TW201811083A - Communication system and communication method - Google Patents

Abstract

This communication system is provided with a first communication device and a plurality of second communication devices. The communication system is characterized in that each of the second communication devices has: a first transmission control unit that transmits first data communication requiring a real-time property; and a second transmission control unit that transmits, as a part of the first data communication, a request for transmitting second data communication not requiring a real-time property to the first communication device and that transmits the second data communication in accordance with information about an idle band received from the first communication device. The communication system is also characterized in that the first communication device has a transmission management unit that manages a communication band for the second data communication, and when having received a request for the second data communication, transmits information about the idle band of the communication band to the second communication device that has transmitted the request for the second data communication.

Description

Communication system and communication method

The invention relates to a communication system and a communication method used in a control network.

In the control network of a plurality of connected devices (nodes), a time-division communication method in which an instant communication bandwidth and a non-immediate communication bandwidth are set is adopted, thereby obtaining a method for ensuring the bandwidth of the instant communication.

In this method of ensuring the bandwidth of instant messaging, for a certain node, during the period when the instant messaging bandwidth is allocated, transmission from other nodes can be suppressed, so the node after the instant messaging bandwidth is allocated can transmit the desired IM information.

However, it is necessary to consider that in a non-immediate communication bandwidth, when a node implements non-immediate communication, non-immediate communication of other nodes occurs at the same time. As a result, this means a tighter tendency to non-IM bandwidth.

This problem can be solved by setting the non-IM bandwidth to a certain level. However, in this case, the communication cycle of instant messaging will become longer this time, and the communication bandwidth of instant messaging will become narrower. Therefore, it is difficult to implement the control to increase the necessity of the priority, which causes problems. .

Patent Document 1: Special Table No. 2004-515122

In contrast, in the conventional communication system, there is a disclosed technology (Patent Document 1). In order not to interfere with the instant communication bandwidth, when transmitting non-immediate communication data, it mainly stores the relay data to the next cycle. Until the non-IM start time of

However, in the conventional communication system, a buffer memory that can perform main storage at all nodes is needed, so the cost is increased.

In addition, even if this buffer memory is made small in order not to affect the cost, data discarding will occur. Therefore, non-IM data is often stored mainly before reaching the address. As far as transmitting data is concerned, retransmission processing will not happen, which will further tighten the bandwidth of non-IM.

The present invention is an invention for eliminating the above-mentioned problems, and provides a communication system including a first communication device and a plurality of second communication devices, characterized in that the second communication device includes: a first messaging control section, and transmission needs to be timely The first data communication; and the second messaging control unit, which transmits the request for the second data communication that does not require immediateness as part of the first data communication, and transmits it to the first communication device, The bandwidth information received by the communication device transmits the second data communication; the first communication device includes: a messaging management unit that manages the communication bandwidth for the second data communication, and after receiving the request for the second data communication, the above-mentioned The information of the space bandwidth of the communication bandwidth is transmitted to the second communication device transmitting the request for the second data communication.

According to the present invention, non-immediate communication can be performed without including a buffer for the slave device to store data such as transmission interruption processing.

1‧‧‧CPU

2‧‧‧Memory

3‧‧‧Memory device

4‧‧‧ communication device

5‧‧‧ input device

6‧‧‧ display device

100‧‧‧ main device

110‧‧‧ Face

110a‧‧‧Interface

110b‧‧‧Interface

120‧‧‧Communication Control Department

121‧‧‧Real-time messaging control department

122‧‧‧ Non-instant messaging control department

123‧‧‧Non-real-time messaging management department

124‧‧‧Communication frame generation department

130‧‧‧Receiving Control Department

140‧‧‧communication cycle control department

200‧‧‧ Slave

200a‧‧‧ slave devicea

200b‧‧‧ slave device b

200c‧‧‧ Slave c

210‧‧‧ Face

210a‧‧‧Interface

210b‧‧‧Interface

220‧‧‧Communication Control Department

221‧‧‧Real-time messaging control department

222‧‧‧ Non-immediate messaging control department

223‧‧‧Communication frame generation department

230‧‧‧Receiving Control Department

240‧‧‧communication cycle control department

500‧‧‧communication system

FIG. 1 is an example of a structure diagram of a communication system according to this embodiment.

