JP2002341907A - Method for transmitting/receiving data in blast furnace facility program logic controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for transmitting/receiving data in blast furnace facilities PLC that minimizes data monitoring transmission of a master station even when the number of texts to be transmitted from a slave station to the master station is increased. SOLUTION: In the method for transmitting/receiving data among a computer and a plurality of PLCs, one bit of transmission request flags are provided in the texts to be generated by every event in the PLCs, all the flags of the transmission request flags are allocated in a fixed area as a scan map, when an event is caused, the PLCs change the transmission request flag corresponding to the event from 'off' to 'on', the computer monitors only the scan map in the fixed area, confirms that the transmission request flag of the scan map becomes 'on' as monitoring it, starts read of the text applicable to 'on' and when the read of the text applicable to 'on' is completed, informs the PLCs of an instruction to change the transmission request flag from 'on' to 'off'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission / reception method of a program logic controller (hereinafter referred to as PLC) in a blast furnace facility.

[0002]

2. Description of the Related Art Conventionally, when the transmission mode between a computer and a PLC is a half-duplex system, the computer is a master station and the PLC is a slave station. When data is sent from the PLC to the computer, the data is directly transmitted from the slave station to the master station. Since it was not possible, the master station monitored the data change of the slave station.

Conventionally, the size of one transmission of data received by a PLC from a computer is limited.
For data that requires synchronization, a method of carefully selecting data so as to fall within the size and determining the transmission content has been adopted.

[0004]

In the prior art, however, a large number of texts are transmitted from the slave station to the master station. If the texts are distributed, the number of transmissions is required by the number of texts. For data monitoring, the number of transmissions and the amount of transmission increase, and the transmission load on the master station is increased. Also, since the data update in the master station is delayed,
Even if C updates the data, the master station does not easily start the reading operation, so that the same text as the text waiting on the PLC side is generated again, and the transmission state of the line is congested.

[0005] In addition, since the data size received by the PLC is limited, it is necessary to select the data carefully. On the other hand, in recent years, it has been difficult to maintain data synchronization because a large amount of data has been handled by the PLC. There was a problem that has become.

JP-A-2000-39907 and JP-A-6-214620 are disclosed as prior arts in which a PLC divides and receives data from a computer.

Japanese Patent Application Laid-Open No. 2000-39907 discloses that in order to transmit a message efficiently, the CPU 2, system bus 3, communication module 4 and I / O module 5 constituting a programmable controller are provided with the type information (communication module or I / O module). / O module, etc.), and a function identification code including the maximum number of data transfer of one message is provided, and basic information is read and transferred according to its size.

Japanese Unexamined Patent Publication No. Hei 6-214620 discloses a method of dividing data exceeding a range of the maximum number of data that can be transmitted at one time in order to input and output data without being limited by the maximum number of data to be transmitted. Only by transmitting and checking the page number and sequential number, the synchronization of the divided input data and output data is ensured, and if it is within the memory capacity, from the small capacity corresponding to the controlled device to the large capacity It is possible to easily incorporate the various I / O devices without any restrictions, thereby improving the operation efficiency of the programmable controller.

Therefore, an object of the present invention is to minimize the data monitoring transmission of the master station even if the number of texts transmitted from the slave station to the master station increases, and to increase the amount of data between the slave station and the master station and perform the data monitoring multiple times. Even if transmission, PL
It is an object of the present invention to provide a data transmission / reception method in a blast furnace facility PLC which can maintain the simultaneity as long as it is handled in the sequence in C.

[0010]

Means for Solving the Problems A first invention of the present invention is:
As a method of transmitting and receiving data between a computer and multiple PLCs as a blast furnace facility, a 1-bit transmission request flag is provided in the text generated for each event in the PLC, and all the transmission request flags are set in a fixed area consisting of several words as a table. Assigning as a scan map;
The PLC changes a transmission request flag corresponding to the event in the scan map from “off” to “on” when an event to transmit the text occurs, the computer monitors only the scan map in the fixed area, The step of monitoring and confirming that the transmission request flag of the scan map is set to "ON", and starting reading of the text corresponding to "ON", and the computer completing reading of the text corresponding to "ON" Then PL
Notifying C of a command to change the transmission request flag from “on” to “off”.

A second invention of the present invention provides a method for transmitting and receiving data between a computer and a plurality of PLCs as a blast furnace facility, wherein the text format includes a text number, a division number, and a text number transmitted between the PLC and the computer. Adding division information such as the number of divisions, the top register number, and the data size to the header. The computer or the PLC temporarily buffers the received data according to the division information of the text header, and completes the reception of all divided data. Transferring to the final storage destination register at the time.

The second invention of the present invention is different from JP-A-2000-39907 and JP-A-6-214620, which are disclosed as prior arts, in the following points.

Japanese Patent Application Laid-Open No. 2000-39907 reads basic information and transmits it according to its size. On the other hand, the present invention provides a buffer for the number of receptions on the receiving side,
It has the function of receiving all the divided data, storing it in a buffer, and finally compiling the text, and keeps the large amount of data of the blast furnace equipment synchronized with the limited transmission size.

Japanese Patent Application Laid-Open No. 6-214620 discloses that
The present invention relates to the relationship between the PLC and the PLC and between the PLC and the computer with respect to the synchronization of the input data and the output data between the PLC and the I / O device. The data division reception is performed according to the division information of the text header. The purpose is to keep the synchronization of receiving data groups.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual block diagram and a flowchart of the operation of the first embodiment of the present invention.

