Patent Application
20240031859
The present invention relates to display and/or operating modules for field devices and to the use of such display and/or operating modules.
Field devices that serve for recording and/or influencing process variables are often used in process automation engineering. Filling level measuring devices, limit level measuring devices and pressure measuring devices with sensors recording the respective process variables filling level, limit level or pressure are examples of such field devices. Such field devices are frequently connected to higher-level units, e.g. to guidance systems or control systems. These higher-level units serve for controlling, visualizing and/or monitoring processes.
The energy and/or signal transmission between the field device and higher-level units is frequently carried out in accordance with the known 4 mA to 20 mA standard, in which a 4 mA to 20 mA current loop or a two-wire line is formed between the field device and the higher-level unit. In addition to the analog transmission of signals, there is the option of the measuring devices transmitting further information to the higher-level unit, or receiving it therefrom, in accordance with various other protocols, particularly digital protocols. The HART protocol or the Profibus PA protocol may be mentioned as examples in this respect. Furthermore, the supply and digital communication may also be realized in accordance with the two-wire standard APL (APL=Advanced Physical Layer), which is currently under development and based on Ethernet.
These field devices are also supplied with power via the 4 mA to 20 mA current signal, so that no additional supply line is required besides the two-wire line. In order to keep the effort for wiring and installation and safety measures, e.g. for use in explosion-protected areas, as small as possible, it is not desired to provide additional power supply lines.
Compared with four-wire field devices, for example, two-wire field devices require a considerably reduced installation and wiring effort. In two-wire field devices, the additional installation and wiring of a supply voltage can be completely dispensed with because it takes place via the two-wire line, as shown above. Particularly in the case of applications in which explosion protection directives have to be observed, this provides considerable advantages because the separate wires for the supply voltage and the additional components required therefor are to be taken into account already during planning.
Moreover, two-wire field devices can be configured in an intrinsically safe manner and thus have an expanded field of application in explosion-protected (ex) regions. Maintenance work on field devices in ex regions is significantly easier and safer in the case of two-wire field devices than, for example, in four-wire field devices because it can safely take place even during a measuring operation. In four-wire devices, however, the energy supply must first be interrupted and secured against being turned back on again. Generally, this takes place in the terminal compartments, which are often located at a great distance from the measurement point.
It is known from the prior art to use radio modules for an easier operation and parameterization of field devices, for example. Solutions are known in which the field devices have integrated radio modules or are arranged in a transmitter power supply unit, a device for supplying the field devices with power.
Field devices are increasingly required to have the capability of being read out remotely, whereby a state of the field device or a value exceeding or dropping below a previously set measurement or threshold value is signaled by means of simple light signals, comparable to traffic lights, because a first information on the state of the field device can be made available in this manner, without the necessity of being on-site at the field device or establishing a radio link with the latter.
Moreover, field devices with a modular configuration are known from the prior art in which a selection may be made from amongst a plurality of combinable sensors, housings, electronics units and operating and/or display units, and a corresponding field device may be composed therefrom. Such a modular field device design is being offered by Vega Grieshaber KG, for example. Generally, a sensor, a corresponding electronics module providing for measurement value processing as well as an interface with a control unit and optionally with a utilized fieldbus, and various display and/or operating units can be combined. The sensors, electronics modules and display and/or operating units are adapted to one another as well as to various available housings.
In this case, the electronics modules are adapted to the respectively used sensors and, for instance, perform signal processing, preferably have analog and/or digital communication interfaces and/or an energy supply unit and/or an interface with the display and/or operating unit. Moreover, the electronics modules may have mechanical interfaces for contacting the sensors and/or the display and/or operating unit.
Wireless interfaces for digitally transmitting measurement and diagnostic information and for the wireless operation and parameterization of field devices are an important cornerstone for industrial IoT applications in the automation technology field. Numerous different radio standards are possible and customary for this purpose, such as WLAN (IEEE 802.11), Bluetooth (IEE 802.15.1), LoRaWAN (LoRa-Alliance Industry consortium), NB-IoT/4G (3GPP release 13), 5G (3GPP Release 15), WirelessHART (IEC 62591), Sigfox (Sigfox Proprietary) etc.
Each of these radio standards has its respective strengths and weaknesses. Bluetooth, for instance, is ideal for operating field devices at close ranges (up to about 25 m), because large data rates can be transmitted over a short distance. Due to the short range, however, it is only of limited use for long-distance data transmission or in large installations as they are common in automation technology. In contrast, for example, LoRaWAN has too small a bandwidth for operating a device—but instead has the advantage that small amounts of data can be transmitted over large distances (several kilometers) with very little energy expenditure, which is very suitable for transmitting measurement values or status information, but less so for operating. The implementation of only one of these radio standards thus greatly limits the possible applications.