FIG. 2 is an example of a hardware configuration diagram of a master device and a slave device in this embodiment.

FIG. 3 is an example of a functional configuration diagram of the master device of this embodiment.

FIG. 4 is an example of a non-immediate communication bandwidth meter according to the embodiment.

FIG. 5 is a flowchart showing the processing of the non-immediate transmission management unit 123 in this embodiment.

FIG. 6 is an example of a functional structure diagram of a slave device according to this embodiment.

FIG. 7 is a flowchart showing the processing of the non-immediate messaging control unit 222 in this embodiment.

FIG. 8 is a flowchart showing the processing of the communication frame generating unit 206 in this embodiment.

FIG. 9 is a diagram showing an example of a structure of a non-immediate communication frame of this embodiment.

FIG. 10 is an example of a communication flowchart of a communication system of this embodiment.

FIG. 11 is an example of a communication flowchart when a plurality of slave devices transmit a transmission request in the same embodiment.

The most suitable mode for carrying out the present invention is shown below. The content of the invention is not limited by the content described below.

1st implementation type.

FIG. 1 shows an example of the structure of a communication system 500 according to this embodiment.

As shown in FIG. 1, the communication system 500 is a linear network and includes a master device (first communication device) 100 and a plurality of slave devices (second communication device) 200. In addition, in FIG. 1, there are examples in which the slave device 200a, the slave device 200b, and the slave device 200c are configured, which will be described below.

In addition, the network connecting the master device 100 and the plurality of slave devices 200 may be a linear network as shown in FIG. 1, or a network of other shapes such as a ring, a star, and a bus. These networks may be This embodiment is applicable.

The master device 100 periodically transmits instant messaging (first data communication) data containing a control instruction to the slave device 200, and each slave device 200 periodically transmits instant messaging data containing a response to the control instruction to the master device 100.

In addition, the master device 100 and the slave device 200 aperiodically transmit and receive non-immediate communication (second data communication) data such as Internet Protocol (IP) communication without a control instruction.

A hardware structure example of the master device 100 and the slave device 200 in this embodiment is shown in FIG. 2. Each device includes a CPU 1, a memory 2, a memory device 3, a communication device 4, an input device 5, and a display device 6.

CPU1 executes the program. More specifically, in the case of the master device 100, the CPU 1 executes a program for realizing the functional components of the master device 100, and in the case of the slave device 200, the CPU 1 executes a program for realizing the functional components of the slave device 200.

The memory 2 is a volatile memory device, specifically, a RAM (Random Access Memory).

The memory device 3 is a non-volatile memory device, which may be HDD (hard disk), flash memory, etc.

The program executed by the CPU 1 is stored in the memory device 3, loaded into the memory 2, and executed by the CPU 1.

The communication device 4 is a circuit for transmitting and receiving with other devices, and may be a large-scale integrated circuit (LSI), a field programmable gate array (FPGA), or the like.

The input / output device 5 is a device connected to a master device and a slave device, and may be a servo motor or the like.

In addition, this structure is not limited to this example, and may be another structure.

A functional configuration diagram of the main device 100 in this embodiment mode is shown in FIG. 3.

The main device 100 includes a network interface 110, a messaging control unit 120, a reception control unit 130, and a communication cycle control unit 140.

In addition, the master device 100 in this embodiment can be used as a bridge device connected across a plurality of networks. Therefore, although the case where the host device 100 shown in FIG. 3 is composed of the network interface portion 110a and the network interface portion 110b will be described, in reality, the network interface portion 110 may have only one or two or more.

The network interface 110 is connected to the network and receives and transmits communication frames to other nodes.

The network interface 110 transmits a communication frame forwarded by the messaging control unit 120 to the network. In addition, the network interface 110 receives a communication frame from the network and analyzes data of the receiving frame.

After the data of the receiving frame is parsed, if it is a unicast frame with the host device 100 as the destination or a multicast group or broadcast frame with the multicast group to which the host device 100 belongs as the destination , The network interface 110 forwards the received data to Receive control unit 130.

In addition, after the data of the receiving frame is parsed, if it is a non-real-time messaging request for information notification or the receiving frame relays the data transmitted from another network interface (the frame sent to other devices, or multiple points) Frame sent or broadcasted), the network interface 110 forwards the received data to the messaging control unit 120.

