Dynamic role change of mesh network nodes

Abstract

A field device configured for integration into a wireless mesh network. The field device has a role within the wireless mesh network, and this role includes a sensor node, a router node, and a gateway node. The field device's role determines its ability to generate, receive, and transmit data packets.The field device comprises the following: a housing; a sensor module that detects and measures a physical quantity of an industrial process, wherein the physical quantity describes a process state of the industrial process, the process state changing over time, and wherein the sensor module outputs an electrical output signal correlated with the physical quantity; a communication module configured to receive and transmit data packets generated by the field device itself and by other field devices in the wireless mesh network via a wireless communication standard; and a processing unit configured for data processing, communication tasks, and device diagnostics. The field device is characterized in that the processing unit defines and modifies the role of the field device in the wireless mesh network.

Description

[0001] The invention relates to field devices configured for integration into a wireless mesh network.

[0002] A wireless mesh network is a communication network or radio network with radio nodes and links that connect the nodes in a meshed structure. The name "mesh network" derives from the topology of the resulting network. In a fully connected mesh network, every node is connected to every other node, thus forming a "mesh".

[0003] This network topology offers high reliability and redundancy, as data can be transmitted over multiple paths. This is particularly advantageous in industrial environments, where communication paths can often be affected by physical obstacles or electromagnetic interference.

[0004] In modern process automation, a field device integrated into a wireless sensor network (e.g., using standard WirelessHART technology) typically comprises several key components essential for its operation. These field devices are often part of a mesh network that enables communication between devices and ensures reliable and efficient data transmission. These components include a sensor module responsible for detecting and measuring process variables such as temperature, pressure, level, or flow rate. The device also features a communication module that adheres to a standard protocol, enabling data transmission to and from the field device via a secure and reliable wireless network. An integrated microcontroller or processor handles data processing, communication tasks, and device diagnostics.Furthermore, the device features a robust and durable housing that provides protection against environmental factors such as dust, moisture, and extreme temperatures, thus ensuring the longevity and reliability of the field device in various industrial environments. Additionally, the field device can be equipped with a power supply module, often utilizing long-life batteries or energy harvesting technologies to guarantee continuous operation in remote or hazardous locations.

[0005] Integrating these field devices into a wireless mesh network significantly improves the efficiency and reliability of process automation.

[0006] In a wireless mesh network, a field device is a node that has a role, which typically includes a sensor node, a router node, and a gateway node.

[0007] The sensor nodes are the primary data acquisition points in the network. Each sensor node measures specific process variables (e.g., temperature, pressure) and transmits this data wirelessly.

[0008] The primary function of router nodes is to forward data between sensor nodes and the gateway node. They improve network coverage and reliability by providing multiple data paths, ensuring that data reaches its destination via an alternative route even if one path is blocked or a node fails.

[0009] A gateway node acts as a bridge between the wireless mesh network and the control system or central server of the plant. It aggregates data from the sensor and router nodes and facilitates communication with external systems.

[0010] It should be noted, however, that while sensor, router, and gateway nodes have different functions, they are all field devices in the wireless mesh network. A router or gateway node can therefore perform all the functions of a sensor node, namely measuring / generating and transmitting data.

[0011] In current WirelessHART technology, device roles within the network are static and cannot be dynamically changed. This means that if a device's role needs to be changed, for example, from a sensor node to a router node, the entire network must be reconfigured. This reconfiguration process is time-consuming and can lead to significant downtime. The lack of flexibility in dynamically adapting device roles hinders the network's ability to quickly adjust to changing operational requirements or optimize performance in real time.

[0012] Furthermore, configuration decisions are made centrally by a single management node. This centralized approach can become a bottleneck as the network grows. The more nodes are added, the more data and configuration tasks the management node has to handle, which can lead to delays and inefficiencies. Network scalability is compromised because the centralized management system struggles to keep pace with the demands of a larger network, resulting in slower response times and potential performance issues.

