices 7a, 7b, 7c
FIG. 3 schematically illustrates a hardware configuration of a C (Programmable Logic Controller). As shown in FIG. 3A, the PLCs constituting the control devices 7a, 7b, 7c
Are a power supply unit 71, a CPU unit 72, an I / O
It has an O unit 73, a communication unit 74, and another high-performance unit 75, which are connected by a system bus (not shown). An input signal source such as a sensor or a switch is connected to the I / O unit 73, and a remote I / O unit is connected to the communication unit 74 via the communication line 14.
15 are connected. As shown in FIG.
The CPU unit 72 controls the entire unit.
A PU (configured with a microprocessor) 721, a ROM 722 for storing a system program, a RAM 723 used as a working area and the like, a user program memory 724 for storing a user program,
It has a parameter holding memory 725 for storing various operation parameters and an I / O memory (CI / O) 726 for storing the state of input / output signals. Are tied through. And
The local tag database 12a, which is a main part of the present invention,
12b and 12c are stored in the parameter memory 725,
The physical address of the input / output signal is the I / O memory 726
Indicates the address of the corresponding input / output data.
In the drawing, reference numeral 728 denotes an interface with a system bus leading to another unit.

FIG. 4 shows the hardware configuration and software configuration of the computers constituting the host computers 8a and 8b. As shown in FIG.
Computer 8 configuring upper computers 8a and 8b
Includes a CPU 81 for controlling the entire apparatus, a ROM 82 for storing a system program, a RAM 83 used as a working area and the like, an auxiliary storage 84 composed of a hard disk or the like and storing various software, an Ethernet, And the like, and other input / output devices 86, which are connected by a system bus 87. The tag databases 10a, 10a, which are main parts of the present invention,
b is stored in the auxiliary storage device 84. As shown in FIG. 4B, the software installed in this computer is an OS (Operating System) located at the lowest level.
811 and distributed middleware 812 located in the middle layer
And a hierarchical structure including the SCADA 813, the simple monitor application 814, and the like located at the uppermost layer. The access support function, which is a main part of the present invention, is incorporated in the distributed middleware 812.

FIG. 5 shows an example of the contents of the local tag databases 12a, 12b, 12c held in the control devices 7a, 7b, 7c. As shown in the figure, the local tag database has five items including “variable name”, “variable type”, “size”, “area type”, and “real I / O address (data storage address)”. Items are defined. According to the local tag database, the "real I / O address (data storage address)" of the input / output signal can be obtained using the "variable name" as an argument.

FIG. 6 shows an example of the contents of the tag database held in the host computers 8a and 8b. As shown in the figure, the tag database includes “group name”, “variable name”, “control device name”, “variable type”, “size”, “area type”, and “real I / O address”. (Data storage address)] are defined. And "group name" and "variable name"
Of the input / output signal as an argument,
/ O address (data storage address)].

FIG. 7A shows an example of the contents of the control device / network address management table incorporated in the middleware of the computers 8a and 8b. As shown in the figure, the “control device / network address management table” stores “control device name” and “control device network address” in pairs. Then, the "network address of the control device" can be obtained using the "name of the control device" as an argument.

PLs constituting control devices 7a, 7b, 7c
FIG. 7 shows an example of the contents of the change notification list table held in C.
This is shown in (b). As shown in the figure, in the change notification list table, one or more network addresses of higher-level computers that need change notification are registered. Therefore, when sending the change notification, the registration column of the change notification list table is searched in order, and the change notification is sent to the registered network address.

Next, the software configuration of the components of the distributed control system of the present invention will be described individually. First,
The processing on the programming tool 13 side will be described with reference to the flowchart of FIG.

The user uses the programming tool to
A control program is created in IEC1131-3 language (ladder, SFC, etc.). The user determines and inputs the correspondence between the logical name (variable) and the real I / O address on this tool (steps 801, 802, 803, 804). The programming tool generates a tag database for each target control device based on the correspondence between the logical name input by the user and the real address I / O (step 805). The programming tool downloads the tag database at the same time as downloading the program to the target control device (steps 806 and 807).

