Apparatus and method for selecting characteristics of a sensor radio module

Abstract

The invention relates to a device (200) for a sensor (100) in automation technology, wherein the device (200) is configured for selecting a radio module characteristic and wherein the radio module characteristic depends on a sensor structure (110, 120, 125). The device comprises a controller (215) configured for selecting the radio module characteristic depending on the sensor structure (110, 120, 125).

Description

Technical Field

[0001] The invention relates to a device configured for selecting radio module characteristics for a sensor in automation technology, a communication module, a sensor, a method for selecting radio module characteristics for a sensor, a program element and the use of the device for selecting radio module characteristics for a fill level sensor, a limit level sensor, a flow sensor or a pressure sensor. Background Art

[0002] Depending on the requirements for mechanical stability, chemical resistance or even UV stability, sensors in process and automation technology have a housing made of a correspondingly suitable material. This can be, for example, UV-stable plastic, aluminum or stainless steel. If one now wants to subsequently expand the range of functions of such sensors by means of a radio communication module, the technical problem arises that the antenna of the radio communication module needs to be adapted differently depending on the material of the sensor structure (e.g. the surrounding housing). Summary of the invention

[0003] It may be an object of the invention to provide a device exhibiting good radio characteristics which are largely independent of the sensor structure.

[0004] The described embodiments similarly relate to an apparatus configured for selecting radio module features for a sensor in automation technology, the use of the apparatus, a communication module, a sensor, a method for selecting radio module features for a sensor, and a program element. Synergistic effects can be generated by various combinations of the embodiments, although they may not be described in detail.

[0005] In addition, it should be noted that all embodiments of the method of the present invention can be performed according to the described step order, but this is not necessarily the only and basic step order of the method. Unless otherwise explicitly stated below, the method proposed herein can be performed in a different order of the disclosed steps without departing from the corresponding method embodiment.

[0006] Technical terms are used in the usual manner. When specific terms are given specific meanings, the definitions of the terms are given below in the context in which they are used.

[0007] According to a first aspect, a device for a sensor in automation technology is provided, wherein the device is configured for selecting a radio module feature and wherein the radio module feature depends on the sensor structure. The device comprises a controller configured to select the radio module feature depending on the sensor structure.

[0008] In this case, the radio module characteristics are characteristics related to the radio technology, which are, for example, electrical characteristics, electromagnetic characteristics or general physical characteristics. In particular, the radio module characteristics also include specific electrical values, electromagnetic values ​​caused by parameters of circuits or data transmission or radio transmission (e.g., parameters of the physical transmission layer).

[0009] In the present disclosure, the term "radio communication module" is synonymous with the shorter term "radio module". Therefore, the term "radio module feature" relates to a radio module or a radio communication module. A radio communication module is a transmitting and / or receiving module of a sensor.

[0010] The sensor structure is characterized in particular by parameters such as its shape, dimensions and material properties. In particular, when the antenna is located inside the sensor, these mechanical parameters can influence the radio transmission quality. The sensor structure can, for example, include a housing, a cover, a glass window integrated into the cover and other elements.

[0011] For example, the controller may include electronic components including hard-wired or programmable logic, or circuits consisting of discrete electronic components, or combinations thereof. Thus, the controller may include circuits without programmable logic, or may be, for example, or include a microcontroller, a field programmable gate array (FPGA), an ASIC, a complex programmable logic device (CPLD), or any other programmable logic device known to those skilled in the art.

[0012] The selection of a radio module feature is to be understood as the selection of one of a plurality of available radio module features. This can be achieved, for example, by closing, closing or switching a component or circuit. Closing, closing or switching can also include simultaneous switching of a plurality of components or circuits, so as to achieve the desired radio module feature in this way. The selection can also be the selection of a specific radio module feature set by a controller, for example, by digital or analog control of a tuning circuit or electronic component.

[0013] The term “automation technology” is to be interpreted in this context in a broad sense and includes in particular process automation and factory automation.

[0014] According to an embodiment, the device further comprises a receiver configured to receive a sensor external signal strength measurement of a signal transmitted by the device, and the controller is configured to select the radio module feature in dependence on the received value. The receiver may be, for example, a receiver that has been arranged to receive data such as control data or configuration data of the sensor.

[0015] In other words, the radio module, for which the controller selects the radio module characteristics, sends a signal, which may for example contain a data packet, to a receiving device external to the sensor. The receiving device measures one or more reception parameters, such as reception strength or reception signal-to-noise ratio, and sends the measurement results back to the sensor. According to this embodiment, the apparatus now comprises a receiver configured to receive the measurement results from the external device. The controller is configured to evaluate the measurement results and to select the radio module characteristics based on the evaluation results. This can also be done, for example, by an iterative process.

