System consisting of a field device, a field device radio module, and a gateway
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- VEGA GRIESHABER GMBH & CO
- Filing Date
- 2025-12-18
- Publication Date
- 2026-07-23
AI Technical Summary
Existing field device systems for process automation lack flexibility and scalability in signal transmission to controllers, particularly when multiple devices and protocols are involved, leading to inefficient and cumbersome wiring and connection requirements.
A three-part system comprising a field device with a radio module, a central radio module, and a gateway, utilizing different transmission protocols (LPWAN, wireless, and wired protocols like LoRaWAN, Bluetooth, and 4-20 mA) to enable flexible and scalable signal transmission, with encryption for security and a network server for connection management.
Facilitates efficient, secure, and scalable communication between field devices and controllers, minimizing wiring efforts and enabling easy expansion of systems without requiring new hardware, while maintaining protocol compatibility and security.
Smart Images
Figure EP2025087887_23072026_PF_FP_ABST
Abstract
Description
[0001] System consisting of field device, field device radio module and gateway
[0002] The invention relates to a system comprising a field device, a field device radio module, and a gateway according to claim 1. Furthermore, the invention relates to a method for commissioning such a system according to claim 10, a method for operating such a system according to claim 11, and a kit comprising a field device and a gateway according to claim 12.
[0003] In process automation technology, field devices are frequently used to detect and / or control process variables. Examples of such field devices include level gauges, limit level gauges, and pressure gauges with sensor units that detect the corresponding process variables such as level, limit level, or pressure, or derived process variables.
[0004] "Field" refers to the area outside of control rooms. Field devices can therefore include, in particular, actuators, sensors, data loggers, and transmitters. Such field devices are often connected to higher-level units, such as control systems or monitoring units. These higher-level units are used for process control, process visualization, and / or process monitoring. Field devices known from the prior art typically consist of a housing, a sensor unit, and an electronic module located within the housing. The measured process variables are usually evaluated, and the results can be used, for example, to generate a switching command and / or a proportional analog or digital output, or to display physical properties or process variables.
[0005] For transmitting measured values or results acquired by a field device to a higher-level controller, the following different architectures are common, among others: the measured values are transmitted directly from the field device to a controller via a wired connection using a 4...20 mA interface, or the measured values are transmitted wirelessly to a higher-level unit, e.g., a cloud. The aforementioned architectures or network systems are not particularly flexible with regard to expansion to multiple field devices or multiple control signals and are therefore poorly scalable.
[0006] The fundamental object of the invention is to provide a system that offers a particularly flexible and simple means of signal transmission from a field device to a controller. Furthermore, the invention aims to provide a method for commissioning such a system, a method for operating such a system, and a kit that are particularly flexible and scalable.
[0007] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments are described in connection with the dependent claims.
[0008] A system according to the invention is composed of three parts and comprises a field device with a field device radio module, a central radio module and a gateway.
[0009] The field device is, in particular, a level gauge, a limit level gauge, or a pressure gauge with a corresponding sensor unit. The field device uses the sensor unit to determine a measured value. Specifically, the field device is battery-operated and does not require a wired power supply.
[0010] The field device radio module communicates with the central radio module in such a way that the measured values acquired by the field device can be transmitted to the central radio module as radio signals according to a first transmission protocol. The term "measured values" is intended to include already processed or evaluated measured values. As described in more detail below, the first transmission protocol can be, in particular, an LPWAN or a LoRaWAN. The central radio module is designed to receive the measured values transmitted by the field device radio module.
[0011] Furthermore, the central radio module and the gateway are interconnected in such a way that measured values received by the central radio module can be transmitted to the gateway using a second transmission protocol. The central radio module is also a gateway in the technical sense, forwarding the measured values received by the field device radio module to the gateway and, in doing so, specifically changing the transmission protocol.
[0012] The third element of the system is the gateway, which is configured to receive the measured values from the central radio module and convert them into a third transmission protocol. As described in detail below, this third transmission protocol can be a wired protocol, specifically a 4-20 mA standard. The gateway serves as the interface to a controller and is uniquely connected to the field device.
