FIELD EQUIPMENT

Description

[0001] The present invention relates to a field device according to the preamble of patent claim 1.

[0002] In process automation technology, field devices are often used to record and / or influence process variables. Examples of such field devices include level measuring devices, point level measuring devices, and pressure measuring devices with sensors that record the corresponding process variables (level, limit level, or pressure). Such field devices are often connected to higher-level units, such as control systems or control units. These higher-level units are used for process control, process visualization, and / or process monitoring. State-of-the-art field devices typically comprise a housing, a sensor, and an electronic module located within the housing.

[0003] The power and / or signal transmission between field devices and higher-level units often follows the well-known 4 mA to 20 mA standard, which uses a 4 mA to 20 mA current loop or a two-wire cable between the field device and the higher-level unit. In addition to analog signal transmission, the measuring devices can transmit or receive additional information to or from the higher-level unit using various other protocols, particularly digital protocols. Examples include the HART protocol and the Profibus-PA protocol.

[0004] These field devices are also powered via the 4 mA to 20 mA current signal, eliminating the need for an additional power supply cable besides the two-wire cable. To minimize wiring and installation effort, as well as safety measures, for example, when used in explosion-proof areas, it is also not desirable to provide additional power supply cables.

[0005] For example, external control units are known from the state of the art. These are physically connected to the 4 mA to 20 mA current loop for communication with the field device, thus enabling operation of the field device via the 4 mA to 20 mA current loop using the HART protocol. Such external control units have the disadvantage that, as already mentioned, they must be physically connected to the 4 mA to 20 mA current loop. For this purpose, the two-wire cable must be modified—for example, stripped and / or severed—so that the control unit can be connected. This represents a relatively high level of effort and is not always easily accomplished on-site.

[0006] It is also known from the prior art to use radio modules to facilitate the operation of field devices. Solutions are known in which the field devices have integrated radio modules, radio modules are retrofitted at great expense, or are arranged in a transmitter power supply, a device for supplying power to the field devices. Particularly in variants with an integrated radio module or with a radio module that is to be retrofitted, the prior art has the problem that when power is supplied via the 4 mA to 20 mA current loop, only extremely low power is available and the energy that can be supplied via the current loop is sometimes insufficient to supply the radio module, the electronics module, and the sensor with sufficient power simultaneously, making operation impossible or very difficult.

[0007] State-of-the-art solutions for this include providing the radio module with its own power supply or providing additional batteries for operating the radio module in the field device. However, dedicated power supply lines require the aforementioned increased installation and security effort, which should be avoided. All field devices equipped with radio modules also carry the risk that they are not always fully controllable, meaning that unintentional operation or even deliberate manipulation cannot always be ruled out or prevented.

[0008] Further prior art is known from DE 10 2010 063226 A1 and DE 10 2017 216677 A1.

[0009] The object of the present invention is to enable simple retrofitting of secure radio modules with extended functionality and to exclude attacks through targeted manipulation of field devices, as these represent an increasing risk.

[0010] The invention is therefore based on the object of developing a known field device with a preferably modular structure in such a way that the disadvantages and risks known from the prior art are avoided.

[0011] This object is achieved by a field device having the features of patent claim 1. Advantageous embodiments and variants of the invention emerge from the subclaims and the following description. The features listed individually in the subclaims can be combined in any technically reasonable manner, both with each other and with the features explained in more detail in the following description, and represent other advantageous embodiments of the invention.

[0012] A field device according to the invention for automation technology comprises a radio module, wherein the radio module is designed to form at least a first radio channel and a second radio channel, wherein the first radio channel is designed for read access and the second radio channel is designed for write access to the field device. According to the invention, the second radio channel is deactivated in a basic state of the field device, and the field device comprises a switching element implemented at least partially in hardware, wherein the switching element is designed to enable the second radio channel to be activated.

[0013] A field device is a technical device in the field of automation technology that is directly related to a production process. In automation technology, "field" refers to the area outside of control cabinets or control rooms. Field devices can therefore be both actuators and sensors (measurement transducers) in factory and process automation.

[0014] A radio module according to the present application is understood to be a unit consisting of a radio transmitter and a radio receiver, which is designed, on the one hand, for radio communication with a higher-level unit and, on the other hand, for communication with the field device's electronics. The radio transmitter and radio receiver can be designed as a single unit, but can also be separate from each other. Furthermore, multiple radio transmitters and / or multiple radio receivers for different radio standards can be installed.

