JP5382329B2 - Communication control device and communication control method - Google Patents

Description

  The present invention relates to a communication control apparatus and a communication control method for receiving a packet from a network and performing data processing by data processing means using the data as received data. The present invention preferentially performs high priority processing and increases processing time. The present invention relates to a communication control device and a communication control method for achieving suppression.

  Communication in industrial applications includes, for example, communication in process control. Process control is performed by a distributed control system, and the distributed control system is used for plant operation control in a wide range of fields such as petrochemical, steel, paper pulp, and electric power.

  Such an apparatus will be described with reference to FIG. In FIG. 2, a plurality of field control stations (hereinafter referred to as FCS) 1 is connected to a network L and controls a plant (not shown). A plurality of safety control stations (hereinafter referred to as SCS) 2 are connected to the network L, monitor the plant, and shut down the plant when there is a plant abnormality. A plurality of human interface stations (hereinafter referred to as HIS) 3 are connected to the network L, communicate with FCS 1 and SCS 2, and operate and display.

  Next, a specific configuration of the SCS 2 will be described with reference to FIG. FCS1 and HIS3 have the same communication configuration as SCS2.

  In FIG. 3, the network interface 21 has a physical layer function of an OSI (Open Systems Interconnection) hierarchical model, is connected to the network L, and transmits and receives a packet including a header and data. The reception processing means 22 has the functions of the data link layer, network layer, and transport layer of the OSI hierarchical model, receives packets from the network interface 21, and checks the destination, that is, that it is addressed to itself and that the data is valid. And the header such as the destination is removed, and the packet data is output as received data. The reception queue unit 23 accumulates the reception data from the reception processing unit 22 in the order of reception and outputs it in the order of reception. The data processing unit 24 receives the reception data from the reception queue unit 23, performs data processing according to the content of the reception data, performs data processing, and outputs transmission data. The transmission queue unit 25 accumulates the transmission data of the data processing unit 24 in the order of transmission and outputs it in the order of transmission. Similar to the reception processing unit 22, the transmission processing unit 26 has functions of a data link layer, a network layer, and a transport layer. The transmission data of the transmission queue unit 25 is used as packet data, and a header such as a destination is added. , Create a packet and pass it to the network interface 21.

  The operation of such an apparatus will be described below. The FCS 1 and the HIS 3 transmit a packet requesting data reference to the SCS 2 via the network L. In other words, the data portion of the packet is a data reference request. This packet is received by the network interface 21 of the SCS 2 via the network L, and the network interface 21 passes the packet to the reception processing means 22. The reception processing unit 22 confirms that the destination in the packet header is addressed to itself, checks the validity of the packet data, etc., removes the header such as the destination, and outputs the received data to the reception queue unit 23. The reception queue means 23 outputs the received data inputted first to the data processing means 24, and the data processing means 24 is a data processing, that is, a data reference request, so that the corresponding data and data indicating the state of the plant are transmitted. The data is output to the transmission queue means 25. The transmission queue unit 25 outputs the transmission data input first to the transmission processing unit 26 first. The transmission processing unit 26 adds a header such as a destination to transmission data, creates a packet, outputs the packet to the network interface 21, and transmits it to the FCS 1 and HIS 3 via the network L.

  Further, the SCS 2 transmits a safety communication packet to another SCS 2 via the network L. That is, the packet data is safety communication. This safety communication packet is a communication that realizes a plant safety control function. If the packet does not arrive correctly within a certain time, the SCS 2 performs a shutdown operation of the plant in order to protect the safety of the plant. Packets between the SCSs 2 are also input to the reception queue unit 23 via the network interface 21 and the reception processing unit 22. Therefore, the reception queue means 23 stores a mixture of data reference communication packets and safety communication packets, which are processed in a first-in first-out manner. Since safety communication is intended to protect the safety of the plant, it has been treated in the same way as data reference communication despite its higher priority than data reference communication. For this reason, there are cases where data processing with high priority is delayed or received data with high priority is discarded because the storage limit of the reception queue means 23 is exceeded.

