Communication monitoring system, base station, history management server, and communication monitoring method

Abstract

The master station (111) and the slave station (121) communicate with each other within a fixed number of communication frames set within a cycle. Each communication frame contains a sequence number and a cycle number as communication information. When the master base station (113) and the slave base station (123) communicate wirelessly for each communication frame, they determine whether any communication frames have been lost based on the communication information of the current communication frame and the communication information of the previous communication frame. If any communication frames have been lost, the history management server (300) records the communication history information of the previous communication frame and the current communication frame as previous and subsequent historical information.

Description

Technical Field

[0001] This disclosure relates to a system for monitoring the transfer of cyclic data. Background Technology

[0002] A large number of devices are connected to the network, and communication between devices is carried out via relay through transmission devices in a certain communication range.

[0003] Within the communication interval sandwiched between two transmission devices, both the transmitting and receiving devices store the communication history of the relayed frames. Communication faults within the communication interval are then detected by comparing and parsing these communication histories.

[0004] Patent document 1 discloses the following: fault detection is performed based on whether the same frame has passed between the transmitting device on the sending side and the receiving device on the receiving side.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-057908 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, in order to detect communication failures, both the transmitting and receiving devices need to store the communication history of all relayed frames. Therefore, the storage capacity for this communication history becomes enormous.

[0010] The purpose of this disclosure is to enable the analysis of communication failures without making the storage of communication history too large.

[0011] means for solving problems

[0012] The communication monitoring system disclosed herein comprises: a master base station connected to a master station via a wired connection; a slave base station connected to a slave station via a wired connection and communicating wirelessly with the master base station to exchange communication frames between the master station and the slave station; and a history management server that records communication history information of communication frames that communicated with the master base station and the slave base station before and after a lost communication frame as before-and-after history information. The master station and the slave station communicate with each other within a predetermined fixed number of communication frames in a cyclic period. Each communication frame includes a sequence number indicating the order within the cyclic period and a period number that increments each time the cyclic period is passed as communication information. When the master base station and the slave base station communicate wirelessly for each communication frame, they determine whether there is a lost communication frame based on the communication information of the current communication frame and the communication information of the previous communication frame. If there is a lost communication frame, the communication history information of the previous communication frame and the current communication frame is sent to the history management server as before-and-after history information.

[0013] The effects of the invention

[0014] According to this disclosure, only the preceding and following historical information is recorded, rather than all communication history information; therefore, the storage capacity of communication history will not become enormous. Furthermore, since the preceding and following historical information of both the primary and secondary base stations is recorded, communication fault analysis is possible. Attached Figure Description

[0015] Figure 1 This is a structural diagram of the communication monitoring system 100 in Implementation Method 1.

[0016] Figure 2 This is a structural diagram of the communication frame 130 in Implementation Method 1.

[0017] Figure 3 This is a diagram illustrating an example of cycle number 143 and sequence number 144 in Embodiment 1.

[0018] Figure 4 This is a diagram illustrating an example of cycle number 143 and sequence number 144 in Embodiment 1.

[0019] Figure 5 This is a diagram illustrating an example of cycle number 143 and sequence number 144 in Embodiment 1.

[0020] Figure 6 This is a structural diagram of the base station 200 in Implementation Method 1.

[0021] Figure 7 This is a structural diagram of the history management server 300 in Implementation Method 1.

[0022] Figure 8 This is a flowchart of the communication monitoring method (receiving) in Implementation Method 1.

[0023] Figure 9 This is a structural diagram of the monitoring table 220 in Implementation Method 1.

[0024] Figure 10 This is a diagram illustrating the loss determination conditions in Implementation 1.

[0025] Figure 11 This is a structural diagram of the historical frame 230 in implementation method 1.

[0026] Figure 12 This is a diagram showing the historical document 391 in Implementation 1.

[0027] Figure 13 This is a flowchart of the communication monitoring method (sending) in Implementation Method 1.

[0028] Figure 14 This is a flowchart of the communication monitoring method (analysis) in Implementation Method 1.

[0029] Figure 15 This is a diagram showing the cause determination conditions (A) and (B) in Implementation 1.

[0030] Figure 16 This is a diagram showing the cause determination conditions (C) and (D) in Implementation 1.

[0031] Figure 17 This is a diagram showing the cause determination conditions (E), (F), and (G) in Implementation 1.

[0032] Figure 18 This is a diagram showing the cause determination conditions (H), (I), and (J) in Implementation 1.

[0033] Figure 19 This is a diagram showing the cause determination conditions (K) and (L) in Implementation 1.

[0034] Figure 20 This is a diagram showing the cause determination conditions (M), (N), and (O) in Implementation 1.

[0035] Figure 21 This is a diagram showing the cause determination conditions (P) and (Q) in Implementation 1.

[0036] Figure 22 This is a hardware structure diagram of base station 200 in implementation method 1.

[0037] Figure 23 This is a hardware structure diagram of the history management server 300 in Implementation Method 1. Detailed Implementation

[0038] In the embodiments and accompanying drawings, the same reference numerals are used to label the same or corresponding elements. Descriptions of elements labeled with the same reference numerals as those described are appropriately omitted or simplified. Arrows in the figures primarily indicate data flow or processing procedures.

[0039] Implementation method 1.

[0040] based on Figures 1 to 23 To illustrate the communication monitoring system 100.

[0041] ***Structure Explanation***

[0042] based on Figure 1 The structure of the communication monitoring system 100 will be described.

[0043] The communication monitoring system 100 is a system for monitoring the communication between the master station 111 and the slave station 121, as well as the communication between the slave stations 121.

[0044] For example, master station 111 and slave station 121 are connected using wired and wireless connections in CC-Link IE TSN.

[0045] TSN is short for Time Sensitive Networking.

[0046] The communication monitoring system 100 has a master device 110 and one or more slave devices 120.

[0047] The main device 110 is the device equipped with the main station 111.

[0048] Slave device 120 is a device that has one or more slave stations 121.

[0049] The main equipment 110 includes a main station 111, a network hub 112, a main base station 113, and a historical management server 300.

[0050] The master station 111 is a device that performs various processes while communicating with the slave station 121, such as using a computer. The master station 111 is connected to the master base station 113 via a network hub 112 in a wired manner.

[0051] The history management server 300 is a server that manages communication history. The history management server 300 is connected to the main base station 113 via a network hub 112 in a wired manner.

[0052] The main base station 113 is a communication device that communicates via wired and wireless means. The main base station 113 communicates with the main station 111 and the historical management server 300 via wired means, and communicates with the slave base stations 123 of each slave device 120 via wireless means.

[0053] The device 120 has one or more slave stations 121, network hubs 122, and slave base stations 123.

[0054] Slave station 121 is a device that performs various processes while communicating with master station 111, such as using a computer. Slave station 121 is connected to slave base station 123 via network hub 122 in a wired manner.

[0055] Base station 123 is a communication device that communicates via wired and wireless means. Base station 123 communicates with each slave station 121 via wired means and with the main base station 113 via wireless means.

[0056] The main base station 113 and each slave base station 123 function as transmission devices for transmitting communication frames between the main base station 111 and each slave base station 121 via wired and wireless means. The transmission device is also called a relay device or a relay device.

[0057] In the case of communication between two slave stations 121 located in different slave devices 120, wireless communication between the two slave base stations 123 is performed via the master base station 113.

[0058] The master station 111 and each slave station 121 perform cyclic data transfer synchronously with the cycle. Cyclic data transfer is also known as cyclic communication.

