JP2002278608A - Exclusive processing data transmission system for plant control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is conventionally difficult to prepare an in-PLC memory referring function capable of referring to the number of a large capacity of data at an HMI side since the number of processable data of software which is being used by a general HMI is smaller than that of a large-scaled distributed control system, and the number of variables which can be held by one HMI node is about not more than ten thousand. SOLUTION: Data to be superimposed on the variables of the variable fixing addresses of HMI are changed according to the destination of an HMI side at a PLC side so that an in-PLC memory referring function for referring to the sufficient number of data can be prepared at the HMI side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data transmission and reception in packet units between a plurality of general-purpose human interfaces (hereinafter abbreviated as MHI) such as personal computers and a plurality of general-purpose programmable logic controllers (hereinafter abbreviated as PLC). Is applied to the plant control system of a general industrial plant that performs
The present invention relates to an exclusive processing data transmission method of a plant control system that can refer to a large amount of data in a PLC.

[0002]

2. Description of the Related Art In recent years, a plant control system used in a general industrial plant has an HMI having a plurality of general-purpose HMIs 2, 3, 4,.
MI unit 1 and a plurality of general-purpose PLCs for controlling plant 10
., A PLC unit 5 including
It is a system connected by. The system then comprises each HMI 2, 3, 4,... And each PLC 6, 7, 8,.
… UDP / TCP (broadcast,
(Multicast) communication, and data transmission / reception is performed in packet units.

In this case, the data in the fixed real address area in the PLC is carried in a transmission packet transmitted from the PLC to the HMI, and the data carried in the transmission packet and the fixed real address in the PLC are paired. 1 so that all data in the memory space in the general-purpose PLC
It is uniquely assigned to a variable on MI software.

[0004]

In such a conventional method of allocating data and addresses, in order to realize the function of referencing one point of data in a general-purpose PLC on the general-purpose HMI side, the inside of the PLC must be controlled. It must have a real I / O variable for each point to be referenced, and it needs other auxiliary role variables. The internal variable used by the general-purpose HMI software is an integral multiple of the variable for one point I / O variable reference.

[0005] In the restricted score frame, the HMI
A plant screen function, a plant operation function, and other functions must be realized. Further, in a system having a plurality of PLCs, the number of data points handled on the HMI increases by the number of the PLCs.

In general, software used in a general-purpose HMI has a smaller number of data points than a large-scale distributed control system (DCS), and the number of variables per HMI node does not exceed about 100,000. Scale. For this reason, conventionally, it has been difficult for the HMI to create a memory reference function in the PLC that can refer to a large number of data points.

The present invention solves the drawbacks of the prior art and provides an exclusive processing data transmission method for a plant control system in which a memory reference function in a PLC capable of referring to a sufficient number of data points is created on the HMI side. The purpose is to:

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of programmable logic controllers and a plurality of human interfaces for transmitting and receiving data in packet units are connected by a network. An exclusive processing data transmission method of a plant control system in which data transmission / reception between a logic controller and a human interface is performed by UDP (multicast, broadband) communication, and all of the programmable logic controllers have a transmission packet data section having the same identifier. A first judging means for judging whether or not each of the human interfaces has a data receiving right to receive packet data, wherein a human interface having the data receiving right is provided. In the packet data sent from the source to the programmable logic controller, a condition part specifying the model number of the programmable logic controller to which the data transmission right is to be assigned, the read start position or the write start position of the internal memory to be referred to in the programmable logic controller Is provided, in each of the programmable logic controllers, a second determination unit that determines the content of the condition unit provided in the packet data is provided, the plurality of human interfaces,
An interlock condition unit is provided so that the plurality of data reception rights are not simultaneously owned by the plurality of programmable logic controllers. And copying and holding the data of the position and the designated amount of the internal memory space of one programmable logic controller designated by the data reception right and the condition part in the transmission packet data part of the plurality of programmable logic controllers. Only the programmable logic controller having the data transmission right can transmit the transmission packet data portion, and only the human interface portion having the data reception right can open the screen for referring to the transmission packet data portion. is there.