[0013] The invention is based on the objective of avoiding a complete reconfiguration of the network when the role of a field device needs to be changed, and of improving the scalability of the network by enabling dynamic role changes between nodes and allowing local configuration decisions.

[0014] The invention is defined by the attached independent claims. Additional features and advantages of the concepts disclosed herein are set forth in the following description.

[0015] This disclosure describes a field device configured for integration into a wireless mesh network. The field device has a role within the wireless mesh network, comprising a sensor node, a router node, and a gateway node. The field device's role determines its ability to generate, receive, and transmit data packets.A sensor node generates data packets relevant to an industrial process and transmits them to a router node or gateway node; a router node performs all the functions of a sensor node and additionally receives data packets from sensor nodes and forwards them to a gateway node; and a gateway node performs all the functions of a sensor node and additionally receives data packets from sensor nodes and router nodes and connects the wireless mesh network to an external network, a control system, and / or a central server of an industrial plant.

[0016] The field device comprises the following: a housing; a sensor module that detects and measures a physical quantity of an industrial process, wherein the physical quantity describes a process state of the industrial process, the process state changing over time, and wherein the sensor module outputs an electrical output signal correlated with the physical quantity; a communication module configured to receive and transmit data packets generated by the field device itself and by other field devices in the wireless mesh network via a wireless communication standard; and a processing unit configured for data processing, communication tasks, and device diagnostics. The field device is characterized in that the processing unit defines and modifies the role of the field device in the wireless mesh network.

[0017] The role of the field device is defined and modified by the field device's processing unit. This allows configuration changes to be made locally, instead of relying on a central control point. Thus, the invention eliminates the dependency on a centralized management node. This decentralization increases the network's scalability and enables a growing number of nodes to be managed more efficiently without performance degradation.

[0018] By enabling dynamic role changes, e.g., between router nodes and sensor nodes, and the resulting restructuring of communication paths within the network, the invention eliminates the need for a complete network reconfiguration. This reduces downtime and improves the network's ability to adapt quickly to changing conditions.

[0019] In some embodiments, a field device is disclosed whose processing unit defines and modifies the role of the field device in the wireless mesh network based on the electrical output signal. The field device uses a current loop interface for the electrical output signal. The current interface itself supplies power to the field device. The current interface conforms, for example, to the standard 4...20 mA.

[0020] In some embodiments, a field device is disclosed, wherein the field device is configured to receive power from a battery. The processing unit can define and change the role of the field device in the wireless mesh network based on the battery's state of charge.

[0021] In some embodiments, a field device is disclosed whose processing unit is configured to determine an energy budget for the field device and to define and change the role of the field device in the wireless mesh network based on this energy budget. The energy budget is the amount of energy that the field device has available, consumes, or allocates for its operations over a specific period of time.

[0022] In some embodiments, a field device is disclosed whose processing unit learns and plans a temporal profile of the energy budget based on one or more factors. The factors include: - Time series components of the electrical output signal, in particular the periodicity of the electrical output signal; - constant minimum energy supply to the field device; and - Time-of-day dependent factors, in particular the supply via solar energy, whereby the field device is configured to receive energy from a solar module.

[0023] In some embodiments, a field device is disclosed whose processing unit defines and modifies the field device's role in the wireless mesh network based on the current state of the field device's current neighborhood. The current neighborhood comprises other field devices in the wireless mesh network within the field device's communication range. The current state of the current neighborhoods includes the current power and the current roles available to each of the current neighborhoods.

[0024] In some embodiments, a field device is disclosed, wherein the field device is configured to receive power from a constant power source. The field device is also configured to connect the wireless mesh network to an external network, a control system, and / or a central server of an industrial plant.

[0025] The present disclosure describes a method for changing the role of a field device in a wireless mesh network. The role of a field device in a wireless mesh network is dynamic and can be defined and changed by a processing unit of the field device. A field device can be a sensor node as well as a router or gateway node; that is, a field device is not limited to a single role. Subsequently, a communication module of the field device sends a data packet containing information about the change in the field device's role to the other field devices of the wireless mesh network within a communication range.