[0059] For example, cyclic data transfer is performed to control each slave station 121.

[0060] The frame sent via cyclic data transfer is called "communication frame 130". Communication frame 130 is also called cyclic data transfer frame.

[0061] In the cyclic data transmission, the master station 111 and each slave station 121 communicate with each other through a fixed number of communication frames 130 within the cycle period. The cycle period is a predetermined fixed time.

[0062] based on Figure 2 The structure of communication frame 130 will be explained. Furthermore, the arrangement of the elements of communication frame 130 and... Figure 2 The arrangement shown can also be different.

[0063] Communication frame 130 includes destination radio address 131, communication information 140, and payload 132.

[0064] Destination wireless address 131 is the address used for wireless communication by base station 200, which is connected to the destination of communication frame 130 via a wired connection.

[0065] The communication information 140 includes the destination address 141, the sending source address 142, the period number 143, and the sequence number 144.

[0066] Destination address 141 is the address of the destination of communication frame 130.

[0067] Source address 142 is the address of the source of communication frame 130.

[0068] The cycle number 143 is an incrementing number that appears each time a cycle is completed; it is called the cycle number.

[0069] The cycle number 143 starts with the minimum number as the initial value, ends with the maximum number as the maximum value, and returns to the minimum number after becoming the maximum number.

[0070] The period number 143 is the same in the master station 111 and each slave station 121. That is, the master station 111 and each slave station 121 use the same period number "n" in the same time zone and the same period number "n+1" in the next time zone.

[0071] Sequence number 144 is a number indicating the order within the cycle.

[0072] Sequence number 144 is incremented each time communication frame 130 is sent.

[0073] Sequence number 144 starts with the initial number and ends with the final number, which is the maximum value. It returns to the initial number each time a cycle is completed.

[0074] The maximum value of sequence number 144 corresponds to the number of communication frames 130 sent within the cycle. The maximum value of sequence number 144 is fixed in the master station 111 and is fixed in each slave station 121.

[0075] The sequence number 144 (and the maximum value) are set in the master station 111 and each slave station 121 respectively.

[0076] based on Figures 3 to 5 Specific examples of period number 143 and sequence number 144 will be explained. Figure 3 This shows a specific example of the first cycle. Figure 4 This shows a specific example of the second cycle. Figure 5 This shows a specific example of the (n+1)th cycle.

[0077] "Master" refers to the master station 111. "From A", "From B", and "From C" refer to three slave stations 121.

[0078] Each quadrilateral represents communication frame 130. “c” represents period number 143. “s” represents sequence number 144.

[0079] In the first cycle, the cycle number 143 of all communication frames 130 sent from the "master" and the three "slaves" is "0".

[0080] In the second cycle, the cycle number 143 of all communication frames 130 sent from the "master" and the three "slaves" is "1".

[0081] In the (n+1)th cycle, the cycle number 143 of all communication frames 130 sent from the "master" and the 3 "slaves" is "n".

[0082] In each cycle, the sequence number 144 of the first communication frame 130 sent from the "master" is "0", and the sequence number 144 of the first communication frame 130 sent from each "slave" is "0".

[0083] In each cycle, the "master" sends 16 communication frames 130, with sequence number 144 incrementing from "0" to "15". "Slave A" sends 21 communication frames 130, with sequence number 144 incrementing from "0" to "20". "Slave B" sends 31 communication frames 130, with sequence number 144 incrementing from "0" to "30". "Slave C" sends 11 communication frames 130, with sequence number 144 incrementing from "0" to "10".

[0084] Without distinguishing between the main base station 113 and the slave base station 123, they are referred to as base station 200.

[0085] based on Figure 6 The structure of base station 200 will be described.

[0086] Base station 200 is a computer equipped with hardware such as processor 201, memory 202, and communication interface 203. These hardware components are interconnected via signal lines.

[0087] Processor 201 is an IC that performs computational processing and controls other hardware. For example, processor 201 is a CPU.

[0088] IC is short for Integrated Circuit.

[0089] CPU is short for Central Processing Unit.

[0090] Memory 202 is a storage device. Memory 202 is also called main storage device or main memory. For example, memory 202 is RAM or flash memory.

[0091] RAM is short for Random Access Memory.

[0092] The communication interface 203 functions as both a receiver and a transmitter. For example, the communication interface 203 is a communication chip or NIC. The communication interface 203 is used for communication between the base station 200 and other devices.

[0093] NIC is short for Network Interface Card.

[0094] The base station 200 includes elements such as a wireless communication unit 211, a transmission destination resolution unit 212, a wired communication unit 213, a communication frame monitoring unit 214, and a historical frame generation unit 215. These elements are implemented by software.

[0095] The memory 202 stores a base station program that enables the computer to function as a wireless communication unit 211, a destination resolution unit 212, a wired communication unit 213, a communication frame monitoring unit 214, and a historical frame generation unit 215.

[0096] The operating system is also stored in memory 202. Processor 201 executes the base station program while executing the operating system.

[0097] OS is short for Operating System.

[0098] The input and output data of the base station program are stored in the storage unit 290. For example, address tables and structure files are stored in the storage unit 290. The address table represents the addresses of the master station 111, slave station 121, master base station 113, slave base station 123, and history management server 300. The structure file represents the interconnection relationships between the master station 111, slave station 121, master base station 113, slave base station 123, and history management server 300.

[0099] The memory 202 functions as a storage unit 290. However, storage devices such as registers and cache memory within the processor 201 may also replace the memory 202 or function as a storage unit 290 together with the memory 202.

[0100] Base station 200 may also have multiple processors instead of processor 201.

[0101] Base station programs can be recorded (stored) in a computer-readable manner on non-volatile recording media such as optical discs or flash memory.

[0102] based on Figure 7 The structure of the historical management server 300 is explained.

[0103] The history management server 300 is a computer equipped with hardware such as a processor 301, a memory 302, an auxiliary storage device 303, a communication device 304, and an input / output interface 305. These hardware components are interconnected via signal lines.

[0104] Processor 301 is an IC that performs computational processing and controls other hardware. For example, processor 301 is a CPU.

[0105] Memory 302 is a volatile or non-volatile storage device. Memory 302 is also called main storage device or main memory. For example, memory 302 is RAM. The data stored in memory 302 is stored in auxiliary storage device 303 as needed.

[0106] RAM is short for Random Access Memory.

[0107] Auxiliary storage device 303 is a non-volatile storage device. For example, auxiliary storage device 303 is ROM, HDD, flash memory, or a combination thereof. Data stored in auxiliary storage device 303 is loaded into memory 302 as needed.

[0108] ROM is short for Read Only Memory.

[0109] HDD is short for Hard Disk Drive.

[0110] Communication device 304 is both a receiver and a transmitter. For example, communication device 304 is a communication chip or NIC. Auxiliary storage device 303 is used for communication with the history management server 300.

[0111] Input / output interface 305 is a port for connecting input devices and output devices. For example, input / output interface 305 is a USB terminal, the input devices are a keyboard and mouse, and the output device is a monitor. Input / output interface 305 is used for input and output of the history management server 300.

[0112] USB is short for Universal Serial Bus.

[0113] The historical management server 300 includes elements such as a historical frame receiving unit 311, a historical record unit 312, an information receiving unit 321, a cause determination unit 322, and a result output unit 323. These elements are implemented by software.

[0114] The auxiliary storage device 303 stores a history management program that enables the computer to function as a history frame receiving unit 311, a history recording unit 312, an information receiving unit 321, a cause determination unit 322, and a result output unit 323. The history management program is loaded into the memory 302 and executed by the processor 301.

