JP2010157912A - Cyclic communication system, communication device and cyclic communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a cyclic communication system capable of reducing consumption of network bands, thereby reducing throughput requests. <P>SOLUTION: In the cyclic communication system where each of terminals 1-1 to 1-5 transmits data about an area of a self-terminal of a holding cyclic memory to other terminals as cyclic data, and a terminal which receives the cyclic data updates the cyclic memory based on the received data, each of the terminals 1-1 to 1-5 transmits the cyclic data including an identifier for identifying the content of the data about the area of the self-terminal at predetermined time intervals, the terminal which receives the cyclic data returns a delivery confirmation response including the identifier included in the data, the terminal which receives the delivery confirmation response stops transmission of the cyclic data of the identifier included in the response and restarts transmission of the cyclic data when the data about the area of the self-terminal is updated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cyclic communication system, a communication apparatus, and a cyclic communication method that perform cyclic communication using a cyclic memory on a ring network.

  Cyclic communication is widely applied to control communication. In conventional cyclic communication, a plurality of terminals connected on the ring network each have a cyclic memory for cyclic communication, and an area that can be updated between each terminal is determined in the cyclic memory. ing. The terminal periodically transmits information on the area allocated to the terminal of the cyclic memory to other terminals. In the terminal that has received the data, the received data is written in the area of the terminal that is the transmission source of the data in the cyclic memory (see, for example, Patent Document 1 and Patent Document 2 below).

  By performing such processing by all the terminals connected to the ring network, the identity of the contents of the cyclic memories of all the terminals is guaranteed. In general, the update frequency of the contents of the cyclic memory is low. However, in the case of communication for control of an industrial plant or the like, the update is reflected in the cyclic memories of all terminals within several ms to several tens of ms from the timing when the data is updated. There is a need. In addition, inconsistencies in cyclic memory caused by the delay in reflecting data updates may lead to accidents in industrial plants, etc., and in systems such as industrial plants, it is necessary to reliably reflect the contents of cyclic memory updates. It is said.

  For this reason, in conventional cyclic communication, a terminal periodically transmits data in its own cyclic memory even when the contents of its own cyclic memory are not updated.

JP-A-6-274463 JP-A-9-270798

  However, according to the above conventional technique, when it is necessary to change the update contents in the cyclic memory of each terminal within several ms to several tens of ms from the update of the data in the cyclic memory, the cyclic memory is based on this request. It is necessary to increase the frequency of regular transmission of data. For this reason, even though the frequency of the actual cyclic memory data update is low, the data is frequently transmitted, and the ring is formed by the same data that has not been updated. There was a problem that the network bandwidth was wasted.

  For example, assuming that the cyclic memory capacity is 1 MB and the notification guarantee time (the time from the update of the data contents until each terminal is reflected) is 10 ms, the bandwidth of 800 Mb / s is obtained even if the protocol overhead and the memory division loss are excluded. Necessary. If the average content of the cyclic memory is updated once every 10 minutes on average, the probability that the content of the cyclic memory is actually updated is 1/60000, and most of the data is accompanied by the update. There will be no unnecessary data.

  Further, the terminal on the reception side of the conventional cyclic communication needs to access the cyclic memory in order to reflect the cyclic memory without receiving all the data coming from the ring network. For this reason, the terminal needs a high-performance CPU (Central Processing Unit) or dedicated hardware that supports the transmission rate of the ring network so that it can perform rapid processing, including data that is not actually needed, and can process There was a problem that most of the capacity was wasted for unnecessary data.

  The present invention has been made in view of the above, and can reduce a network bandwidth consumption and a processing capacity required for a communication apparatus, a cyclic communication system, a communication apparatus, and a cyclic The purpose is to obtain a communication method.