[0015] In particular, any communication standards for short-range communication and / or long-range communication can be used. For example, the radio module can be a WLAN (Wireless Local Area Network), a GPRS (General Packet Radio Service), a cellular network, an LTE (Long Term Evolution), a 3G, a 4G, or a 5G radio module. Other radio modules such as NBIoT, Zigbee, Sigfox, LPWAN, LoRa, Bluetooth, or Bluetooth LE modules can also be used. Several such communication modules can be provided to enable communication via different communication standards or a combination thereof. For example, NB-IoT or LoRa technologies can be used for radio transmission. These technologies make it possible to bridge long distances wirelessly. In addition, short-range radio modules such as Bluetooth or NFC can also be used to enable convenient parameterization over short distances, e.g.using a portable input device.

[0016] A radio channel according to the present application is to be understood as a separate communication path via which data and values ​​can be transmitted. The first radio channel is designed for read access, i.e., data from the field device, in particular from a memory of the field device, can be read via the first radio channel, while the second radio channel enables write access, i.e., the modification and / or creation of entries in a memory of the field device. The memory accessed by the first radio channel and the memory accessed by the second radio channel can be implemented as different memory areas of a shared physical memory. However, separate memory modules can also be provided.

[0017] In particular, a radio channel cannot be understood as a specific frequency or frequency range on which signals are physically transmitted.

[0018] According to the invention, the radio module has a switching element that is at least partially implemented in hardware and is designed to activate the second radio channel. The switching element can be implemented entirely in hardware, but in particular can be designed as a combination of hardware and software. Deactivation of write access can be achieved by blocking write access to a memory or memory area assigned to the second radio channel and / or by physically interrupting the second radio channel.

[0019] A complete hardware implementation can, for example, interrupt a line between the radio module, in particular the radio receiver of the radio module, and an electronics of the field device or make it impermeable to the signals.

[0020] However, a combination of hardware and software is preferred, whereby a hardware switch or button can be read by the software and access can be activated accordingly via the software. However, a purely software-based activation of the second radio channel, and thus write access, is excluded, so the hardware switch or button must be actuated locally.

[0021] According to the invention, the second radio channel, and thus the write access, can be activated by the switching element, meaning that the second radio channel is initially inactive and can be switched to an active state by the switching element. This prevents write access by persons who do not have direct physical access to the field device. Only those who have physical access to the field device and can activate the second radio channel by activating the switching element can obtain write access to the field device.

[0022] Wireless communication via the first and second radio channels makes it possible to transmit measured values ​​from the field device to a higher-level unit, e.g., a cloud system such as the VEGA Inventory System offered by the applicant. In addition, it is also possible to transmit values ​​from the higher-level unit to the field device, the radio module, or a sensor installed in the field device. Such values ​​can be parameters or software update packages for the field device or sensor. Likewise, it is of course possible not only to transfer parameters to the field device and write them to a memory there, but also to read them. This functionality makes it possible to completely configure the sensor remotely and also to provide it with software updates.

[0023] The present invention can effectively prevent unauthorized write access to the sensor, for example, from making unauthorized parameter changes or even installing malware. However, read access remains possible. According to the invention, only write access is deactivated in the field device's initial state and can be activated later. Read access should be permanently possible.

[0024] In a further development of the field device, the switching element is designed such that the second radio channel can be deactivated. Thus, actuating the switching element can both activate and deactivate the second radio channel, and thus write access to the field device.

[0025] In addition to or as an alternative to manually deactivating the second radio channel, the switching element can be coupled to a timer such that the second radio channel is automatically deactivated after a predefined time has elapsed following activation. This effectively ensures that after activating the second radio channel, e.g., for parameterizing the field device that requires write access, the field device automatically returns to a state in which the second radio channel is deactivated, thus preventing write access to the field device. This effectively prevents unauthorized personnel from changing parameters.

[0026] Additionally, the switching element can be designed and arranged in such a way that actuation is only possible when the radio module is removed from the field device. With such a design, the radio module must be separated from the field device to actuate the switching element. Such separation is registered by the field device and also by a higher-level unit, so that activation of the second radio channel can be detected in this way. Furthermore, an appropriate mechanical arrangement ensures that accidental activation or deactivation of write access is excluded.