[0115] The OS is also stored in the auxiliary storage device 303. At least a portion of the OS is loaded into the memory 302 and executed by the processor 301.

[0116] Processor 301 executes the OS and the history management program simultaneously.

[0117] The input and output data of the historical management program are stored in storage unit 390. For example, address tables and structure files are stored in storage unit 390.

[0118] The memory 302 functions as a storage unit 390. However, storage devices such as auxiliary storage device 303, registers within the processor 301, and cache memory within the processor 301 may also replace the memory 302 or function as a storage unit 390 together with the memory 302.

[0119] The historical management server 300 can also have multiple processors to replace the processor 301.

[0120] Historical management programs can be recorded (stored) in a computer-readable manner on non-volatile recording media such as optical discs or flash memory.

[0121] ***Instructions for the Actions***

[0122] The steps of operating the communication monitoring system 100 are equivalent to those of a communication monitoring method. Furthermore, the steps of operating the communication monitoring system 100 are equivalent to the steps of processing based on a communication monitoring program. The communication monitoring program includes a base station program and a history management program.

[0123] based on Figure 8 The communication monitoring method (receiving) is explained.

[0124] The communication monitoring method (receiving) is the method used when the base station 200 receives the communication frame 130.

[0125] In step S101, the wireless communication unit 211 receives the communication frame 130 wirelessly and hands the communication frame 130 over to the destination resolution unit 212.

[0126] The destination resolution unit 212 receives communication frame 130 and hands it over to the wired communication unit 213 and the communication frame monitoring unit 214. The destination wireless address 131 can also be deleted from the communication frame 130.

[0127] After step S101, the process proceeds to steps S102 and S103.

[0128] In step S102, the wired communication unit 213 receives the communication frame 130 and sends the communication frame 130 in a wired manner.

[0129] Specifically, when base station 200 is a slave base station 123, wired communication unit 213 sends communication frame 130 to slave station 121 identified by destination address 141 of communication frame 130.

[0130] Furthermore, when base station 200 is the main base station 113, wired communication unit 213 sends communication frame 130 to the main base station 111.

[0131] In step S103, the communication frame monitoring unit 214 receives the communication frame 130 and uses the destination address 141 and the sending source address 142 as search keywords to search the monitoring table 220.

[0132] based on Figure 9 Explanation of monitoring table 220. Figure 9 This shows an example of the initial state of monitoring table 220.

[0133] The monitoring table 220 is pre-stored in the storage unit 290.

[0134] The monitoring table 220 shows the final number 224, communication time 225, cycle number 226, and sequence number 227 for each group of communication category 221, source address 222, and destination address 223.

[0135] Communication categories 221 through sequence numbers 227 will be referred to as “surveillance information”.

[0136] Communication category 221 is a category for wireless communication, indicating "transmit" or "receive". "1" means "receive" and "0" means "transmit".

[0137] The source address 222 identifies the source of communication frame 130.

[0138] Destination address 223 identifies the destination of communication frame 130.

[0139] The final number 224 is the maximum value of period number 143 in the source of communication frame 130.

[0140] Communication time 225 is the time when communication frame 130 was communicated wirelessly.

[0141] Period number 226 is period number 143 of communication frame 130.

[0142] Sequence number 227 is sequence number 144 of communication frame 130.

[0143] Specifically, the source address 222 and the destination address 223 are MAC addresses.

[0144] MAC is short for Media Access Control address.

[0145] Communication category 221, source address 222, destination address 223, and final number 224 are preset.

[0146] Return to Figure 8 Continuing with the explanation of step S103.

[0147] Monitoring information in which communication category 221 is indicated as "received" and the group of sending source address 222 and destination address 223 is consistent with the group of destination address 141 and sending source address 142 is called "consistent monitoring information".

[0148] If the communication time 225 is set in the matching monitoring information, in other words, if the matching monitoring information is registered in the monitoring table 220, the process proceeds to step S110.

[0149] If the communication time 225 is not set in the matching monitoring information, in other words, if the matching monitoring information is not registered in the monitoring table 220, the process proceeds to step S104.

[0150] In step S104, the communication frame monitoring unit 214 registers the matching monitoring information in the monitoring table 220.

[0151] Specifically, the communication frame monitoring unit 214 sets the reception time of the communication frame 130 in the communication time 225 field of the matching monitoring information. In addition, the communication frame monitoring unit 214 sets the period number 143 of the communication frame 130 in the period number 226 field of the matching monitoring information, and sets the sequence number 144 of the communication frame 130 in the sequence number 227 field of the matching monitoring information.

[0152] In step S110, the communication frame monitoring unit 214 determines whether there is any lost communication information 140 based on the communication information 140 of the current communication frame 130 and the communication information 140 of the previous communication frame 130.

[0153] This communication frame 130 is the communication frame 130 received wirelessly this time.

[0154] The last communication frame 130 was the last communication frame 130 received wirelessly.

[0155] The communication information 140 of the previous communication frame 130 is equivalent to the monitoring information.

[0156] The lost communication frame 130 is the communication frame 130 that was not received wirelessly before this communication frame 130.

[0157] based on Figure 10 The determination method in step S110 will be explained.

[0158] For example, the communication frame monitoring unit 214 makes a determination in sequence according to conditions (1) to (7). Then, at any point in time when any of the conditions (1) to (7) are met, the communication frame monitoring unit 214 determines that there is a lost communication frame 130.

[0159] "Current cycle number" refers to cycle number 143 of the current communication frame 130.

[0160] "Last cycle number" refers to cycle number 226, which matches the monitoring information.

[0161] The "minimum number" is the initial value of period number 143, which is predetermined.

[0162] The "maximum number" is the maximum value of period number 143, which is predetermined.

[0163] "This sequence number" refers to sequence number 144 of this communication frame 130.

[0164] "Previous sequence number" refers to sequence number 227, which matches the monitoring information.

[0165] The "starting number" is the initial value of sequence number 144, which is predetermined.

[0166] "Final Number" refers to the final number 224 that matches the monitoring information.

[0167] Condition (1) is as follows. Condition (1) is satisfied if both (1a) and (1b) are satisfied.

[0168] (1a) The current cycle number is the same as the previous cycle number.

[0169] (1b) The current sequence number is more than 2 greater than the previous sequence number.

[0170] Condition (2) is as follows.

[0171] The current cycle number is more than 2 greater than the previous cycle number.

[0172] Condition (3) is as follows. Condition (3) is satisfied if both (3a) and (3b) are satisfied.

[0173] (3a) The current cycle number is 1 greater than the previous cycle number.

[0174] (3b) The previous sequence number is smaller than the final number.

[0175] Condition (4) is as follows. Condition (4) is satisfied if both (4a) and (4b) are satisfied.

[0176] (4a) The current cycle number is 1 greater than the previous cycle number.

[0177] (4b) This sequence number is not the first number.

[0178] Condition (5) is as follows. Condition (5) is satisfied if both (5a) and (5b) are met.

[0179] (5a) The previous cycle number is the maximum number.

[0180] (5b) The current cycle number is neither the largest number nor the smallest number.

[0181] Condition (6) is as follows. Condition (6) is satisfied if all of (6a) to (6c) are satisfied.

[0182] (6a) The previous cycle number is the maximum number.

[0183] (6b) This period number is the smallest number.

[0184] (6c) The previous sequence number is smaller than the final number.