  In order to solve the above-described problems and achieve the object, the present invention comprises a plurality of terminals connected to a network, and the terminals have a cyclic memory for storing information shared between the terminals. In addition, it transmits its own terminal memory data, which is data stored in an area allocated to its own terminal in the cyclic memory, to other terminals as cyclic communication data, while receiving cyclic communication data. The terminal is a cyclic communication system that updates data in an area allocated to a transmission source terminal in its cyclic memory based on the cyclic communication data, and the terminal has the content of its own terminal memory data Data pattern identifiers are generated so that they have the same value when they are the same and different values when the contents are different. The cyclic communication data including the data pattern identifier is transmitted at a predetermined time interval, and the terminal receiving the cyclic communication data returns a delivery confirmation response including the data pattern identifier included in the data and receives the delivery confirmation response. The terminal has stopped transmitting the cyclic communication data including the data pattern identifier included in the delivery confirmation response, and resumes the transmission of the cyclic communication data when the contents of the own terminal memory data are updated. Features.

  According to the present invention, when transmitting cyclic communication data, the transmission source terminal has the same value when there is no change in its own terminal memory data, and the data pattern ID whose value is changed when there is a change. When the terminal receiving the data receives the data including the cyclic communication data, the terminal transmits a delivery confirmation message including the data pattern ID of the data to the transmission source terminal and receives the delivery confirmation message. Since the terminal stops transmission of cyclic communication data corresponding to the same data pattern ID, it is possible to reduce network bandwidth consumption and processing capacity required for the communication device. , Has the effect.

  Hereinafter, embodiments of a cyclic communication system, a communication apparatus, and a cyclic communication method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a cyclic communication system according to the present invention. As shown in FIG. 1, the cyclic communication system according to the present embodiment includes terminals 1-1 to 1-5, and each terminal is connected to a control network 2 that is a ring network. In the present embodiment, terminals 1-1 to 1-5 will be described as examples of communication apparatuses according to the present invention. Although FIG. 1 shows a case where there are five terminals, the number of terminals constituting the cyclic communication system of the present embodiment is not limited to this, and any number may be used.

  The terminals 1-1 to 1-5 include an application processing unit 11, a cyclic communication processing unit 12, and a general-purpose communication processing unit 13. In FIG. 1, only the terminal 1-1 shows the internal configuration, but the terminals 1-2 to 1-5 have the same configuration as the terminal 1-1. The cyclic communication processing unit 12 includes a cyclic memory 14 inside. The content of the cyclic memory 14 is required to be identical between all terminals connected to the control network 2.

  The general-purpose communication processing unit 13 performs general-purpose protocol processing such as IP (Internet Protocol), Ethernet (registered trademark), and ATM (Asynchronous Transfer Mode). In the same way as a general-purpose communication processing unit performs, the general-purpose communication processing unit 13 of the present embodiment mainly performs processing below the IP layer. The cyclic communication processing unit 12 performs processing related to cyclic communication, and performs operations such as writing to the cyclic memory 14 holding data shared by cyclic communication. In addition, the application processing unit 11 refers to the contents of the cyclic memory 14 and performs the operation of the application.

  FIG. 2 is a diagram showing a configuration of the cyclic memory 14 and a method for transmitting data stored in the cyclic memory 14. As shown in FIG. 2, similarly to a general cyclic memory, the cyclic memory 14 is allocated with an area for each terminal constituting the cyclic communication system. Here, the identifiers of the terminals 1-1, 1-2,..., 1-5 are shown as # 1, # 2,... #N (N = 5 in this case), respectively.

  The terminal constituting the cyclic communication system of the present embodiment reads the data in the area allocated to itself of the cyclic memory 14 provided in the terminal, and re-clicks the read data at a predetermined time interval by re-click communication. 2 to notify other terminals. For example, when the terminal #i (i = 1 to N) transmits data in its own cyclic memory 14, the data stored in the terminal #i area of the cyclic memory 14 is read and the data is stored in the data. Add location information on the click memory. The position information on the cyclic memory is a value (cyclic memory address) indicating an address on the cyclic memory such as an address offset on the cyclic memory of the read data (data stored in the terminal #i area). is there. As in the example of FIG. 4, the memory size (transmission memory size) of the read data may be inserted after the position information on the cyclic memory.

  Then, the information with the address added is used as cyclic communication data, and a header of a general-purpose communication protocol (Ethernet (registered trademark), IP, etc.) is added to the cyclic communication data for transmission.