According to the first aspect of the present invention, P having transmission right
The exclusive processing is performed so that only the LC can transmit the transmission packet data and only the HMI that has the reception right can open the screen that refers to the transmission packet data. The address of the variable that refers to the data on the HMI is fixed, Since the data to be stored in the variables is changed on the PLC side according to the designation of the HMI side, the number of variables on the HMI side can be greatly reduced, and a large amount of memory space in the PLC can be referenced with a small number of variables on the HMI side. it can.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Although FIG. 7 is used for describing the conventional example, the arrangement relationship between the HMI and the PLC is also common to the present invention, so that it is used again for describing the present embodiment with reference to FIG. FIG. 1 is a diagram for explaining data transfer between a plurality of HMIs and a PLC, and FIG.
FIG. 6 is a diagram showing an example of an operation screen of FIG.

First, in FIG. 7, an operator operates a plurality of H
A case will be described in which an arbitrary one MHI (for example, 2) is selected from MI2, 3, 4,.... In this case, “Operation permission P” in the “PLC data reference list display screen” shown in FIG.
Enter the number "2" in the PC No. window in the "C designation" column (A), and then press the execution button of the adjacent "Confirmation switch" (B). As a result, a signal specifying operation permission HMI is transmitted from the HMI 2 to each of the PLCs 6, 7, 8,... Of the PLC unit 5 via the network 9.

This situation will be described with reference to the flowchart of FIG. First, in the operation input section INPUT, PC No. “2”
Is input (a) and the execution button is pressed (b), the data of the operation permission HMI designation is output from the output function unit (c) via the network 9 to the PLCs 6, 7, 8,.
Sent to ...

In each PLC of FIG. 1, the second judgment means (d)
When the number of the operation-permitted HMI is determined to be “2” and the operation permission (reception right) is given to the transmission source HMI 2, the data of the operation-permitted HMI is output from the output function unit (e). Send to HMI. Each HMI 2, 3, 4,
.. Input the data of the operation-permitted HMI, and the first determination means (f) in the HMI determines the HMI number. As a result, only the HMI 2 obtains the right to receive.

Next, the HMI 2 sends "a condition specifying the model number of the PLC to which the data transmission right is to be granted and the reading or writing position of the internal memory to be referred" to the PLC.

That is, in FIG. 2, from the "PLC data reference list display screen", the model number (in this case, "6") of the operation-permitted PLC is designated and input in the PLC No. column (g), and the process is continued. Then, a number (in this case, "1") is specified in the integer PLN No. column (h), and a number (in this case, "0") is specified and input in the real PLN No. column (h). And
Select and press either the integer button (i) or the real number button (nu). The PLN is a polygonal line (POLY
GONAL LINE), and is an example of a data group (No.) prepared in the PLC.

In each PLC, "PLN maximum number × quantity used in 1 PLN" is prepared.
By determining whether to access the N number, a write start position or a read start position of the internal memory to be referred to in the PLC is uniquely determined. Note that the writing amount and the reading amount are continuous data that does not exceed the maximum amount (for example, 700 words) of one transmission packet.

The model number of the above-mentioned operation-permitted PLC,
By specifying the integer PLN No. and the real PLN No., it is determined which data group (PLN) of the target PLC 6 is to be accessed from the HMI 2. FIG. 5 shows an example of the data group (PLN).

Returning to FIG. 2 again, when the integer button (i) is selected, the screen “Detailed drawing for referring to data in PLC (integer)” of FIG. 3 is opened on the display screen, and the real number button (h) is selected. If this is done, the screen “PLC data reference detailed drawing (real number)” of FIG. 4 is opened.

The data on the X-axis and the Y-axis on the XY plane in the screens of FIGS.
A desired polygonal line is obtained by specifying a numerical value in each of the columns "0 to 10" and "0 to 10" of Y.

Thereafter, the primary transmission data of FIG.
Is sent to each PLC. In each PLC, the second determining means (d) determines whether the request is addressed to itself. At this time, only the PLC 6 that has determined that the request is addressed to itself acquires the transmission right.

