Communication system and converter device

Abstract

The present invention achieves high scalability and high communication efficiency in a communication system including a device for performing communication processing in a token passing communication method. In the communication system (1000), devices conforming to a first communication standard (TP standard) are connected one-to-one to converters, which perform protocol conversion of the first communication standard (TP standard) and a second communication standard (for example, Nessum standard), over a first network that is a network based on the first communication standard (TP standard). In addition, the converters are connected to a second network that is a network based on the second communication standard. Thus, high scalability and high communication efficiency can be achieved.

Description

Communication system and converter device

[0001] The present invention relates to data communication technology. In particular, it relates to a technology for achieving high scalability and high communication efficiency in a communication system including a device that performs communication processing based on a token passing method.

[0002] As an international standard for communication protocol specifications for intelligent building networks, a standard called BACnet (Building Automation and Control Networking Protocol) has been established.

[0003] By complying with BACnet, even if various devices have manufacturer-specific specifications, all of them can be connected via a common interface. For example, by using the common interface of the BACnet protocol for building facilities such as air conditioning, lighting, access control, electric power, and fire detection, comprehensive and easy monitoring / control can be achieved.

[0004] In BACnet, there is the "BACnet MS / TP" protocol (MS: Master Slave, TP: Token Passing) that uses EIA-485 (RS-485) for the physical layer of data transmission. In a communication system compliant with the BACnet MS / TP protocol, MS (master-slave communication method) and TP (token passing communication method) are used in combination.

[0005] The master-slave communication method is a method in which a master device controls a slave device. In the token passing communication method, a token (control right) circulates on the same network, and the device that acquires the token becomes the master device to perform communication and control with other devices (slave devices). This enables communication without collision between communication messages from different devices.

[0006] In communication systems using token-passing communication methods such as BACnet, various technologies are employed to realize diverse applications while maintaining good communication efficiency. For example, Patent Document 1 discloses a communication system that realizes multiple different transmission cycles according to the application on a single transmission path.

[0007] In the communication system described in Patent Document 1, a token circuit is established for each transmission cycle, and a station managing the token circuit (referred to as the "token master") selects the circuit for each transmission cycle, thereby enabling multiple different transmission cycles depending on the application. As a result, a variety of applications can be realized in a communication system using the token passing communication method.

[0008] Japanese Patent Publication No. 2009-201013

[0009] However, with the conventional technology described above, each circuit must be constructed based on the token master, so as the number of circuits increases, the overall transmission efficiency of the communication system deteriorates. In other words, communication systems using the token passing communication method described above (conventional communication systems) have the problem that the time interval (communication cycle) for each station to obtain a token becomes long.

[0010] Furthermore, in communication systems compliant with the BACnet MS / TP protocol, which use token-passing and master-slave communication methods, the device holding the token has the right to speak. Therefore, replies can only be sent at the time of the request, which leads to longer response times and a decrease in the overall performance of the communication system.

[0011] Thus, it is difficult to achieve high scalability and high communication efficiency with conventional communication systems that conform to the BACnet MS / TP protocol.

[0012] Therefore, in view of the above problems, the present invention aims to realize a communication system and a converter device that can achieve high scalability and high communication efficiency in a communication system including a device that performs communication processing using a token passing communication method.

[0013] To solve the above problems, a representative example (one aspect) of the invention disclosed in this application is a communication system including a device connected to a first network for communication using a first communication standard employing a token passing communication method, and a device connected to a second network for communication using a second communication standard, comprising N converter devices (N: a natural number of 2 or more) from the first converter device to the Nth converter device, and N terminal devices from the first terminal device to the Nth terminal device.

[0014] The first to the Nth converter devices are connected to the first network and the second network, respectively.

[0015] The first to the nth terminal devices are each terminal devices for communication according to the first communication standard, and are connected one-to-one to the converter device via the first network.

[0016] Furthermore, the kth terminal device (k: a natural number, 1 ≤ k ≤ N) is connected one-to-one with the kth converter device via the first network.

[0017] The k-th converter device communicates with the k-th terminal device via the first network using the first communication standard, and communicates with other converter devices connected via the second network using the second communication standard.

[0018] According to the present invention, a communication system and a converter device can be realized that include a device for performing communication processing using a token-passing communication method, and that can achieve high scalability and high communication efficiency.

[0019] A schematic diagram of the communication system 1000 according to the first embodiment. A schematic diagram of the converter NC-k of the communication system 1000 according to the first embodiment. A communication sequence diagram of the process executed by the communication system 1000 of the first embodiment (when initial address resolution processing is performed). A communication sequence diagram of the process executed by the communication system 1000 of the first embodiment (when communication is performed after initial address resolution processing). A communication sequence diagram of the process executed by the communication system 1000 of the first embodiment (when address resolution has not been achieved). A schematic diagram of the communication system 1000A according to the first modified example of the first embodiment. A diagram showing the CPU bus configuration.

[0020] [First Embodiment] The first embodiment will be described below with reference to the drawings.

[0021] <1.1: Configuration of the Communication System> Figure 1 is a schematic diagram of the communication system 1000 according to the first embodiment.

[0022] Figure 2 is a schematic diagram of the converter NC-k of the communication system 1000 according to the first embodiment.

[0023] As shown in Figure 1, the communication system 1000 comprises (1) a monitoring device Dev1-0, a 1-1 device Dev1-1, ..., and a 1-N device Dev1-N (N: a natural number), which are devices having a communication function according to a first communication standard, and (2) converters NC-0 to NC-N (N+1 converters) which have a communication function according to a first communication standard and a communication function according to a second communication standard. The monitoring device Dev1-0 is connected one-to-one with converter NC-0 via a first network, which is a network that performs communication according to the first communication standard. The 1-1 devices Dev1-1, ..., and the 1-N devices Dev1-N are each connected one-to-one with converters NC-1 to NC-N via a first network, which is a network that performs communication according to the first communication standard. In other words, the first k device Dev1-k (k: natural number, 1 ≤ k ≤ N) is connected one-to-one with the converter NC-k via the first network, which is a network that communicates according to the first communication standard.

[0024] Furthermore, converters NC-0 to NC-N are connected to a second network, which is a network that uses the second communication standard, and can communicate with each other using the second communication standard.

[0025] The first communication standard is a communication standard that employs a token-passing communication method, such as ARCNET (Attached Resource Computer Network), Token Ring, and BACnet® MS / TP.

[0026] The second communication standard is the L (Layer) 2 protocol communication standard that supports retransmission control, such as Wi-Fi®, ZIGBEE®, and Nessum®.

[0027] In the communication system 1000, the communication bandwidth of the second network of the second communication standard is wider than the communication bandwidth of the first network of the first communication standard. However, the communication bandwidth of the second network of the second communication standard may be less than or equal to the communication bandwidth of the first network of the first communication standard.

[0028] For the sake of explanation, in the following, the first communication standard will be the MS / TP standard, the second communication standard will be the Nessum standard, which is one of the power line carrier communication standards, the network that performs communication using the first communication standard will be referred to as the first network NW1, and the network that performs communication using the second communication standard (power line carrier communication using the Nessum standard) will be referred to as the second network NW2.

[0029] Monitoring device Dev1-0 is a device with communication capabilities according to the first communication standard (MS / TP standard), and is connected to converter NC-0 on a one-to-one basis via the first network NW1 of the first communication standard (MS / TP standard). Monitoring device Dev1-0 communicates with devices compliant with the first communication standard (MS / TP standard) (for example, devices Dev1-1 to Dev1-N) via the first network NW1, converter NC-0, and second network NW2, thereby monitoring and controlling the above-mentioned devices.

[0030] The first-k device (k: a natural number, 1 ≤ k ≤ N) is a device having communication capabilities according to the first communication standard (MS / TP standard), and is connected one-to-one to converter NC-k via the first network NW1 of the first communication standard (MS / TP standard). The first-k device communicates with devices compliant with the first communication standard (MS / TP standard) (for example, monitoring device Dev1-0 or devices other than itself among the first-1 devices Dev1-1 to Dev1-N) via the first network NW1, converter NC-k, and second network NW2, thereby realizing predetermined applications or receiving monitoring and control from monitoring device Dev1-0.