Moreover, some of these radio standards (e.g. LoRaWAN or NB-IoT or 5G) are dependent on public or private networks in order to transmit the data of the field device further to the destination. None of the above-mentioned radio standards is available in all locations in the world with public or private networks.
It is the object of the invention to develop a display and/or operating module and a field device according to the prior art in such a way that it can be used more flexibly and no longer has the disadvantages described above.
This object is accomplished by a display and/or operating module having the features of claim 1, a field device with a modular configuration having the features of claim 11, and the use of a display and/or operating module according to claim 14.
A display and/or operating module according to the invention for a field device, with a housing, a display unit arranged in the housing and an electronics unit, wherein the display and/or operating module has at least one mechanical interface for connecting the display and/or operating module to the field device and a data interface for a communication between the display and/or operating module and an electronics module of the field device. The display and/or operating module according to the invention is characterized in that the electronics unit has at least one first radio interface and at least one further second radio interface different from the first radio interface, wherein the radio interfaces are suitably configured and arranged for an external communication.
Usually, field devices are equipped already in the prior art with a display and/or operating module, from which measurement values can be read out on-site, or on which configurations of the field device can be carried out. A space-saving structure and an electrically advantageous structure can be obtained by integrating at least two radio interfaces into such a display and/or operating module, because the display and/or operating module generally already has corresponding electronics components for displaying measurement values and/or the configuration of the field device. In such a configuration, it is possible that the radio interfaces only transmit the already processed measurement values or corresponding configuration features, so that an installation of multiple corresponding electronic components is not required.
Advantageously, display and/or operating information is transmitted between the display and/or operating module and the electronics unit in a wired manner. Thus, if the radio interfaces are also arranged in the display and/or operating module, then there is also a wired transmission of the display and/or operating information between the radio interfaces and the electronics unit of the display and/or operating module. A corresponding structure permits a particularly simple integration of the radio interfaces into existing field device designs, wherein, in particular, no changes to the field device, in particular to the electronics module of the field device, are required for this purpose.
It is accomplished by the present combination that both new and existing devices can be equipped with the present display and/or operating module with several radio interfaces for external communication and use the resultant advantages. Particularly in large and complex installations in which the field devices are used, it is advantageous if an operator does not have to work directly on the field device for a parameterization or other configuration, but if this can take place via a radio link.
In the present application, an external communication is to be understood to be a communication that takes place with components or units arranged outside the field device with which the display and/or operating module is coupled. In this case, outside means an arrangement at a distance in space of at least 10 cm.
In particular, the radio interfaces may be configured as a Bluetooth interface WiFi interface or LPWAN interface. The above-mentioned interfaces are tried and tested, have a sufficient data throughput, and are used in industrial environments already today.
Moreover, the display and/or operating module may also have an NFC interface, which may be used, in particular, for a user authentication. By means of the NFC interface, it may be ensured the user has physical access to the field device and is authorized to operate it. In addition, the establishment of a Bluetooth connection may be supported by means of NFC, for example by connection parameters being exchanged and/or other parameters for the Bluetooth connection being made available via NFC.
NFC is an international transmission standard based on RFID technology for the contactless exchange of data via electromagnetic induction by means of loose, coupled coils across short distances of a few centimeters at a frequency of 13.56 MHz.
A Bluetooth connection is an industrial standard according to IEEE 802.15.1 for data transmission via radio signals across short distances.
WIFI, also known as wireless LAN (WLAN) according to IEEE 802.11, also means a data transmission by radio signal. This is probably the most common standard for radio data transmission in the office, home and industrial areas.
Various classes of network protocols for connecting low-energy devices, such as battery-operated sensors, with a server are subsumed under the abbreviation LPWAN (Low Power Wide Area Network). The protocols are designed such that a great range and a low energy consumption of the terminal devices can be achieved at low operating costs. Exemplary LPWAN technologies include LoRaWAN, LTE-M, NB-IoT and Sigfox.
LoRaWAN, which is short for Long Range Wide Area Network (LoRaWAN), is a standard of the LoRa Alliance. This describes both the radio technology as well as the protocol technology.
LTE-M and NB-IoT are wireless communication standards standardized by 3GPP and still available in the 4G mobile network and also under 5G. For example, NB-IoT uses the mobile communication frequencies of the GSM-900 frequency band becoming available due to the continued development of mobile terminal devices towards higher frequency bands.