According to FIG. 1, a first embodiment comprises a computer 11 for receiving PLC data, a PLC 12,
Are comprised of registers 13 to 15.

The register 13 is a scan map request flag for notifying the computer of the occurrence of an event, and the register 14
Is a text which is the original transmission purpose, and the register 15 is a scan map read completion flag (pulse signal) for notifying that the text has been read from the computer to the PLC. The scan map request flag and the scan map read completion flag are arranged in the same order in order to simplify the program structure, and are combined in one area of about several words.
Further, the bit transfer between the two scan maps may be performed by direct wiring instead of by transmission.

First, when an event such as dump completion, which is a signal for collecting performance data, occurs in the PLC, data such as performance data is edited and set in a corresponding text, and a scan map request flag is turned on (S1).
1).

The computer monitors the scan map request flag (S100). A flag changed from OFF to ON is detected in the scan map request flag (S10).
1) Then, the text corresponding to the changed flag is read from the PLC (S102). Reading is completed (S
lO3) and the corresponding scan map reading completion flag to O
N is sent to the PLC (Sl04).

In the PLC, the scan map read completion flag is set to O
When N is detected, the corresponding scan map request flag is set to O.
FF is performed (S12).

If the scan map request flag continues to be ON for a longer time than the transmission time, it is determined that a transmission failure has occurred, and the scan map request flag is turned off.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a conceptual block diagram and a flowchart of the operation of the second embodiment of the present invention.

Referring to FIG. 2, the second embodiment comprises a transmission partner device 21 such as a computer, a PLC 22, and registers 23 to 25 in the PLC. Register 23
Is an area for receiving data from the transmission partner,
Is a register for temporarily storing data received by division, and a register 25 is a final storage destination register used for the sequence.

The transmission partner device 21 assigns a header (text N) to each data group divided by the transmission size limit value.
o. , Division No. , Division number, top register No. , Data size) to the PLC 22 as many times as the number of divisions. The PLC 22 checks the data for each reception.

First, it is determined whether or not the PLC has received (S200). It is confirmed whether the received PLC is data to be received (S201). If the data is to be received, the received data is transferred to the temporary storage register 4 (S202). At this time, the division No. Alternatively, the position in the temporary storage destination register is calculated from the final storage destination register in the header, and the destination of the received data is determined. Next, the division No. Is determined to be equal to the number of divisions (S
203). If they match, the data is moved from the temporary storage destination register to the final storage destination register.

[0026]

As described above, according to the present invention, the computer does not need to monitor the data change of the distributed text, but only needs to monitor the scan map request flag of a very small size. As a result, unnecessary transmission is eliminated, and since the scan map request can be transmitted instantaneously, there is an effect that the read transmission in the computer can be performed almost simultaneously with the PLC request.

As described above, according to the present invention, even if one piece of data is divided and transmitted in the computer due to the limitation of the transmission data size, the data is temporarily stored by receiving the PLC, and the final data is stored. If the data is moved to the sequence register area by reception, there is an effect that the synchronization can be maintained as one data even when the data is divided and received.

[Brief description of the drawings]

FIG. 1 is a conceptual block diagram and a flowchart of an operation of a first exemplary embodiment of the present invention.

FIG. 2 is a conceptual block diagram and a flowchart of an operation of a second exemplary embodiment of the present invention.

[Explanation of symbols]

11: Computer 12: PLC 13: Scan Map Request Flag (PLC Internal Register) 14: Transmission Data (Text) (PLC Internal Register) 15: Scan Map Read Complete Flag (PLC Internal Register) 21: Transmission Device of Computer 22: PLC 23: Reception area from transmission partner (PLC internal register) 24: Transmission data temporary storage buffer (PLC internal register) 25: Sequence final storage destination register (PLC internal register) S11: Event generation processing unit S12: Scan map request Flag reset unit S100: Scan map reading unit S101: Scan map request flag monitoring unit S102: Text reading unit S103: Text reading completion confirmation unit S104: Text reading completion notification (scan map reading completion flag set) unit S200: Over data reception determination section S201: text No. Checking unit S202: Transferring unit to receive data temporary storage buffer S203: Data reception completion determining unit

 ──────────────────────────────────────────────────続 き Continuation of the front page F term (reference)

Claims (2)

[Claims] 1. A method for transmitting and receiving data between a computer and a plurality of program logic controllers as a blast furnace facility, wherein one bit of a transmission request flag is provided in a text generated for each event in the program logic controller. Allocating all the flags as a table as a scan map in a fixed area consisting of several words, and when an event to transmit text occurs, the program logic controller sets a transmission request flag corresponding to the event in the scan map from “OFF” to “OFF”. "on"
And the computer monitors only the scan map in the fixed area. The computer checks that the transmission request flag of the scan map is set to “ON”, and corresponds to “ON”. Starting reading of the text to be read, and, when the computer completes reading of the text corresponding to the “on”, notifying the program logic controller of a command to change the transmission request flag from “on” to “off”. A method for transmitting and receiving data in a blast furnace equipment program logic controller having the following. 2. A method for transmitting and receiving data between a computer and a plurality of program logic controllers as a blast furnace facility, wherein the format of the text transmitted between the program logic controller and the computer is a text number, a division number, and a division number. Adding division information such as the number, the top register number, and the data size to the header; and the computer or the program logic controller temporarily stores the received data in a buffer according to the division information of the text header, and stores all divided data. A data transmission / reception method in a blast furnace equipment program logic controller, comprising a step of transferring the data to a final storage destination register when reception is completed.