JP3302033B2 - Data transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission apparatus for performing high-speed reception data processing by a microprocessor for each node.

[0002]

2. Description of the Related Art A scan data transmission system applied in continuous process automation for iron, papermaking, and the like will be described with reference to FIG.

FIG. 5 shows a rolling process as an example of continuous process automation.
The cutter and the cutter C are sequentially arranged in the flow direction of the workpiece. In such a process, it is necessary to transmit the processing information of the preceding device to the subsequent device instantaneously, and a scan data transmission method capable of high-speed data transmission is adopted.

The scan data transmission system is assigned to each of the control devices of the devices a, b, and c in order to realize an operation with an access time (scan cycle) of several milliseconds to several tens of milliseconds. Have a shared memory d. Each control device broadcasts the data in the shared memory allocated to the own station from the transmission line 1 at a fixed period, and the other station on the receiving side receives the data from the transmission line 1 and transmits the data to the shared memory. Store in the area corresponding to the station on the side. An application program for process automation provided in each control device extracts the scan data at each access time (scan cycle) and uses the information to execute actual equipment (roller a, width meter b, cutter c, etc.).
Is performed. Next, a specific description of scan data reception processing according to the related art will be given with reference to FIG.
This is performed using

[0005] Data transmitted from another station is converted into a digital signal by a modem 4 (or a decoder) through a transmission line 1 and sent to a transmission control circuit 3. In the dedicated receiving circuit 51, the received data determination circuit 5A checks whether the received data is image data or scan data, and stores the address value and the effective length in an internal register.
The direct memory access circuit 5B transfers the received scan data to the scan data memory 6 by block. Thereafter, it is checked whether or not the data has been normally received by the frame of the received data. If the data is not normal, the area to which the scan data has been transferred is released, and the process is terminated. If normal, scan address setting circuit 5
C converts the head address of the stored scan data block into an address that can be accessed by the host, and stores it in an area that matches the address of the scan address conversion table 71. The host application 8
Beforehand, where the effective scan data is stored in the scan data memory 6 is assigned and the location is stored, the scan data is read.

[0006]

As described above, according to the prior art, which scan data is valid for each reception data processing device is assigned in advance and operated, so that the scan data is changed every time the system is changed. Data memory had to be reallocated. Further, when an assignment error occurs, transmission rights of scan data of a plurality of data transmission devices overlap, and a system error may occur.

An object of the present invention is to dynamically allocate a scan data memory by adding information to a scan management table so as to reduce the load on application software and to abnormally access a scan data memory (invalid area). Access) can be prevented.

[0008]

A data transmission apparatus according to the present invention converts transmission data transmitted through a transmission line into digital data, stores scan data in a scan data memory by a transmission control circuit, and stores the scan data in a scan data memory. The processor reads and passes the data to another application process, and transmits data to the transmission control circuit in response to a data transmission request of the application process, and transfers the scan data received from the transmission control circuit to a scan data memory. The scan information corresponding to the scan data block number includes a direct memory access circuit, a memory address of a scan data memory storing the scan data, and transmission / reception of scan data, priority, and effective length of data. Management table A scan address setting circuit and a scan state setting circuit, and read information in the scan management table, check whether the scan data requested to be accessed by the application existing in the host is valid / invalid, and send the result to the application. And a scan access control circuit for notification.

[0009]

According to the scan transmission method, when transmitting / receiving scan data, the scan transmission system has a table including an address indicating where the corresponding scan data is stored in the memory and information indicating whether or not the scan data is accessible.
Necessary information is extracted from the table at the time of accessing the scan data of the application, and whether the access is permitted or not is notified to the application. Therefore, it is possible to reduce the load of the application processing and avoid the mistake of accessing invalid data.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention (using the FDDI standard of the ring ANSI in data transmission mode) will be described below with reference to the drawings. First, the overall configuration of the embodiment will be described with reference to FIG.