Sigfox is a proprietary radio system of the eponymous French company Sigfox SA transmitting in the SRD band (868 megahertz in Europe, 902 megahertz in the US).
On the whole, a larger geographical area of use of the field device in combination with the field device is possible due to a plurality of radio interfaces for different radio communications, because the quality of the network coverage varies depending on the radio standard and the region.
The display and/or operating module may be attached to a field device and/or coupled to a field device; in particular, the display and/or operating module may be mechanically and/or communicatively coupled to the field device. A mechanical coupling of such a display and/or operating module may take place, for instance, via a snap-in mechanism, a clip mechanism, a hook mechanism, a bayonet mechanism, a magnetic coupling mechanism or the like. A communicative coupling between the field device and the display and/or operating module is preferably effected by wires, but may also be effected via another radio interface for internal communication. Both a data and an energy transmission may take place via NFC or RFID, so that a wired coupling of the display and/or operating module may be dispensed with.
It may also be provided that the display and/or operating module is arranged separately from the field device and has a separate energy supply unit.
The display and/or operating module is designed such that it can be mounted within the housing of the associated field device. Thus, it is protected from external environmental influences in the same manner as the associated sensor without causing additional costs for a separate housing.
Moreover, an enhanced security level and thus an improved protection against the manipulation of a process plant in which a field device is used can be attained by a configuration with several radio interfaces. If a parametrization of the device is carried out via the first radio interface, for instance, e.g. Bluetooth, then this information can be forwarded to a system or person via another radio interface, e.g. the second radio interface. A confirmation or authorization for access via the first radio interface, for example, may then also take place via the second radio interface.
In a preferred embodiment, the first radio interface and the second radio interface use different frequency bands and/or protocols. A particularly flexible utilization can be achieved by using different frequency bands, because a geographical coverage of different radio standards can thus be used in a combined manner. Moreover, different local conditions of the respective installation may result in the one or other radio interface being more or less suitable for communication. For example, sub-gigahertz frequency bands (LPWAN) are capable of transmitting only little data, but across large distances and with a high penetration capability. In contrast, higher frequencies are capable of transmitting more data, but only across shorter distances. For instance, only the status, i.e. the notification that the sensor has a problem, can be transmitted via the sub-gigahertz network. In order to fix the problem, i.e. read out the echo curve of the sensor, the customer/user needs to come closer to the sensor with the operating tool via Bluetooth in order to read out the echo curves.
In addition or as an alternative, the radio interfaces may have different data rates. Depending on the desired service, different data rates are required. A configuration and parameterization of a field device, for instance, requires a higher data rate than the transmission of a measurement value. At the same time, a radio interface with a higher data rate also requires more energy than a radio interface with a lower data rate. Depending on the respective use, however, the radio interface may thus be selected which consumes the least energy at the required data rate.
In one embodiment, it may be provided that the first radio interface is configured for communication with a first higher-level unit and the second radio interface for communication with a second higher-level unit, wherein the first and the second higher-level unit perform different functions.
It is possible, for example, that one of the radio interfaces is connected to a central maintenance and monitoring platform, another radio interface to a higher-level unit for data acquisition and visualization of measurement values, and another radio interface to a higher-level unit for a configuration and parameterization of the field device.
It is noted at this point that the present invention is not limited to two or three radio interfaces but may also be configured with several radio interfaces, such as four or five radio interfaces.
Moreover, it is possible that one radio interface also communicates with several higher-level units simultaneously or alternately.
The different radio interfaces may further form parallel data paths. This may make sense if a redundancy is to be created. In particular, the first radio interface, for example, may form a first data path and the second radio interface a second data path and be connected to the same higher-level unit. In this case, it is possible, for instance, that the connection to a higher-level unit is established on different levels.
In addition or as an alternative, the different radio interfaces may have different access rights and/or authorizations and/or a different availability. For instance, a read-and-write access may only be provided via one of the radio interfaces, with all other radio interfaces being designed purely as information paths with reading rights.
The display and/or operating module is advantageously supplied with energy via the field device, and may be supported, for instance, by means of an internal energy storage unit and/or a, preferably internal, energy harvesting module. This is particularly advantageous in field devices in which the available energy is sufficient, in certain or all operating states, only for operating the field device, but not for operating additional devices in every operating state. In these cases, the display and/or operating module itself is capable of accumulating and temporarily storing energy, or, in operating states in which energy of the field device is available that is not required, that may be stored and used at a later point in time.