Next, the processing on the control devices 7a, 7b, 7c side will be described with reference to the flowcharts of FIGS.

The control devices 7a, 7b, 7c start communication processing and wait for reception. According to the received command (FIG. 9, steps 901 and 901A to 901D), the following 4
(FIG. 9, steps 902, 903,
904, 905).

When it is determined that the content of the received command is a request to download the tag database (FIG. 9,
Step 901A), a process at the time of a request to download the tag database is executed (FIG. 9, step 902).
That is, as shown in FIG. 10, upon receiving the tag database from the programming tool (steps 101 and 102), the control device searches the “change notification list” table (step 104), and registers the plurality of registered computers. To the database (steps 104 to 107). If no computer is registered (step 105 NO), no notification is made to any computer.

When the content of the received command is interpreted as a request for uploading the tag database (step 901B), the processing at the time of the request for uploading the tag database is executed (FIG. 9, step 903). That is, as shown in FIG. 11, the control device stores the tag database owned by the device in the response and returns it (steps 1101 and 1102).

When the content of the received command is interpreted as a computer registration request (FIG. 9, step 90)
1C), the process at the time of the computer registration request is executed (FIG. 9, step 904). That is, as shown in FIG. 12, the transmitted network address of the computer is registered in the "notification change list" (step 1).
201 to 1203).

When the content of the received command is interpreted as a data read / write request (step 901 in FIG. 9).
D), the processing at the time of the data read / write request is executed (FIG. 9, step 905). That is, as shown in FIG. 13, in the case of the read processing (read in step 1301), the data stored in the specified physical address is stored in the response and returned (step 1313).
02, 1303). On the other hand, in the case of the write processing (write in step 1301), the returned data is written in the specified physical address (step 1304).

Next, the processing of the middlewares 11a and 11b on the computers 8a and 8b will be described with reference to FIGS.

The middlewares 11a and 11b activate two threads and wait for a request from an application and a reception process from a control device.

When the application makes a registration request for the control device (FIG. 14, steps 1401 and 1401)
A), Processing at the time of registration request (FIG. 14, step 1402)
Execute That is, as shown in FIG. 15, the logical name of the control device and the address of the network are paired and recorded in a table (steps 1501 to 1503).

When the application issues a request to start communication with the control device (FIG. 14, steps 1401, 1)
401B), the processing at the start of communication is executed (FIG. 14,
Step 1403). That is, as shown in FIG. 16, the middleware searches its own tag database (step 1601), and checks whether a group of the corresponding control device name exists (step 1602).
If there is no corresponding group name (step 1602N
O), a command is issued to the corresponding control device via the network and the database is uploaded (steps 1603 and 1604).

When the application makes a data read / write request (FIG. 14, steps 1401 and 1401)
C), the processing at the time of the data read / write request is executed (FIG. 1)
4, step 1404). That is, as shown in FIG. 17, the middleware searches the tag database for the network address from the control device name and the physical address from the variable name (steps 1701 and 1702), and creates a communication command bucket from the information. (Step 1
703), issue a data read / write request to the target control device (step 1704, 1705 or 1704, 17).
08). If a response is returned from the target control device (YES in step 1706 or 1709YE
S), the completion of the request is notified to the application on the computer side (step 1707). In the case of data reading, data is transferred (step 1710).

When a database change notification arrives from the control device, the access from the application is temporarily locked as shown in FIG. 18 (step 1801). Subsequently, a command is issued to the corresponding control device via the network and the database is uploaded (steps 1802 and 1803). continue,
A group having the same logical name as the control device is searched (step 1804), and the uploaded database is overwritten and stored (step 1805). Finally, release the access lock from the application (step 1
806).