[0013] The three-part design provides a particularly flexible system, offering the ability to leverage the advantages of various transmission protocols, especially a combination of wired and wireless protocols. Furthermore, the system is scalable in terms of the number of field devices and gateways, including the use of associated third-party transmission protocols. Multiple gateways and / or field devices can be easily connected to the central radio module without requiring new hardware or separate antennas for each additional device.
[0014] In contrast to transmission using, for example, the 4...20 mA standard alone, the effort required for connections and wiring can be kept to a minimum.
[0015] In particular, the three transmission protocols are each different. Specifically, the first and second transmission protocols are different. Specifically, the second and third transmission protocols are different. Specifically, the first and third transmission protocols are different. However, it is also conceivable that two or even three transmission protocols are identical. In one practical embodiment, the first transmission protocol is an LPWAN (Low Power Wide Area Network), specifically LoRaWAN. Communication via LPWAN or LoRaWAN is particularly suitable for field devices that do not have a wired power supply but are powered by battery or other means.They are battery-powered, as radio communication over these networks requires very little energy. As an alternative to LoRaWAN, a transmission protocol such as Sigfox, NB-IoT, or mioty, or a comparable LPWAN protocol, can also be used.
[0016] It may be provided that the central radio module has an external antenna for improved reception and transmission of the measured values.
[0017] In particular, the radio signals sent from the field device radio module to the central radio module, which contain the measured values, are encrypted so that they are protected as much as possible against access by third parties and manipulation.
[0018] In particular, the central radio module includes a network server. This network server is primarily responsible for connection management. The advantage of locating the network server on the central radio module lies in the ease with which the number of field devices and gateways can be scaled, as multiple unique identifiers and keys can be stored there. The network server then ensures a secure and unambiguous connection between each field device and gateway pair.
[0019] In particular, a unique identifier for establishing a connection between the central radio module and the field device radio module is stored on the field device radio module, especially on the network server. Alternatively or additionally, a key for establishing an encrypted connection between the field device radio module and the central radio module is stored on the field device radio module for encrypting and decrypting the radio signal. As explained below, the central radio module is connected to the gateway in such a way that the unique identifier for establishing a connection between the central radio module and the field device radio module, and / or the key—especially during initial commissioning—can be transferred from the gateway to the central radio module.
[0020] The corresponding identifier and / or key are also stored in the field device radio module, so that a unique connection can be assigned and / or the measured values sent by the field device radio module and received by the central radio module can be decrypted.
[0021] The second transmission protocol can be either a wired or a wireless transmission protocol. Bluetooth is a particularly suitable wireless connection, while common wired connections such as USB or SPE are also possibilities.
[0022] In particular, the gateway can be connected to the central radio module via a plug, cable, or wirelessly. Multiple gateways can also be connected to the central radio module via one or more of the aforementioned connections.
[0023] In another practical embodiment, the third transmission protocol is wired. Specifically, this includes 4...20 mA, 4...20 mA / HART, IO-Link, Profibus PA, and APL. The advantages of the three-part system are particularly evident in this configuration, as the gateway can be connected to the existing mechanical interface, and a connection to the central radio module and the field device radio module can then be established very easily. Specifically, the gateway can output signals to control a relay or a transistor, or a PWM signal or a standardized current signal for sensors, especially level sensors (Namur). This involves, in particular, the output of specific voltages or currents, which are also considered part of the third transmission protocol. Specifically, the gateway can have a relay or a transistor as a switching output for a level sensor.
[0024] If the third transmission protocol is the 4-20 mA standard, this has the advantage that it can not only transmit the measured value but also supply power to the gateway. An additional power source for the gateway is then not required. Power can also be supplied via another protocol, such as IO-Link, 8 / 16 mA, or a NAMUR interface.
[0025] In one embodiment, the central radio module is designed to have a first antenna for connecting to the field device radio module (e.g., for communication via LoRaWAN) and a second antenna for connecting to the gateway (e.g., for communication via Bluetooth). The central radio module can then be installed in a control cabinet and communicate both internally and externally.