The messaging control section 120 includes an instant messaging control section 121, a non-immediate messaging control section 122, a non-immediate messaging management section (messaging management section) 123, and a communication frame generating section 124.

The instant messaging control unit 121 compares the time information notified from the communication cycle control unit 140 with the current time to determine whether it is time to transmit real-time data.

If it is determined that the real-time data is transmitted, the real-time messaging control unit 121 forwards the real-time data to the communication frame generating unit 124.

The non-immediate messaging control unit 122 compares the time information notified from the communication cycle control unit 140 with the air-bandwidth information notified by the non-immediate messaging management unit 123 when there is non-immediate communication data to be transmitted. If it is determined that the time can be transmitted, the non-real-time data to be transmitted is forwarded to the communication frame generating unit 124.

The non-immediate messaging management unit 123 manages the non-immediate messaging bandwidth when the data of the receiving frame transmitted from the network interface 110 is non-immediate messaging request information from the slave device.

The so-called non-instant messaging bandwidth refers to a bandwidth other than the bandwidth used for instant messaging during the communication cycle. That is, in the non-immediate messaging management department, the available non-immediate communication bandwidth for each communication cycle can be shown in the non-immediate communication bandwidth table shown in FIG. 4 Manage and allocate non-immediate messaging bandwidth to slave devices.

Here, the "management of non-immediate messaging bandwidth" performed by the non-immediate messaging management unit 123 will be described using FIG. 5.

The non-immediate messaging management unit 123 determines whether the receiving frame received from the slave device 200 is a non-immediate messaging request (S301).

When the received message frame is a non-immediate messaging request (S301: YES), the non-immediate messaging management unit 123 retrieves the empty bandwidth in each communication cycle and allocates the empty bandwidth to the non-immediate messaging requester (S302).

For example, in each communication cycle, a communication bandwidth for non-immediate messaging that has not been used for instant messaging and has not been allocated to the slave device 200 so far is allocated to the non-immediate messaging request slave device.

The non-immediate messaging management unit 123 uses the allocated bandwidth information and the assigned ID as non-immediate messaging permission information, and notifies the communication frame generating unit 124 (S303). The non-immediate messaging permission information may be a communication cycle number in FIG. 4. In addition, it may be the number of elapsed cycles since the cycle in which time information and non-immediate messaging permission information were transmitted to the slave device.

If the received receiving frame is not a non-immediate messaging request (S301: NO), the non-instant messaging management unit 123 repeatedly receives the receiving frame (S301).

The communication frame generating unit 124 generates a communication frame when the received data is transferred from the instant messaging control unit 121 or the non-immediate messaging control unit 122, and transfers the communication frame to the network interface 110.

In addition, when a communication frame is generated, if there is a notification of non-immediate messaging permission information from the non-immediate communication management section 123, the frame header or non- Instant messaging box Store non-instant messaging permission information.

The receiving control unit 130 stores the data transferred from the network interface 110 in the memory 2 or the storage device 3.

The communication cycle control unit 140 manages communication cycle information uniquely set in the communication system 500. The communication cycle information may be information on a master device's transmission time (communication bandwidth) set on the basis of an absolute time, or point-in-time information that starts transmitting real-time data. The communication cycle information is notified to the messaging control unit 120.

The communication cycle information is a value set by the user, which is a value loaded into memory after being programmed.

A functional configuration diagram of the slave device 200 in this embodiment is shown in FIG. 6.

The slave device 200 includes a network interface section 210, a messaging control section 220, a reception control section 230, and a communication cycle control section 240.

In addition, the slave device 200 and the master device 100 in the present embodiment have the same status, and can also be used as a bridge device connected across a plurality of networks. Therefore, the slave device 200 shown in FIG. 6 will be described in terms of a network interface portion 210a and a network interface portion 210b. However, the network interface portion 210 may be one or more than two.

The network interface 210 is connected to the network and receives and transmits communication frames to other nodes.

The network interface unit 210 transmits a communication frame forwarded by the messaging control unit 220 to the destination. In addition, the network interface 210 receives a communication frame from the network and analyzes data of the receiving frame.

After the data of the receiving frame is parsed, if the slave device is the frame that should be received, the network interface 210 transmits the receiving data to the receiving control unit 230.