The internal energy storage unit may be configured as a capacitor or rechargeable battery or similar energy storage unit, for example, which is used for the interim buffering of energy. Depending on the radio standard, more energy is required for a short period of time, particularly for transmitting and/or receiving data, than can be obtained via the associated field device. In times in which less energy is required, this energy can be temporarily stored, little by little, in the internal energy storage unit so that it is available for transmitting/receiving data in the future. Optionally, an energy harvesting module may also be included, which recovers energy from the environment and temporarily stores it in the internal energy storage unit.
Advantageously, both the field device and the display and/or operating module are configured to be intrinsically safe in accordance with the ignition protection category Ex ia and are advantageously completely supplied with energy via a two-wire line of the field device. The field device is in this case supplied with energy preferably in accordance with the 4 mA to 20 mA standard, two-wire Profibus PA or via a two-wire Ethernet connection, preferably Ethernet APL, a Foundation Fieldbus connection.
Optionally, at least one of the radio interfaces may have an antenna adapter for connecting at least one external antenna. By connecting an external antenna, it is possible to accomplish that a radio link is made possible by suitably positioning the antenna, even in the case of an unfavorable installation situation of the field device, in which a radio link is possible only to an insufficient extent or not at all at the location of the field device.
In a preferred embodiment, a common antenna adapter, which is suitably configured and arranged for an external multi-band antenna to be connected, is provided for a part of or all of the incorporated radio interfaces.
Advantageously, the display and/or operating module has a power management unit that activates and/or deactivates the radio modules in a time-controlled and/or event-controlled manner.
With such a power management unit, it is possible to accomplish that as little energy as possible is required for radio communication, by the radio interfaces being deactivated if they are not needed and activated only if radio communication is actually imminent or scheduled. Such an activation may take place both in a time-controlled, e.g. in regular intervals, or event-controlled manner, e.g. if a measurement value or alarm notification or the like are provided.
The display and/or operating module is supplied with energy via an interface with the field device coupled to the display and/or operating module. In this case, the device, e.g. an electronics module of the field device, which is situated underneath it, is responsible for the amount of energy available to the display and/or operating module. In that case, the power management of the display and/or operating module decides how it controls the individual radio interfaces. Thus, the further radio interfaces can be turned off or be used only very sporadically, while a user communicates with the device via Bluetooth, for instance. For this purpose, the display and/or operating module may have its own energy storage unit or intermediate energy storage unit, which supplies the radio interfaces with energy for a sufficient time. In that case, the power management of the display and/or operating module decides how it controls the individual radio interfaces.
Advantageously, the display and/or operating module is configured as a retrofittable replacement module for an existing field device. In this way, already existing display and/or operating modules can be replaced with the present module, and existing devices may thus be retrofitted without any problems. The display and/or operating module is detachable, i.e. it may also be plugged on subsequently if required, and is thus retrofittable; it can be removed from a field device and plugged onto another field device. This also results in cost advantages—only if radio interfaces are needed does a display and/or operating module with integrated radio interfaces have to be plugged on—in applications without any radio transmission, it can be omitted.
A field device with a modular configuration, with a display and/or operating module according to the above description is also in accordance with the invention. As is the use of a display and/or operating module according to the above description for retrofitting an existing field device.
A modular field device concept for constructing field devices has a plurality of different housings, a plurality of different sensors and a plurality of different display and/or operating units that can be connected with the sensors, wherein the field device system has at least one display and/or operating unit with at least two different radio modules for different radio standards for wireless communication with another unit.
In this case, such a field device concept includes a series of replaceable modules that are adapted to one another, wherein at least one display and/or operating unit has at least two different integrated radio modules. In this way, field devices that are initially designed without a radio module may be equipped with radio modules by simply replacing the display and/or operating unit. Thus, it is possible in a simple manner to retrofit even older field devices with a modular configuration.
Preferably, the field device and the display and/or operating module are completely supplied with energy via a two-wire interface of the field device. Thus, the radio interface is preferably also supplied with energy via the associated field device; in process measuring technology, this typically is a two-wire 4 to 20 mA current interface, optionally with HART communication. In one embodiment, the two-wire interface may be configured in accordance with the 4 mA to 20 mA standard. However, other supply options, such as four-wire interfaces, are also possible. This simplifies installation and reduces costs, because no separate supply unit needs to be produced for the module. Thus, it is easily retrofittable even in the case of existing devices.