[0031] Converter NC-k is a protocol conversion device. Converter NC-k is connected to the first network NW1 and the second network NW2, receives communication data of the first communication standard (MS / TP standard) from a device of the first communication standard, analyzes the received communication data of the first communication standard, and if, as a result of the analysis, determines that the received communication data should be transmitted to the second network NW2, converts the received communication data of the first communication standard to communication data of the second communication standard (Nessum standard), and transmits the converted communication data to a predetermined device (device of the second communication standard (Nessum standard)) (converter). Furthermore, converter NC-k receives communication data in the second communication standard (Nessum standard) from a device (converter) of the second communication standard, analyzes the received communication data in the second communication standard, and if, as a result of the analysis, determines that the received communication data should be transmitted to the first network NW1, converts the received communication data in the second communication standard to communication data in the first communication standard (MS / TP method standard), and transmits the converted communication data to a predetermined device (device of the first communication standard (MS / TP method standard)).

[0032] Furthermore, the converter NC-k generates communication data for the first communication standard (MS / TP standard) (communication data necessary for communication using the first communication standard (MS / TP standard)), and transmits the generated communication data to a device using the first communication standard (MS / TP standard) via the first network NW1.

[0033] Furthermore, converter NC-k generates communication data for the second communication standard (Nessum standard) (communication data necessary for performing communication using the second communication standard (Nessum standard)), and transmits the generated communication data to a device (another converter) that uses the second communication standard (Nessum) via the second network NW2.

[0034] The converter NC-k includes, for example, a first communication interface 11, a data communication processing unit 12, a storage unit 13, and a second communication interface 14, as shown in Figure 2.

[0035] The first communication interface 11 is connected to the first network NW1 and is a communication interface for communicating with a device conforming to the first communication standard (MS / TP standard) via the first network NW1. The first communication interface 11 outputs data received from a device conforming to the first communication standard (MS / TP standard) via the first network NW1 to the data communication processing unit 12 as data Drx_NW1. The first communication interface 11 also receives data Dtx_NW1 output from the data communication processing unit 12 and transmits the data Dtx_NW1 to a device conforming to the first communication standard (MS / TP standard) via the first network NW1.

[0036] The data communication processing unit 12 is a functional unit that performs protocol conversion processing, address table management processing, etc. The data communication processing unit 12 analyzes the data Drx_NW1 (communication data received from a device of the first communication standard (MS / TP standard)) output from the first communication interface 11, and if, as a result of the analysis, it determines that the data Drx_NW1 should be transmitted to the second network NW2, it performs protocol conversion processing on the data Drx_NW1 to obtain communication data of the second communication standard (Nessum standard), and outputs the obtained communication data as data Dtx_NW2 to the second communication interface 14.

[0037] Furthermore, the data communication processing unit 12 analyzes the data Drx_NW2 (communication data received from a device using the second communication standard (Nessum standard)) output from the second communication interface 14. If, as a result of the analysis, it determines that the data Drx_NW2 should be transmitted to the first network NW1, it performs a protocol conversion process on the data Drx_NW2 to obtain communication data of the first communication standard (MS / TP method standard), and outputs the obtained communication data as data Dtx_NW1 to the first communication interface 11.

[0038] Furthermore, the data communication processing unit 12 performs address table management processing based on the data Drx_NW1 output from the first communication interface 11 and / or the data Drx_NW2 output from the second communication interface 14, and the data (address table) stored in the storage unit. The data communication processing unit 12 stores the information of devices connected to the first network NW1 and devices connected to the second network NW2, obtained through the address table management processing, in the storage unit 13 (stores the address table in the storage unit 13). The data communication processing unit 12 also reads the address table data from the storage unit 13, and if there is data that should update the address table from the data Drx_NW1 output from the first communication interface 11 and / or the data Drx_NW2 output from the second communication interface 14, it performs an update process in the address table using that data, so that the updated address table is stored in the storage unit 13.

[0039] Furthermore, the data communication processing unit 12 generates communication data for the first communication standard (MS / TP standard) (communication data necessary to perform communication using the first communication standard (MS / TP standard)), and outputs the generated communication data as data Dtx_NW1 to the first communication interface 11.

[0040] Furthermore, the data communication processing unit 12 generates communication data conforming to the second communication standard (Nessum standard) (communication data necessary for performing communication conforming to the second communication standard (Nessum standard)), and outputs the generated communication data to the second communication interface 14 as data Dtx_NW2.

[0041] The storage unit 13 is a functional unit capable of storing and retaining data, and performs data write processing and / or data read processing in accordance with instructions from the data communication processing unit 12.

[0042] The second communication interface 14 is connected to the second network NW2, and is a communication interface for communicating with devices conforming to the second communication standard (Nessum standard) via the second network NW2. The second communication interface 14 outputs data received from a device conforming to the second communication standard (Nessum standard) via the second network NW2 to the data communication processing unit 12 as data Drx_NW2. Furthermore, the second communication interface 14 receives input of data Dtx_NW2 output from the data communication processing unit 12, and transmits the data Dtx_NW2 to a device conforming to the second communication standard (Nessum standard) via the second network NW2.

[0043] <1.2: Operation of Data Processing System> The operation of the communication system 1000 configured as described above will be described.

[0044] FIG. 3 is a communication sequence diagram of processing executed in the communication system 1000 according to the first embodiment (when an initial address resolution process is performed).

[0045] FIG. 4 is a communication sequence diagram of processing executed in the communication system 1000 according to the first embodiment (when communication is performed after an initial address resolution process).

[0046] FIG. 5 is a communication sequence diagram of processing executed in the communication system 1000 according to the first embodiment (when address resolution has not been completed).

[0047] Hereinafter, the operation of the communication system 1000 will be described with reference to the communication sequence diagrams.

[0048] For convenience of explanation, it is assumed that the addresses of the first communication standard (the MS / TP standard) (referred to as "MS / TP addresses") and the addresses of the second communication standard (the Nessum standard, which is a method compatible with the international standard IEEE 1901 series) (referred to as "Nessum addresses") of the monitoring device Dev1-0, the 1-1-th device Dev1-1 to the 1-N-th device Dev1-N, and the converters NC-0 to NC-N are set as follows. (1) Monitoring device Dev1-0: MS / TP address: A000 (for example, A000 is 8-bit data) Nessum address: None (2) 1-k-th device Dev1-k (k: natural number, 1≦k≦N): MS / TP address: A10k (for example, A10k is 8-bit data) Nessum address: None (3) Converter NC-k (k: natural number, 1≦k≦N): MS / TP address: A0k (for example, A0k is 8-bit data) Nessum address: B0k Hereinafter, the operation of the communication system 1000 will be described separately into (1) processing when performing initial address resolution, (2) processing when performing communication after initial address resolution, and (3) processing when address resolution has not been completed.

[0049] (1.2.1: Processing when executing initial address resolution processing) First, processing when executing initial address resolution processing will be described with reference to the communication sequence diagram of FIG. 3.

[0050] (Steps S11 to S14): In steps S11 to S14, the converter NC-0 performs processing to acquire the MS / TP address of a device (here, the monitoring device Dev1-0) connected to the first network NW1 to which the converter NC-0 is connected. Specifically, the following processing is executed.

[0051] For example, at startup, converter NC-0 performs an address scan on the first network NW1 (MS / TP network) to which converter NC-0 is connected. To this end, converter NC-0 generates communication data for address querying, targeting addresses in the MS / TP address space, using the data communication processing unit 12. The generated communication data is output as data Dtx_NW1 to the first communication interface 11, and the first communication interface 11 transmits the data Dtx_NW1 to the monitoring device Dev1-0. If the MS / TP address space is a space of 8-bit data (8-bit addresses), the converter NC-0 sequentially generates communication data for querying addresses for each of the addresses 0x00 to 0xff (the communication data for querying the address of address 0xYY is denoted as "Inq("0xYY")) (Who-is message) (for example, the address is incremented by +1 from 0x00 to generate communication data for querying addresses). Then, the converter NC-0 sequentially transmits the generated address query communication data (Inq("0x00") to Inq("0xff")) (Who-is messages "Who is "0x00") to "Who is "0xff")) to the monitoring device Dev1-0 (steps S11, S12, S13). Furthermore, if the MS / TP address "0xff" is assigned to, for example, the broadcast address, the communication data for address querying should be Inq("0x00") to Inq("0xfe").