  FIG. 3 is a chart showing an example of data transmission by the cyclic communication method of the present embodiment. First, the terminal of the cyclic communication data transmission source (any one of the terminals 1-1 to 1-5) is the data of the area allocated to itself from the cyclic memory 14 (hereinafter referred to as own terminal memory data). And data in a data format for transmission by adding position information on the cyclic memory, a header, and the like to the data.

  FIG. 4 is a diagram illustrating an example of a data format of transmission data according to the present embodiment for transmitting cyclic communication data. As shown in FIG. 4, this transmission data is cyclic data composed of data on the cyclic memory (own terminal memory data), position information of the data on the cyclic memory, and a memory size (transmission memory size). To the click communication data, a general-purpose communication protocol header and an ID (Identifier) indicating a data pattern (pattern of contents of the own terminal memory data) are added. This data pattern uniquely corresponds to the content of the own terminal memory data. The ID of the data pattern is the same if the own terminal memory data is the same, and this ID is also the same if the own terminal memory data is changed. It will be changed. The cyclic communication data and the data pattern ID are generated by the cyclic communication processing unit 12, and the general-purpose communication protocol header is added by the general-purpose communication processing unit 13.

  Returning to the description of FIG. 3, the transmission source transmits transmission data having the data format shown in FIG. 4, the cyclic memory address A1, and the data pattern ID X1 (step S11). In the terminal of the receiving destination (all terminals constituting the cyclic communication system), when the transmission data transmitted in step S11 is received, after the general-purpose communication processing unit 13 performs a predetermined process, the cyclic communication processing unit 12 Then, a delivery confirmation message for the received data (including the data pattern ID of the received transmission data) is generated and transmitted to the transmission source terminal via the general-purpose communication processing unit 13 (step S12). Then, in the receiving terminal, after the cyclic communication processing unit 12 updates the corresponding area of its own cyclic memory 14 based on the received data, transmission data (ID of the data pattern received thereafter X1 ( For example, the transmission data transmitted in the following step S13) is not updated to the cyclic memory 14.

  On the other hand, the transmission source terminal that transmitted the transmission data in step S11 periodically transmits the same data as the transmission data transmitted in step S11 at a predetermined time interval when the content of the self-terminal memory data does not change (step S11). S13, S14). At this time, assuming that the delivery confirmation message transmitted in step S12 is received, the periodic transmission of transmission data in which the subsequent cyclic memory address is A1 and the data pattern ID is X1 is stopped. For example, if this delivery confirmation message is received between step S13 and step S14, the transmission in step S14 is not actually performed.

  The transmission source terminal periodically checks the contents of the cyclic memory 14 and resumes data transmission when the contents are updated. For example, the updated data pattern is set to X2, cyclic communication data including the updated self-terminal memory data is generated, and transmission data having the data pattern ID X2 is generated and transmitted (step S15).

  Thereafter, similarly, when the transmission destination data including the same cyclic memory address is received at the receiving terminal, when the data pattern ID is changed (for example, changed from X1 to X2), the delivery terminal confirms the delivery. A message is transmitted and its own cyclic memory 14 is updated based on the transmitted data. When transmission data including the same cyclic memory address is received, if the data pattern ID is the same as the data already received, the contents of the cyclic memory 14 are not updated.

  In addition, when the source terminal memory data is updated, the transmission source terminal updates the data pattern ID, periodically transmits the transmission data, and receives a delivery confirmation message corresponding to the data pattern Then, the transmission of the transmission data is stopped. Note that FIG. 3 shows an example in which a delivery confirmation message is received from one recipient terminal for the sake of simplicity, but generally there are a plurality of recipient terminals, so delivery is made from all recipient terminals. When a confirmation message is received, the transmission of the transmission data may be stopped.

  In the present embodiment, it is assumed that cyclic communication is performed on a physical ring network, but the same operation can be performed on any network shape other than this. For example, it can be performed in a form in which a logical network is configured in a ring shape by a VLAN (Virtual Local Area Network).

  Thus, in this embodiment, when transmitting cyclic communication data, the transmission source terminal has the same value when there is no change in its own terminal memory data, and the value is changed when there is a change. Added data pattern ID. Then, when receiving the data including the cyclic communication data, the terminal that has received the data transmits a delivery confirmation message including the data pattern I of the data to the transmission source terminal. In addition, the terminal that has received the delivery confirmation message stops transmission of cyclic communication data corresponding to the same data pattern ID. Therefore, it is possible to reduce the bandwidth consumption of the network and reduce the processing capability required for the terminal.