Alternatively, the two-wire interface may be configured as a two-wire Ethernet interface, in particular as an Ethernet APL interface. Preferably, the display and/or operating module is preferably configured to be intrinsically safe, i.e. it complies with the ignition protection category Ex ia. For this purpose, the energy in the display and/or operating module, in particular due to the fact that it is exclusively supplied by the associated, preferably also intrinsically safe, field device, is limited to the extent that an ignition of explosive gases is prevented. This is advantageous in that it can be plugged onto intrinsically safe field devices without violating the ignition protection of intrinsic safety. An intrinsically safe configuration of the display and/or operating module considerably expands the range of applications because, particularly in process measurement technology, many field device are configured with the ignition protection category intrinsically safe and can only be expanded with intrinsically safe modules without losing the ignition protection.
Use of a display and/or operating module according to any one of the claims 1 to 7 for retrofitting an existing field device.
An important advantage of the present invention lies in the fact that radio standards are subject to frequent changes and currently undergo a very dynamic development. With a removable display and/or operating module with integrated radio interfaces, even already installed field devices can be retrofitted with new technology without having to replace the associated field device. In addition, it is frequently unclear which radio standard will establish/prove itself for which application. By implementing several radio standards in a replaceable display and/or operating module, it is more likely that the appropriate radio standard is supported.
The present invention will be explained in detail below based on an exemplary embodiment and with reference to the attached FIGURE.
The field device 100 has a sensor 15 for detecting a physical quantity and an electronics module 13 arranged in a field device housing 17, and is closed off on the end side by the display and operating module 1 configured as a housing lid 3.
The field device 100 of the present exemplary embodiment is a part of a field device series with a modular configuration, with a plurality of different sensors 15, electronics modules 13, which are adapted to the sensors 15, for processing the sensor signals, and field device housings 17, which are in turn adapted, for accommodating the above components.
The display and operating module 1 is connected to the electronics module 13 via electrical contacts 11 and has a housing 3, an electronics unit 7 disposed in the housing 3, a display unit 5 configured as an LED status light, and a first radio interface 9 as well as a second radio interface 10. Due to the comparatively high data rate attainable by means of Bluetooth, an operation and, in particular, configuration and parametrization of the field device 100 is possible via the first radio interface 9, which in the present case is configured as a Bluetooth interface.
In the present case, the second radio interface 10 is configured as a LoRaWAN interface, and thus has too small a bandwidth for operating a device, for instance—but instead it has the advantage that small amounts of data can be transmitted over large distances (several kilometers) with very little energy expenditure.
In the present exemplary embodiment, the second radio interface 10 is therefore used for a measurement value transmission to a web-based system for displaying and processing the measurement values of the sensor 15. Moreover, data on the status of the field device 100 are transmitted via the second radio interface 10 to a second higher-level unit which, based on these data, monitors the field device status and indicates to the operator the requirement for maintenance before a defect or failure of the field device 100 occurs.
The two radio interfaces 9, 10 have a common antenna adapter 21, which is configured as a socket and to which an external multi-band antenna (not shown here) can be connected. The external multi-band antenna can be installed at a distance from the field device 100 by a between the multi-band antenna and the antenna adapter 21, so that radio communication is possible even if the field device 100 itself is disposed at an unfavorable location, e.g. shielded from a radio network.
In the present exemplary embodiment, the housing 3 is configured as a lid for the field device housing 17, wherein an optical signal of the display unit 5 is visible on the outside of the field device in such a manner that the successful coupling of the field device 100 with a Bluetooth operating device, for example, can be made visible.
In addition to the components already described, the display and operating module 1 according to
Moreover, a separate power management is integrated into the electronics unit 5 of the display and operating module 1. Energy and measurement data are provided to the display and operating module 1 by the electronics module 13 of the field device 100 via the electrical contacts 11. Thus, the display and operating module 1 is supplied with energy by the device underneath it. In this case, the electronics module 13, which is situated underneath the display and operating module 1, is responsible for the amount of energy available to it. The power management of the display and operating module 1 then decides how it controls the individual radio interfaces. Thus, the further radio interfaces can be turned off or be used only very sporadically, while a user communicates with the device via Bluetooth.
The present display and operating module 1 is adapted to the field device series with a modular configuration in such a manner that it can replace other display and/or operating modules 1 from the series and thus can be used for retrofitting existing field devices 100.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/082743 | Nov 2020 | WO | international |
This application is a US National Phase of PCT Application Serial Number PCT/EP2021/059924 filed Apr. 16, 2021, which published as PCT Publication WO2022/106070, which claims priority to PCT/EP2020/082743 filed Nov. 19, 2020, both of which are hereby incorporated by reference herein in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/059924 | 4/16/2021 | WO |