[0052] Since the monitoring device Dev1-0's MS / TP address is A000 (for example, A000 = "0x10"), when it receives communication data Inq(A000) from converter NC-0, it generates response communication data Ans(A000) for communication data Inq(A000) to notify converter NC-0 that the device with MS / TP address A000 is monitoring device Dev1-0, and sends the generated response communication data Ans(A000) (I-am message "I am A000") to converter NC-0 (step S14).

[0053] Alternatively, instead of the above process (using the "who-is" message and the "I-am" message), you may perform the following process to obtain an MS / TP address (address resolution process).

[0054] Converter NC-0 sends both the "Pol for Master" command and the "Who-is" message within the first network NW1 to which it belongs (the "Pol for Master" command is sent at a predetermined timing as defined by the protocol, and the "Who-is" message is sent at any time that Converter NC-0 deems appropriate). (1) When a terminal belonging to the first network NW1 is a master node, it responds to both "Poll for Master" and "Who is", so the converter can recognize the terminal regardless of which is returned. Therefore, when a terminal belonging to the first network NW1 is a master node, and monitoring device Dev1-0 is also a master node, monitoring device Dev1-0 responds to both "Poll for Master" and "Who is", and converter NC-0 obtains the MS / TP address of monitoring device Dev1-0 from the data returned from monitoring device Dev1-0. (2) If a terminal belonging to the first network NW1 is a slave node, it does not respond to the "Poll For Master" command, but only to the "Who is" message, and the converter recognizes the terminal. Therefore, when monitoring device Dev1-0 is a slave node, monitoring device Dev1-0 responds to the "Who is" message, and converter NC-0 obtains the MS / TP address of monitoring device Dev1-0 from the data returned from monitoring device Dev1-0.

[0055] (Step S15): In step S15, the converter NC-0 receives the response communication data Ans(A000) (I-am message "I am A000") transmitted from the monitoring device Dev1-0. The first communication interface 11 of the converter NC-0 outputs the received communication data as data Drx_NW1 to the data communication processing unit 12.

[0056] The data communication processing unit 12 generates communication data for broadcast to the second network NW2, which includes data (I-am message "I am A000") indicating that a device with MS / TP address A000 exists on the first network NW1 to which converter NC-0 is connected, and outputs the generated communication data as data Dtx_NW2 to the second communication interface 14.

[0057] The second communication interface 14 broadcasts the communication data input from the data communication processing unit 12 to the second network NW2 as communication data Bcast_Ans(A000) (it is sent to all converters NC-k connected to the second network NW2).

[0058] Furthermore, the data communication processing unit 12 of converter NC-0 updates the address table data stored in the storage unit 13 with data indicating that the device with MS / TP address A000 is connected to the first network NW1 to which converter NC-0 is connected.

[0059] Converters NC-k other than converter NC-0 receive the communication data Bcast_Ans(A000) broadcast from converter NC-0 (Nessum address: B00), and update the address table data stored in the storage unit 13 with data indicating that the device with MS / TP address A000 is connected to the first network NW1 to which converter NC-0 is connected. For example, the Nessum address B00 of converter NC-0 and the MS / TP address A000 are associated and stored in the address table (the data in the address table (for example, address-corresponding data (A000, B00)) is stored in the storage unit 13).

[0060] (Steps S16 to S19): In steps S16 to S19, the converter NC-k (k: natural number, 1 ≤ k ≤ N) performs the process of obtaining the MS / TP address of the device (in this case, the first-k device Dev1-k) connected to the first network NW1 to which the converter NC-k is connected. Specifically, the following processes are performed.

[0061] For example, at startup, converter NC-k performs an address scan on the first network NW1 (MS / TP network) to which converter NC-k is connected. To this end, converter NC-k generates communication data for address queries targeting addresses in the MS / TP address space using the data communication processing unit 12, outputs the generated communication data as data Dtx_NW1 to the first communication interface 11, and the first communication interface 11 transmits the data Dtx_NW1 to the first-k device Dev1-k. If the MS / TP address space is a space of 8-bit data (8-bit addresses), converter NC-0 sequentially generates communication data for address queries for each of the addresses 0x00 to 0xff (for example, it generates communication data for address queries by incrementing the address by +1 from 0x00). Then, the converter NC-k sequentially transmits the generated communication data for address inquiry (Inq("0x00") to Inq("0xff") (Who-is message) "Who is "0x00") to "Who is "0xff") to the first-k device Dev1-k (steps S16, S17, S18). Note that if the MS / TP address "0xff" is assigned to, for example, the broadcast address, the communication data for address inquiry should be Inq("0x00") to Inq("0xfe").

[0062] Since the MS / TP address of the first-k device Dev1-k is A10k (for example, A10k = "0x0k"), when it receives communication data Inq(A10k) from converter NC-k, the device with MS / TP address A10k generates response communication data Ans(A10k) to the communication data Inq(A10k) in order to notify converter NC-k that it is the first-k device Dev1-k, and sends the generated response communication data Ans(A10k) (I-am message "I am A10k") to converter NC-k (step S19).

[0063] Alternatively, instead of the above process (using the "who-is" message and the "I-am" message), you may perform the following process to obtain an MS / TP address (address resolution process).

[0064] Converter NC-k sends both the "Pol for Master" command and the "Who-is" message within the first network NW1 to which it belongs (the "Pol for Master" command is sent at a predetermined time as defined by the protocol, and the "Who-is" message is sent at any time that converter NC-k deems appropriate). (1) When a terminal belonging to the first network NW1 is a master node, it responds to both "Poll for Master" and "Who is", so the converter can recognize the terminal regardless of which response is received. Therefore, when a terminal belonging to the first network NW1 is a master node, and the first-k device Dev1-k is a master node, the first-k device Dev1-k responds to both "Poll for Master" and "Who is", and the converter NC-k obtains the MS / TP address of the first-k device Dev1-k from the data returned from the first-k device Dev1-k. (2) If a terminal belonging to the first network NW1 is a slave node, it does not respond to the "Poll For Master" command, but only to the "Who is" message, and the converter recognizes the terminal. Therefore, when the first-k device Dev1-k is a slave node, the first-k device Dev1-k responds to the "Who is" message, and the converter NC-k obtains the MS / TP address of the first-k device Dev1-k from the data returned from the first-k device Dev1-k.

[0065] (Step S20): In step S20, the converter NC-k receives the response communication data Ans(A10k) (I-am message "I am A10k") transmitted from the first-k device Dev1-k. The first communication interface 11 of the converter NC-k outputs the received communication data as data Drx_NW1 to the data communication processing unit 12.

[0066] The data communication processing unit 12 generates communication data for broadcast to the second network NW2, which includes data (I-am message "I am A10k") indicating that a device with MS / TP address A10k exists on the first network NW1 to which converter NC-k is connected, and outputs the generated communication data as data Dtx_NW2 to the second communication interface 14.

[0067] The second communication interface 14 broadcasts the communication data input from the data communication processing unit 12 to the second network NW2 as communication data Bcast_Ans(A10k) (it is sent to all converters connected to the second network NW2 (all converters except the converter NC-k, which is the device itself)).

[0068] Furthermore, the data communication processing unit 12 of converter NC-k updates the address table data stored in the storage unit 13 with data indicating that the device with MS / TP address A10k is connected to the first network NW1 to which converter NC-k is connected.

[0069] Converters other than converter NC-k receive the communication data Bcast_Ans(A10k) broadcast from converter NC-k (Nessum address: B0k), and update the address table data stored in the storage unit 13 with data indicating that the device with MS / TP address A10k is connected to the first network NW1 to which converter NC-k is connected, based on the received communication data. For example, the Nessum address B0k of converter NC-k and the MS / TP address A10k are associated and stored in the address table (the data in the address table (for example, address-corresponding data (A10k, B0k)) is stored in the storage unit 13).

[0070] By processing as described above, each of the converters NC-0 and NC-1 to NC-N of the communication system 1000 can store and retain address table data that associates the Nessum address B0k with the MS / TP address A10k.

[0071] For example, in the case of N=3, the above process allows converter NC-0 and converters NC-1 to NC-N (N=3) to each store the following address table data Data_addr_tab in the storage unit 13. Data_addr_tab = [(A000, B00), (A101, B01), (A102, B02), (A103, B03)] (Axxx, Bxx): Address correspondence data (Axxx is the MS / TP address. Bxx is the Nessum address) With the above, the communication system 1000 can perform the initial address resolution process.