Embodiment 2. FIG.
FIG. 5 is a diagram showing a configuration example of the second embodiment of the cyclic communication system according to the present invention. The cyclic communication system according to the present embodiment includes a plurality of terminals including the terminals 1a-1 to 1a-3, and is connected to the ring network as in the first embodiment.

  The terminal 1a-1 of the present embodiment is the same as the terminal 1-1 of the first embodiment except that the cyclic communication processing unit 12 of the terminal 1-1 of the first embodiment is replaced with a cyclic communication processing unit 12a. To do. Terminals 1a-1 to 1a-3 have the same configuration (other terminals connected to the same ring network have the same configuration). The cyclic communication processing unit 12a includes a cyclic memory 14 as in the first embodiment. Components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In the present embodiment, as in the first embodiment, the data pattern ID, the protocol header, etc. are added to the cyclic communication data for transmission. The terminal that has received the cyclic data transmits a delivery confirmation message in the same manner as in the first embodiment. In this embodiment, the terminal confirms this delivery confirmation message. Hereinafter, the operation of the present embodiment will be described with specific examples.

  The identifiers of the terminals 1a-1, 1a-2, and 1a-3 are #i, #j, and #k, respectively. In the example of FIG. 5, terminal #i, terminal #j, and terminal #k transmit cyclic communication data, respectively, similarly to Embodiment 1, and transmit the delivery confirmation message.

  When the cyclic communication processing unit 12a receives the cyclic communication data and transmits the delivery confirmation message, the cyclic communication processing unit 12a transmits the transmission transmitted from the other terminal within a predetermined time from the start of the transmission process of the delivery confirmation message. When a delivery confirmation message having the same data pattern ID as the confirmation destination (the sender of the cyclic communication data subject to delivery confirmation) is received, the received delivery confirmation message and the delivery confirmation message transmitted by the terminal itself are displayed. Combined and sent as one delivery confirmation message to the source terminal.

  In the example of FIG. 5, it is assumed that the terminal #j receives a delivery confirmation message having the same data pattern ID and the same destination as the transmission destination terminal transmitted from the terminal #k within the predetermined time. In this case, terminal #j integrates the delivery confirmation message from terminal #j, which is its own terminal, and the delivery confirmation message from terminal #k, and transmits the integrated message to the transmission source terminal. If terminal #i receives the above-mentioned integrated message within the predetermined time, terminal #i integrates the delivery confirmation message from its own terminal #i and the received integrated message. Then, it is transmitted as one integrated message (integrated message of the delivery confirmation message of terminal #i, terminal #j, terminal #k) to the destination of the delivery confirmation message (terminal of cyclic communication data transmission source). Here, the integration is performed when the data pattern ID and the destination are the same, but the integration may be performed when only the destination is the same. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  As described above, in the present embodiment, when the cyclic communication processing unit 12a receives the cyclic communication data and transmits the delivery confirmation message, within a predetermined time after starting the delivery confirmation message transmission process. When receiving a delivery confirmation message having the same data pattern ID as the destination of the delivery confirmation sent by the own terminal from another terminal, the received delivery confirmation message is integrated with the delivery confirmation message sent by itself. I made it. Therefore, the overhead of the delivery confirmation message can be reduced, and the bandwidth utilization efficiency is improved as compared with the first embodiment.

Embodiment 3 FIG.
FIG. 6 is a diagram showing a data format of transmission data in the third embodiment of the cyclic communication system according to the present invention. The configuration of the cyclic communication system of the present embodiment and the configuration of the terminals constituting the cyclic communication system are the same as those of the first embodiment.

  In the present embodiment, as in the first embodiment, the data pattern ID, the protocol header, etc. are added to the cyclic communication data for transmission. The terminal that has received the cyclic communication data transmits a delivery confirmation message in the same manner as in the first embodiment. In this embodiment, the terminal confirms this delivery confirmation message with transmission data for transmitting the cyclic communication data. To be included and sent.