In a data transmission device 2 configured in a ring transmission form by a transmission line 1 using an optical fiber as a transmission medium, reference numeral 3 denotes a transmission control circuit. The data received through the transmission line 1 is converted to a digital signal by the modem 4 and sent to the transmission control circuit 3.
It is sent to the function expansion dedicated receiving circuit 5. The function-enhancement-dedicated receiving circuit 5 includes a received-data determining circuit 5A that checks whether the transmitted data is message data or scan data that has been subjected to scan processing. In addition, a direct memory access circuit 5B for transferring the received data to the scan data memory 6 via the data bus D1 and the address bus A1 is provided, and the scan information T1 (shown in FIG. 3) per scan data block and its physical The address is transferred between the data bus D2 and the address bus A in FIG.
2, a scan address setting circuit 5C and a scan state / scan state setting circuit 5D that are set in the scan management table 7 via the scan address setting circuit 5C.

Reference numeral 9 denotes a scan data access control circuit, which reads information from the scan management table 7 to obtain a real address in response to a request from the application 8, and reads out the scan data information stored in the scan data memory 6.

The scan data access control circuit 9 monitors the scan information T1 of the scan data to be accessed by the host application while taking out the scan information T1 from the scan management table 7, so that the request is an invalid data access command. For example, a signal S1 is issued to notify the application 8 on the host side, and the processing is interrupted.

That is, in this embodiment, when the host application 8 accesses the scan data in the scan data memory 6, the scan state is registered in order to improve the pre-processing part for recognizing whether or not access is possible. An extended scan management table 7 is provided in the scan address conversion table, and a scan data access control circuit 9 for notifying the application 8 of whether or not access is possible according to the contents of the scan management table 7 is newly provided. Next, a specific operation will be described with reference to FIGS. 2, 3, and 4. FIG.

As shown in FIG. 3, the transmitting side of the scan data includes, in the scan information T1 of the scan management table 7 corresponding to the scan block allocated to the data transmission apparatus itself, an identifier indicating transmission / reception of a record. T11 and T12, priority T13 (for example, eight stages from # 000 to # 111 can be designated as high speed (for process control), medium speed (for instrumentation), and low speed (for computer control)), scan data effective length T14 ( A valid data area length of the scan block contents is set, and data is transmitted to another transmission device via the transmission path 1.

On the receiving side, the data received from the transmission line 1 is converted into a digital signal by the modem 4 (or a decoder), and transmitted to the function-extended receiving circuit 5 from the transmission control circuit 3 via the bus. As shown in FIG. 2, in the function-extended reception-only receiving circuit 5, first, the reception data determination circuit 5
A, the FC identification code (DF1) in the frame of the received data shown in FIG. data frame (C
L01r000 to r111) (F
1). At this time, LLC data If not frame, the process ends. Here, the frame format of the received data will be described with reference to FIG.

DF1 is an FC identification code. When this part is c101r000 to r111, LLC of the data link layer is used. data frame.
DF2 has the structure of DF3 as an information storage area.
It has a format of DF6 or DF7 depending on whether DATA in F3 is scan data or message data. In DF6, ADRSDF4 is an address, WnDF5
Stores the scan data block length.

Returning to FIG. 2, the priority is stored in an internal register (F2). The priority is the ZZZZ portion of the FC code (DF1) shown in FIG. 4, and since the first bit is a future reservation r, eight levels can be specified as described above. Next, CONTROL in the received data frame
It is determined whether the L identification code DF8 is a scan data code (F3) and whether it is registered in the scan processing, that is, whether the DSAP is a SAP registered in the scan processing (F4). If it is registered as scan data, the direct memory access circuit 5B stores the address value DF4 (scan block number) and the data length DF5 (scan data block length) of FIG. 4 in an internal register (F5, F6). If the data is not scan data, the process ends.

Thereafter, the direct memory access circuit 5B
Then, the received scan data is transferred to the previously secured scan data memory 6 by the length of the block (F7). After the transfer, it is checked from the FCS (DF9) and FS (DF10) in the frame of the received data in FIG. 4 whether the received data is normal (F8).