[0072] For the sake of explanation, the above description assumes that steps S16 to S20 are executed after steps S11 to S15. However, the explanation is not limited to this, and steps S11 to S15 and steps S16 to S20 may be processed in parallel (or almost simultaneously).

[0073] (1.2.2: Processing when performing communication after initial address resolution) Next, the processing when performing communication after initial address resolution will be explained with reference to the communication sequence diagram in Figure 4.

[0074] As an example of communication after the initial address resolution process, the following explanation describes a case where monitoring device Dev1-0 sends a request signal to the 1st-1st device Dev1-1, and the 1st-1st device Dev1-1 sends a reply signal to monitoring device Dev1-0 in response to the request signal.

[0075] Furthermore, for the sake of explanation, N=3, and converters NC-0 to NC-N each store the following address table data Data_addr_tab in the storage unit 13, and perform various processing using the address table data Data_addr_tab. Data_addr_tab = [(A000, B00), (A101, B01), (A102, B02), (A103, B03)] (Step SA0_tkn): In step SA0_tkn, token transmission and reception processing is performed between the monitoring device Dev1-0 and converter NC-0. The monitoring device Dev1-0 and converter NC-0 are connected one-to-one via the first network NW1 of the first communication standard (MS / TP standard), and the device that holds the token has the right to speak. When monitoring device Dev1-0 and converter NC-0 are configured as master nodes, they alternately hold tokens, as shown in Figure 4, and send and receive tokens. In addition, under the first communication standard (MS / TP standard), Poll for Master packets for managing the master nodes are sent periodically (not shown in Figure 4).

[0076] (Step SB0_tkn): In step SB0_tkn, token transmission and reception processing is performed between the 1-1 device Dev1-1 and the converter NC-1. The 1-1 device Dev1-1 and the converter NC-1 are connected on a one-to-one basis via the 1st network NW1 of the 1st communication standard (MS / TP standard), and the device holding the token has the right to speak. When the 1-1 device Dev1-1 and the converter NC-1 are set as master nodes, as shown in Figure 4, they take turns holding tokens and transmitting and receiving tokens. In addition, the 1st communication standard (MS / TP standard) periodically transmits Poll for Master packets to manage the master nodes (not shown in Figure 4).

[0077] (Step S31): In step S31, the monitoring device Dev1-0, which has a token, generates a request signal Req(A101) destined for the first-first device Dev1-1, and transmits the request signal Req(A101) to the converter NC-0 via the first network NW1. Note that in the first network NW1 of the first communication standard (MS / TP standard), the response signal (Reply) to the request signal (Request) can be transmitted at the same time as the request signal (Request) is transmitted.

[0078] (Step S32): In step S32, the converter NC-0 transmits an extension signal (Postpone) to the monitoring device Dev1-0, instructing it to extend the response to the request signal Req (A101) (extend the waiting time). The monitoring device Dev1-0 receives the extension signal (Postpone), recognizes that the response to the request signal Req (A101) has been extended, and waits for the response signal reception process.

[0079] (Step S33): In step S33, converter NC-0 refers to the address table data Data_addr_tab (= [(A000, B00), (A101, B01), (A102, B02), (A103, B03)]) and understands that the device at address A101, the destination of the request signal Req(A101), is connected to the converter for Nessum address B01. Then, converter NC-0 generates communication data Req1_NC(A101) (communication data obtained by the data communication processing unit 12 after protocol conversion processing of the request signal Req(A101)) to be sent to converter NC-1 for Nessum address B01 via the second network NW2. Then, converter NC-0 transmits the communication data Req1_NC(A101) to converter NC-1, which has the Nessum address B01, via the second network NW2.

[0080] Converter NC-1 receives the communication data Req1_NC(A101) transmitted from converter NC-0 via the second network NW2.

[0081] (Step S34): In step S34, converter NC-1 analyzes the communication data Req1_NC(A101) received from converter NC-0 and recognizes that a request signal for the device with MS / TP address A101 is being requested. Then, converter NC-1 generates a request signal Req1(A101) for the 1-1 device Dev1-1 with MS / TP address A101 and transmits the request signal Req1(A101) to the 1-1 device Dev1-1 via the first network NW1. Note that converter NC-1 transmits the request signal Req1(A101) to the 1-1 device Dev1-1 via the first network NW1 when it has a token.

[0082] (Step S35): In step S35, the first-first device Dev1-1 receives the request signal Req1(A101) transmitted from the converter NC-1 and generates a reply signal Rep1(A000) for the request signal Req1(A101). The destination of the reply to the request signal Req1(A101) can be determined from the address information of the sender, which is included in the request signal Req1(A101).

[0083] Then, the first-first device Dev1-1 transmits the generated reply signal Rep1 (A000) to the converter NC-1 via the first network NW1.

[0084] (Step S36): In step S36, converter NC-1 refers to the address table data Data_addr_tab (= [(A000, B00), (A101, B01), (A102, B02), (A103, B03)]) and understands that the device with address A000, the destination of the reply signal Rep(A000), is connected to the converter for Nessum address B00. Then, converter NC-1 generates communication data Rep1_NC(A000) (communication data obtained by the data communication processing unit 12 after protocol conversion processing of the reply signal Rep(A000)) to be sent to converter NC-0 for Nessum address B00 via the second network NW2. Then, converter NC-1 transmits the communication data Rep1_NC(A000) to converter NC-0, which has the Nessum address B00, via the second network NW2.

[0085] Converter NC-0 receives the communication data Rep1_NC(A000) transmitted from converter NC-1 via the second network NW2.

[0086] (Step SA1_tkn): In step SA1_tkn, token transmission and reception processing is performed between the monitoring device Dev1-0 and the converter NC-0. After the monitoring device Dev1-0 receives the extension signal (Postpone), the above token transmission and reception processing (same processing as in step SA0_tkn) is performed until the monitoring device Dev1-0 receives a response signal for the request signal Req (A101).

[0087] (Step S37): In step S37, converter NC-0 analyzes the communication data Rep1_NC(A000) received from converter NC-1 and recognizes that a reply signal to the device with MS / TP address A000 is requested. Then, converter NC-0 generates a reply signal Rep1(A000) to the monitoring device Dev1-0 with MS / TP address A000 and transmits the reply signal Rep1(A000) to the monitoring device Dev1-0 via the first network NW1.

[0088] The monitoring device Dev1-0 receives the reply signal Rep1 (A000) transmitted from the converter NC-0.

[0089] (Step SA2_tkn): In step SA2_tkn, token transmission and reception processing is performed between the monitoring device Dev1-0 and the converter NC-0, similar to step SA0_tkn.

[0090] (Step SB1_tkn): In step SB1_tkn, token transmission and reception processing is performed between the first-first device Dev1-1 and the converter NC-1, similar to step SB0_tkn.

[0091] In steps SB0_tkn and SB1_tkn, if the terminal device is a slave node, the slave node terminal device does not send or receive tokens. Therefore, no tokens are sent or received between the converter connected to the slave node terminal device and the slave node terminal device.

[0092] As a result, the communication system 1000 can perform communication after the initial address resolution process. By processing as described above, the communication system 1000 can send only a limited number of signals (packets) to the Nessum layer (the network of the second communication standard (Nessum standard)), thereby achieving high communication efficiency. In other words, the communication system 1000 does not send unnecessary MS / TP tokens to the Nessum layer (the network of the second communication standard (Nessum standard)), but only sends the signals necessary for data transmission and reception (request signals and reply signals) to the Nessum layer (the network of the second communication standard (Nessum standard)), thus achieving high communication efficiency.

[0093] As described above, in the communication system 1000, devices of the first communication standard (MS / TP standard) and converters that perform protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is a network of the first communication standard (MS / TP standard), thus enabling high communication efficiency. In other words, by configuring the communication system 1000 as described above, one device of the first communication standard (MS / TP standard) can be placed in the first network NW1 which is divided by the converter. As a result, the problem of long response times in the token passing communication method and degradation of the overall network performance can be avoided, and high communication efficiency can be achieved. In the first communication standard (MS / TP standard), the device holding the token has the right to speak, so a reply can only be sent at the timing of a request, resulting in long response times and a decrease in the overall performance of the communication system. This tendency becomes more pronounced the more devices there are in the network using the first communication standard (MS / TP standard). However, in communication system 1000, only one converter and one first communication standard (MS / TP standard) are deployed within the network using the first communication standard (MS / TP standard), so the above problem is less likely to occur.