[0026] In particular, the central receiver module is connected to multiple field devices. These can be field devices of the same type (e.g., all level sensors or limit level sensors) or field devices of different types. Establishing a wireless connection with multiple field devices is simple and requires no wiring. If the corresponding unique identifiers and / or keys are also stored on the network server, the connection can be established automatically. This is ensured by the connected gateways transmitting this information to the central receiver module or the network server.
[0027] Alternatively or additionally, the central receiver module can be connected to multiple gateways. These gateways can be connected to the central radio module via multiple connectors, cables, and / or wireless connections, and the different gateways can, in particular, have identical or preferably different transmission protocols, e.g., transmitting a measured value to a controller and switching a relay or transistor.
[0028] The invention also relates to a method for commissioning a system, in particular a system as described above. The method comprises the following steps:
[0029] a) Establishing a connection between the gateway and the central radio module. This connection is established automatically, particularly after the gateway and / or the central radio module are switched on. b) Transmitting a unique identifier from the gateway to the central radio module to establish a connection between the field device radio module and the central radio module. This unique identifier is stored in the gateway, the central radio module, and the field device radio module. Additionally, a key for establishing an encrypted connection is also transmitted.
[0030] c) Establishing a connection between the field device radio module and the central radio module using the unique identifier. In particular, the connection is established as soon as the field device radio module is activated.
[0031] d) Transmission of radio signals from the field device radio module to the central radio module according to a first transmission protocol.
[0032] The unique identifier is stored only on the gateway and the field device radio module before commissioning. Only during commissioning is the unique identifier (and, if applicable, the key) transferred to the central radio module. The central radio module can be configured accordingly for different systems and multiple gateways and / or field device radio modules. For further details and advantages of this method, please refer to the description above.
[0033] The invention further relates to a method for operating a system, in particular a system as described above. The method comprises the following steps:
[0034] a) Transmission of a measured value from the field device radio module to the central radio module according to a first transmission protocol,
[0035] b) Receiving the measured value by the central radio module and forwarding the measured value from the central radio module to the gateway according to a second transmission protocol,
[0036] c) Receiving the measured value by the gateway and converting the measured value according to a third transmission protocol.
[0037] For further details and advantages of the method, reference is made to the preceding description. The invention also relates to a kit comprising a field device radio module and a gateway for a system as described above, wherein a mutually matching unique identifier is stored on both the gateway and the field device radio module, and wherein the field device radio module and the gateway are configured to establish a connection to a central radio module. The central radio module is then independent of specific field devices and gateways and is freely configurable. Only the field device radio module and the gateway are initially configured to match each other.
[0038] Further practical embodiments and advantages are explained below in conjunction with the figures. They show
[0039] Fig. 1 shows a schematic representation of a system consisting of a field device, a central radio module and a gateway.
[0040] Fig. 2 shows the system from Fig. 1 in operation in a schematic representation.
[0041] Fig. 3 shows the system from Fig. 1 during commissioning in a schematic representation.
[0042] Fig. 4 shows a system according to Fig. 1 with several field devices of the same type and several corresponding gateways, and
[0043] Fig. 5 shows a system according to Fig. 1 with several field devices of different types and corresponding gateways of different types.
[0044] Fig. 1 shows a three-part system 10 with a field device 12, in this case a level gauge for recording measured values, here a fill level. The field device 12 has a field device radio module 14 for sending and receiving radio signals.
[0045] The system also includes a central radio module 16, which receives the measured values transmitted by the field device radio module 16. The central radio module 16 is wirelessly connected to the field device radio module 14, and the measured values are transmitted using a first transmission protocol (shown here as 15), in this case via LPWAN, specifically LoRaWAN.
[0046] System 10 further includes a gateway 18, which is connected to the central radio module 16 and receives the measured values from the central radio module 16 via a second transmission protocol 17. The second transmission protocol 17 is, for example, Bluetooth.
[0047] The gateway 18 can then forward the received measured values to a controller (not shown) via a third transmission protocol 19. This third protocol 19 is wired and uses the 4...20 mA standard, which also supplies power to the gateway 18.
[0048] As schematically shown in Fig. 1, all three parts 14, 16, 18 of the system 10 have a key symbol 20. The key symbol 20 represents the unique identifier of the field device radio module 14 and its associated gateways 18, as well as a key for encrypting and decrypting the transmitted measured values between the field device radio module 14 and the central radio module 16. The central radio module 16 has a network server 22 for storing the unique identifier and the key.
