A redundant communication method for dual wireless link hot standby circuit

Abstract

The present invention relates to a redundant communication method of a dual wireless link hot standby circuit, wherein a module that actively sends data is set in a network composed of N modules; ZIGBEE is preset as a default wireless link between the N modules that need to communicate; when the transmitting end cannot receive confirmation information fed back by any receiving end after sending data, or the received confirmation information is wrong; the transmitting end first checks the fault list; if the receiving end is not recorded in the fault list, the transmitting end suspends the current data communication task; when it is determined that the communication failure is due to the receiving end being unable to receive data, the transmitting end starts the ZIGBEE link test thread; after the main link is restored, the transmitting end switches the data back to the ZigBee communication link. The present invention solves the problem that data cannot be transmitted when the wireless link fails to communicate due to interference or equipment failure in a single wireless communication ad hoc network, thereby improving the stability and real-time performance of wireless communication.

Description

Technical Field

[0001] The present invention relates to a redundant communication method of a dual wireless link hot standby circuit, which can be applied to various application fields involving industrial control, smart transportation, smart municipal administration, water treatment, petrochemical industry, etc. that require the construction of loosely coupled and decentralized wireless communication networks. Background Art

[0002] With the development of wireless communication technology of the Internet of Things, the application of wireless transparent transmission technology is becoming more and more extensive, and more equipment control and instrument collection scenarios use wireless communication to transmit data. Especially for the expansion or upgrade of some traditional control systems, wireless communication technology of the Internet of Things plays an increasingly important role.

[0003] In traditional control systems, substations, controlled equipment, and data acquisition instruments are generally connected to the main controller via wired connections. When upgrading and renovating the system, many owners focus on wireless communication technology. Wireless communication has significant advantages. The system transformation is simple, the cycle is short, it does not affect the existing production or has little impact, and it can be effective quickly. However, wireless communication also has its fatal weakness, that is, the connection is unreliable and it is easy to fail due to interference. Many owners are also deterred by this and dare not use wireless communication technology in control systems, especially in core control systems with high reliability and real-time requirements. At the same time, relatively speaking, the unreliable and unstable characteristics of wireless communication also restrict the development of the technology itself.

[0004] The reason for this problem is that in practical applications, most wireless communication gateways use single-link wireless communication devices. Once interfered, the communication may fail or the communication delay may be prolonged, making it impossible to guarantee the reliability and real-time performance of data transmission.

[0005] Common products on the market include the ZIGBEE to MODBUS-485 gateways launched by Shenzhen Zhongdingtai and Chengdu Yibite. Based on the ZIGBEE self-organizing network wireless transparent transmission technology, the original wired communication protocol is converted into a wireless connection, which greatly reduces the difficulty of communication and networking of the automatic control system. It is especially suitable for instrument data collection or small control system data transmission in some dispersed locations, long distances, difficult and costly cable laying.

[0006] The ZIGBEE network is a MESH structure network. A network consists of a Coordnator (coordinator, master module) and N Routers (router, slave modules). All nodes have the same channel and group number. The biggest feature of the MESH network is automatic routing and dynamic maintenance routing, such as Fig. 9When C communicates with B3, if it cannot be reached directly, it will automatically route the data to B3 through B1 and B2. Moreover, when B1 or B2 is damaged, it will automatically find a new routing path.

[0007] But there are the following problems:

[0008] In practical applications, there may be a situation where there is only one route for data transmission. In this case, it is difficult to ensure reliable communication with a single wireless communication link. Fig.10 Communication between coordinator C and node B5: If node B5 is far away from coordinator C, it can only communicate with coordinator C through router B4. Router B4 plays a very important role as a transit node. Once the wireless communication between coordinator C and router B4 fails due to failure or interference, since there is only one ZIGBEE wireless communication link between node B5 and coordinator C, node B5 cannot connect to coordinator C before the ZIGBEE communication link is restored. Summary of the invention

[0009] In view of the existing technical status and its shortcomings, the present invention provides a redundant communication method for a dual wireless link hot standby circuit. The present invention develops a dual wireless link hot standby technology, which changes the traditional single wireless communication link into a dual wireless communication link. The dual links maintain a real-time connection state, and the dual links serve as a primary and a backup for each other. When the main link is disturbed, the MCU can quickly determine the current communication state. Once the communication fails, the data stream can be switched to the backup link in the shortest time. The entire switching time can reach milliseconds, thereby ensuring the reliability and real-time performance of wireless communication.

[0010] To achieve the above object, the present invention adopts a technical solution: a dual wireless link hot standby circuit, characterized in that: it includes a microprocessor and a wireless communication module, wherein the microprocessor module is composed of an MCU module and a memory external circuit connected to each other;

[0011] The wireless communication module is composed of a ZIGBEE module and a LORA module;

[0012] The microprocessor module is connected to the ZIGBEE module and the LORA module respectively.