[0094] Furthermore, in the communication system 1000, the communication bandwidth of the second network NW2 connecting converters NC-0 to NC-N is far wider than the communication bandwidth of the first network NW1, which is a network of the first communication standard (MS / TP standard). Therefore, the packet size of the communication signals transmitted and received on the first network NW1 can be made considerably smaller than the packet size of the communication signals transmitted and received on the second network NW2. For this reason, even if multiple converters in different first networks NW1 (for example, converters NC-0 and NC-1) transmit signals onto the second network NW2 simultaneously, collisions are less likely to occur due to the wide communication bandwidth of the second network NW2. Moreover, even if a collision does occur, the data can be resent through retransmission processing.

[0095] (1.2.3: Handling cases where address resolution fails) Next, we will explain the handling cases where address resolution fails, referring to the communication sequence diagram in Figure 5.

[0096] As an example of a case where address resolution fails, the following explains a situation where, at the point when the MS / TP address of a device using the first communication standard (MS / TP method standard) and the Nessum address of a converter are shared on the second network NW2 (Nessum network), the address table is not created (or updated) in a particular converter due to reasons such as the receiving converter not being ready to receive.

[0097] For the sake of explanation, the following description assumes that converter NC-0 does not know the address of converter NC-3 (for example, because converter NC-3 was not started during the initial address resolution process), and that converter NC-3 does not know any address information other than that of terminal device Dev1-3, which is connected to its own device via the first network NW1. It is assumed that converter NC-0 stores the following address table Data_addr_tab in the storage unit 13. Data_addr_tab = [(A000, B00), (A101, B01), (A102, B02)] (Step SA3_tkn): In step SA3_tkn, token transmission and reception processing is performed between monitoring device Dev1-0 and converter NC-0 (the same processing as in step SA0_tkn is performed).

[0098] (Step SB2_tkn): In step SB2_tkn, token transmission and reception processing is performed between the first-first device Dev1-4 and the converter NC-4 (same processing as in step SB1_tkn).

[0099] (Step S41): In step S41, the monitoring device Dev1-0, which has a token, generates a request signal Req(A103) destined for the first-third device Dev1-3, and transmits the request signal Req(A103) to the converter NC-0 via the first network NW1.

[0100] (Step S42): In step S42, the converter NC-0 transmits an extension signal (Postpone) to the monitoring device Dev1-0, instructing it to extend the response to the request signal Req (A103) (extend the waiting time). The monitoring device Dev1-0 receives the extension signal (Postpone), recognizes that the response to the request signal Req (A103) has been extended, and waits for the response signal reception process. Note that the converter NC-0 does not have to transmit an extension signal (Postpone) to the monitoring device Dev1-0, instructing it to extend the response to the request signal Req (A103) (extend the waiting time).

[0101] (Step S43): In step S43, converter NC-0 refers to the address table data Data_addr_tab (= [(A000, B00), (A101, B01), (A102, B02)]) and, since it cannot identify the converter to which the device at address A103, the destination of the request signal Req (A103), is connected in the second network NW2, it generates communication data Bcast_Inq (A103) (Who-is message "Who is A103") for address querying to be transmitted (broadcast) to the second network NW2. Then, converter NC-0 broadcasts the generated communication data Bcast_Inq (A103) for address querying to the second network NW2.

[0102] (Step S44): In step S44, converter NC-3 receives the address query communication data Bcast_Inq(A103) sent from converter NC-0, and generates the communication data Bcast_Ans(A103) indicating that the converter connected to the device of the MS / TP address A103 being queried via the first network NW1 is converter NC-3. Then, converter NC-3 broadcasts the generated communication data Bcast_Ans(A103) to the second network NW2.

[0103] Converter NC-0 receives the communication data Bcast_Ans (A103) broadcast from Converter NC-3, recognizes that the converter connected to the device with MS / TP address A103 via the first network NW1 is Converter NC-3 (Nessum address: B03), and adds data indicating the address correspondence (A103, B03) to the address table data Data_addr_tab. As a result, the address table data Data_addr_tab managed by Converter NC-0 becomes Data_addr_tab = [(A000, B00), (A101, B01), (A102, B02), (A103, B03)]).

[0104] (Step S45): In step S45, converter NC-0 refers to the updated address table data Data_addr_tab (= [(A000, B00), (A101, B01), (A102, B02), (A103, B03)]) and understands that the device at address A103, the destination of the request signal Req(A103), is connected to the converter for Nessum address B03. Then, converter NC-0 generates communication data Req1_NC(A103) (communication data obtained by the data communication processing unit 12 after protocol conversion processing of the request signal Req(A103)) to be sent to converter NC-3 for Nessum address B03 via the second network NW2. Then, converter NC-0 transmits the communication data Req1_NC(A103) to converter NC-3, which has the Nessum address B03, via the second network NW2.

[0105] Converter NC-3 receives the communication data Req1_NC(A103) transmitted from converter NC-0 via the second network NW2.

[0106] (Step S46): In step S46, converter NC-3 analyzes the communication data Req1_NC(A103) received from converter NC-0 and recognizes that a request signal for the device with MS / TP address A103 is being requested. Then, converter NC-3 generates a request signal Req1(A103) for the first-third device Dev1-3 with MS / TP address A103 and transmits the request signal Req1(A103) to the first-third device Dev1-3 via the first network NW1.

[0107] (Step S47): In step S47, the first-third device Dev1-3 receives the request signal Req1 (A103) transmitted from the converter NC-3 and generates a reply signal Rep1 (A000) for the request signal Req1 (A103). The destination of the reply to the request signal Req1 (A101) can be determined from the address information of the sender, which is included in the request signal Req1 (A103).

[0108] Then, the first-third device Dev1-3 transmits the generated reply signal Rep1 (A000) to the converter NC-3 via the first network NW1.

[0109] (Step S48): In step S48, converter NC-3 refers to the address table data Data_addr_tab (= [(A000, B00), (A101, B01), (A102, B02), (A103, B03)]) and understands that the device with address A000, the destination of the reply signal Rep(A000), is connected to the converter for Nessum address B00. Then, converter NC-3 generates communication data Rep1_NC(A000) (communication data obtained by performing protocol conversion processing on the reply signal Rep(A000) by the data communication processing unit 12) to send to converter NC-0 for Nessum address B00 via the second network NW2. Then, converter NC-3 transmits the communication data Rep1_NC(A000) to converter NC-0, which has the Nessum address B00, via the second network NW2.

[0110] Converter NC-0 receives the communication data Rep1_NC(A000) transmitted from converter NC-3 via the second network NW2.

[0111] (Step SA4_tkn): In step SA4_tkn, token transmission and reception processing is performed between the monitoring device Dev1-0 and the converter NC-0. After the monitoring device Dev1-0 receives the extension signal (Postpone), the above token transmission and reception processing (same processing as in step SA0_tkn) is performed until the monitoring device Dev1-0 receives a response signal for the request signal Req (A103).

[0112] (Step S49): In step S49, converter NC-0 analyzes the communication data Rep1_NC(A000) received from converter NC-3 and recognizes that a reply signal to the device with MS / TP address A000 is requested. Then, converter NC-0 generates a reply signal Rep1(A000) to the monitoring device Dev1-0 with MS / TP address A000 and transmits the reply signal Rep1(A000) to the monitoring device Dev1-0 via the first network NW1.

[0113] The monitoring device Dev1-0 receives the reply signal Rep1 (A000) transmitted from the converter NC-0.

[0114] (Step SA5_tkn): In step SA5_tkn, token transmission and reception processing is performed between the monitoring device Dev1-0 and the converter NC-0, similar to step SA0_tkn.

[0115] (Step SB3_tkn): In step SB3_tkn, token transmission and reception processing is performed between the first-third device Dev1-3 and the converter NC-3, similar to step SB0_tkn.

[0116] As described above, the communication system 1000 can perform processing when address resolution has not been completed. By processing as described above, the communication system 1000 can appropriately perform communication processing between devices of the first communication standard included in the communication system 1000, even if, for example, the address table is not created (or updated) in a particular converter for reasons such as the receiving converter not being ready to receive when the MS / TP address of a device of the first communication standard (MS / TP method standard) and the Nessum address of a converter are shared on the second network NW2 (Nessum network), or if a converter and / or a device of the first communication standard is added.