  Therefore, as shown in Patent Document 1 below, it is conceivable that reception queue means and transmission queue means are provided for each priority level so that received data with a high priority is preferentially processed. Such an apparatus is shown and described in FIG. Here, the same components as those in FIG.

  In FIG. 4, the reception processing means 220 is provided in place of the reception processing means 22 and has functions of the data link layer, network layer, and transport layer of the OSI hierarchical model. The reception processing unit 220 receives a packet from the network interface 21, performs destination verification, that is, addressing itself or data validity, removes the header of the destination, and the priority newly added to the header Based on the information, output is assigned to high priority and low priority. The reception queue unit 231 accumulates the high-priority reception data from the reception processing unit 220 in the order of reception and outputs it in the order of reception. The reception queue unit 232 accumulates the low-priority reception data from the reception processing unit 220 in the order of reception and outputs it in the order of reception. The data processing means 240 preferentially processes the reception data from the reception queue means 231 and performs data processing on the reception data of the reception queue means 232 when there is no more data from the reception queue means 231. In addition, the data processing unit 240 performs data processing, sorts the data according to priority, and outputs transmission data. The transmission queue unit 251 accumulates the high priority transmission data of the data processing unit 240 in the order of transmission and outputs it in the order of transmission. The transmission queue means 252 accumulates low priority transmission data of the data processing means 240 in the order of transmission and outputs them in the order of transmission. The transmission processing unit 260 is provided instead of the transmission processing unit 26 and has functions of a data link layer, a network layer, and a transport layer of the OSI hierarchical model. The transmission processing unit 260 preferentially adds a header such as a destination to the transmission data from the transmission queue unit 251, creates a packet, passes it to the network interface 21, and when there is no transmission data in the transmission queue unit 251, A header is added to the transmission data from the transmission queue means 252 to create a packet and pass it to the network interface 21.

  The operation of such an apparatus will be described below. The FCS 1 and the HIS 3 transmit a data reference communication packet with low priority information added to the header to the SCS 2 via the network L. This packet is received by the network interface 21 of the SCS 2 via the network L, and the network interface 21 passes the packet to the reception processing means 220. The reception processing means 220 confirms that the destination in the packet header is addressed to itself, checks the validity of the packet data, etc., removes the header based on the low priority information of the header, and then receives the received data in the reception queue means 232. Output to. On the other hand, high priority information is added to the header from another SCS 2, a safety communication packet is received by the network interface 21 via the network L, and the network interface 21 passes the packet to the reception processing unit 220. The reception processing unit 220 confirms the destination and the validity of the data in the header of the packet, and after removing the header based on the high priority information of the header, outputs the reception data to the reception queue unit 231. The data processing unit 240 inputs the reception data input from the reception queue unit 231 first, and performs data processing, that is, plant safety control. When there is no reception data of the reception queue unit 231, the data processing unit 240 inputs the reception data of the reception queue unit 232 in the order of reception and performs data processing.

  On the other hand, the data processing means 240 outputs to the transmission queue means 251 if the transmission data is high priority data, and outputs it to the transmission queue means 252 if the transmission data is low priority data. The transmission data processing unit 260 adds a header with high priority information added to the transmission data of the transmission queue unit 251, creates a packet, outputs the packet to the network interface 21, and sends it to another SCS 2 via the network L. Send. When there is no transmission data of the transmission queue unit 252, the transmission data processing unit 260 creates a packet by adding a header with low priority information added to the transmission data of the transmission queue unit 252, and sends it to the network interface 21. The data is output and transmitted to the FCS 1 and the HIS 3 via the network L.

Japanese Patent No. 3723980 (paragraph number 0078-0083, FIG. 13)

  However, in the apparatus shown in FIG. 4, the data processing unit 240 distributes the data to the transmission queue units 251 and 252 and stores the transmission data, and the transmission processing unit 260 must add priority information, which requires processing time. End up.