In addition, after the data of the receiving frame is parsed, if it is a non-real-time messaging request for information notification or the receiving frame relays the data transmitted from another network interface (the frame sent to other devices, or multiple points) Send or broadcast frame), and forward the receive frame to another network interface.

The messaging control unit 220 is composed of an instant messaging control unit (first messaging control unit) 221, a non-instant messaging control unit (second messaging control unit) 222, and a communication frame generation unit 223.

The reception control unit 230 is the same as the reception control unit 130 of the main device 100 described in FIG. 3.

The instant messaging control unit 221 is the same as the instant messaging control unit 121 of the host device.

The processing flow of the non-immediate messaging control unit 222 is shown in FIG. 7.

The non-immediate messaging control unit 222 determines whether there is a non-immediate messaging request in the slave device 200 (S501). For example, non-instant messaging requests notification from the CPU.

If there is a non-immediate messaging request (S501: YES), the non-immediate messaging control section 222 notifies the communication frame generating section 223 of the messaging request information (S502).

The messaging request information may be the number of frames to be transmitted, priority information of the frame, and the like.

The non-immediate messaging control unit 222 notifies the communication frame generating unit 223 of the messaging request information, and then receives a receiving frame from the network interface 210 (S503).

If the non-immediate communication permission information is obtained from the network interface 210 (S503: YES), the non-immediate communication control unit 222 will not immediately The time data is transferred to the communication frame generating section 223.

The processing flow of the communication frame generating unit 223 is shown in FIG. 8.

If the communication frame generating unit 223 has the transfer data of the instant messaging control unit 221 or the non-immediate messaging control unit 222, it will be activated.

If the received data is transferred from the non-immediate messaging control section 222 (S602: non-real-time), the communication frame generating section 223 generates a non-immediate communication frame (S603) and transfers it to the network interface 210 (S604 ). FIG. 9 shows an example of the structure of a non-IM frame.

If the non-immediate communication frame is an Ethernet (registered trademark), etc., the instant communication frame will be identified by the Ethernet type. The identification area of real-time data and non-real-time data can be set in the Ethernet PDU for identification.

If the received data is transfer data from the instant messaging control section 221 (S602: real-time), the communication frame generating section 223 generates a real-time data frame (S605).

Next, the communication frame generating unit 223 determines whether the transferred data contains non-real-time messaging request information (S606).

If the transferred data contains non-immediate messaging request information (S606: YES), the communication frame generating unit 223 stores the non-immediate messaging request information in the header information of the instant messaging frame to be generated (S607).

If the forwarded data does not contain non-immediate messaging request information (S606: NO), the communication frame generating unit 223 stores the header information of the generated instant messaging frame without the content of non-immediate messaging request (S608).

The communication frame generation unit 223 forwards the generated instant communication frame to the network interface 210 (S609).

The communication cycle control unit 240 is the same as the communication cycle control unit 140 of the host device 100.

Next, the communication flow will be described using FIG. 10 and FIG. 11. In Figs. 10 and 11, as in Fig. 1, an example having a master device 100, a slave device 200a, a slave device 200b, and a slave device 200c will be described.

The master device 100 performs instant communication (down communication) to each slave device at a predetermined cycle, and each slave device performs instant communication to the master device 100 for upward communication.

The communication cycle is set by the user. For example, if the communication period is set to 1 ms, 700 μs is used as the bandwidth of the instant communication, and the remaining 300 μs is used as the bandwidth available for non-immediate communication. These times can be calculated from the amount of IM data in the entire system.

Here, taking only the slave device 200b to perform non-real-time messaging as an example, description is made using FIG. 10.

For the instant messaging frame, the slave device 200b stores the non- instant messaging request information expressing the desire to transmit 1500 bytes of non- instant messaging data in the header of the instant messaging frame (701).

The master device 100 that has received the instant messaging frame storing the non-immediate messaging request data allocates the communication cycle shown in FIG. 4 and the bandwidth from the bandwidth permission transmission that can be used for non- instant messaging to the slave device 200b. Here, the bandwidth of the communication cycle number 12 is allocated to the slave device 200b.

The allocated bandwidth is stored as non-instant messaging permission information in the header information of the instant messaging frame and transmitted to the slave device 200b (702).