[0027] In one embodiment, the radio module is mechanically anchored and the switching element is arranged on an underside of the radio module in such a way that the switching element is only accessible after loosening the anchoring and removing the radio module from a housing of the field device. For example, if the radio module is mechanically attached to the electronic module by means of a snap-in or bayonet lock, an operating element arranged on the underside of the radio module, i.e., on a side of the radio module facing the electronic module, can only be operated if the mechanical anchoring of the radio module is loosened and removed from the electronic module.

[0028] In a further development, the radio module can be integrated into a display and / or operating module. Field devices often have a removable and replaceable display and / or operating module, which can be used, for example, to display measured values ​​and parameters on site and / or for entering and parameterizing the field device. Such a display and / or operating module can be supplemented with a radio module, so that the radio module is integrated into the display and / or operating module. By integrating the radio module into such a display and / or operating module, a space-saving design and an electrically favorable structure can be achieved, since the display and / or operating module usually already has the appropriate electronic components for displaying measured values ​​and / or configuring the field device.In such a configuration, it is possible for the radio module to only transmit the already processed measured values ​​or corresponding configuration features, thus eliminating the need to install multiple corresponding electronic components. In this case, the hardware-implemented part of the switching element can be arranged on the display and / or operating module in such a way that it is accessible from the outside. Preferably, however, the display and / or operating module is mechanically arranged and anchored to the field device in such a way that the switching element is only accessible after loosening the anchor and removing the display and / or operating module from a housing of the field device.

[0029] The part of the switching element implemented in hardware can be, for example, a switch or a button that is coupled to the control electronics of the radio module in such a way that the second radio channel can be activated and / or deactivated.

[0030] If the second radio channel is designed exclusively for write access to a parameter memory of the field device, this access can be prevented precisely and exclusively without further restrictions, thus achieving increased security of the field device.

[0031] The field device also has an independent communication channel that enables read access to at least the field device's diagnostic data. The independent communication channel can be wireless or wired. For example, the independent communication channel can be the first radio channel or a wired communication channel that enables read access to the diagnostic data. This approach is particularly interesting for existing systems, as intelligent devices are often already installed in the field, but diagnostic data remains largely unused.

[0032] Access to diagnostic data enables a more comprehensive analysis of field device functionality and measured values. For example, the diagnostic data can be used to perform subsequent measurement value compensation or initiate predictive maintenance of the field device before a fault condition occurs. In the event of a fault condition, detailed diagnostic information can help identify the exact cause so that it can be remedied as quickly as possible.

[0033] The independent communication channel can also be implemented via a wired connection. For example, read communication can take place via an Ethernet module and / or a LAN (Local Area Network) module, or similar. Communication can also take place via a fieldbus, such as a HART bus, a Profibus, a Foundation Fieldbus bus, a Modbus, an SDI-12 bus, an Ethernet IP bus, a Profinet bus, an IP-based bus, an Ethernet IP bus, APL, a serial bus, and / or a parallel bus. Other communication connections, e.g., via IO-Link, a 4-20 mA / HART interface, and / or a USB connection, are also conceivable.

[0034] To further increase security against unauthorized access, the field device can be designed with a mechanical lock and secured against unauthorized operation. For example, the field device can have a locking mechanism in the form of a lock.

[0035] Also disclosed, but not claimed, is a modular field device system for constructing field devices, wherein the modular field device system has a plurality of housings, a plurality of sensors, a plurality of electronic modules connectable to the sensors and a plurality of display and / or operating units connectable to the electronic modules, and wherein the field device system has at least one display and / or operating module with a radio module for wireless communication with at least one further unit, wherein the radio module forms at least a first radio channel and a second radio channel, wherein the first radio channel is designed for read access and the second radio channel is designed for write access to the field device.The modular field device system is characterized according to the invention in that at least one display and / or operating unit has a radio module and a switching element that is at least partially implemented in hardware, wherein the switching element is designed such that write access to the field device can be activated.

[0036] With a modular field device concept, a module can be selected from a variety of combinable sensors, housings, electronic modules, and operating and / or display modules, and a corresponding field device can be constructed. Such a modular field device concept is offered, for example, by Vega Grieshaber KG. Typically, a sensor for converting the measured value into an electrical signal, a corresponding electronic module that provides measured value processing and various interfaces, for example to a controller and, if necessary, various communication media, and includes a power supply, as well as various display and / or adjustment modules, can be combined. The sensors, electronic modules, and display and / or adjustment modules are adapted both to each other and to various available housings.