[0185] Condition (7) is as follows. Condition (7) is satisfied if all of (7a) to (7d) are satisfied.

[0186] (7a) The previous cycle number is the maximum number.

[0187] (7b) This period number is the smallest number.

[0188] (7c) The previous sequence number is the final number.

[0189] (7d) This sequence number is not the first number.

[0190] Return to Figure 8 Continuing with the explanation of step S110.

[0191] If it is determined that there is a lost communication frame 130, the process proceeds to step S121.

[0192] If it is determined that there is no lost communication frame 130, the process proceeds to step S123.

[0193] In step S121, the history frame generation unit 215 generates previous and previous history information 240, sets the previous and previous history information 240, and generates a history frame 230.

[0194] based on Figure 11 Explanation of historical frame 230.

[0195] Historical frame 230 is a frame that contains previous and subsequent historical information 240.

[0196] The preceding and following historical information 240 is the communication history information of the communication frames 130 received before and after the lost communication frame 130.

[0197] The historical frame 230 contains the destination radio address 231 and previous and previous historical information 240.

[0198] Destination wireless address 231 is the address used for wireless communication by base station 200 connected to historical management server 300. Specifically, destination wireless address 231 is the address used for wireless communication by main base station 113.

[0199] The historical information 240 includes the base station address 241, communication type 242, destination address 243, and source address 244.

[0200] Base station address 241 is the address of base station 200 that received this communication frame 130.

[0201] Communication category 242 is the communication category of this communication frame 130, which is the same as communication category 221 that matches the monitoring information.

[0202] Destination address 243 is the same as destination address 141 of this communication frame 130.

[0203] The source address 244 is the same as the source address 142 of the current communication frame 130.

[0204] In addition, the previous and previous historical information 240 includes the last communication time 251, the last cycle number 252, the last sequence number 253, the current communication time 254, the current cycle number 255, and the current sequence number 256.

[0205] The last communication time 251 is the same as the communication time 225 of the monitoring information.

[0206] The previous cycle number 252 was the same as the cycle number 226 that matched the monitoring information.

[0207] The previous sequence number 253 was the same as the sequence number 227 that matched the monitoring information.

[0208] The communication time 254 is the reception time of the communication frame 130.

[0209] The current cycle number 255 is the same as the current cycle number 143 of communication frame 130.

[0210] This sequence number 256 is the same as the sequence number 144 of this communication frame 130.

[0211] Return to Figure 8 The explanation will continue from step S122.

[0212] In step S122, the history frame generation unit 215 hands over the history frame 230 to the destination resolution unit 212.

[0213] The destination resolution unit 212 receives the historical frame 230 and hands it over to the wireless communication unit 211 or the wired communication unit 213.

[0214] Specifically, when base station 200 is a slave base station 123, the destination resolution unit 212 sets the wireless communication address of the master base station 113 in the destination wireless address 231 field of the historical frame 230. Then, the destination resolution unit 212 hands over the historical frame 230 to the wireless communication unit 211.

[0215] Furthermore, when base station 200 is the main base station 113, the destination resolution unit 212 hands over the historical frame 230 to the wired communication unit 213.

[0216] When the historical frame 230 is handed over to the wireless communication unit 211, the wireless communication unit 211 receives the historical frame 230 and sends the historical frame 230 wirelessly to the historical management server 300.

[0217] When historical frame 230 is handed over to wired communication unit 213, wired communication unit 213 receives historical frame 230 and sends historical frame 230 to historical management server 300 via wired means.

[0218] After step S122, the process proceeds to steps S123 and S131.

[0219] In step S123, the communication frame monitoring unit 214 updates the matching monitoring information.

[0220] Specifically, the communication frame monitoring unit 214 uses the reception time of the current communication frame 130 to overwrite the communication time 225 that matches the monitoring information. In addition, the communication frame monitoring unit 214 uses the period number 143 of the current communication frame 130 to overwrite the period number 226 that matches the monitoring information, and uses the sequence number 144 of the current communication frame 130 to overwrite the sequence number 227 that matches the monitoring information.

[0221] In step S131, the history frame receiving unit 311 receives the history frame 230.

[0222] Specifically, the historical frame receiving unit 311 receives historical frames 230 from the main base station 113 via a wired connection through the network hub 112.

[0223] In step S132, the history frame receiving unit 311 hands over the history frame 230 to the history recording unit 312.

[0224] The historical record unit 312 receives the historical frame 230, obtains the previous and subsequent historical information 240 from the historical frame 230, and records the previous and subsequent historical information 240 in the historical file 391.

[0225] based on Figure 12 Explanation of historical document 391.

[0226] Historical file 391 is a file stored in storage unit 390 for managing previous and previous historical information 240, and records one or more previous and previous historical information 240.

[0227] based on Figure 13 The communication monitoring method (sending) is explained.

[0228] The communication monitoring method (transmission) is the method used when base station 200 transmits communication frame 130.

[0229] In step S201, the wireless communication unit 211 wirelessly transmits the communication frame 130.

[0230] Communication frame 130 is sent as follows.

[0231] First, the wired communication unit 213 receives the communication frame 130 in a wired manner.

[0232] Specifically, when base station 200 is a slave base station 123, wired communication unit 213 receives communication frame 130 from slave station 121 identified by the source address 142 of communication frame 130.

[0233] Furthermore, when base station 200 is the main base station 113, wired communication unit 213 receives communication frame 130 from the main base station 111.

[0234] Next, the wired communication unit 213 hands over the communication frame 130 to the destination resolution unit 212, which receives the communication frame 130.

[0235] Next, the destination resolution unit 212 refers to the address table and structure file to determine the address for wireless communication with the base station 200, which is connected to the destination identified by the destination address 141 via a wired connection, and sets the determined address in the field of the destination wireless address 131.

[0236] Next, the destination resolution unit 212 hands over the communication frame 130 to the wireless communication unit 211, and the wireless communication unit 211 receives the communication frame 130.

[0237] Then, the wireless communication unit 211 wirelessly transmits communication frame 130.

[0238] Furthermore, the wired communication unit 213 hands over the communication frame 130 to the communication frame monitoring unit 214. However, the destination wireless address 131 is not required.

[0239] In step S202, the communication frame monitoring unit 214 receives the communication frame 130 and searches the monitoring table 220.

[0240] Step S202 is the same as step S103. However, the communication category 221 that matches the monitoring information indicates "Send".

[0241] If the matching monitoring information is registered in monitoring table 220, the process proceeds to step S210.

[0242] If the matching monitoring information is not registered in monitoring table 220, the process proceeds to step S203.

[0243] In step S203, the communication frame monitoring unit 214 registers the matching monitoring information in the monitoring table 220.

[0244] Step S203 is the same as step S104.

[0245] In step S210, the communication frame monitoring unit 214 determines whether there is any lost communication information 140 based on the communication information 140 of the current communication frame 130 and the communication information 140 of the previous communication frame 130.

[0246] This communication frame 130 is the communication frame 130 transmitted wirelessly this time.

[0247] The last communication frame 130 was the last communication frame 130 sent wirelessly.

[0248] The communication information 140 of the previous communication frame 130 is equivalent to the monitoring information.

[0249] The lost communication frame 130 is the communication frame 130 that was not transmitted wirelessly before this communication frame 130.

[0250] The determination method in step S210 is the same as the determination method in step S110.

[0251] If it is determined that there is a lost communication frame 130, the process proceeds to step S221.

[0252] If it is determined that there is no lost communication frame 130, the process proceeds to step S223.