[0049] A corresponding procedure for operating system 10 is explained below in conjunction with Fig. 2.
[0050] The field device 12, in the form of a level gauge, is mounted on a container 24 to measure the fill level in the container 24. As an example, a fill level of 38.1% is recorded by the field device 12. The fill level recorded by the field device 12 is then encrypted in the field device radio module 14 using the stored key and transmitted via LoRaWAN 15 to the central radio module 16.
[0051] The central radio module 16 includes the network server 22, which contains the unique identifier for identifying the radio connection with the field device radio module as well as the key for decoding the radio signal with the measured value (represented by key symbol 20).
[0052] The measured value is then decoded in the central radio module 16 and transmitted to the corresponding gateway 18 using the second transmission protocol 17. The information 38.1% is also transmitted here.
[0053] Using the stored unique identifier, the central radio module 16 identifies the gateway 18 belonging to the field device radio module 14 and sends the measured value to it. For this to happen, both the gateway 18 and the central radio module 16 have the same unique identifier. Alternatively, the central radio module sends the information to all connected gateways, and the corresponding gateway recognizes the correct message.
[0054] The measured value is then received by gateway 18 and converted there into a 4...20 mA output signal (third transmission protocol 19), where the 38.1% fill level corresponds to a current of 10.1 mA. This signal can then be forwarded to a controller.
[0055] In conjunction with Fig. 3, a method for commissioning system 10 is described below.
[0056] First, a field device 12 with a field device radio module 14 and a gateway 18 are provided, each of which has the corresponding unique identifier and key for encrypting the radio signal stored (represented by key symbol 20). This combination of gateway 18 and corresponding field device radio module 14 is also referred to as a kit.
[0057] First, the gateway 18 is connected to the central radio module 16. This can be done via a plug, cable, or wirelessly. The signals are transmitted according to the second transmission protocol 17. The unique identifier and key (key symbol 20) are transferred from the gateway 18 to the central radio module 16 and stored on the central radio module 16 in the network server 22. The transmission starts automatically upon connection. When the field device radio module 14, which also stores the unique identifier and key (key symbol 20), is activated, the central radio module 16 and the field device radio module 14 establish a connection through which, among other things, the measurement data is transmitted according to the first transmission protocol 15.
[0058] Figure 4 shows another embodiment of a system 10, in which several field devices 12a-d, here four field devices 12a-d by way of example, are connected to the central radio module 16. In Figure 4, four field devices 12a-d of the same type, namely level measuring devices, are connected to the central radio module.
[0059] The field devices 12a-d each have a field device radio module 14a-d and are each connected to the central radio module 16 via a radio link. They transmit the respective measured values to the central radio module 16 according to the first transmission protocol 15. For this purpose, the field device radio modules 14a-14d each have a unique identifier and a key (key symbols 20a-d). The fill levels of 19%, 81%, 25%, and 7% are shown as examples. The measured values are sent to the central radio module 16 in encrypted form and decrypted there using the respective key received from the gateways 18a-d.
[0060] The central radio module 16 is connected to several gateways 18a-d, corresponding to the number of field devices 12a-d, with each gateway 18a-d being assigned to a field device radio module 14a-d via a unique identifier. The gateways 18a-d then forward the fill levels received from the corresponding field device 12a-d via the central radio module 16 to the controller (not shown) according to the third transmission protocol 19.
[0061] Figure 5 shows another embodiment of a system 10, in which several field devices 12a-d, here four field devices 12a-d by way of example, are connected to the central radio module 16, analogous to Figure 4. In Figure 4, four field devices 12a-d of different types, namely a flow meter 12a, a level meter 12b, a differential pressure sensor 12c, and a limit level sensor 12d, are connected to the central radio module 16. The field devices 12a-d each have a field device radio module 14a-d and are each connected to the central radio module 16 via a radio link and transmit the respective measured values to the central radio module 16 according to the first transmission protocol 15. For this purpose, the field device radio modules 14a-14d each have a unique identifier and a key (key symbols 20a-d). The measured values are each encrypted and sent to the central radio module 16, where they are decrypted using the respective key received from the gateways 18a-d.