Next, the overall flow will be described according to the operation procedure. First, the user uses the programming tool 13 to create a control program in IEC1131-3 language (ladder, SFC, etc.). The user determines and inputs the correspondence between the logical name (hereinafter, referred to as a variable) and the real I / O address on this tool (FIG. 8, steps 801 to 8).
04). The programming tool generates a tag database for each target control device based on the correspondence between the logical name input by the user and the real address (FIG. 8, step 80).
5) At the same time as downloading the program to the target control device, the tag database is also downloaded (FIG. 8, steps 806 and 807).

The computer registers the control device to be communicated with the middleware. At this time, the logical name of the control device (hereinafter, control device name) and the address on the network are recorded as a pair (FIG. 5, steps 1501 to 1501).
503).

The application on the computer side designates a control device to communicate with the middleware by a logical name and declares the start of communication. At this time, if there is no tag database for the target control device in the middleware (FIG. 16, steps 1601 and 1603 NO), the tag database is uploaded from the target control device via communication. The middleware uploads the uploaded database in units of the control device. The middleware grooves and stores the uploaded base in units of the control device (FIG. 16, steps 1603, 1).
604). The group name is the control device name.

The middleware records the network address of the computer in the "change notification list" table in the control device in order to clearly indicate to the control device that the tag database in the control device is used. (FIG. 12, steps 1201 to 1203).

Next, the application on the computer side requests the middleware to read and write data by designating the control device name and the variable name. The middleware searches the network address rather than the control device name and the physical address from the variable name, creates a communication command bucket based on the information, and issues a data read / write request to the target control device (FIG. 17, step 1701, step 1701). 1702, 1703, 1
705, 1708).

When a response is returned from the target control device (FIG. 17, steps 1706, 170)
9), the completion of the request is notified to the application on the computer side (step 1707. In the case of reading the data, the data is passed (step 1710 in FIG. 17).

Next, the processing when the database is changed will be described. When the programming tool changes and downloads the program or tag database in the control device during the operation of the application on the computer side (FIG. 8, steps 801 to 807), the control device executes the “change notification” in the memory. List ”table,
The computer (middleware) in the list is notified that the tag database in the control device has been changed (FIG. 10, steps 101 to 107).

When the middleware receives this change notification, it temporarily locks the access from the application, uploads the database again from the corresponding control device, and performs consistency with the tag database in the control device (FIG. 1).
8, steps 1801 to 1806).

As is apparent from the above description, according to this embodiment, a programming tool having a function of downloading a tag database created at the time of programming to a control device, and a tag database of only relevant parts are held in a distributed manner. When the assignment is changed due to a program change, etc., the controller that has a function to notify the middleware in the related computer and the tag database of multiple controllers are uploaded, and one database is created from the data. The provision of the middleware on the computer to be reconfigured eliminates the need for setting work for each of a plurality of computers, the management of database consistency, and the monitoring that operates on a plurality of computers. Software is the same I / Guarantee to access the same logical name to an address, an excellent effect such that integrated debugging steps of the entire system is reduced.

[0064]

As is apparent from the above description, according to the present invention, the local tag database held in each control device is common to all the upper computers, and is a normal FA network. However, since each host computer can freely download local tag data from the control device, Ethernet (TCP)
/ IP protocol), if the assignment of the logical name and the physical address is changed for any of the control devices without using the network OS or the distributed database for OA based on the use of the Can be instantly shared with all computers, and as before,
This eliminates the need for the designer or maintenance staff to re-enter the database for each computer or manually copy files between computers, and as a result, there is no need to check input data or create a database. This has the effect that it is not necessary to take a lot of man-hours to ensure consistency.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a distributed control system to which the present invention is applied.

FIG. 2 is an explanatory diagram of an operation of the distributed control system to which the present invention is applied.

FIG. 3 is a block diagram illustrating a hardware configuration of a PLC.

FIG. 4 is a block diagram illustrating a hardware configuration of a host computer.