At this point, one PLC having a transmission right and
One HMI having the reception right is determined, and the PLC 6 having the transmission right and the HMI 2 having the reception right are connected by a virtual line on the network 9, and the HMI 2 outputs the secondary reception data (ヲ) to the PLC 6.

Here, there are two types of output of the secondary reception data (ヲ): a data read request and a data write request. When a data read request is made, the data shown in FIGS. Read request (READ)
When the data write request is made by pressing the button (W) and the execution button (F), change the display data and press the data write request (WRITE) (Y) button and the execution button (F). I just need. (F) is a data input unit.

As a result, the HMI 2 has a right to access the internal data of the PLC 6 by using the in-PLC data reference screen created on its own display screen. FIG.
Is the packet data PLN between the HMI 2 and the PLC 6.
0 shows transmission and reception states of PLN1000. As can be seen from this figure, each of the PLCs 6, 7, 8,... Is provided with a memory having the same memory space, and the HMI side is also provided with a memory having the same memory space.

When the transmission right is transferred, the display returns to the "PLC data reference list display screen" in FIG. 2, and in the PLC No. column, the number of the operated-permitted PLC is changed from "6" to another number, for example, "7".
Change to integer display SW (Re) or real number display SW
By pressing (NU), the transmission right is changed from PLC6 to PLC7.
Is changed to

FIG. 6 shows a state in which the transmission right of the PLC has been changed. Thus, the transmission right is changed from PLC6 to PLC7.
To the HMI variable fixed address variable,
By changing the data to be loaded on the variables on the PLC side according to the designation on the HMI side, the number of variables on the HMI side can be greatly reduced. Therefore, an enormous memory space in the PLC can be referenced with a small number of variables on the HMI.

[0026]

As described above, according to the present invention, the HM
By changing the data to be stored in the variable corresponding to the variable at the fixed address of I according to the designation of the HMI side on the PLC side, the number of variables on the HMI side can be greatly reduced. Therefore, an enormous memory space in the PLC can be referenced with a small number of variables on the HMI.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a connection relationship between an MHI and a PLC.

FIG. 2 is a diagram showing a first display example of a display screen of an HMI.

FIG. 3 is a diagram showing a second display example of the display screen of the HMI.

FIG. 4 is a diagram showing a third display example of a display screen of the HMI.

FIG. 5 is a diagram showing an example of the arrangement of packet data.

FIG. 6 is a view for explaining a state of transfer of a transmission right.

FIG. 7 is a configuration diagram showing a connection relationship between a general HMI and a PLC.

[Explanation of symbols]

1 ... HMI section, 2, 3, 4 ... HMI, 5 ... PLC section,
6, 7, 8 ... PLC, 9 ... network 10 ... plant, b ... operation permission number column, b ... confirmation execution switch button, g ... operation permission target PLC, h ... PLC data number, l ... integer display switch, nu ... Real number display switch.

Claims (1)

[Claims] A plurality of programmable logic controllers and a plurality of human interfaces for transmitting and receiving data in packet units are connected by a network, and data transmission and reception between the programmable logic controller and the human interface are performed by user datagram protocol communication. In the exclusive processing data transmission method of the plant control system in which all of the programmable logic controllers have a transmission packet data portion having the same identifier, whether or not each of the human interfaces has a data reception right to receive packet data. A first determining unit for determining whether the packet data is transmitted from the human interface having the data receiving right to the programmable logic controller. A condition part that specifies the model number of the programmable logic controller to which the data transmission right is to be granted, the read start position or the write start position of the internal memory that the programmable logic controller wants to refer to, Providing a second determination means for determining the content of the condition part provided in the, the plurality of human interfaces, has an interlock condition part so as not to possess the plurality of data reception rights at the same time, The plurality of programmable logic controllers have an interlock condition section so that the plurality of programmable logic controllers do not own a plurality of the data transmission rights at the same time. Held by copying the data of the position and the indicated amounts of the indicated programmable logic controller one of the internal memory space by the serial condition part, only a programmable logic controller having the data transmission right and can transmit the transmission packet data unit,
An exclusive processing data transmission method for a plant control system, wherein only a human interface unit having a data receiving right can open a screen for referring to the transmission packet data unit.