[0117] ≪Summary≫ As described above, in the communication system 1000, devices of the first communication standard (MS / TP standard) and converters that perform protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is a network of the first communication standard (MS / TP standard), thus enabling high communication efficiency. In other words, by configuring the communication system 1000 as described above, one device of the first communication standard (MS / TP standard) can be placed in the first network NW1 which is divided by the converter. As a result, the problem of long response times in the token passing communication method and deterioration of the overall network performance can be avoided, and high communication efficiency can be achieved.

[0118] Furthermore, in the communication system 1000, the communication bandwidth of the second network NW2 connecting converters NC-0 to NC-N is far wider than the communication bandwidth of the first network NW1, which is a network of the first communication standard (MS / TP standard). Therefore, the packet size of the communication signals transmitted and received on the first network NW1 can be made considerably smaller than the packet size of the communication signals transmitted and received on the second network NW2. For this reason, even if multiple converters in different first networks NW1 (for example, converters NC-0 and NC-1) transmit signals onto the second network NW2 simultaneously, collisions are less likely to occur due to the wide communication bandwidth of the second network NW2. Moreover, even if a collision does occur, the data can be resent through retransmission processing.

[0119] Furthermore, in the communication system 1000, a device conforming to the first communication standard (MS / TP standard) and a converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is the network of the first communication standard (MS / TP standard). Therefore, the number of devices connected to the first network NW1, which is the network of the first communication standard (MS / TP standard), is "2". As a result, the device conforming to the first communication standard (MS / TP standard) can acquire tokens at a high frequency, and the waiting time required to acquire tokens can be reduced compared to the case where more master devices are connected.

[0120] Furthermore, in the communication system 1000, a device conforming to the first communication standard (MS / TP standard) and a converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is a network conforming to the first communication standard (MS / TP standard). Therefore, the baud rate only needs to be set between devices connected to the first network NW1, which is a network conforming to the first communication standard (MS / TP standard). This makes it possible to set the baud rate according to each device, even when connecting a new device to an existing network, as in conventional MS / TP networks, without having to match the baud rate set by devices already connected to that network.

[0121] Furthermore, in the communication system 1000, the network of the first communication standard can be divided by a converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard). Therefore, by adding devices of the first communication standard along with the converter, the number of devices of the first communication standard to be added to the communication system 1000 can be increased while maintaining high communication efficiency. In other words, the communication system 1000 can achieve high expandability.

[0122] Furthermore, the communication system 1000 can also solve the following problems of communication systems compliant with the BACnet MS / TP protocol that use a token passing communication method and a master-slave communication method: (1) In communication systems compliant with the BACnet MS / TP protocol, it was necessary to set the communication baud rate of each device in the network to the communication baud rate specified in the BACnet MS / TP protocol specifications, and when connecting a new device to an existing network, it was necessary to match the baud rate of the existing network, but this is not necessary with the communication system 1000. (2) In a communication system compliant with the BACnet MS / TP protocol, the delay due to the waiting time required to acquire a token becomes large, so the number of devices that can be connected to the network must be limited to about 35, and the scalability of the communication system is poor. However, in the communication system 1000, the device of the first communication standard (MS / TP method standard) and the converter that performs protocol conversion between the first communication standard (MS / TP method standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is the network of the first communication standard (MS / TP method standard). Therefore, the delay due to the waiting time required to acquire a token does not become large, the number of devices that can be connected to the network can be increased, and the communication system has high scalability.

[0123] Furthermore, in the communication system 1000, devices conforming to the first communication standard (MS / TP method standard (physical layer conforming to the RS485 standard)) and converters that perform protocol conversion between the first communication standard (MS / TP method standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is the network of the first communication standard (MS / TP method standard). Therefore, the following problems of the physical layer of the MS / TP method can also be solved. (1) In the communication system 1000, the network conforming to the first communication standard (MS / TP method standard (physical layer conforming to the RS485 standard)) is bridged to another physical layer (physical layer of the second communication standard (Nessum standard)). Therefore, by making the network conforming to the second communication standard a bus connection, the problem of communication failures occurring due to loosening of physical connections in daisy-chain connections can be solved. (2) The communication system 1000 has a configuration that bridges a network of the first communication standard (MS / TP method standard (physical layer conforms to the RS485 standard)) to another physical layer (physical layer of the second communication standard (Nessum standard)). Therefore, the problem of communication failures caused by polarity reversal in the communication lines of the first communication standard (MS / TP method standard (physical layer conforms to the RS485 standard)) can be solved by making the signals nonpolar by performing OFDM modulation with the Nessum standard. (3) The communication system 1000 has a configuration that bridges a network of the first communication standard (MS / TP method standard (physical layer conforms to the RS485 standard)) to another physical layer (physical layer of the second communication standard (Nessum standard)). Therefore, by using a transformer (since Nessum uses high-frequency signals, the size of the transformer can be reduced) for isolation, the problem of grounding between communication devices is eliminated. (4) The communication system 1000 has a configuration that bridges a network of the first communication standard (MS / TP method standard (physical layer conforms to the RS485 standard)) to another physical layer (physical layer of the second communication standard (Nessum standard)), so that the restrictions on cable quality, length, etc. that are imposed by the RS485 standard can be relaxed.(5) The communication system 1000 has a configuration that bridges a network of the first communication standard (MS / TP method standard (physical layer conforms to the RS485 standard)) to another physical layer (physical layer of the second communication standard (Nessum standard)), so an EOL resistor (EOL: End of Line) to suppress signal reflection (transmission line reflection) that occurs in the RS485 standard network is unnecessary (the Nessum standard network uses the OFDM method, so bit allocation can be made dynamic, and communication can be performed without problems even if signal reflection occurs in the transmission line).

[0124] As described above, in the communication system 1000, a device conforming to the first communication standard (MS / TP standard) and a converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, which is a network conforming to the first communication standard (MS / TP standard). Therefore, in a communication system including a device that performs communication processing for token passing and master-slave communication, high scalability and high communication efficiency can be achieved.

[0125] <<First Modification>> Next, a first modification of the first embodiment will be described. Note that parts similar to those in the above embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0126] Figure 6 is a schematic diagram of a communication system 1000A according to a first modified example of the first embodiment.

[0127] The modified communication system 1000A has a configuration in which, in addition to the communication system 1000 of the first embodiment, a network NW1a of the first communication standard and a network NW2a of the second communication standard are further added, and a switching hub DevHub for MS / TP, MS / TP routers DevRT1 and DevRT2, and MS / TP devices, namely the 2-1st device Dev2-1 to the 2-Mth device Dev2-M (M: natural number), are added.

[0128] Converters NC-0a to NC-Ma are connected to the NW2a network, which is the second communication standard. Converters NC-0a to NC-Ma have the same configuration and functions as converter NC-k.

[0129] As shown in Figure 6, the monitoring device Dev1-0 is connected to two MS / TP routers, MS / TP router DevRt1 and MS / TP router DevRt2, via an IP communication network (IP: Internet Protocol) through a switching hub, DevHub.

[0130] MS / TP router DevRt1 has the function of converting IP packets (IP communication data) to MS / TP packets (MS / TP communication data) and converting MS / TP packets (MS / TP communication data) to IP packets (IP communication data) (protocol conversion function between IP communication and MS / TP communication). MS / TP router DevRt1 is connected to converter NC-0 via the first network NW1, and its MS / TP address is set to "A001".

[0131] The MS / TP router DevRt2 has the function of converting IP packets (IP communication data) to MS / TP packets (MS / TP communication data) and converting MS / TP packets (MS / TP communication data) to IP packets (IP communication data) (protocol conversion function between IP communication and MS / TP communication). The MS / TP router DevRt2 is connected to converter NC-0a via the first network NW1a (the network of the first communication standard (MS / TP)), and its MS / TP address is set to "A002".

[0132] The converter NC-ka (k: natural number, 1 ≤ k ≤ M) is connected to the second-k device Dev2-k, which is a device of the first communication standard (MS / TP), via the first network NW1a (network of the first communication standard (MS / TP)).

[0133] In the communication system 1000A configured as described above, by performing communication processing in the same manner as in the first embodiment, highly efficient communication processing can be performed between devices of the first communication standard (MS / TP).