If the received data is normal, the scan address setting circuit 5C and the scan state setting circuit 5D use the scan information T1 per scan data block.
And the address at which the scan data was transferred to the scan data memory 6 are set in the scan management table 7. That is, after converting the address into a physical address usable by the host, the data bus D2 and the address bus A
2, a block start address, a priority, and a data block length are set in an area corresponding to the scan data block number in the scan management table 7 (F9). If the received data is abnormal, the area to which the scan data has been transferred is released so that it can be used for the next scan data transfer (F10), and the process is terminated.

As shown in FIG. 3, the scan management table 7 includes scan information T1 and a block PTR (T2). The scan information T1 includes an area T11 / T12 for identifying transmission data or reception data, an area T13 of priority in which high speed, medium speed, or low speed is specified in eight stages of 000 to 111, and a scan block T1. And an effective scan block effective length storage area T14. Data transfer is performed based on the scan information. The block PTRT2 stores the starting block address of the scan block in the scan data memory.

When reading the received data, the application 8 existing in the host tries to access the scan data in the scan data memory 6 via the data bus D3 and the address bus A3 at regular intervals. Since the scan data access control circuit 9 monitors the scan information of the scan data that the host application 8 is trying to access while extracting it from the scan management table 7, the host application 8 deletes the invalid scan data shown in FIG. Upon access, an abnormal access is notified by an interrupt signal S1.
As described above, after checking whether the address portion of the designated scan data memory 6 is valid or invalid, the scan data memory 6 is accessed. If the access command is an invalid data access command, the access is not actually performed as described above, but an interrupt signal S1 is issued to notify the application 8 on the host side and the process is terminated.

As described above, the host application 8
However, if an invalid scan data area is accessed by mistake, an error is notified by an interrupt. Therefore, by examining the contents of the scan management table in advance, it is possible to process highly reliable scan data. Conventionally, scan data that can be transmitted by each station had to be allocated before system startup, but the above-described operation dynamically allocates scan data that can be transmitted by each station even after system startup. Is now possible.

In the above embodiment, the ANSI FDDI
By setting a rule pattern in the standard frame format,
It is used to determine scan data.
By defining the scan data determination rule pattern in the frame format used in 2.4, the same processing as in the above embodiment can be performed.

[0025]

As described above, according to the present invention, the dedicated receiving circuit for receiving the received data from the transmission control circuit transfers the data from the content of the received scan data to the corresponding scan data memory and stores the scan management table. By creating the scan data, high-speed reception processing such as FDDI can be handled, and the load on an application that processes the scan data can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration block diagram showing an embodiment of a data transmission device according to the present invention.

FIG. 2 is a flowchart illustrating an operation algorithm of FIG. 1;

FIG. 3 is a structural diagram of a scan management table used in the present invention.

FIG. 4 is a diagram showing the structure of a received data frame according to the present invention.

FIG. 5 is a configuration diagram illustrating general process automation.

FIG. 6 is a block diagram showing the entire configuration of a conventional technique.

[Explanation of symbols]

1: transmission medium optical fiber transmission line, 2: data transmission device,
3 ... Transmission control circuit, 5 ... Reception circuit for exclusive use of function extension, 5A ...
Received data determination circuit, 5B: direct memory access circuit, 5C: scan address setting circuit, 5D: scan state setting circuit, 6: scan data memory, 7: scan management table, 8: application, 9: scan data access control circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04L 13/08 G06F 13/00 353

Claims (1)

(57) [Claims] After converting transmission data sent through a transmission line into digital data, a transmission control circuit stores scan data in a scan data memory, which is read out by a microprocessor and passed to another application process. A data transmission device that transmits data to the transmission control circuit in response to a data transmission request of the application processing; a direct memory access circuit that transfers scan data received from the transmission control circuit to a scan data memory; The scan address for setting the scan information including the memory address of the scan data memory storing the scan data and the transmission / reception of the scan data, the priority, and the effective length of the data in the scan management table corresponding to the scan data block number. A setting circuit and a scan state setting circuit, and scan access control for reading information in the scan management table, checking validity / invalidity of scan data requested to be accessed by an application existing in the host, and notifying the application of the result. A data transmission device comprising: a circuit;