For example, if the allocated bandwidth allows transmission after one cycle, Real-time messaging permission information can store the communication cycle (communication cycle number 12 bandwidth has been allocated since the communication cycle (communication cycle number 11) from which the communication permission notification was sent, so the communication cycle is 1) (in the figure, After 1 cycle as a messaging permission).

The slave device 200b that has received the non-immediate messaging permission information transmitted from the master device 100 performs non-immediate messaging after one cycle of the communication cycle of receiving the non-immediate messaging permission information (703).

Next, a case where a plurality of slave devices 200 transmit non-immediate messaging requests in the same cycle will be described using FIG. 11.

FIG. 11 illustrates a case where the slave devices 200a, 200b, and 200c transmit non-immediate messaging requests to the master device 100 at the same time (801, 802, 803). The slave devices 200a, 200b, and 200c each require the transmission of 1500 bytes of non-IM data.

When the master device 100 receives the non-immediate messaging request from the slave devices 200a, 200b, 200c, it refers to the non-immediate communication bandwidth table and allocates the bandwidth from the non-immediate communication bandwidth available in each communication cycle to the slave device.

When the non-immediate communication bandwidth table is in the state shown in FIG. 4, the master device 100 transmits to the slave device 200a and the slave device 200b one cycle after the cycle of transmitting the communication permission notification (communication cycle number 13). The notification of non-immediate communication is permitted, and the slave device 200c transmits a notification of permission of non-immediate communication after 2 cycles.

The slave device 200a, the slave device 200b, and the slave device 200c receive the permission information. The slave device 200a and the slave device 200b perform the required non-immediate communication in the next communication cycle (821,822) when the notification of permission is received. The slave device 200c performs desired non-immediate communication after two cycles (823).

In addition, when the master device 100 receives the non-immediate communication request from the slave device 200 and considers the empty bandwidth, the master device 100 may give priority to the order of receiving the messaging request notification, and may also notify the slave device of the communication time point.

In addition, the communication request information sets in advance the priority indicating which slave device is to be processed in priority. The master device 100 can compare the priority sent from each slave device with reference, thereby allowing the slave device with higher priority to allow earlier time. Messaging.

As described above, according to this embodiment, when the master device 100 receives a non-immediate messaging request from the slave device 200, the bandwidth is allocated to the slave device 200 from the available instant messaging bandwidth in each managed communication cycle. The communication permission notification is transmitted. By having such a structure, it does not need a buffer memory with a large capacity for storing data, and it will not interfere with instant communication due to non-immediate communication, which can ensure the bandwidth of non-immediate communication, and Efficient implementation of non-IM.

100‧‧‧ main device

200a‧‧‧ slave devicea

200b‧‧‧ slave device b

200c‧‧‧ Slave c

500‧‧‧communication system

Claims (3)

A communication system includes a first communication device and a plurality of second communication devices, which are characterized in that the second communication device includes: a first messaging control section that transmits first data communication that requires immediacy; and a second messaging control section As a part of the first data communication, transmitting the second data communication request that does not require immediacy to the first communication device, and transmitting the second data according to the information of the bandwidth received from the first communication device Communication; the first communication device includes: a messaging management unit that manages the communication bandwidth for the second data communication, and after receiving the request for the second data communication, transmits the information of the empty bandwidth of the communication bandwidth to the transmission The second communication device requested by the above-mentioned second data communication. For example, the communication system of the first scope of the patent application, wherein the request for the second data communication has priority information, and the above-mentioned messaging management section receives the request for the second data communication from a plurality of second communication devices in the same communication cycle. The second communication device that has transmitted the request for the second data communication with high priority as a priority, transmits the information of the empty bandwidth. A communication method for a communication system including a first communication device and a plurality of second communication devices, characterized in that the communication steps in the second communication device include: a first messaging control step for transmitting first data requiring immediateness Communications; and The second messaging control step includes a messaging request that does not require instantaneous second data communication as part of the first data communication, and transmits it to the first communication device. According to the bandwidth received from the first communication device, Information transmission second data communication; the communication step in the first communication device includes: a messaging management step to manage the communication bandwidth for the second data communication, and after receiving the request for the second data communication, the communication bandwidth is adjusted The information of the empty bandwidth is transmitted to the second communication device transmitting the request for the second data communication.