[0253] In step S221, the history frame generation unit 215 generates previous and previous history information 240, sets the previous and previous history information 240, and generates a history frame 230.

[0254] Step S221 is the same as step S121. However, the current communication time 254 in the historical frame 230 is the transmission time of the current communication frame 130.

[0255] In step S222, the wireless communication unit 211 or the wired communication unit 213 sends a historical frame 230 to the historical management server 300.

[0256] Step S222 is the same as step S122.

[0257] After step S222, the process proceeds to steps S223 and S231.

[0258] In step S223, the communication frame monitoring unit 214 updates the matching monitoring information.

[0259] Step S223 is the same as step S123.

[0260] In step S231, the history frame receiving unit 311 receives the history frame 230.

[0261] Step S231 is the same as step S131.

[0262] In step S232, the history record unit 312 obtains the previous and previous history information 240 from the history frame 230 and records the previous and previous history information 240 in the history file 391.

[0263] Step S232 is the same as step S132.

[0264] based on Figure 14 This section explains the communication monitoring method (analysis).

[0265] The communication monitoring method (analysis) is a method for determining the cause of system failures based on historical information 240.

[0266] System failure is a failure that occurs in the system being monitored.

[0267] The monitored system is the system that becomes the monitored object of the communication monitoring system 100, and has a master device 110 (in addition to the historical management server 300) and one or more slave devices 120.

[0268] A specific example of a monitored system is a product manufacturing system, which has one or more production devices controlled by a master station 111 and one or more slave stations 121. Each production device has one or more production units.

[0269] In step S310, the information receiving unit 321 receives the fault information.

[0270] The fault information includes the time when the system fault was detected (fault detection time).

[0271] Fault information is processed as follows.

[0272] In the event of a system malfunction, the malfunction information will be entered into or sent to the historical management server 300.

[0273] For example, if a person identifies that the production equipment has stopped, the person will input or send the fault information to the historical management server 300.

[0274] For example, when an alarm occurs in the production unit, the production unit sends the fault information to the historical management server 300.

[0275] Then, the information receiving department 321 receives the fault information that has been entered or sent.

[0276] In step S320, the cause determination unit 322 retrieves matching historical information from the historical file 391 based on the fault information.

[0277] The consistent historical information refers to the historical information 240 before and after the last communication time 251 within a fixed time before the fault detection time or the current communication time 254 within a fixed time after the fault detection time.

[0278] If matching historical information is found, proceed to step S330.

[0279] If no matching historical information is found, the cause determination unit 322 determines that the cause of the system failure is not the main base station 113 or the slave base station 123. Then, the process proceeds to step S340.

[0280] In step S330, the cause determination unit 322 determines the cause of the system failure based on the matching historical information and whether there is corresponding historical information.

[0281] The corresponding historical information is the preceding and following historical information 240 that corresponds to the historical information.

[0282] The determination method in step S330 will then be described.

[0283] In step S340, the result output unit 323 outputs the determination result of the cause of the system fault.

[0284] based on Figures 15 to 21 This will be used to explain the determination method in step S330.

[0285] For example, the cause determination unit 322 performs determinations sequentially from condition (A) to condition (Q). Then, at the point in time when any of the conditions from condition (A) to condition (Q) is satisfied, the cause determination unit 322 ends the determination.

[0286] Furthermore, if none of conditions (A) to (Q) are met, the cause determination unit 322 determines that the cause of the system failure is unclear.

[0287] "Matching base station" refers to base station 200 identified by base station address 241 that matches historical information.

[0288] "Matching Communication Category" refers to communication category 242 that matches historical information.

[0289] "Matching destination address" refers to destination address 243 that matches the historical information.

[0290] "Counterpart slave station" refers to slave station 121 identified by the matching destination address. When the matching destination address is a multicast address, "counterpart slave station" refers to each slave station 121 belonging to the multicast group. When the matching destination address is a broadcast address, "counterpart slave station" refers to each slave station 121.

[0291] "The other party's slave base station" refers to slave base station 123 that is connected to the other party's slave station via wired connection.

[0292] "Matching source address" refers to the source address 244 that matches the historical information.

[0293] "Matching slave" refers to slave 121 identified by matching the source address of the sender.

[0294] "Slave base station" refers to slave base station 123 that is connected to slave station via wired connection.

[0295] exist Figure 15 In this context, conditions (A) and (B) are conditions related to the unicast transmission from slave station 121 to master station 111.

[0296] Condition (A) is as follows. Condition (A) is satisfied if all (Aa) to (Ad) are satisfied.

[0297] (Aa) The matching base station is from base station 123.

[0298] (Ab) matches the communication category "Send".

[0299] (Ac) Matching destination address is a unicast address.

[0300] If the matching destination address is neither a multicast address nor a broadcast address, the cause determination unit 322 determines that the matching destination address is a unicast address. Alternatively, if the matching destination address is the address of the master station 111 or the slave station 121, the cause determination unit 322 determines that the matching destination address is a unicast address.

[0301] (Ad) The corresponding historical information is recorded in historical file 391 [A].

[0302] The corresponding historical information [A] is the previous and subsequent historical information 240 that satisfies all [A1] to [A4].

[0303] [A1] Base station address 241 is the address of the main base station 113.

[0304] [A2] Communication category 242 is "receiving".

[0305] [A3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0306] [A4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0307] If condition (A) is met, the cause determination unit 322 determines that the cause is the matching slave station or the wired communication path between the matching slave station and the matching slave base station.

[0308] Condition (B) is as follows. Condition (B) is satisfied if all (Ba) to (Bd) are satisfied.

[0309] (Ba) The matching base station is the main base station 113.

[0310] (Bb) The matching communication category is "receive".

[0311] (Bc) Matching destination address is a unicast address.

[0312] (Bd) Corresponding historical information [B] was not recorded in historical file 391.

[0313] The corresponding historical information [B] is the historical information 240 that satisfies all [B1] to [B3].

[0314] [B1] Base station address 241 is the address of the slave base station.

[0315] [B2] Communication category 242 is "transmission".

[0316] [B3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0317] If condition (B) is met, the cause determination unit 322 determines that the wireless transmission from the matching slave base station to the master base station 113 is the cause.

[0318] exist Figure 16 In this context, conditions (C) and (D) are conditions related to the unicast transmission from master station 111 to slave station 121.

[0319] Condition (C) is as follows. Condition (C) is satisfied if all (Ca) to (Cd) are satisfied.

[0320] (Ca) The matching base station is from base station 123.

[0321] (Cb) The matching communication category is "receive".

[0322] (Cc) Matching destination address is a unicast address.

[0323] (Cd) The corresponding historical information is recorded in historical file 391 [C].

[0324] The corresponding historical information [C] is the previous and subsequent historical information 240 that satisfies all [C1] to [C4].

[0325] [C1] Base station address 241 is the address of the main base station 113.

[0326] [C2] Communication category 242 is "Send".

[0327] [C3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0328] [C4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0329] If condition (C) is met, the cause determination unit 322 determines that the cause is the main station 111 or the wired communication path between the main station 111 and the main base station 113.

[0330] Condition (D) is as follows. Condition (D) is satisfied if all (Da) to (Dd) are satisfied.

[0331] (Da) The matching base station is from base station 123.

[0332] (Db) The matching communication category is "Receive".

[0333] (Dc) Matching destination address is a unicast address.

[0334] (Dd) Corresponds to historical information [D] which is not recorded in historical file 391.

[0335] The corresponding historical information [D] is the previous and subsequent historical information 240 that satisfies all [D1] to [D4].