[0037] The electronic module has various components that are combined in one unit and preferably form a self-contained unit. In particular, the electronic module can have interfaces to one or more measuring transducers (sensors) and / or display and / or operating modules, wherein the interfaces can be wired and / or wireless. The electronic module can furthermore comprise, in particular, circuit components for processing measured values, i.e. in particular computing units, such as application-specific integrated circuits (ASICs), controllers or processors, filters, or the like, and optionally one or more memory units. Furthermore, the electronic module can have one or more communication interfaces, in particular for communication with a higher-level unit, a display and / or operating module and / or the sensor.The communication interfaces can be designed as digital or analog interfaces and support direct point-to-point communication and / or bus communication and / or packet-switched communication, e.g., Ethernet communication. The communication interfaces can be bidirectional or unidirectional. Furthermore, the communication interfaces can be wired or wireless and support wired and / or wireless, i.e., in particular, radio communication and communication protocols. Furthermore, the electronic module can additionally provide a power supply for the field device, e.g., in the form of a power interface, preferably in the form of an energy input and / or an energy storage device.

[0038] In one variant, the electronic module preferably has a combined power and data interface, which simultaneously transmits power and data. Two-wire interfaces are preferred because they can be designed to be intrinsically safe. A combined power and data interface can be configured, for example, according to the 4-20 mA standard, with analog or digital data transmission, e.g., according to the HART protocol. Additionally or alternatively, the electronic module can also have a two-wire Ethernet interface, which can preferably implement communication according to the Ethernet APL standard.

[0039] It should be noted at this point that all of the above-mentioned interfaces can form a mechanical interface and / or an electrical interface and / or a data interface.

[0040] The field device is preferably designed as a modular field device, wherein it has at least one measuring transducer, an electronic module adapted to the measuring transducer and a display and / or operating module adapted thereto with a radio module which forms at least a first radio channel and a second radio channel, wherein the first radio channel is designed for read access and the second radio channel is designed for write access to the field device, wherein the field device and in particular the radio module is designed according to the above description.

[0041] The present invention will be explained in detail below using exemplary embodiments with reference to the accompanying figures. They show: Figure 1 shows an exploded view of a field device according to the present application and Figure 2 shows a block diagram of the field device according to Figure 1

[0042] In the figures, unless otherwise stated, the same reference symbols designate the same or corresponding components with the same function.

[0043] Figure 1 shows an exploded perspective view of a field device 1 according to the present application.

[0044] The field device 1 essentially comprises a housing 3 in which an electronic module 6 (indicated here by a dashed line within the housing) is arranged. A sensor 5, shown only schematically here, is connected to one end of the electronic module 6 and arranged on the housing 3. However, the sensor 5 can also be separated from the housing 3 via appropriate measuring lines and arranged in a measuring environment, for example, via appropriate extensions.

[0045] The field device 1 can be connected to a higher-level unit, for example a control, monitoring or measuring station, via a two-wire cable that is guided through a corresponding opening in the housing 3 and can be supplied with energy via this cable at the same time.

[0046] The electronics module 6 has various components that are housed in a common inner housing, the so-called electronics can, and combined to form a single unit. The electronics module 6 can thus be handled as a single component. The electronics module 6 has an interface to the sensor 5 and a further interface to a display and operating module 7, wherein the interfaces in the present exemplary embodiment are designed to be wired. The electronics module 6 further has circuit components for processing measured values, ie in particular computing units, in this case a controller, and a memory for storing measured data, diagnostic data, operating parameters and operating programs of the field device 1. In alternative embodiments, multiple controllers and / or memories are also possible.

[0047] Furthermore, the electronic module 6 has several communication interfaces for communication with a control room. In this case, the communication interface is designed as a combined power and data interface, via which power and data transmission occur simultaneously. In the present embodiment, the communication interface is designed as an Ethernet-APL interface. However, other wired and wireless communication interfaces, with and without an integrated power supply for the field device 1, are also conceivable.

[0048] In the present exemplary embodiment, a display and / or operating module 7 with an integrated radio module 9 is arranged on a side of the electronics module 6 opposite the sensor side. The display and / or operating module 7 can be mechanically connected to the electronics module 6 via a bayonet lock 17 provided on a peripheral edge of the display and / or operating module 7, wherein, with a mechanical connection, an electrical connection is simultaneously established via connection contacts 15 arranged on the underside of the display and / or operating module 7. In the present exemplary embodiment, a display for showing measured values ​​or other device-specific information and a keypad for entering operating information, for example for configuring the electronics module 6, are arranged on a side of the display and / or operating module 7 facing away from the electronics module 6.In the present exemplary embodiment, the housing 3 can be closed with a cover 4, wherein a viewing window 19 is arranged in the cover 4 so that the display of the display and / or operating module 7 remains visible from the outside even when the cover 4 is in place.