[0062] The central radio module 16 is connected to several gateways 18a-d, corresponding to the number of field devices 12a-d, with each gateway 18a-d being assigned to a field device radio module 14a-d via a unique identifier. The gateways 18a-d then transmit the fill levels received from the corresponding field device 12a-d via the central radio module 16 to the controller (not shown) according to the third transmission protocol 19. Since these are different field devices 12a-d that output different measured values, the output, or rather the third transmission protocol 19, also differs for the respective gateways 18a-d. For example, gateway 18a, which is connected to the flow meter, outputs a PWM signal. Gateway 18b, which corresponds to the level sensor 12b, outputs a fill level using the 4...20 mA standard. The gateway 18c, which is connected to the differential pressure sensor 12c, outputs a corresponding differential pressure via the 4th...The .20 mA / HART protocol is used, and the gateway 18d has an output for switching a transistor to control the limit level sensor 12d. Reference symbol list.
[0063] 10 System
[0064] 12a-d field device
[0065] 14a-d Field Device Radio Module
[0066] 15 first transmission protocol
[0067] 16 Central radio module
[0068] 17 second transmission protocol
[0069] 18a-d Gateway
[0070] 19 third transmission protocol
[0071] 20a-d Key symbol (unique identifier, key) 22 Network server
[0072] 24 containers
Claims
Patent claims 1. System consisting of a field device (12) with a field device radio module (14), a central radio module (16) and a gateway (18), wherein the field device radio module (14) and the central radio module (16) are interconnected, and wherein the field device radio module (14) is configured to transmit measured values acquired by the field device (12) as radio signals to the central radio module (16) according to a first transmission protocol (15), and wherein the central radio module (16) and the gateway (18) are interconnected, and wherein the central radio module (16) is configured to transmit received measured values to the gateway (18) according to a second transmission protocol (17), and wherein the gateway (18) is configured to convert the received measurement values into a third transmission protocol (19).
2. System according to the preceding claim, characterized by the fact that The first transmission protocol (15) is an LPWAN.
3. System according to one of the preceding claims, characterized by the fact that the radio signals are encrypted.
4. System according to one of the preceding claims, characterized by the fact that the central radio module (16) has a network server (22).
5. System according to one of the preceding claims, characterized by the fact that 6. System according to one of the preceding claims, characterized by the fact that the third transmission protocol (19) is wired.
7. System according to one of the preceding claims, characterized by the fact that The third transmission protocol (19) is a 4...20 mA standard.
8. System according to the preceding claim, characterized by the fact that The gateway (18) is powered via the 4...20 mA standard.
9. System according to one of the preceding claims, characterized by the fact that the central receiving module (16) is connected to several gateways (18a-d) and / or to several field device radio modules (14a-d).
10. knowledge of commissioning a system (10) according to one of the preceding claims, characterized by the following steps: a) Establishing a connection between the gateway (18) and the central radio module (16); b) Transmission of a unique identifier to establish a connection between the field device radio module (14) and the central radio module (16) from the gateway (18) to the central radio module (16); c) Establishing a connection between the field device radio module (14) and the central radio module (16) using the unique identifier; d) Transmission of radio signals from the field device radio module (14) to the central radio module (16) according to a first transmission protocol (15).
11. Method for operating a system (10) according to any one of the preceding claims 1 to 9, characterized by the following steps: a) transmitting a measured value from the field device radio module (14) to the central radio module (16) according to a first transmission protocol (15), b) Receiving the measured value by the central radio module (16) and forwarding the measured value from the central radio module (16) to the gateway (18) according to a second transmission protocol (17), c) Receiving the measured value by the gateway (18) and converting the measured value according to a third transmission protocol (19).
12. Kit comprising a field device radio module (14) and a gateway (18) for a system (10) according to any one of the preceding claims 1 to 9, wherein a mutually matching unique identifier for establishing a connection between the field device radio module (14) and a central radio module (16) is stored on the gateway (18) and on the field device radio module (14), and wherein the field device radio module (14) and the gateway (18) are configured to establish a connection to the central radio module (16).