FIG. 5 is an explanatory diagram showing an example of contents of a local tag database held in a PLC.

FIG. 6 is an explanatory diagram showing an example of the contents of a tag database held in a host computer.

FIG. 7 shows an example of the contents of a logical name / network address management table held in a host computer, and a PLC.
FIG. 9 is an explanatory diagram showing an example of the content of a change notification list table held in the storage device.

FIG. 8 is a flowchart showing processing on the programming tool side.

FIG. 9 is a general flowchart showing processing on the control device side.

FIG. 10 is a flowchart showing a process at the time of a request for downloading a tag database.

FIG. 11 is a flowchart showing a process at the time of an upload request of a tag database.

FIG. 12 is a flowchart illustrating a process performed when a computer requests registration.

FIG. 13 is a flowchart showing a process at the time of a data read / write request.

FIG. 14 is a flowchart illustrating processing of middleware on a computer.

FIG. 15 is a flowchart illustrating a process when a control device requests registration.

FIG. 16 is a flowchart showing a process at the time of a request to start communication with the control device.

FIG. 17 is a flowchart illustrating a process at the time of a data read / write request.

FIG. 18 is a flowchart showing processing when a database change notification comes from a control device.

FIG. 19 is a configuration diagram of a conventional distributed control system.

[Explanation of symbols]

 Reference Signs List 1 distributed control system 2a, 2b, 2c control device 3a, 3b host computer 4 FA network 5a, 5b tag database 6 distributed control system 7a, 7b, 7c control device 8a, 8b host computer 9 FA network 10a, 10b tag database 11a, 11b Middleware 12a, 12b, 12c Local tag database 13 Programming tool 14 Communication line 15 Remote I / O 725 Parameter holding memory 84 Auxiliary storage 812 Distributed middleware

Continued on the front page F term (reference) 5B045 AA05 BB02 DD18 5B089 GA21 JA11 JB07 JB22 KB06 KC15 KH03 5H215 AA06 BB10 CC07 CC09 CX01 CX04 GG04 GG09 HH03 KK04 5H220 AA06 BB07 BB12 CC07 CC09 DD04JJ07 DD10 DD01 DD07 DD10 JJ59 JJ60

Claims (4)

[Claims] At least one control device is connected to one or more high-level devices via a network, and the high-level device has an assignment relationship between a physical address of a signal handled by the control device and a logical name thereof. And an access support unit having a function of accessing a signal after converting a logical name into a physical address with reference to the tag data storage unit. In the case where a data access request specifying a name is issued, in a distributed control system in which data access to a corresponding physical address is automatically performed by the intervention of the access support means, Holds a local tag data storage unit indicating the assignment relationship between the physical address of the signal handled by the own device and its logical name. In addition, each of the access support means is provided with a function of updating tag data based on information of local tag data from the control device, and the assignment of a logical name and a physical address is changed for any control device. A distributed control system characterized in that the change information can be shared by all higher-level devices even in the event of a change. 2. An apparatus which can be incorporated in a higher-level device capable of communicating with a control device via a network, and which supports input / output signal access from the higher-level device to the control device by designating a logical name. Data acquisition means for acquiring local tag data information indicating an assignment relationship between a physical address of a device signal and a logical name thereof, and data updating for updating tag data information of the own device based on the acquired local tag data information An access support device, comprising: 3. A control device capable of exchanging signals with a host device via a network, storing local tag data information indicating an assignment relationship between a physical address of a signal handled by the control device and a logical name thereof. A data read / write processing means for executing data read / write processing for an input / output signal corresponding to the physical address in response to a data read / write request specifying a physical address from a higher-level device; A tag data output means for outputting local tag data information stored in the control device to the higher-level device designated as the first device. 4. A tag database generating means for generating a tag database indicating an assignment relationship between a logical name and a physical address of an input / output signal included in the control program in accordance with an operation of generating the control program; Download means for downloading the tag database together with the created control program to a designated control device.