[0336] [D1] Base station address 241 is the address of the main base station 113.

[0337] [D2] Communication category 242 is "Send".

[0338] [D3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0339] [D4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0340] If condition (D) is met, the cause determination unit 322 determines that the wireless transmission from the master base station 113 to the slave base station 123 is the cause.

[0341] exist Figure 17 In this context, conditions (E), (F), and (G) are conditions related to a unicast transmission from slave station 121 to slave station 121 as the other party via wireless communication.

[0342] Condition (E) is as follows. Condition (E) is satisfied if all (Ea) to (Ed) are satisfied.

[0343] (Ea) The matching base station is from base station 123.

[0344] (Eb) The matching communication category is "Send".

[0345] (Ec) Matching destination address is a unicast address.

[0346] (Ed) The corresponding historical information is recorded in historical file 391 [E].

[0347] The corresponding historical information [E] is the historical information 240 that satisfies all [E1] to [E4].

[0348] [E1] Base station address 241 is the address of the other party's base station.

[0349] [E2] Communication category 242 is "receive".

[0350] [E3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0351] [E4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0352] If condition (E) is met, the cause determination unit 322 determines that the cause is the matching slave station or the wired communication path between the matching slave station and the matching slave base station.

[0353] Condition (F) is as follows. Condition (F) is satisfied if all (Fa) to (Fc) are satisfied and (Fd) or (Fe) is satisfied.

[0354] (Fa) Matching base station is from base station 123.

[0355] (Fb) The matching communication category is "Receive".

[0356] (Fc) Matching destination address is a unicast address.

[0357] (Fd) corresponds to historical information [F] which is not recorded in historical file 391.

[0358] (Fe) The corresponding historical information [F'] is recorded in historical file 391.

[0359] The corresponding historical information [F] is the previous and subsequent historical information 240 that satisfies all [F1] to [F3].

[0360] [F1] Base station address 241 is the address of the slave base station.

[0361] [F2] Communication category 242 is "Send".

[0362] [F3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0363] The corresponding historical information [F'] is the previous and subsequent historical information 240 that satisfies all [F'1] to [F'4].

[0364] [F'1] Base station address 241 is the address of the main base station 113.

[0365] [F'2] Communication category 242 is "Send".

[0366] [F'3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0367] [F'4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0368] If condition (F) is met, the cause determination unit 322 determines that the wireless transmission from the matching slave base station to the master base station 113 is the cause.

[0369] Condition (G) is as follows. Condition (G) is satisfied if all (Ga) to (Gc) are satisfied and (Gd) or (Ge) is satisfied.

[0370] (Ga) Matching base stations are from base station 123.

[0371] The (Gb) matching communication category is "Receive".

[0372] (Gc) Matching destination address is a unicast address.

[0373] (Gd) corresponds to the historical information [G] which is not recorded in historical file 391.

[0374] (Ge) has corresponding historical information [G'] recorded in historical file 391.

[0375] The corresponding historical information [G] is the previous and subsequent historical information 240 that satisfies all [G1] to [G3].

[0376] [G1] Base station address 241 is the address of the slave base station.

[0377] [G2] Communication category 242 is "Send".

[0378] [G3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0379] The corresponding historical information [G'] is the previous and subsequent historical information 240 that satisfies all [G'1] to [G'3].

[0380] [G'1] Base station address 241 is the address of the main base station 113.

[0381] [G'2] The group of destination address 243 and source address 244 is the same as the group of destination address 243 and source address 244 of the matching historical information.

[0382] [G'3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0383] If condition (G) is met, the cause determination unit 322 determines that the wireless transmission from the main base station 113 to the other party's slave base station is the cause.

[0384] exist Figure 18 In this context, conditions (H), (I), and (J) are conditions related to multicast transmission from slave station 121 to multiple stations.

[0385] Condition (H) is as follows. Condition (H) is satisfied if all (Ha) to (Hd) are satisfied.

[0386] (Ha) Matching base station is from base station 123.

[0387] (Hb) matches the communication category "Send".

[0388] (Hc) matches a multicast address.

[0389] (Hd) The corresponding historical information [H] is recorded in historical file 391.

[0390] The corresponding historical information [H] is the historical information 240 that satisfies all [H1] to [H4].

[0391] [H1] Base station address 241 is the address of the main base station 113.

[0392] [H2] Communication category 242 is "receive".

[0393] [H3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (multicast address) and source address 244 of the matching historical information.

[0394] [H4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0395] If condition (H) is met, the cause determination unit 322 determines that the cause is the matching slave station or the wired communication path between the matching slave station and the matching slave base station.

[0396] Condition (I) is as follows. Condition (I) is satisfied if all (Ia) to (Id) are satisfied.

[0397] (Ia) The matching base station is the main base station 113.

[0398] (Ib) The matching communication category is "Receive".

[0399] (Ic) Matching destination address is a multicast address.

[0400] (Id) The corresponding historical information [I] is not recorded in historical file 391.

[0401] The corresponding historical information [I] is the previous and subsequent historical information 240 that satisfies all [I1] to [I3].

[0402] [I1] Base station address 241 is the address of the slave base station.

[0403] [I2] Communication category 242 is "transmission".

[0404] [I3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0405] If condition (I) is met, the cause determination unit 322 determines that the wireless transmission from the matching slave base station to the master base station 113 is the cause.

[0406] Condition (J) is as follows. Condition (J) is satisfied if all (Ja) to (Jd) are satisfied.

[0407] (Ja) The matching base station is from base station 123.

[0408] (Jb) The matching communication category is "Receive".

[0409] (Jc) matches a multicast address.

[0410] (Jd) The corresponding historical information [J] and the corresponding historical information [J'] are not recorded in historical file 391.

[0411] The corresponding historical information [J] is the historical information 240 that satisfies all [J1], [J2] and [J3].

[0412] The corresponding historical information [J'] is the historical information 240 that satisfies all [J'1], [J2] and [J3].

[0413] [J1] Base station address 241 is the address of the slave base station.

[0414] [J'1] Base station address 241 is the address of the main base station 113.

[0415] [J2] Communication category 242 is "transmission".

[0416] [J3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0417] If condition (J) is met, the cause determination unit 322 determines that the wireless transmission from the main base station 113 to the corresponding slave base station is the cause.

[0418] exist Figure 19 In this context, condition (K) and condition (L) are conditions related to multicast transmission from master station 111 to multiple stations.

[0419] Condition (K) is as follows. Condition (K) is satisfied if all (Ka) to (Kd) are satisfied.

[0420] (Ka) Matching base station is main base station 113.

[0421] The (Kb) matching communication category is "Send".

[0422] (Kc) matches a multicast address.

[0423] (Kd) Records all the corresponding historical information [K] of each of the other party's base stations in historical file 391.

[0424] The corresponding historical information [K] is the previous and subsequent historical information 240 that satisfies all [K1] to [K4].

[0425] [K1] Base station address 241 is the address of the other party's base station.

[0426] [K2] Communication category 242 is "receive".

[0427] [K3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (multicast address) and source address 244 of the matching historical information.

[0428] [K4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0429] If condition (K) is met, the cause determination unit 322 determines that the cause is the master station 111 or the wired communication path between the master station 111 and the master base station 113.

[0430] Condition (L) is as follows. Condition (L) is satisfied if all (La) to (Ld) are satisfied.

[0431] (La) Matching base station is from base station 123.

[0432] (Lb) matches the communication category as "receive".

[0433] (Lc) matches the destination address, which is a multicast address.