[0016] In one example, there are two selectable radio module features A and B. The controller causes the sensor to transmit a signal under radio module feature A, and the receiver in the sensor then receives back a measurement result, such as a signal strength value, and transmits it to the controller. The controller can now compare this value with, for example, a predetermined signal strength value, and, for example, set or switch radio module feature B for further operation time of the sensor when this value is below a threshold.

[0017] In another example, the controller causes the sensor to first transmit a signal under radio module characteristic A and then transmit a signal under radio module characteristic B. A receiver in the sensor receives the two measurements so that the controller can compare the two measurements to each other and select the radio module characteristic that provides a better measurement (e.g., a higher signal strength value).

[0018] According to an embodiment, the device comprises at least one switch, wherein in each switch position, a different circuit for determining the radio module characteristics is active, and the controller is configured to implement the radio module characteristics by switching the switch. The circuit may be, for example, an antenna circuit or a frequency circuit.

[0019] According to an embodiment, the circuit is an antenna impedance matching network.

[0020] That is, in this case, the radio module feature is a feature corresponding to the matching impedance of the antenna driver. For example, the antenna requires different matching according to the surrounding shell, that is, the impedance of the radio module must be selected according to the shell, especially according to the shell material, so that the impedance of the antenna in the environment matches the impedance of the circuit providing the high-frequency signal. For this reason, in one example, there are the following matching networks: a first matching network that matches the antenna impedance to the high-frequency circuit in the case of a plastic shell, a second matching network that matches the antenna impedance to the high-frequency circuit in the case of a stainless steel shell, and a third matching network that matches the antenna impedance to the high-frequency circuit in the case of an aluminum shell. After determining the best signal quality, transmission or reception power or shell type, a matching network is selected, for example, according to the shell material, and the input end of the matching network is connected to the high-frequency circuit, for example, through a switch, and the output end of the matching network is connected to the antenna. The switch, for example, causes switching, so that the other matching networks are disconnected from the high-frequency path and antenna on the input side and output side, respectively, at the same time.

[0021] According to an embodiment, the apparatus is configured to implement radio module features by changing the value of one or more electronic components. For example, in a matching network, instead of switching from one complete matching network to another, a tap of an inductor, resistor or capacitor may be selected so that the corresponding value of the component changes, and thereby the impedance of the matching network also changes. Accordingly, the frequency, frequency filter characteristics or other related parameters may also be changed.

[0022] According to one embodiment, the sensor structure is characterized by the housing material. Depending on the requirements for mechanical stability, chemical resistance or UV stability, sensors in process and automation technology have a housing made of a correspondingly suitable material. In this case, it can be, for example, UV-stabilized plastic, aluminum or stainless steel.

[0023] The sensor structure may be variable. In particular, the housing may be replaceable. For example, the housing or frame of the sensor has threads so that the housing (e.g. a plastic housing) can be removed from the sensor and another housing (e.g. a metal housing) can be screwed on. The material or type of housing used may depend, for example, on the use environment and the application. For example, a chemical environment may not be suitable for plastics, or a plastic housing may be more economical, but conditions such as UV stability may have to be met.

[0024] According to one embodiment, the device is configured to determine electrical characteristics of the housing material. Thus, in addition to or as an alternative to the above-mentioned measurement value receiver, the device comprises a circuit for measuring electrical characteristics of the sensor structure (e.g. the housing) and sending a digital or analog measurement signal to a controller, so that the controller can evaluate the signal or data and can select the radio module characteristics.

[0025] According to an embodiment, the electrical characteristic is capacitance and / or conductivity. That is, returning to the above example, the device may include a circuit for measuring capacitance or conductivity or resistance value as an electrical characteristic, wherein the capacitance or conductivity is a characteristic of the sensor structure (e.g., the housing or housing material), and the controller selects the radio module characteristic (e.g., impedance or other parameters described herein), for example, via a switch.

[0026] According to one embodiment, the controller is configured to query the housing material and / or electrical characteristics from a database, a stored configuration and / or a received configuration. Preferably, one of these options is selected, but any arrangement consisting of these options can also be used. For example, the controller obtains the housing material from a memory module, wherein the memory is a volatile or non-volatile memory. For example, such a configuration can be permanently implemented for the sensor, or the configuration can be transmitted, for example, via a radio connection and stored in a memory. The memory can be located, for example, in the device of the sensor or in another electronic unit. The configuration can also be implemented by manual input. Alternatively, the controller initiates a database query, for example, via a radio connection to a server. To this end, the logic of the controller can, for example, have client software.