  As shown in FIG. 6, the data format of the transmission data of the present embodiment is added to the data format of the first embodiment as a delivery confirmation message area. The area of the delivery confirmation message includes the position information on the cyclic memory and the data pattern ID. When the terminal transmits a delivery confirmation message to another terminal, the terminal transmits the data in the data format of FIG. 6 together with the cyclic communication data used when transmitting the self-terminal memory data. Since this message is confirmed by the cyclic communication processing unit 12a of all terminals, it can also be confirmed by the source terminal. When transmitting the delivery confirmation message, if the own terminal memory data is not updated and it is not necessary to transmit the cyclic communication data, the delivery confirmation message is individually transmitted as in the first embodiment. You may do it. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  Thus, in this embodiment, the terminal transmits the delivery confirmation message together with the cyclic communication data. Therefore, it is not necessary to individually generate a delivery confirmation message, and overhead can be reduced as compared with the first embodiment.

Embodiment 4 FIG.
The cyclic communication system according to the fourth embodiment of the present invention will be described below. The configuration of the cyclic communication system of the present embodiment and the configuration of the terminals constituting the cyclic communication system are the same as those of the first embodiment.

  The data format for transmitting the cyclic communication data of the present embodiment is the same as that of the first embodiment, and the cyclic communication data including the data pattern ID is transmitted. In the present embodiment, the delivery confirmation method is different from that in the first, second or third embodiment. In this embodiment, the terminal transmits an unreceived message for requesting transmission of cyclic communication data to each terminal at regular intervals, and when the cyclic communication data is received, the terminal transmits the cyclic communication data. Transmission of unreceived messages to the original terminal is stopped for a predetermined stop period. Note that this stop period is sufficiently longer than a certain interval for transmitting unreceived messages. After the stop period, transmission of unreceived messages is resumed.

  In addition, the terminal does not periodically transmit the cyclic communication data, but when the own terminal memory data is updated and when an unreceived message is received, the terminal memory data is used as the cyclic communication data. Transmission is performed in the same data format as in the first embodiment. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  Here, the cyclic communication data is transmitted in the same data format as in the first embodiment. However, the cyclic communication data may be transmitted in the same format as in general cyclic communication without adding a data pattern ID. Good.

  As in the case of the delivery confirmation message in the second embodiment, when an unreceived message is transmitted, if an unreceived message of the same destination is received from another terminal within a predetermined time, integration is performed. An unreceived message may be transmitted.

  Thus, in this embodiment, when a terminal transmits unreceived messages to each terminal at regular intervals and receives cyclic communication data, the unreceived message to the terminal that is the source of the cyclic communication data Transmission is stopped, and each time an unreceived message is received from another terminal, the own terminal memory data is transmitted as cyclic communication data. Therefore, as in the first embodiment, it is possible to reduce the bandwidth consumption of the network and reduce the processing capability required for the terminal.

Embodiment 5 FIG.
The cyclic communication system according to the fifth embodiment of the present invention will be described below. The configuration of the cyclic communication system according to the present embodiment is the same as that of the first embodiment. However, the terminal configuring the cyclic communication system according to the present embodiment uses the cyclic communication processing unit 12 according to the first embodiment. A cyclic memory 14 is provided, and read / write control of the cyclic memory 14 is performed by read / write control means in a general-purpose terminal.

  In the present embodiment, the terminal periodically transmits the cyclic communication data with the data pattern ID, the protocol header, etc. added to the cyclic communication data, as in the first embodiment. Implemented by read / write control means. Then, the terminal that has received the cyclic communication data updates its own cyclic memory 14 with a general-purpose read / write control unit based on the cyclic communication data. Then, the same general-purpose communication processing unit 13 as in the first embodiment refers to only the data pattern portion of the received data, and the same source as the cyclic communication data whose update has been reflected in its cyclic memory 14 While the ID of the data pattern included in the data transmitted from (the same cyclic memory address) is the same, the data is discarded, and when the data is changed, the data is passed to the general-purpose control means. The control means updates the cyclic memory 14 based on the data.