[0434] (Ld) The corresponding historical information [L] is not recorded in historical file 391.

[0435] The corresponding historical information [L] is the previous and subsequent historical information 240 that satisfies all [L1] to [L4].

[0436] [L1] Base station address 241 is the address of the main base station 113.

[0437] [L2] Communication category 242 is "Send".

[0438] [L3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (multicast address) and source address 244 of the matching historical information.

[0439] [L4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0440] If condition (L) is met, the cause determination unit 322 determines that the wireless transmission from the main base station 113 to the other party's slave base station is the cause.

[0441] exist Figure 20 In this context, condition (M), condition (N), and condition (O) are conditions related to the broadcast transmission from slave station 121 to the entire station.

[0442] Condition (M) is as follows. Condition (M) is satisfied if all (Ma) to (Md) are satisfied.

[0443] (Ma) Matching base station is from base station 123.

[0444] The (Mb) matching communication category is "Send".

[0445] (Mc) matches the broadcast address.

[0446] (Md) The corresponding historical information [M] is recorded in historical file 391.

[0447] The corresponding historical information [M] is the previous and subsequent historical information 240 that satisfies all [M1] to [M4].

[0448] [M1] Base station address 241 is the address of the main base station 113.

[0449] [M2] Communication category 242 is "receive".

[0450] [M3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (broadcast address) and source address 244 of the matching historical information.

[0451] [M4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0452] If condition (M) is met, the cause determination unit 322 determines that the cause is the matching slave station or the wired communication path between the matching slave station and the matching slave base station.

[0453] Condition (N) is as follows. Condition (N) is satisfied if all (Na) to (Nd) are satisfied.

[0454] (Na) Matching base station is main base station 113.

[0455] (Nb) The matching communication category is "Receive".

[0456] (Nc) Matching destination address is a broadcast address.

[0457] (Nd) The corresponding historical information [N] is not recorded in historical file 391.

[0458] The corresponding historical information [N] is the previous and subsequent historical information 240 that satisfies all [N1] to [N3].

[0459] [N1] Base station address 241 is the address of the slave base station.

[0460] [N2] Communication category 242 is "transmission".

[0461] [N3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0462] If condition (N) is met, the cause determination unit 322 determines that the wireless transmission from the matching slave base station to the master base station 113 is the cause.

[0463] Condition (O) is as follows. Condition (O) is satisfied if all (Oa) to (Od) are satisfied.

[0464] (Oa) Matching base station is from base station 123.

[0465] (Ob) The matching communication category is "Receive".

[0466] (Oc) Matching destination address is a broadcast address.

[0467] (Od) The corresponding historical information [O] and the corresponding historical information [O'] are not recorded in historical file 391.

[0468] The corresponding historical information [O] is the previous and subsequent historical information 240 that satisfies all [O1], [O2] and [O3].

[0469] The corresponding historical information [O'] is the historical information 240 that satisfies all [O'1], [O2] and [O3].

[0470] [O1] Base station address 241 is the address of the slave base station.

[0471] [O'1] Base station address 241 is the address of the main base station 113.

[0472] [O2] Communication category 242 is "Send".

[0473] [O3] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0474] If condition (O) is met, the cause determination unit 322 determines that the wireless transmission from the main base station 113 to the corresponding slave base station is the cause.

[0475] exist Figure 21 In this context, conditions (P) and (Q) are conditions related to the broadcast transmission from master station 111 to the entire station.

[0476] Condition (P) is as follows. Condition (P) is satisfied if all (Pa) to (Pd) are satisfied.

[0477] (Pa) The matching base station is the main base station 113.

[0478] (Pb) matches the communication category as "Send".

[0479] (Pc) Matching destination address is a broadcast address.

[0480] (Pd) The historical file 391 contains all the corresponding historical information of each other's base stations [P].

[0481] The corresponding historical information [P] is the previous and subsequent historical information 240 that satisfies all [P1] to [P4].

[0482] [P1] Base station address 241 is the address of the other party's base station.

[0483] [P2] Communication category 242 is "receive".

[0484] [P3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (broadcast address) and source address 244 of the matching historical information.

[0485] [P4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0486] If condition (P) is met, the cause determination unit 322 determines that the cause is the master station 111 or the wired communication path between the master station 111 and the master base station 113.

[0487] Condition (Q) is as follows. Condition (Q) is satisfied if all (Qa) to (Qd) are satisfied.

[0488] (Qa) Matching base stations are from base stations 123.

[0489] (Qb) The matching communication category is "Receive".

[0490] (Qc) Matching destination address is a broadcast address.

[0491] (Qd) The corresponding historical information [Q] is not recorded in historical file 391.

[0492] The corresponding historical information [Q] is the previous and subsequent historical information 240 that satisfies all [Q1] to [Q4].

[0493] [Q1] Base station address 241 is the address of the main base station 113.

[0494] [Q2] Communication category 242 is "Sending".

[0495] [Q3] The group of destination address 243 and source address 244 is the same as the group of destination address 243 (broadcast address) and source address 244 of the matching historical information.

[0496] [Q4] The current communication time 254 is included between the previous communication time 251 that matches the historical information and the current communication time 254 that matches the historical information.

[0497] If condition (Q) is met, the cause determination unit 322 determines that the cause is the wireless transmission from the main base station 113 to the other party's slave base station.

[0498] ***Effects of Implementation Method 1***

[0499] According to Implementation 1, only the minimum amount of communication history information (previous and subsequent history information 240) required for fault cause analysis is stored. Therefore, the storage capacity of the communication history information and the frequency of communication history transmission can be limited to a minimum.

[0500] Implementation 1 monitors for the loss of communication frames 130 for each source device and each destination device, and stores the communication history information (previous and subsequent history information 240) only for the parts where communication failures may occur. As a result, the storage capacity required can be reduced, and thus the parsing time can be reduced.

[0501] Implementation 1 detects the loss of communication frames 130 for wireless transmission, wireless reception, and wired reception, and records only the communication history information before and after the loss (before and after history information 240) in the history file 391. Therefore, it is possible to store a sufficient amount of communication history information required for communication fault analysis, thereby reducing the storage amount of communication history information.

[0502] In Implementation 1, it is possible to determine, solely by the stored communication history information, the situation where the base station 200 lost the communication frame 130 in wireless communication because the communication frame 130 was not received by the master station 111 or slave station 121, which is the transmission source, through wired communication. Therefore, the determination of the cause of the fault becomes easy.

[0503] In Implementation 1, even if the final serial number is different depending on the slave station 121, the loss of communication frame 130 can be detected correctly.

[0504] In Implementation 1, the master base station 113 or slave base station 123 sends previous and subsequent historical information 240 to the historical management server 300 only when a loss of wireless reception or transmission is detected. Therefore, the communication band for cyclic data transfer is not suppressed.

[0505] ***Supplement to Implementation Method 1***

[0506] The historical management server 300 can also be built into the main base station 113 or any slave base station 123.

[0507] based on Figure 22 The hardware structure of base station 200 is described.

[0508] Base station 200 has processing circuit 209.

[0509] The processing circuit 209 is the hardware that implements the wireless communication unit 211, the transmission destination resolution unit 212, the wired communication unit 213, the communication frame monitoring unit 214, and the historical frame generation unit 215.

[0510] The processing circuit 209 can be dedicated hardware or a processor 201 that executes the program stored in the memory 202.

[0511] When the processing circuit 209 is dedicated hardware, the processing circuit 209 may be, for example, a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC, an FPGA, or a combination thereof.