[0026] The present disclosure further comprises a computer-readable medium for storing program code that causes a field device to perform at least the steps of the procedure described above and in this description.

[0027] This will be explained in more detail using the following figures. Fig. Figure 1 shows an example wireless mesh network. Fig. Figures 2a-2b show an exemplary embodiment of the claimed field devices in a wireless mesh network.

[0028] In the figures, identical features are marked with the same reference symbols.

[0029] An exemplary wireless mesh network in its entirety has the reference number 100 and is in Fig. 1 shown.

[0030] The Mesh Network 100 has three types of roles or nodes: Sensor Node 1, Router Node 2, and Gateway Node 3. The nodes are wirelessly connected. The Mesh Network 100 is based on a clustered tree structure. A Router Node 2 manages the use of radio resources within the cluster 5 or the connection it controls. The Mesh Network 100 transmits data using Router Node 2, which provides multiple paths for data to reach Gateway Node 3. Gateway Node 3 aggregates data from Sensor Node 1 and Router Node 2 and enables communication, for example, via an internet connection 4, with external systems.

[0031] Fig. Figures 2a-2b show an exemplary embodiment of the claimed field devices in a wireless mesh network 200.

[0032] Field devices that are in the mesh network 200 as sensor nodes 11, 12 and 13, router node 21 or gateway node 3 in Fig.The devices shown in section 2a are designed for integration into the 200 wireless mesh network. Each field device has a housing, a sensor module that detects and measures a physical parameter of an industrial process, a communication module for sending / transmitting and receiving data packets, and a processing unit that manages data processing, communication tasks, and device diagnostics. Sensor nodes 11, 12, and 13, router node 21, and gateway node 3 communicate with each other via the communication modules using a wireless communication standard. All sensor nodes 11, 12, and 13 of the 200 mesh network have at least one connection to gateway node 3, either directly or via router node 21.

[0033] The processing unit defines and modifies the role of the field device in the Mesh Network 200, which can be a gateway node, a router node, or a sensor node depending on the currently available power. The routes in the network are dynamically reconfigured.

[0034] In some embodiments, the role of the field device in the wireless mesh network 200 is dynamically defined and changed based on the currently available power derived from the electrical output signal. The field device uses a current loop interface for the electrical output signal and is powered via this interface, adhering to the 4...20 mA standard.

[0035] In industrial process control, analog 4...20 mA current loops are frequently used for electronic signals, with the two values ​​4 and 20 mA representing 0-100% of the measurement or control range. These loops are used both for transmitting sensor information from field devices and for transmitting control signals to process modulation devices, such as a valve.

[0036] When the available energy is high, e.g., a container is full, the field device can become router node 2 for other field devices. In Fig. 2a, the first container 6 is full, corresponding to a value of 20 mA for the electrical output signal; then the field device, e.g., a level gauge, can become router node 21 for other field devices, i.e., sensor nodes 11, 12, and 13.

[0037] In this example, sensor node 13, which is also a level sensor measuring the fill level of the second container 7, sends data packets directly to gateway node 3. Router node 21 forwards data packets from sensor nodes 11 and 12 to gateway node 3. Sensor nodes 11 and 12 forward data packets via router node 21 instead of sending them directly to gateway node 3 because gateway node 3 is out of range of sensor nodes 11 and 12. Other reasons why sensor node 1 might send a data packet to gateway node 3 via router node 2 could include: saving energy, balancing network load, maintaining signal strength and reliability, and ensuring redundancy and fault tolerance.

[0038] Over time, the process status / state changes, as shown in Fig. 2b. The first container 6 was no longer full, and the corresponding electrical output signal was reduced to 6 mA. Router node 21 can no longer maintain its role because forwarding data packets requires significantly more energy than a sensor node 1, which only sends data packets to router node 2 or gateway node 3. Therefore, the processing unit of router node 21 changed its role to that of a sensor node 14 and informed sensor nodes 11, 12, and 13 of this change.