  In this case, the cyclic communication data transmission side periodically performs cyclic communication data and may not perform delivery confirmation, or may perform delivery confirmation by using a general-purpose communication processing unit. Similarly to the first mode, when the delivery confirmation is confirmed, the transmission of the same cyclic communication data may be stopped.

  As described above, in the present embodiment, the terminal does not use a processing unit dedicated to cyclic communication, and the general-purpose control means for controlling the cyclic memory 14 uses the cyclic communication data having the same data pattern ID. Was to be discarded. Therefore, resources for cyclic communication can be reduced as compared with the first embodiment.

Embodiment 6 FIG.
FIG. 7 is a diagram showing a configuration example of a sixth embodiment of a terminal constituting the cyclic communication system according to the present invention. The configuration of the cyclic communication system of the present embodiment is the same as that of the first embodiment except that the terminals 1-1 to 1-5 of the first embodiment are respectively replaced with the terminals of the present embodiment. The terminal 1b of the present embodiment is implemented except that the cyclic communication processing unit 12 and the general-purpose communication processing unit 13 of the terminal 1-1 of the first embodiment are replaced with the cyclic communication processing unit 12b and the general-purpose communication processing unit 13a, respectively. It is the same as that of the terminal 1-1 of the form 1. The general-purpose communication processing unit 13a performs an Ethernet OAM (Operation And Maintenance) process when the transmission path is Ethernet (registered trademark), and performs an ATM OAM process when the transmission path is ATM. It has. In addition, the cyclic communication processing unit 12b includes a cyclic memory 14 as in the first embodiment.

  In the present embodiment, the delivery confirmation performed in the first embodiment is performed using a general-purpose communication framework. In the first embodiment, the cyclic communication processing unit 12 transmits a delivery confirmation message. However, in the present embodiment, the general-purpose communication processing unit 13 confirms the delivery using a general-purpose communication framework. In OAM, functions related to maintenance management are standardized (ITU-T Y.1731, etc.), but for other functions, a Vendor Specific area is provided and functions can be freely defined using this area. .

  8A and 8B are diagrams illustrating a delivery confirmation method for cyclic communication when using Ethernet OAM. FIG. 8A illustrates transmission processing, and FIG. 8B illustrates reception processing. As shown in FIG. 8A, when transmitting the cyclic communication data, the Ethernet (registered trademark) OAM frame 21 is transmitted before the transmission of the cyclic communication packets 31, 32, 33 for transmitting the cyclic communication data. To do. The Ethernet (registered trademark) OAM frame 21 includes a cyclic memory address of cyclic communication data to be transmitted in the subsequent cyclic communication packets 31, 32, and 33 and a data pattern ID for identifying data contents. It is.

  For example, in the example of FIG. 8A, the Ethernet (registered trademark) OAM frame 21 includes the cyclic memory address A1 and the data pattern ID X1 of the subsequent cyclic communication packets 31, 32, and 33. Yes. When the data pattern ID of the cyclic communication packet to be transmitted is changed to X2, the Ethernet (registered trademark) OAM frame 22 having the cyclic memory address A1 and the data pattern ID X2 is transmitted. After transmitting the Ethernet (registered trademark) OAM frame 22, a cyclic communication packet having a cyclic memory address A1 and a data pattern ID X2 is transmitted.

  On the other hand, as shown in FIG. 8B, in the terminal on the cyclic communication data receiving side, the Ethernet OAM processing unit 15 receives the cyclic memory address and data pattern ID of the received Ethernet (registered trademark) OAM frame 21, and When the cyclic memory address and the data pattern ID of the subsequent cyclic communication packet 31 match, it is determined that the reception of the cyclic communication data of the cyclic memory address and the data pattern ID is completed, and Ethernet (registered trademark) An OAM frame 23 similar to the OAM frame 21 is returned to the transmission source terminal (the OAM frame 21 is returned).