  Therefore, an object of the present invention is to realize a communication device and a communication method that preferentially perform processing with high priority and suppress increase in processing time.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a communication control apparatus that is used in a control system that performs process control, receives a packet from a network, performs data processing by data processing means, using the data as received data,
A network interface for connecting to the network and transmitting and receiving the packets;
A reception processing means for receiving a packet from the network interface, removing a header, and obtaining the received data;
First reception queue means for accumulating received data from the reception processing means in the order of reception and outputting in the order of reception;
Second reception queue means for accumulating reception data having a low priority of the reception data in the order of reception and outputting to the data processing means in the order of reception;
The priority is determined based on the content of the received data of the first reception queue means, and if the data does not arrive correctly within a certain time, the received data of safety communication in which a plant shutdown operation is performed is output to the data processing means And determining means for outputting the received data of the data reference communication requesting data reference to the second reception queue means in the order of reception;
It is characterized by comprising.
According to a second aspect of the invention, an invention of claim 1,
Transmission queue means for accumulating transmission data from the data processing means in the order of transmission and outputting in the order of transmission;
Transmission processing means for adding a header to the transmission data of the transmission queue means to create a packet and passing it to the network interface is provided .
The invention described in claim 3
In a communication control method that is used in a control system that performs process control, receives a packet from a network , uses data as received data, and performs data processing by a data processing unit.
A network interface connected to the network transmits and receives the packet;
Receiving a packet from the network interface, removing a header and making the received data;
A step of storing the reception data from the reception processing means in a reception order in a first reception queue means;
Determines the priority depending on the contents of the received data of the first receive queue means, if not reached correctly within a predetermined time, receiving the reception data of the safety communication plant shutdown operation is performed in the data processing means The received data of the data reference communication requesting data reference is stored in the second reception queue means in the order of reception, and when there is no received data in the first reception queue means, the data processing means And a step of processing data received in the reception queue means in the order of reception.

The present invention has the following effects.
According to claim 1 or 2 , the determining means determines the priority based on the content of the received data of the first reception queue means, and the priority is high , that is, the safety communication received data is output to the data processing means. Since the priority is low , that is, the received data of the data reference communication is stored in the second reception queue means in the order of reception, it is possible to preferentially perform the processing with high priority and suppress an increase in processing time.

According to claim 3 , the priority is determined based on the content of the reception data of the first reception queue means, the priority is high , that is, the safety communication reception data is output to the data processing means, and the priority is low . That is, since the received data of the data reference communication is stored in the second reception queue means in the order of reception, it is possible to preferentially perform processing with high priority and suppress increase in processing time.

It is the block diagram which showed one Example of this invention. It is the figure which showed the structure of the distributed control system. It is the figure which showed the specific structure of conventional SCS2. It is the figure which showed the other specific structure of the conventional SCS2.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. 2 and 3 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 1, the reception queue means 27 accumulates reception data with low priority of reception data in the order of reception and outputs them in the order of reception. The determination unit 28 determines the priority of the reception data of the reception queue unit 23, outputs the reception data with a high priority, and outputs the reception data with a low priority to the reception queue unit 27 in the order of reception. The data processing means 29 receives received data with high priority from the judging means 28 and processes the data preferentially. When there is no data from the judging means 28, the received data in the receiving queue means 27 is processed in the order of reception. Further, the data processing unit 29 performs data processing and outputs transmission data to the transmission skew unit 25.

  The operation of such an apparatus will be described below. The FCS 1 and the HIS 3 transmit data reference communication packets to the SCS 2 via the network L. This packet is received by the network interface 21 of the SCS 2 via the network L, and the network interface 21 passes the packet to the reception processing means 22. The reception processing unit 22 checks that the destination in the packet header is addressed to itself, verifies the validity of the packet data, and outputs the received data to the reception queue unit 23. On the other hand, a safety communication packet is received from another SCS 2 via the network L by the network interface 21, and the network interface 21 passes the safety communication packet to the reception processing unit 22. The reception processing means 22 checks the validity of the destination and data in the header of the packet, removes the header, and outputs the received data to the reception queue means 23. In this way, the reception queue means 23 stores the reception data in the order of reception.