[0027] According to an embodiment, the radio module characteristic is radiated energy. Thus, the controller may determine, for example, from measurements received from an external device or by determining housing material or housing electrical characteristics, that an increase in energy is required for data transmission.

[0028] This embodiment may be used generally, or may also come into play when it is determined that the quality or performance of the sensor structure is insufficient to transmit data accurately enough despite other adjustments.

[0029] The radiated energy is defined, for example, by the transmission intensity or the data rate. The transmission intensity or the transmission power directly influences the radiated RF energy. If the transmission power is fixed and therefore cannot be changed, the data rate can also be reduced, for example. The data rate influences the energy per bit, for example, and plays a decisive role in the decoding of the data. It should also be noted here that the radio module characteristics (as described above) can also be the values ​​of parameters such as impedance, transmission power or data rate.

[0030] According to one embodiment, the radio module feature is modulation, radio standard and / or frequency. The electrical characteristics of the housing may cause, for example, signal distortion, and the modulation type no longer allows error-free decoding, so it must be changed. Accordingly, the coding method can also be changed, so as to, for example, achieve greater redundancy and / or improved error checking and / or error correction. For example, signal distortion may be caused by interference, which is caused, for example, by reflections associated with, for example, the housing or transmission of undesirable electromagnetic waves in the housing. As a requirement for the selection of modulation, coding method and radio standard, suitable alternatives are available and can be implemented by the radio standard used. For example, suitable radio standards are LoRa, LoRaWAN, NB-IOT, Cat-M1, Sigfox, Mioty, Bluetooth or similar standards.

[0031] In one example, the device includes a user interface for user selection of radio module features, the user interface being, for example, a manual switch, a touch-sensitive screen, a button, or an external wired or wireless interface such as a Bluetooth interface, an NFC interface, a WLAN interface, or a cellular interface for a smartphone, laptop, or tablet.

[0032] According to another aspect, there is provided a communication module comprising the apparatus described herein, wherein the communication module further comprises an antenna and a radio module, wherein the antenna is connected to the radio module, and wherein the radio module is configured to receive from a controller of the apparatus a radio module feature selected by the controller. The radio module may be configured to send a data packet to an external receiver so that the receiver can, for example, measure the signal strength and can send the measurement result back to a sensor or a receiver in the communication module. In an example, the antenna is switchably connected to the radio module via a first network or a second network to match the antenna impedance.

[0033] According to another aspect, a sensor is provided comprising a communication module having a device for selecting a radio module feature as described in the present disclosure. For example, the sensor further comprises a structure having a housing, and the selection of the radio module feature depends on the housing. Here, the housing can be made of metal such as stainless steel or aluminum, plastic or other materials.

[0034] According to a further aspect, a method for selecting a radio module feature for a sensor in automation technology is provided, wherein the radio module feature depends on the sensor structure and wherein a controller selects the radio module feature as a function of the sensor structure.

[0035] In one example, the method includes the following steps:

[0036] Determine the sensor structure such as the shell type, select the radio module characteristics such as the antenna network impedance, frequency, modulation type or radio standard, and switch the electronic components, circuits (e.g., antenna matching network) to match the impedance and / or radio standard, etc., so that the selected radio module characteristics take effect. For example, determining the sensor structure may include: determining the electrical characteristics of the shell by measuring the shell capacitance or the shell conductivity. Alternatively or additionally, determining the sensor structure can be accomplished by receiving the measurement results after the sensor sends a signal. In the latter case, it is not necessary to explicitly determine the sensor structure. It is sufficient to determine whether the current radio module characteristics are suitable for the current sensor structure or which of the attempted radio module characteristics is the most suitable. As described above and in the exemplary embodiments, these steps are controlled by the controller and are at least partially performed by the controller itself.

[0037] According to one aspect, a program element is provided, for example a computer program element, which, when executed on a controller of the device, performs the steps of the method. The program element may be part of a computer program, but it may also be the entire program itself. For example, the program element may be used to update an already existing computer program to implement the invention.

[0038] The program element may be stored on a provided computer-readable medium. A computer-readable medium may be considered a storage medium, such as a memory module, a USB stick, a CD, a DVD, a data storage device, a hard disk or other medium that may store a program element as described above.

[0039] According to a further aspect, a use of a device as described herein for selecting radio module characteristics for a fill level sensor, a limit level sensor, a flow sensor or a pressure sensor is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Exemplary embodiments of the invention will be explained in more detail below with reference to schematic diagrams.

[0041] Figure 1 A schematic diagram of a sensor with means for selecting characteristics of a radio module is shown.