[0039] The fill level of the second container 7 has risen, and the corresponding electrical output signal has increased to 18 mA, which is sufficient for forwarding data packets to sensor nodes 11 and 12. Therefore, the processing unit of sensor node 13 has changed its role to that of a router node 22 and informed sensor nodes 11 and 12 of this change so that router node 22 can be located by them. Furthermore, the new router node 22 sends a request to other nodes within its communication range to obtain connection information for gateway node 3. The former router node 21, receiving the request, responds by sending the connection information for gateway node 3 to the new router node 22.

[0040] Router node 22 now forwards data packets from sensor nodes 11 and 12 to gateway node 3. Sensor node 14 sends data packets directly to gateway node 3 because it is in close proximity to gateway node 3 and / or the mesh network 200 is not heavily congested. The current network topology enables a strong, reliable direct connection between sensor node 14 and gateway node 3, which is more efficient in terms of energy consumption and data transmission speed.

[0041] Since the changes are made locally via the processing unit of the field device, no central control center is required, thus increasing the scalability of the network.

[0042] In some embodiments, the field device is configured to receive power / energy from a battery, with the processing unit defining and changing the field device's role based on the battery's state of charge. This ensures that the field device can adapt its functionality based on the energy currently available from the battery.

[0043] In some embodiments, the field device's processing unit determines an energy budget, i.e., the amount of energy available for its operations over a specific period. The processing unit plans this energy budget based on factors such as time-series components of the electrical output signal, a constant minimum energy input, and diurnal factors, including solar power supply. This allows the field device to optimize its energy consumption and maintain efficient operation.

[0044] In some embodiments, the processing unit defines and modifies the role of the field device in the wireless mesh network 100, 200 based on the current state of the field device's neighboring devices or neighborhood within the communication range. This current state includes the available power and / or power budget of each of these neighborhoods. This ensures that the field device can dynamically adjust its role to maintain the stability and efficiency of the mesh network 100, 200 and to optimize its power consumption.

[0045] In some configurations, the field device is set up to receive power from a constant energy source, ensuring a reliable power supply. Furthermore, the field device can connect the wireless mesh network 100, 200 to an external network, a control system, and / or a central server, enabling seamless integration and communication in an industrial environment.

[0046] Gateway node 3 typically has a constant power supply, as it connects the mesh network 100, 200 to the outside world (Internet, production network, etc.). A router node 2 can become a gateway node 3 if it has the necessary external interfaces (cellular, Wi-Fi, etc.). Reference symbol list 1, 11, 12, 13, 14 Sensor nodes 2, 21, 22 Router nodes 3 Gateway nodes 4 Internet connection 5 clusters 6 First container 7 Second container 100, 200 mesh network