  The judging means 28 judges the priority based on the contents of the received data in the receiving queue means 23 in the order of reception, and outputs the received data to the data processing means 29 in the case of received data having a high priority, ie, safety communication received data. . Then, the determination unit 28 outputs the reception data to the reception queue unit 27 in the case of reception data having a low priority, that is, reception data of data reference communication. Then, the data processing means 29 processes the received data from the judging means 28, and if there is no received data from the judging means 28, that is, if there is no received data in the receiving queue means 23, the data is received from the receiving queue means 27. Received data is received in order and data processing is performed.

  On the other hand, the data processing unit 29 outputs the transmission data to the transmission queue unit 25. The transmission queue unit 25 outputs the transmission data input first to the transmission processing unit 26 first. The transmission processing unit 26 adds a header such as a destination to the transmission data, creates a packet, outputs the packet to the network interface 21, and transmits it to the FCS 1, SCS 2, and HIS 3 via the network L.

  As described above, the determination unit 28 determines the priority of the reception data of the reception queue unit 23, outputs the reception data having a high priority to the data processing unit 29, and receives the reception data having a low priority to the reception queue unit 27. Since they are stored in the order of reception, it is possible to preferentially perform processing with high priority and suppress increase in processing time.

  Note that the present invention is not limited to this, and the configuration in which the reception queue unit 27 and the determination unit 28 directly output to the data processing unit 29 has been described, but the output of the reception queue unit 27 and the output of the determination unit 28 It is also possible to provide a switching means for switching to the data processing means 29. In this case, the switching unit determines that there is no reception data in the reception queue unit 23 and switches from the determination unit 28 to the reception queue unit 27.

  Further, the data processing unit 29 is configured to receive the reception data from the reception queue unit 27 when there is no reception data from the determination unit 28. However, the data processing unit 29 does not have the reception data directly from the reception queue unit 23. It may be configured to receive an empty signal indicating that the received data is received from the reception queue means 27.

L network 2 SCS
21 Network Interface 22 Reception Processing Unit 23, 27 Reception Queue Unit 25 Transmission Queue Unit 26 Transmission Processing Unit 27 Determination Unit 28 Determination Unit 29 Data Processing Unit

Claims (3)

In a communication control apparatus that is used in a control system that performs process control, receives a packet from a network, performs data processing by data processing means, using the data as received data,
A network interface for connecting to the network and transmitting and receiving the packets;
A reception processing means for receiving a packet from the network interface, removing a header, and obtaining the received data;
First reception queue means for accumulating received data from the reception processing means in the order of reception and outputting in the order of reception;
Second reception queue means for accumulating reception data having a low priority of the reception data in the order of reception and outputting to the data processing means in the order of reception;
The priority is determined based on the content of the received data of the first reception queue means, and if the data does not arrive correctly within a certain time, the received data of safety communication in which a plant shutdown operation is performed is output to the data processing means And determining means for outputting the received data of the data reference communication requesting data reference to the second reception queue means in the order of reception;
A communication control apparatus comprising: Transmission queue means for accumulating transmission data from the data processing means in the order of transmission and outputting in the order of transmission;
The header to the transmission data in the transmission queue means adds to create a packet, the communication control apparatus according to claim 1, characterized in that it comprises a transmission processing means to pass to the network interface. In a communication control method that is used in a control system that performs process control, receives a packet from a network , uses data as received data, and performs data processing by a data processing unit.
A network interface connected to the network transmits and receives the packet;
Receiving a packet from the network interface, removing a header and making the received data;
A step of storing the reception data from the reception processing means in a reception order in a first reception queue means;
Determines the priority depending on the contents of the received data of the first receive queue means, if not reached correctly within a predetermined time, receiving the reception data of the safety communication plant shutdown operation is performed in the data processing means The received data of the data reference communication requesting data reference is stored in the second reception queue means in the order of reception, and when there is no received data in the first reception queue means, the data processing means And a step of processing the received data of the reception queue means in the order of reception.

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