[0013] A redundant communication method for a dual wireless link hot standby circuit, characterized in that the steps are as follows:

[0014] 1) In a network composed of N modules, a single module that actively sends data is set, hereinafter referred to as the sender, and the other N-1 modules are data receiving ends, hereinafter referred to as the receiving ends. The sender actively sends data to the receiving end, and the receiving end feeds back confirmation information to the sender after receiving the data sent by the sender. After receiving the correct confirmation information fed back by the receiving end, the sender completes an effective data communication;

[0015] 2) ZIGBEE is preset as a default wireless link between the N modules that need to communicate. That is, the ZIGBEE link is used for communication first after the module is powered on. At the same time, the LORA link on any module is used as a backup wireless link and is in a listening state.

[0016] 3) The monitoring state means: the sender starts a monitoring thread, which sends a custom data packet to each receiving end in turn through the LORA backup communication link at a custom unit time interval. After receiving the data packet sent by the sender, the receiving end feeds back a custom confirmation message to the sender. The sender completes a monitoring task after receiving the confirmation information from each receiving end; if any receiving end does not feed back confirmation data, or the feedback confirmation data is wrong, the receiving end will be recorded in the fault list;

[0017] 4) When data is wirelessly communicated between any modules among N modules through the ZIGBEE communication link, the sender cannot receive confirmation information from any receiving end after sending the data, or the received confirmation information is wrong;

[0018] 5) The sender first checks the fault list. If the receiver has been recorded in the fault list, the sender sets a fault mark for the receiver and sends an alarm message. At the same time, the sender continues to perform data communication tasks through the ZIGBEE link. If a fault mark is found during the execution, the receiver is automatically skipped.

[0019] 6) If the receiving end is not recorded in the fault list, the sending end suspends the current data communication task and retransmits the data packet to the receiving end for a specified number of times through the ZIGBEE link to determine whether the communication failure is caused by the sending end's failure to send data or the receiving end's inability to receive data;

[0020] 7) When it is determined that the communication failure is due to the inability of the receiving end to receive data, the sending end considers that the currently used ZIGBEE communication link has failed, and the sending end will switch the data communication task to the backup LoRa communication link and communicate with the receiving end; at the same time, the sending end starts the ZIGBEE link test thread, and the sending end continuously sends custom test data packets to the receiving end that was previously unable to communicate through the ZIGBEE communication link at custom unit intervals until the receiving end receives the correct confirmation information feedback, and then the sending end sends the test data packets to each receiving end on the link in turn. After each receiving end feedbacks the correct confirmation information, the sending end considers that the ZIGBEE link has recovered;

[0021] 8) After the main link is restored, the transmitter switches the data back to the ZigBee communication link, closes the ZIGBEE link test thread, switches the backup LORA link back to the listening state, and continues to use the ZIGBEE link to send data to each receiving end until communication failure occurs again.

[0022] The beneficial effects of the present invention are as follows: the present invention solves the problem that data cannot be transmitted when the wireless link fails to communicate due to interference or equipment failure in a single wireless communication ad hoc network, which makes up for the shortcomings of wireless communication technology in practical applications, significantly improves the stability and real-time performance of wireless communication, and improves the use effect of wireless communication in control systems, while promoting the upgrade of wireless communication products and the development of wireless communication technology. The dual wireless link hot standby technology developed by this patent is suitable for various medium and long-distance wireless communication scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a circuit connection block diagram of the present invention;

[0024] Figure 2 is a flow chart of the redundant communication method of the present invention;

[0025] Figure 3 A schematic diagram of the network configuration of the redundant communication method of the present invention;

[0026] Figure 4 This is a circuit connection block diagram of Embodiment 1 of the present invention;

[0027] Figure 5 This is a schematic diagram of a normal communication situation in a typical application of Example 2 of the present invention;

[0028] Figure 6 This is a schematic diagram of a ZIGBEE main link failure or interference situation in a typical application of Example 2 of the present invention;

[0029] Figure 7 A schematic diagram of automatically enabling the LORA standby link in a typical application of Example 2 of the present invention;

[0030] Figure 8 This is a schematic diagram of the ZIGBEE main link recovery situation in a typical application of Example 2 of the present invention;

[0031] Fig. 9 It is a schematic diagram of a ZigBee network in the prior art;

[0032] Fig.10 This is a schematic diagram of a single wireless communication link failure in the prior art. DETAILED DESCRIPTION

[0033] like Figure 1As shown, a dual wireless link hot standby circuit includes a microprocessor and a wireless communication module. The microprocessor is composed of an MCU module, a memory and an external circuit that are interconnected; the wireless communication module is composed of a ZIGBEE module and a LORA module; the MCU module is respectively connected to the ZIGBEE module and the LORA module to realize wireless communication.