Claims

Field device configured for integration into a wireless mesh network (100, 200), wherein the field device has a role in the wireless mesh network (100, 200), the role comprising a sensor node (1, 11, 12, 13, 14), a router node (2, 21, 22), and a gateway node (3), wherein the role determines the field device's ability to generate, receive, and transmit data or data packets, wherein: a sensor node (1, 11, 12, 13, 14) generates data packets relevant to an industrial process and transmits them to a router node (2, 21, 22) or gateway node (3); a router node (2, 21, 22) performs all the functions of a sensor node (1, 11, 12, 13, 14) executes and additionally receives data packets from sensor nodes (1, 11, 12, 13, 14) and forwards them to a gateway node (3);a gateway node (3) performs all the functions of a sensor node (1, 11, 12, 13, 14) and additionally receives data packets from sensor nodes (1, 11, 12, 13, 14) and router nodes (2, 21, 22) and connects the wireless mesh network (100, 200) to an external network, a control system, and / or a central server of an industrial plant, wherein the field device comprises: - a housing; - a sensor module that detects and measures a physical quantity of an industrial process, wherein the physical quantity describes a process state of the industrial process, the process state changing over time, and wherein the sensor module outputs an electrical output signal correlated with the physical quantity; - a communication module configured to receive data packets sent by the field device itself and by other field devices in the wireless mesh network (100, 200) are generated, receives and transmits via a wireless communication standard;and- a processing unit configured for data processing, communication tasks and device diagnostics, characterized in that the processing unit defines and modifies the role of the field device in the wireless mesh network (100, 200). Field device according to claim 1, wherein the processing unit defines and changes the role of the field device in the wireless mesh network (100, 200) based on the currently available energy. Field device according to claim 2, wherein the currently available energy depends on the electrical output signal, wherein the field device uses a current loop interface for the electrical output signal, wherein the field device is powered by the current interface itself, and wherein the current interface conforms to the standard 4...20 mA. Field device according to claim 2, wherein the field device is configured to receive energy from a battery, wherein the processing unit determines the state of charge of the battery, and wherein the currently available energy depends on the state of charge of the battery. Field device according to one of claims 2 to 4, wherein the processing unit is configured to determine an energy budget of the field device, wherein the processing unit defines and changes the role of the field device in the wireless mesh network (100, 200) on the basis of the energy budget, and wherein the energy budget is an amount of energy that the field device has available, consumes or allocates for its operations over a certain period of time. Field device according to claim 5, wherein the processing unit learns and plans a temporal profile of the energy budget based on one or more factors, the factors comprising: - time series components of the electrical output signal, in particular periodicity of the electrical output signal; - constant minimum energy supply of the field device; and - time-of-day dependent factors, in particular the supply by means of solar energy, wherein the field device is configured to receive energy from a solar module. Field device according to claim 6, wherein the processing unit defines and changes the role of the field device in the wireless mesh network (100, 200) based on a current state of the current neighborhood of the field device, wherein the current neighborhood are other field devices in the wireless mesh network (100, 200) within a communication range of the field device, and wherein the current state includes the current available power and / or power budget as well as the role of each of the current neighborhood. Field device according to any one of claims 1 to 7, wherein the field device is configured to receive energy from a constant energy source. Field device according to claim 8, wherein the field device is configured to connect the wireless mesh network (100, 200) to an external network, a control system, and / or a central server of an industrial plant. Wireless mesh network (100, 200) comprising at least one first field device and one second field device according to any one of claims 1 to 8 and one third field device according to claim 9, wherein the first, second and third field devices communicate with each other via the communication modules of the first, second and third field devices using a wireless communication standard. A method for changing the role of a field device according to any one of claims 1 to 9 comprises: - Defining and changing a role of the field device in a wireless mesh network (100, 200) by a processing unit of the field device; - Sending a data packet containing information about the change of the role of the field device to the other field devices of the wireless mesh network (100, 200) within a communication range by a communication module of the field device. Method according to claim 11, wherein the role of the field device in the mesh network (100, 200) changes from a router node (2, 21, 22) to a sensor node (1, 11, 12, 13, 14) when the energy currently available to the field device falls below a first predetermined value, wherein the communication module of the field device receives and transmits data packets when the role of the field device is a router node (2, 21, 22), and wherein the communication module of the field device transmits data packets but no longer receives data packets for forwarding when the role of the field device is a sensor node (1, 11, 12, 13, 14). Method according to claim 12, wherein the role of the field device in the mesh network (100, 200) changes from a sensor node (1, 11, 12, 13, 14) to a router node (2, 21, 22) when the energy currently available to the field device increases to / above the first predetermined value, and wherein the communication module of the field device receives information for the gateway connection from a previous router node (2, 21, 22) within the communication range. A method according to claim 12 or 13, wherein the role of the field device in the mesh network (100, 200) changes from a sensor node (1, 11, 12, 13, 14) or a router node (2, 21, 22) to a gateway node (3) when the field device receives its energy from a constant energy source, wherein the gateway node (3) connects to an external network, a control system, and / or a central server of an industrial plant, and wherein the communication module of the field device transmits information for the gateway connection to a router node (2, 21, 22) within the communication range. Computer program product comprising instructions which, when the program is executed by the processing unit of a field device according to any one of claims 1 to 9, cause the latter to execute the method according to any one of claims 11 to 14.

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