[0512] ASIC is short for Application Specific Integrated Circuit.

[0513] FPGA is short for Field Programmable Gate Array.

[0514] The base station 200 may also have multiple processing circuits that can replace the processing circuit 209.

[0515] In the processing circuit 209, some functions can be implemented by dedicated hardware, while the remaining functions can be implemented by software or firmware.

[0516] In this way, the functions of base station 200 can be implemented through hardware, software, firmware, or a combination thereof.

[0517] based on Figure 23 The hardware structure of the historical management server 300 is described.

[0518] The historical management server 300 has a processing circuit 309.

[0519] The processing circuit 309 is the hardware that implements the historical frame receiving unit 311, the historical record unit 312, the information receiving unit 321, the cause determination unit 322, and the result output unit 323.

[0520] The processing circuit 309 can be dedicated hardware or a processor 301 that executes the program stored in the memory 302.

[0521] When the processing circuit 309 is dedicated hardware, the processing circuit 309 may be, for example, a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC, an FPGA, or a combination thereof.

[0522] The history management server 300 may also have multiple processing circuits that can replace the processing circuit 309.

[0523] In the processing circuit 309, some functions can be implemented by dedicated hardware, while the remaining functions can be implemented by software or firmware.

[0524] Thus, the functions of the historical management server 300 can be implemented through hardware, software, firmware, or a combination thereof.

[0525] Embodiment 1 is an example of a preferred embodiment and is not intended to limit the scope of this disclosure. Embodiment 1 may be implemented in part or in combination with other embodiments. The steps described using flowcharts or the like may also be modified as appropriate.

[0526] The term "department" which is an element of base station 200 and historical management server 300 can also be replaced with "process", "procedure", "circuit" or "line".

[0527] Explanation of reference numerals in the attached figures

[0528] 100 Communication monitoring system, 110 Master device, 111 Master station, 112 Network hub, 113 Master base station, 120 Slave device, 121 Slave station, 122 Network hub, 123 Slave base station, 130 Communication frame, 131 Destination radio address, 132 Payload, 140 Communication information, 141 Destination address, 142 Source address, 143 Periodic number, 144 Sequence number, 200 Base station, 201 Processor, 202 Memory, 203 Communication interface, 209 Processing circuit, 211 Wireless communication unit, 212 Sending and destination resolution unit, 213 Wired communication unit, 214 Communication frame monitoring unit, 215 Historical frame generation unit, 220 Monitoring table, 221 Communication category, 222 Source address, 223 Destination address, 224 Final number, 225 Communication time 226 Period number, 227 Sequence number, 230 Historical frame, 231 Destination radio address, 240 Previous and previous historical information, 241 Base station address, 242 Communication category, 243 Destination address, 244 Source address, 251 Last communication time, 252 Last period number, 253 Last sequence number, 254 Current communication time, 255 Current period number, 256 Current sequence number, 290 Storage unit, 300 Historical management server, 301 Processor, 302 Memory, 303 Auxiliary storage device, 304 Communication device, 305 Input / output interface, 309 Processing circuit, 311 Historical frame receiving unit, 312 Historical record unit, 321 Information receiving unit, 322 Cause determination unit, 323 Result output unit, 390 Storage unit, 391 Historical file.

Claims

1. A communication surveillance system, wherein, The communication monitoring system includes: The main base station is connected to the main station via a wired connection; The base station is connected to the slave station via a wired connection and communicates with the master base station wirelessly via communication frames between the master station and the slave station. as well as The historical management server records the communication history information of communication frames that communicated with the main base station and the slave base station before and after the lost communication frame, which is used as historical information for fault cause analysis. The master station and the slave station communicate with each other within a set fixed number of communication frames during the cycle. The communication frame contains a sequence number representing the order within the cycle and a cycle number that increments with each iteration of the cycle as communication information. When the master base station and the slave base station communicate wirelessly for each communication frame, they determine whether there are any lost communication frames based on the communication information of the current communication frame and the communication information of the previous communication frame. If there are any lost communication frames, they send the communication history information of the previous communication frame and the current communication frame as the previous and previous history information to the history management server.

2. The communication monitoring system according to claim 1, wherein, The period numbering starts from the minimum number and ends at the maximum number. After becoming the maximum number, it reverts to the minimum number. The sequence numbering starts from the beginning number and ends at the final number corresponding to the fixed number, and returns to the beginning number each time the cycle is completed.

3. The communication monitoring system according to claim 2, wherein, If the period number of the current communication frame is the same as the period number of the previous communication frame, and the sequence number of the current communication frame is more than 2 greater than the sequence number of the previous communication frame, the master base station and the slave base station determine that there is a lost communication frame.

4. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the current communication frame is more than 2 greater than the period number of the previous communication frame, the master base station and the slave base station determine that there is a lost communication frame.

5. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the current communication frame is 1 greater than the period number of the previous communication frame, and the sequence number of the previous communication frame is less than the final number, the master base station and the slave base station determine that there is a lost communication frame.

6. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the current communication frame is 1 greater than the period number of the previous communication frame, and the sequence number of the current communication frame is not the start number, the master base station and the slave base station determine that there is a lost communication frame.

7. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the previous communication frame is the maximum number, and the period number of the current communication frame is neither the maximum number nor the minimum number, the master base station and the slave base station determine that there is a lost communication frame.

8. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the previous communication frame is the maximum number, the period number of the current communication frame is the minimum number, and the sequence number of the previous communication frame is smaller than the final number, the master base station and the slave base station determine that there is a lost communication frame.

9. The communication monitoring system according to claim 2 or 3, wherein, If the period number of the previous communication frame is the maximum number, the period number of the current communication frame is the minimum number, the sequence number of the previous communication frame is the final number, and the sequence number of the current communication frame is not the beginning number, the master base station and the slave base station determine that there is a lost communication frame.

10. The communication surveillance system according to any one of claims 1 to 3, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

11. The communication monitoring system according to claim 4, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

12. The communication monitoring system according to claim 5, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

13. The communication monitoring system according to claim 6, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

14. The communication surveillance system according to claim 7, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

15. The communication monitoring system according to claim 8, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

16. The communication surveillance system according to claim 9, wherein, The historical management server determines the cause of the fault based on matching historical information and the presence or absence of corresponding historical information. The matching historical information is the communication frames before and after the fault detection time, and the corresponding historical information is the communication frames before and after the matching historical information.

17. A base station that is used as a master base station or a slave base station in the communication surveillance system according to any one of claims 1 to 16.

18. A history management server, wherein, The history management server is used in the communication monitoring system according to any one of claims 1 to 16.

19. A communication monitoring method, which is a communication monitoring method for a communication monitoring system, wherein, The communication monitoring system includes: The main base station is connected to the main station via a wired connection; The base station is connected to the slave station via a wired connection and communicates with the master base station wirelessly via communication frames between the master station and the slave station. as well as The historical management server records the communication history information of communication frames that communicated with the main base station and the slave base station before and after the lost communication frame, which is used as historical information for fault cause analysis. The master station and the slave station communicate with each other within a set fixed number of communication frames during the cycle. The communication frame contains a sequence number representing the order within the cycle and a cycle number that increments with each iteration of the cycle as communication information. When the master base station and the slave base station communicate wirelessly for each communication frame, they determine whether there are any lost communication frames based on the communication information of the current communication frame and the communication information of the previous communication frame. If there are any lost communication frames, they send the communication history information of the previous communication frame and the current communication frame as the previous and previous history information to the history management server.

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