[0034] like Figure 2 , Figure 3 As shown, a redundant communication method of a dual wireless link hot standby circuit, the steps are as follows:

[0035] 1) In a network composed of N modules, a single module that actively sends data is set, hereinafter referred to as the sender, and the other N-1 modules are data receiving ends, hereinafter referred to as the receivers. The sender can actively send data to the receiver, and the receiver feeds back confirmation information to the sender after receiving the data sent by the sender. After receiving the correct confirmation information fed back by the receiver, the sender completes an effective data communication;

[0036] 2) ZIGBEE is preset as a default wireless link between the N modules that need to communicate. That is, the ZIGBEE link is used for communication first after the module is powered on. At the same time, the LORA link on any module is used as a backup wireless link and is in a listening state.

[0037] 3) The monitoring state means: the sender starts a monitoring thread, which sends a custom data packet to each receiving end in turn through the LORA backup communication link at a custom unit time interval. After receiving the data packet sent by the sender, the receiving end feeds back a custom confirmation message to the sender. The sender completes a monitoring task after receiving the confirmation information from each receiving end; if any receiving end does not feed back confirmation data, or the feedback confirmation data is wrong, the receiving end will be recorded in the fault list;

[0038] 4) When data is wirelessly communicated between any modules among N modules through the ZIGBEE communication link, the sender cannot receive confirmation information from any receiving end after sending the data, or the received confirmation information is wrong;

[0039] 5) The sender first checks the fault list. If the receiver has been recorded in the fault list, the sender sets a fault mark for the receiver and sends an alarm message. At the same time, the sender continues to perform data communication tasks through the ZIGBEE link. If a fault mark is found during the execution, the receiver is automatically skipped.

[0040] 6) If the receiving end is not recorded in the fault list, the sending end suspends the current data communication task and retransmits the data packet to the receiving end for a specified number of times through the ZIGBEE link to determine whether the communication failure is caused by the sending end's failure to send data or the receiving end's inability to receive data;

[0041] 7) When it is determined that the communication failure is due to the inability of the receiving end to receive data, the sending end considers that the currently used ZIGBEE communication link has failed, and the sending end will switch the data communication task to the backup LoRa communication link and communicate with the receiving end; at the same time, the sending end starts the ZIGBEE link test thread, and the sending end continuously sends custom test data packets to the receiving end that was previously unable to communicate through the ZIGBEE communication link at custom unit intervals until the receiving end receives the correct confirmation information feedback, and then the sending end sends the test data packets to each receiving end on the link in turn. After each receiving end feedbacks the correct confirmation information, the sending end considers that the ZIGBEE link has recovered;

[0042] 8) After the main link is restored, the transmitter switches the data back to the ZigBee communication link, closes the ZIGBEE link test thread, switches the backup LORA link back to the listening state, and continues to use the ZIGBEE link to send data to each receiving end until communication failure occurs again.

[0043] Embodiment 1, as Figure 4 As shown:

[0044] After the dual wireless links are established, more other applications can be expanded based on the microprocessor-wireless communication module architecture. Since the MCU has excellent expansion capabilities, various types of interfaces can be expanded.

[0045] For example: Based on dual wireless communication, digital input and output modules can be expanded, and digital input and output modules can be connected to digital control devices to achieve remote wireless monitoring of devices. Based on the expansion of digital input and output interfaces, standard industrial communication protocol interfaces can be expanded, including but not limited to mainstream industrial protocol interfaces such as MODBUS-485 and CAN-BUS.

[0046] Embodiment 2, as Figures 5 to 8 Typical application scenarios shown:

[0047] In this scenario, module A extends the digital input and output module and the standard MODBUS-485 interface module, connects to the controller, and acts as a communication master. It acts as a coordinator node in the ZIGBEE self-organizing network and as a base station in the LORA self-organizing network. Module B extends the digital input and output module, connects to the controlled equipment on site, and acts as a communication slave. It acts as a router node in the ZIGBEE self-organizing network and as a node in the LORA self-organizing network. Module B is closer to module A, and the ZIGBEE signal can be directly connected to the coordinator node without transfer. Module N extends the standard MODBUS-485 interface module, connects to the on-site acquisition instrument, and acts as a communication slave. It acts as a terminal node in the ZIGBEE self-organizing network and as a node in the LORA self-organizing network. Module N is far away from module A, and the ZIGBEE signal cannot be directly connected to the coordinator node, and needs to be transferred through module B, which acts as a router node.