[0134] In other words, in the first embodiment, the monitoring device Dev1-0 is set to MS / TP router DevRt1, and communication processing can be performed in the same manner as in the first embodiment. The data transmission process from monitoring device Dev1-0 and the data transmission process to monitoring device Dev1-0 are performed via the switching hub DevHub and MS / TP router DevRt1.

[0135] Furthermore, in the first network NW1a and the second network NW2a, which are extensions of the communication system 1000 of the first embodiment, communication processing can be performed in the same manner as in the first embodiment, enabling highly efficient communication processing between devices of the first communication standard (MS / TP) (MS / TP router DevRt2, second-k device Dev2-k (k: natural number, 1 ≤ k ≤ M)). Data transmission processing from monitoring device Dev1-0 and data transmission processing to monitoring device Dev1-0 are performed via the switching hub DevHub and MS / TP router DevRt2.

[0136] As shown in this modified example, by connecting a device of the first communication standard (MS / TP standard) and a converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) (a converter also connected to the second network NW2a) on a one-to-one basis via the first network NW1a, which is a network of the first communication standard (MS / TP standard), and adding communication equipment, the network can be easily expanded while maintaining high communication efficiency.

[0137] As described above, in the communication system 1000A of this modified example, the device of the first communication standard (MS / TP standard) and the converter that performs protocol conversion between the first communication standard (MS / TP standard) and the second communication standard (Nessum standard) are connected one-to-one by the first network NW1, NW1a, which is a network of the first communication standard (MS / TP standard). Therefore, in a communication system including a device that performs communication processing for token passing communication and master-slave communication, high expandability and high communication efficiency can be achieved.

[0138] Furthermore, in Figure 6, if bridging was not performed in the second network NW2 and tokens were exchanged between all MS / TP terminals, crosstalk occurred between the first network NW1 and the first network NW1a, causing token collisions and loss. In contrast, in the communication system 1000A of this modified example, tokens are sent and received only between the terminal converter and the MS / TP terminal, making such crosstalk less likely to occur.

[0139] [Other Embodiments] Some or all of the above embodiments and modifications may be combined to configure a communication system, converter, etc.

[0140] Furthermore, each block (each functional unit) of the communication system and converter described in the above embodiment may be individually integrated into a single chip using semiconductor devices such as LSIs, or they may be integrated into a single chip including some or all of them. Also, each block (each functional unit) of the fault attack countermeasure processing device, data processing device, and control device described in the above embodiment may be realized by multiple semiconductor devices such as LSIs.

[0141] Although we have used the term LSI here, depending on the degree of integration, they may also be called IC, system LSI, super LSI, or ultra LSI.

[0142] Furthermore, the method of integrated circuit implementation is not limited to LSIs; it may also be implemented using dedicated circuits or general-purpose processors. After LSI manufacturing, FPGAs (Field Programmable Gate Arrays) that can be programmed, or reconfigurable processors that allow for the reconfiguration of the connections and settings of circuit cells inside the LSI, may also be used.

[0143] Furthermore, some or all of the processing of each functional block in each of the above embodiments may be implemented by a program. And some or all of the processing of each functional block in each of the above embodiments is performed by the central processing unit (CPU) in a computer. The programs for performing each of these processes are stored in a storage device such as a hard disk or ROM, and are read from the ROM or RAM and executed.

[0144] Furthermore, each of the processes in the above embodiments may be implemented by hardware, or by software (including cases where it is implemented together with an OS (operating system), middleware, or a predetermined library). Moreover, it may be implemented by a hybrid process of software and hardware.

[0145] For example, when each functional part of the above embodiment is implemented by software, the hardware configuration shown in Figure 7 (for example, a hardware configuration in which a CPU, GPU, processor, ROM, RAM, memory, input unit, output unit, etc. are connected by a bus) may be used to implement each functional part by software processing.

[0146] Furthermore, when each of the functional units of the above embodiment is implemented by software, the software may be implemented using a single computer having the hardware configuration shown in Figure 7, or it may be implemented using distributed processing with multiple computers.

[0147] Furthermore, the execution order of the processing method in the above embodiments is not necessarily limited to the description of the embodiments, and the execution order can be changed without departing from the spirit of the invention. Also, in the processing method in the above embodiments, some steps may be executed in parallel with other steps without departing from the spirit of the invention. Also, in the processing method in the above embodiments, processes that are executed in parallel may be executed in series (sequentially).

[0148] A computer program that causes a computer to execute the method described above, and a computer-readable recording medium on which such program is recorded, are included in the scope of the present invention. Examples of computer-readable recording media include flexible disks, hard disks, CD-ROMs, MOs, DVDs, DVD-ROMs, DVD-RAMs, high-capacity DVDs, next-generation DVDs, and semiconductor memory.

[0149] The above-mentioned computer program is not limited to one recorded on the above-mentioned recording medium, but may also be transmitted via telecommunications lines, wireless or wired communication lines, networks such as the Internet, etc.

[0150] Furthermore, the term "part" may include the concept of "circuitry." A circuit may be realized in whole or in part through hardware, software, or a combination of hardware and software.

[0151] The functions of the elements disclosed herein may be implemented using general-purpose processors, dedicated processors, integrated circuits, ASICs ("Application-Specific Integrated Circuits"), conventional circuit configurations and / or combinations thereof, or processing circuit configurations, which are configured to perform the disclosed elements or programmed to perform the disclosed functions. A processor is considered a processing circuit configuration or circuit configuration if it includes transistors and other circuit configurations within it. In this disclosure, a circuit configuration, unit or means is hardware that performs the listed functions or hardware programmed to perform such functions. Hardware may be any hardware disclosed herein or other known hardware programmed to perform the listed functions or configured to perform such functions. When hardware is a processor that may be considered a type of circuit configuration, a circuit configuration, means or unit is a combination of hardware and software, software used to configure the hardware and / or processor.

[0152] It should be noted that the specific configuration of the present invention is not limited to the embodiments described above, and various changes and modifications are possible without departing from the spirit of the invention.

[0153] [Note] This invention can also be realized as follows.

[0154] The first invention is a communication system including a device connected to a first network for communication using a first communication standard employing a token passing communication method, and a device connected to a second network for communication using a second communication standard, comprising N converter devices (N: a natural number of 2 or more) from the first converter device to the Nth converter device, and N terminal devices from the first terminal device to the Nth terminal device.

[0155] The first to the Nth converter devices are connected to the first network and the second network, respectively.

[0156] The first to the nth terminal devices are each terminal devices for communication according to the first communication standard, and are connected one-to-one to the converter device via the first network.

[0157] Furthermore, the kth terminal device (k: a natural number, 1 ≤ k ≤ N) is connected one-to-one with the kth converter device via the first network.

[0158] The k-th converter device communicates with the k-th terminal device via the first network using the first communication standard, and communicates with other converter devices connected via the second network using the second communication standard.

[0159] In this communication system, devices conforming to the first communication standard (MS / TP protocol) and converters that perform protocol conversion between the first communication standard (MS / TP protocol) and the second communication standard (e.g., Nessum protocol) are connected one-to-one via the first network, which is a network conforming to the first communication standard (MS / TP protocol). This enables high communication efficiency.

[0160] Furthermore, in this communication system, if the communication bandwidth of the second network to which the converter device is connected is wider than the communication bandwidth of the first network, which is a network of the first communication standard (MS / TP method standard), the packet size of the communication signals transmitted and received on the first network can be made considerably smaller than the packet size of the communication signals transmitted and received on the second network. For this reason, even if multiple converters in different first networks (for example, the first converter and the second converter NC-1) transmit signals onto the second network simultaneously, collisions are less likely to occur because the communication bandwidth of the second network is wider. Moreover, even if a collision does occur, the data can be resent through retransmission processing.

[0161] The second invention is the same as the first invention, wherein the token used in the token-passing communication scheme is not transmitted to the second network.

[0162] This allows the communication system to avoid sending unnecessary tokens to the second network, thereby improving communication efficiency.

[0163] The third invention is the first invention, and the second communication standard is the power line carrier communication standard.

[0164] This allows the communication system to be implemented using a second communication standard, such as a power line communication standard (e.g., the Nessum standard).

[0165] The fourth invention is the first invention, wherein the k-th terminal device has a first communication standard address, which is an address based on the first communication standard.

[0166] Furthermore, the k-th converter device has a second communication standard address, which is an address based on the second communication standard, and a first communication standard address, which is an address based on the first communication standard.