[0042] Figure 2 A block diagram of a radio communication module is shown.

[0043] Figure 3 A flow chart of a method for selecting radio module features for a sensor in automation technology is shown.

[0044] Figure 4 A schematic diagram with a device for determining the capacitance of a housing material is shown. DETAILED DESCRIPTION

[0045] In all figures, mutually corresponding parts are provided with the same reference numerals. The description of the invention mainly refers to an exemplary embodiment in which an antenna matching network is selected and switched, wherein the selection is made according to the housing material determined in the model. However, this example does not limit the invention.

[0046] Figure 1 Schematically shown is an industrial sensor 100 in automation technology, which comprises an electronics unit 105, a sensor housing 110, for example made of plastic, aluminum or stainless steel, and a screw-open housing cover 120, which is usually made of the same material as the sensor housing 110. A communication module 130 can be retrofitted and comprises means for selecting the radio module features of a radio module of the communication module 130. In the case of a metal housing 110, a glass viewing window 125, for example, can be provided in the cover 120 to allow data to be sent out of the sensor housing 110 via the supplementary communication module 130.

[0047] Figure 2 A block diagram of a radio communication module 130 for supplementing a sensor in an exemplary embodiment is shown, the radio communication module 130 comprising a device 200 for selecting radio module characteristics, a radio module 260, an antenna 240, and two matching networks 250 and 251 for matching the impedance of the antenna 240. Figure 2 In the embodiment, antenna 240 is connected to radio module 60 via matching network 250. Radio module 60 is connected to radio module 60 via matching network 250. Figure 1 The sensor electronics 105 shown obtains its energy 270, which can be temporarily stored or collected in an energy buffer 210 such as a battery or capacitor. All components of the communication module 130 can obtain their energy from this energy buffer 210. On the one hand, the microcontroller 215 controls the communication 220 with the sensor electronics 105 and prepares the data to be sent. In this example, the microcontroller 215 also controls the matching of the transmitting antenna 240 with the radio module 260.

[0048] Depending on the installation situation, i.e. depending on the sensor structure 110, 120, 125, the microcontroller 215 can switch to the corresponding matching network 250 and 251 for matching the impedance of the antenna 240. As shown here, the at least two antenna matching networks 250, 251 are separate. Alternatively, they can be a single electronically tunable antenna matching network.

[0049] The device 200 may also include a module 280 for determining the sensor structure, which module 280 may be, for example, a receiver that can receive the measurement result of an external sensor. For example, the measurement result indicates the signal strength or signal-to-noise ratio when the external receiver receives the signal transmitted by the communication module 130 via the antenna 240. The module 280 may also be a memory unit from which the controller can read one or more values ​​related to the shell characteristics and indicating, for example, the shell material, so that the controller can, for example, determine which matching network 250, 251 to select. The module 280 may also be a user interface so that the user can input the shell characteristics, or may be a client for receiving corresponding configuration data from an external server and / or database and / or smart phone. The module may also be, for example, a sensor or circuit that determines the electrical characteristics of the shell, such as capacitance or conductivity. The module 280 may also be an interface for the memory of the electronic unit 105, through which the memory is read and the corresponding sensor structure data is stored in the memory. In a very simple case, one bit or one flag is sufficient to indicate, for example, the "metallic characteristics" and "non-metallic characteristics" of the shell characteristics.

[0050] Figure 3 A corresponding method 300 is shown for selecting radio module features for a sensor 100 in automation technology, for example to adapt the antenna 240 of a radio communication module 130 to the housing of the sensor. In a first step 302, the radio communication module 130 is placed on the electronic module 105 of the sensor 100. This can be achieved, for example, by a screw mechanism, a plug mechanism or a snap mechanism. In a further step 304, the radio communication module 130 is supplied with power via the electronic module 105 of the sensor. In step 306, it is determined whether the radio communication module 130 is installed in a metal housing or a plastic housing, and this determination can be carried out by different methods.

[0051] For example, the supplementary radio communication module 130 can send at least two data packets under different matching of the antenna 240. The quality of each match can be quantitatively determined by a received signal strength indication (RSSI: ReceivedSignal Strength Indicator) determined at a receiver (e.g., a LoRa gateway) or a measured signal-to-noise ratio (SNR: Signal-to-Noise Ratio), and the determined quality is transmitted to the communication module 130 through bidirectional communication. As long as the communication module is powered, the antenna matching that has achieved a higher received signal strength or a better signal-to-noise ratio can be maintained for future communications. Alternatively, the installation situation can be detected by capacitive measurement of the device 200 itself (e.g., module 280 of the device 200).