[0048] like Figure 5 As shown: Normal situation: The dual wireless communication links between each module are kept in real-time connection state. One of the links can be set as the main communication link, and the other link can be set as the auxiliary communication link (the ZIGBEE link in the figure is the main communication link, and the LORA link is the backup link). The field equipment data and the controller control instruction data stream are transmitted through the main communication link. (Wireless communication is transparent transmission for self-organizing network, and the specific data stream format depends on the selected communication protocol). As shown in the figure, first of all, in order to ensure that each module can realize self-organizing network, the frequency band and grouping of ZIGBEE module and LORA module in the module should be unified. The ZIGBEE module in module A is configured as a "coordinator" and the LORA module is configured as a "base station", the ZIGBEE module in module B is configured as a "router" and the LORA module is configured as a "node", and the ZIGBEE module in module N is configured as a "terminal" and the LORA module is configured as a "node".

[0049] Module N is far away from module A and cannot be directly connected to module A through ZIGBEE. Therefore, the routing forwarding function of ZIGBEE in module B is used to forward the data to module A to achieve communication with module A.

[0050] like Figure 6 As shown: When the ZIGBEE communication link between module N and module B is disturbed, a link cannot be established with module B, and data cannot reach module A, and communication is interrupted.

[0051] like Figure 7 As shown: At this time, the module will automatically switch the data stream to the LORA auxiliary link and restore data communication.

[0052] like Figure 8 As shown: After the main circuit link is restored, the data flow is switched back to the main circuit, and the communication is restored to the state as shown below: Figure 5The normal working state shown here ensures the stability of wireless communication.

Claims

1. A redundant communication method for a dual wireless link hot standby circuit, characterized in that: The dual wireless link hot standby circuit includes a microprocessor and a wireless communication module, wherein the microprocessor module is composed of an MCU module and a memory external circuit connected to each other; The wireless communication module is composed of a ZIGBEE module and a LORA module; The microprocessor module is connected to the ZIGBEE module and the LORA module respectively; The communication method steps are as follows: 1) In a network composed of N modules, a single module that actively sends data is set, hereinafter referred to as the sender, and the other N-1 modules are data receiving ends, hereinafter referred to as the receiving ends. The sender actively sends data to the receiving end, and the receiving end feeds back confirmation information to the sender after receiving the data sent by the sender. After receiving the correct confirmation information fed back by the receiving end, the sender completes an effective data communication; 2) ZIGBEE is preset as a default wireless link between the N modules that need to communicate. That is, the ZIGBEE link is used for communication first after the module is powered on. At the same time, the LORA link on any module is used as a backup wireless link and is in a listening state. 3) The monitoring state means: the sender starts a monitoring thread, which sends a custom data packet to each receiving end in turn through the LORA backup communication link at a custom unit time interval. After receiving the data packet sent by the sender, the receiving end feeds back a custom confirmation message to the sender. The sender completes a monitoring task after receiving the confirmation information from each receiving end; if any receiving end does not feed back confirmation data, or the feedback confirmation data is wrong, the receiving end will be recorded in the fault list; 4) When data is wirelessly communicated between any modules among N modules through the ZIGBEE communication link, the sender cannot receive confirmation information from any receiving end after sending the data, or the received confirmation information is wrong; 5) The sender first checks the fault list. If the receiver has been recorded in the fault list, the sender sets a fault mark for the receiver and sends an alarm message. At the same time, the sender continues to perform data communication tasks through the ZIGBEE link. If a fault mark is found during the execution, the receiver is automatically skipped. 6) If the receiving end is not recorded in the fault list, the sending end suspends the current data communication task and retransmits the data packet to the receiving end for a specified number of times through the ZIGBEE link to determine whether the communication failure is caused by the sending end's failure to send data or the receiving end's inability to receive data; 7) When it is determined that the communication failure is due to the inability of the receiving end to receive data, the sending end considers that the currently used ZIGBEE communication link has failed, and the sending end will switch the data communication task to the backup LoRa communication link and communicate with the receiving end; at the same time, the sending end starts the ZIGBEE link test thread, and the sending end continuously sends custom test data packets to the receiving end that was previously unable to communicate through the ZIGBEE communication link at custom unit intervals until the receiving end receives the correct confirmation information feedback, and then the sending end sends the test data packets to each receiving end on the link in turn. After each receiving end feedbacks the correct confirmation information, the sending end considers that the ZIGBEE link has recovered; 8) After the main link is restored, the transmitter switches the data back to the ZigBee communication link, closes the ZIGBEE link test thread, switches the backup LORA link back to the listening state, and continues to use the ZIGBEE link to send data to each receiving end until communication failure occurs again.

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