  When the terminal that has transmitted the Ethernet (registered trademark) OAM frame 21 receives the returned Ethernet (registered trademark) OAM frame 21, the terminal determines that the cyclic memory address and the data pattern ID have been delivered, The transmission of the cyclic communication packet with the data pattern ID is stopped. When the own terminal memory data is updated, a cyclic communication packet including the updated data is transmitted after transmitting the Ethernet (registered trademark) OAM frame including the data pattern ID corresponding to the updated data. . The operation of the cyclic communication processing unit 12b of the present embodiment is the same as that of the cyclic communication processing unit 12 of the first embodiment, except that the above-described operation related to delivery confirmation is not performed. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

  As described above, in the present embodiment, as in the first embodiment, the data pattern ID is transmitted when the cyclic communication data is transmitted, and the data pattern ID of which the delivery confirmation indicating that the receiving terminal has received can be performed. The transmission of cyclic communication data was stopped. And this delivery confirmation is performed using the framework of general-purpose communication. Therefore, the configuration of the dedicated processing unit can be simplified as compared with the first embodiment.

  As described above, the cyclic communication system, the communication apparatus, and the cyclic communication method according to the present invention are useful for a system that performs cyclic communication using a cyclic memory on a ring network. It is suitable for a system with a limited time from update to reflection.

It is a figure which shows the structural example of Embodiment 1 of the cyclic communication system concerning this invention. It is a figure which shows the structure of a cyclic memory, and the transmission method of stored data. 6 is a chart diagram illustrating an example of data transmission by the cyclic communication method according to Embodiment 1. FIG. 6 is a diagram illustrating an example of a data format for transmitting cyclic communication data according to Embodiment 1. FIG. 6 is a diagram illustrating a configuration example of a cyclic communication system according to a second embodiment. FIG. 10 is a diagram illustrating a data format of transmission data of the cyclic communication system according to the third embodiment. FIG. FIG. 10 is a diagram illustrating a configuration example of a terminal configuring the cyclic communication system according to the sixth embodiment. It is a figure which shows the delivery confirmation system of cyclic communication at the time of using Ether OAM. It is a figure which shows the delivery confirmation system of cyclic communication at the time of using Ether OAM.

Explanation of symbols

1-1 to 1-5, 1a-1 to 1a-3, 1b Terminal 2 Control network 11 Application processing unit 12, 12a, 12b Cyclic communication processing unit 13, 13a General-purpose communication processing unit 14 Cyclic memory 15 OAM processing unit 21, 22 Ethernet (registered trademark) OAM frame 31-33 Cyclic communication packet

Claims (13)

Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. A cyclic communication system for updating data in an area allocated to an original terminal,
The terminal generates a data pattern identifier such that the contents of the own terminal memory data are the same when the contents are the same, and different values when the contents are different, and cyclic communication data including the data pattern identifier is generated. Send at predetermined time intervals,
The terminal that has received the cyclic communication data returns a delivery confirmation response including the data pattern identifier included in the data,
The terminal that has received the delivery confirmation response stops the transmission of cyclic communication data including the data pattern identifier included in the delivery confirmation response, and transmits the cyclic communication data when the content of the own terminal memory data is updated. A cyclic communication system characterized by restarting the communication.   The terminal that has received the cyclic communication data waits for a predetermined waiting time before returning a delivery confirmation response, and receives a delivery confirmation response of the same destination as the delivery confirmation response from another terminal during the waiting time. 2. The cyclic communication system according to claim 1, wherein, when received, the received delivery confirmation response and the delivery confirmation response returned by itself are integrated, and the integrated delivery confirmation response is returned.   3. The cyclic communication system according to claim 1, wherein the terminal that has received the cyclic communication data transmits the cyclic communication data for transmitting its own terminal memory data including the delivery response confirmation. .   The terminal that has received the cyclic communication data, after updating the data in the area allocated to the terminal of the transmission source, the cyclic communication data and the transmission source are the same, and the same as the cyclic communication data The cyclic communication data according to claim 1, 2 or 3, wherein when the cyclic communication data including the data pattern identifier is newly received, the update based on the newly received cyclic communication data is not performed. Communications system.   The terminal that has received the cyclic communication data, after updating the data in the area allocated to the terminal of the transmission source, the cyclic communication data and the transmission source are the same, and the same as the cyclic communication data 4. The cyclic communication system according to claim 1, 2 or 3, wherein when the cyclic communication data including the data pattern identifier is newly received, the newly received cyclic communication data is discarded.   The cyclic communication system according to claim 1, wherein a general-purpose memory control unit that controls the cyclic memory executes the process according to claim 1. When the terminal data is updated, the terminal inserts a data pattern identifier corresponding to the updated terminal memory data before transmitting the cyclic communication data corresponding to the updated terminal memory data. Send general-purpose OAM frames,
The terminal that has received the cyclic communication data, when the data pattern identifier included in the cyclic communication data is the same as the data pattern identifier included in the latest OAM frame received from the same transmission source, The cyclic communication system according to claim 1, wherein the OAM frame is returned as a response and returned to the transmission source. Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. A cyclic communication system for updating data in an area allocated to an original terminal,
The terminal
A data transmission request for requesting transmission of cyclic communication data to another terminal is transmitted at a predetermined time interval. When cyclic communication data is received, data transmission to the transmission source of the cyclic communication data is performed. Stop transmission of the request, resume transmission of the data transmission request after a certain period of time longer than the time interval has elapsed since the start of the stop,
A cyclic communication system which transmits cyclic communication data when the content of its own terminal memory data is updated or when the data transmission request is received.   The cyclic communication system according to claim 1, wherein the network is a logical network. Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. In a cyclic communication system that updates data in an area allocated to an original terminal, a communication device that operates as the terminal,
A data pattern identifier is generated that has the same value when the content of its own terminal memory data is the same, and a different value when the content is different, and cyclic communication data including the data pattern identifier is transmitted at a predetermined time interval. When a cyclic communication data is received, a delivery confirmation response including the data pattern identifier included in the data is returned, and when a delivery confirmation response is received, it is included in the delivery confirmation response. Cyclic communication processing means for stopping transmission of cyclic communication data including the data pattern identifier to be transmitted and restarting transmission of cyclic communication data when the content of the self-terminal memory data is updated,
A communication apparatus comprising: Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. In a cyclic communication system that updates data in an area allocated to an original terminal, a communication device that operates as the terminal,
When a data transmission request for requesting transmission of cyclic communication data to another terminal is transmitted at a predetermined time interval and cyclic communication data is received, a data transmission request to the transmission source of the cyclic communication data is transmitted. Stop transmission, perform data transmission request transmission processing to resume transmission of a data transmission request after a certain period longer than the time interval from the start of the stop, and when the content of its own terminal memory data is updated or Cyclic communication processing means for transmitting cyclic communication data when a data transmission request is received;
A communication apparatus comprising: Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. A cyclic communication method in a cyclic communication system for updating data in an area allocated to an original terminal,
The terminal generates a data pattern identifier that has the same value when the contents of its own terminal memory data are the same, and a different value when the contents are different, and generates cyclic communication data including the data pattern identifier. A cyclic communication data transmission step for transmitting at a predetermined time interval;
A delivery confirmation response step in which the terminal receiving the cyclic communication data returns a delivery confirmation response including the data pattern identifier included in the data;
When the terminal that has received the delivery confirmation response stops sending cyclic communication data including the data pattern identifier included in the delivery confirmation response, and the content of the own terminal memory data is updated, the cyclic communication data is transmitted. A data transmission stop step for resuming
A cyclic communication method comprising: Consists of a plurality of terminals connected to the network, the terminal has a cyclic memory for storing information shared between the terminals, and stored in an area allocated to the own terminal in the cyclic memory The terminal memory data that is the data being transmitted is transmitted as cyclic communication data to other terminals, while the terminal that has received the cyclic communication data transmits in its cyclic memory based on the cyclic communication data. A cyclic communication method in a cyclic communication system for updating data in an area allocated to an original terminal,
A data transmission request step in which the terminal transmits a data transmission request for requesting transmission of cyclic communication data to another terminal at a predetermined time interval;
When the terminal receives cyclic communication data, the terminal stops transmission of the data transmission request to the transmission source of the cyclic communication data, and after a certain period longer than the time interval has elapsed since the start of the stop, the data transmission request A data transmission request stop step for resuming transmission of
A cyclic communication data transmission step of transmitting cyclic communication data when the terminal updates the content of its own terminal memory data or when receiving the data transmission request;
A cyclic communication method comprising:

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