[0052] In another exemplary embodiment, the device 200 can read the sensor structure such as the installation condition, the installation type or the housing material through the parameters from the sensor electronics 105. In another exemplary embodiment, the device 200 can query the installation condition from the database using the serial number of the sensor electronics 105. In yet another exemplary embodiment, the sensor structure is transmitted to the device 200 through manual input.

[0053] In step 308, the corresponding antenna matching of the radio communication module 130 is maintained as long as the power supply is not interrupted or disconnected. In the event of an interruption or disconnection, it can be assumed that the module 130 has been installed in a different sensor with a possibly different housing material and the antenna matching must therefore be determined again.

[0054] Figure 4 An exemplary embodiment with a device enabling capacitive determination of the type of sensor housing material is shown. Figure 1 The cross section of the communication module 130 and the sensor housing 110 is taken at the section A marked in FIG. For this purpose, the capacitance between the sensor housing 110 and the counter electrode 400 located in the communication module 130 is determined. In the simplest case, this can be done via the port pins of the microcontroller 215. If the communication module 130 is installed in a grounded metal housing, the capacitance measured in this way is many times higher than in a plastic housing. Based on the measured capacitance, the microcontroller can set the matching network according to the current housing.

[0055] Those skilled in the art can understand and implement other variations of the disclosed embodiments when implementing the claimed invention by studying the drawings and the disclosed contents. In this article, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can implement the functions of multiple objects or steps mentioned in this article. The computer program can be stored / distributed on a suitable medium such as an optical storage medium or a semiconductor medium, which is provided together with other hardware or as part of other hardware, but the computer program can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

Claims

1. A device (200) configured for selecting radio module characteristics for a sensor (100) in automation technology, comprising a controller (215), in, The radio module characteristics depend on the sensor structure, The controller (215) is configured to select the radio module characteristics based on the sensor structure (110, 120, 125), The sensor structure (110, 120, 125) is characterized by a housing material, and Wherein the controller (215) is configured to determine electrical characteristics of the housing material based on measurements to select the radio module characteristics.

2. The device (200) according to claim 1, wherein: The apparatus further comprises a receiver, a receiving device external to the sensor measuring a reception parameter of a signal sent by the apparatus and sending the measurement result back to the sensor, the receiver being configured to receive a value of the measurement result, and wherein the controller is configured to select the radio module feature based on the received value.

3. The device (200) according to claim 1 or 2, wherein: The device also includes at least one switch (230), wherein in each switch position, a different circuit (250, 251) for determining the radio module characteristics is active, and the controller (215) is configured to implement the radio module characteristics by switching the switch (230).

4. The device (200) according to claim 3, wherein: The circuit (250, 251) for determining the characteristics of the radio module is an antenna impedance matching network.

5. The device (200) according to claim 1 or 2, wherein: The apparatus (200) is configured to implement the radio module feature by changing the value of one or more electronic components.

6. The device (200) according to claim 1 or 2, wherein: The electrical characteristic is capacitance and / or conductivity.

7. The device (200) according to claim 1 or 2, wherein: The controller (215) is configured to query the housing material and / or the electrical characteristics from a database, a stored configuration, and / or a received configuration.

8. The device (200) according to claim 1 or 2, wherein: The radio module is characterized by radiating energy.

9. The device (200) according to claim 1 or 2, wherein: The radio module characteristics are modulation, radio standard and / or frequency.

10. A communication module (130) comprising the device according to any one of claims 1 to 9, wherein: The communication module also includes an antenna (240) and a radio module (260), wherein the antenna (240) is connected to the radio module (260), and wherein the radio module (260) is configured to receive a radio module feature selected by the controller (215) from the controller (215) of the device (200).

11. A sensor (100) comprising the communication module (130) according to claim 10, wherein: The sensor (100) also includes a sensor structure (110, 120, 125) characterized by a housing material, and the selection of the radio module characteristics depends on the sensor structure.

12. A method (300) for selecting radio module characteristics for a sensor (100) according to claim 11 in automation technology, wherein: The radio module characteristic depends on a sensor structure (110, 120, 125), wherein the controller (215) performs a selection (306) of the radio module characteristic based on the sensor structure (110, 120, 125), the sensor structure (110, 120, 125) being characterized by a housing material, and wherein the controller (215) determines an electrical characteristic of the housing material based on a measurement to select the radio module characteristic.

13. A program element, which, when executed on the controller (215) of the device according to any one of claims 1 to 9, performs the steps of the method according to claim 12.

14. Use of the device according to any one of claims 1 to 9 for selecting radio module characteristics for a fill level sensor, a limit level sensor, a flow sensor or a pressure sensor.

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