[0167] The k-th converter device obtains the address for the first communication standard of the k-th terminal device connected to itself via the first network. By doing so, it obtains address correspondence data that associates the address for the first communication standard of the k-th terminal device with the address for the second communication standard of itself, and transmits the obtained address correspondence data to a converter device other than itself via the second network.

[0168] Furthermore, the k-th converter device receives address-corresponding data transmitted from converter devices other than itself, and obtains address table data by aggregating the received address-corresponding data.

[0169] In this communication system, terminal devices and converter devices are connected on a one-to-one basis. This allows for a one-to-one correspondence between the terminal device's address for the first communication standard and the converter device connected to it for the second communication standard, and enables the acquisition of address correspondence data indicating this correspondence. Furthermore, in this communication system, each converter device can acquire address table data by receiving and aggregating address correspondence data transmitted from other converter devices. Each converter device can then use this address table data to perform address management processing, data filtering during data communication (selection of communication data to be transmitted), and other similar processes.

[0170] The fifth invention is the fourth invention, wherein the k-th converter device (1) when it receives communication data of the first communication standard from the k-th terminal device via the first network, it obtains the destination of the communication data, obtains the address for the second communication standard of the converter device corresponding to the address of the first communication standard of the obtained destination based on address table data, and transmits the second communication standard communication data, which is obtained by converting the communication data of the first communication standard into communication data for the second communication standard, to the converter device of the obtained second communication standard address, and (2) when it receives communication data of the second communication standard from another converter device via the second network, it obtains the destination of the communication data, and if the obtained destination is the k-th terminal device connected to the device via the first network, it transmits the first communication standard communication data, which is obtained by converting the communication data of the second communication standard into communication data for the first communication standard, to the k-th terminal device.

[0171] As a result, this communication system can perform filtering processing during data transmission (selection of communication data to be transmitted) using address table data, preventing unnecessary communication data from being transferred to the second network and achieving high communication efficiency.

[0172] The sixth invention is a converter device used in a communication system according to any of the first to fourth inventions, comprising: a first communication interface unit; a second communication interface unit; a storage unit; a first communication interface unit which is connected to a first network and is a communication interface for communicating with a terminal device for communicating according to a first communication standard via the first network; and a data communication processing unit.

[0173] The second communication interface unit is connected to the second network and is a communication interface for communicating with other converter devices via the second network.

[0174] The memory unit is a functional unit that can store and retain data.

[0175] The data communication processing unit performs data communication processing on the data acquired by the first communication interface unit and / or the data acquired by the second communication interface unit.

[0176] The data communication processing unit then performs the following processes: (1) The data communication processing unit obtains the address for the first communication standard of a terminal device connected to itself via the first network, thereby obtaining address correspondence data that associates the address for the first communication standard of the terminal device with the address for the second communication standard of itself, stores the obtained address correspondence data in the storage unit, and transmits it to a converter device other than itself via the second communication interface unit. (2) The data communication processing unit receives the address correspondence data transmitted from the converter device other than itself via the second communication interface unit, obtains address table data that aggregates the received address correspondence data, and stores the obtained address table data in the storage unit. (3) When the data communication processing unit receives communication data of the first communication standard from a terminal device connected to itself via the first communication interface unit, it obtains the destination of the communication data, obtains the address for the second communication standard of the converter device corresponding to the address of the obtained destination of the first communication standard based on the address table data, and transmits the second communication standard communication data, which is the communication data of the first communication standard converted into communication data for the second communication standard, to the converter device of the obtained second communication standard address via the second communication interface unit. (4) When the data communication processing unit receives communication data of the second communication standard from another converter device via the second communication interface unit, it obtains the destination of the communication data, and if the obtained destination is a terminal device connected to itself, it transmits the first communication standard communication data, which is the communication data of the second communication standard converted into communication data for the first communication standard, to that terminal device via the first communication interface unit.

[0177] As a result, by using this converter device in the communication system described in the first to fourth inventions, the same effects as those of the first to fourth inventions can be achieved.

[0178] 1000, 1000A Communication System NW1 First Network NW2 Second Network NC-0 to NC-N Converter (Converter Device) Dev1-0 Monitoring Device (Terminal Device) Dev1-1 1st-1 Device (Terminal Device) Dev1-2 1st-2 Device (Terminal Device) Dev1-N 1st-N Device (Terminal Device) 11 First Communication Interface (First Communication Interface Unit) 12 Data Communication Processing Unit 13 Storage Unit 14 Second Communication Interface (Second Communication Interface Unit)

Claims

1. A communication system comprising: a device connected to a first network for communication using a first communication standard employing a token-passing communication method; and a device connected to a second network for communication using a second communication standard, wherein the system comprises: a first network and N (N: a natural number of 2 or more) converter devices, namely the first to the Nth converter devices, connected to the first network and the second network; and a terminal device for communication using the first communication standard, namely the first to the Nth terminal devices, each connected one-to-one to the converter device via the first network, wherein the kth terminal device (k: a natural number, 1 ≤ k ≤ N) is connected one-to-one to the kth converter device via the first network, and the kth converter device communicates with the kth terminal device via the first network using the first communication standard, and communicates with other converter devices connected to the second network using the second communication standard.

2. The communication system according to claim 1, wherein the token used in the token-passing communication method is not transmitted to the second network.

3. The communication system according to claim 1, wherein the second communication standard is a power line carrier communication standard.

4. The communication system according to claim 1, wherein the k terminal device has a first communication standard address which is an address based on the first communication standard, the k converter device has a second communication standard address which is an address based on the second communication standard and a first communication standard address which is an address based on the first communication standard, and by performing a process to acquire the first communication standard address of the k terminal device which is connected to itself via the first network, it acquires address correspondence data which associates the first communication standard address of the k terminal device with the second communication standard address of itself, transmits the acquired address correspondence data to a converter device other than itself via the second network, receives the address correspondence data transmitted from the converter device other than itself, and acquires address table data which aggregates the received address correspondence data.

5. The k converter device (1) when it receives communication data of the first communication standard from the k terminal device via the first network, it obtains the destination of the communication data, obtains the address of the converter device for the second communication standard corresponding to the address of the first communication standard of the obtained destination based on the address table data, and transmits second communication standard communication data, obtained by converting the communication data of the first communication standard into communication data for the second communication standard, to the converter device of the obtained address for the second communication standard; (2) when it receives communication data of the second communication standard from another converter device via the second network, it obtains the destination of the communication data, and if the obtained destination is the k terminal device connected to the device via the first network, it transmits first communication standard communication data, obtained by converting the communication data of the second communication standard into communication data for the first communication standard, to the k terminal device, according to claim 4.

6. A converter device used in a communication system according to any one of claims 1 to 4, comprising: a first communication interface unit which is connected to the first network and is a communication interface for communicating with the terminal device for communicating according to the first communication standard via the first network; a second communication interface unit which is connected to the second network and is a communication interface for communicating with other converter devices via the second network; a storage unit for storing and holding data; and a data communication processing unit which performs data communication processing on data acquired by the first communication interface unit and / or data acquired by the second communication interface unit, wherein the data communication processing unit (1) performs processing to acquire the address for the first communication standard of the terminal device connected to itself via the first network, thereby acquiring address correspondence data that associates the address for the first communication standard of the terminal device with the address for the second communication standard of itself, stores the acquired address correspondence data in the storage unit, and transmits it to a converter device other than itself via the second communication interface unit. (2) The device receives the address-corresponding data transmitted from a converter device other than itself via the second communication interface unit, obtains address table data aggregated from the received address-corresponding data, and stores the obtained address table data in the storage unit. (3) When the device receives communication data of the first communication standard from a terminal device connected to itself via the first communication interface unit, it obtains the destination of the communication data, obtains the address for the second communication standard of the converter device corresponding to the obtained address of the first communication standard of the destination based on the address table data, and transmits the second communication standard communication data, which is the communication data of the first communication standard converted into communication data for the second communication standard, to the converter device of the obtained address for the second communication standard via the second communication interface unit.(4) A converter device that, when it receives communication data of the second communication standard from another converter device via the second communication interface unit, obtains the destination of the communication data, and if the obtained destination is the terminal device connected to itself, transmits to the terminal device, via the first communication interface unit, the communication data for the first communication standard obtained by converting the communication data of the second communication standard into communication data for the first communication standard.

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