[0049] The second electrical interface transmits measured values ​​to the higher-level unit, and a separate communication channel can be established for read-only access to a memory area of ​​field device 1. Diagnostic data and parameters of field device 1, for example, are stored in this memory area. For example, diagnostic data can be read out via the separate communication channel, enabling predictive device maintenance.

[0050] The decisive factor here is that the read access is non-reactive, i.e., the additional communication channel has no effect on any parameterization or software (firmware) installed on the field device 1. This is achieved by enabling write access to the memory via a separate communication channel configured as a second radio channel of the radio module 9, which is deactivated in a basic state of the field device 1.

[0051] In the present embodiment, an operating element 11 for activating and deactivating the second radio channel of the radio module 9 arranged in the display and / or operating module 7 is arranged on the side facing the electronics module 6. In the present embodiment, the operating element 11 is designed as a mechanical slide switch, but can also be designed as a toggle switch, push button, magnetic switch, or the like. The operating element 11 interacts with control software of the field device 1 to form a switching element that enables the second radio channel and thus write access to the memory only when the slide switch is in a switched position and blocks it otherwise.

[0052] In one variant, the control element 11 is designed as a push button. The push button is linked to the control software in such a way that the second radio channel is activated when the button is pressed and then automatically deactivated after a specified period of time, in this case 15 minutes. Re-enabling can only occur by pressing the button again.

[0053] Alternatively, it may also be possible to extend the access by resetting the timer in the control software, although initial access is only granted via control element 11. To prevent future extensions of access in this way, the number of extensions can be limited via the control software, for example, to three extensions per session initialized (started) via control element 11.

[0054] In the present embodiment, the control element 11 for activating and deactivating the radio module 9 is only accessible when the display and / or control module 7 is detached from the electronic module 6 and removed from the housing 3. This provides effective protection against incorrect operation.

[0055] Furthermore, since the display and / or operating module 7 must be removed from the electronic module 6 in order to actuate the operating element 11, a signal is sent to the higher-level unit so that manipulation can be reliably detected.

[0056] Alternatively, the operating element 11, i.e. the part of the switching element implemented in hardware, which in the present case is designed as a slide switch, can also be designed as a toggle switch, push button or magnetic switch or the like.

[0057] Figure 2 shows a block diagram of field device 1 from Figure 1with a radio module 9 designed according to the present application.

[0058] The block diagram essentially shows the electronic module 6, the display and / or operating module 7 with the radio module 9 and a higher-level unit with a radio interface 100.

[0059] The electronics module 6 has a communication unit 99, which communicates with a second communication unit 94 in the display and / or operating module 7 via a transmission channel 97 and a reception channel 98. The communication unit 94 is in turn connected to a transmission and / or reception unit 93 of the radio module 9 via a transmission channel 95 and a reception channel 96. The transmission and / or reception unit 93 can transmit data to the higher-level unit 100 via the first radio channel 91 and receive data via the second radio channel 92. Data can be sent and received from the electronics module 6 to the higher-level unit 100 via these communication paths.

[0060] Transmitted data via communication paths 97, 95, and 91 can be, for example, measured values / diagnostic values. Received data via communication paths 92, 96, and 98 can be, for example, parameter values ​​sent from the higher-level unit 100 to the electronic module 6, where they are written to a memory area. Communication paths 97, 98 and 95, 96 can be, for example, RXD and TXD lines of a serial communication interface.

[0061] One embodiment is, for example, the realization of the control element 11 as a hardware switch in the receiving line 96. If the switch is opened, no more data is forwarded to the communication unit 94 and thus to the electronic module 6.

[0062] In a further possible embodiment, the switch is connected to the radio module 93 and is evaluated by the radio module so that, for example, when the switch is open, no data is accepted via the radio channel 92. List of reference symbols

[0063] 1Field device 3Housing 4Cover 5Sensor 6Electronic module 7Display and / or operating module 9Radio module 11Operating element 15Connection contact 17Bayonet lock 19Viewing window 91first radio channel 92second radio channel

Claims

1. An automation technology field device (1), comprising a radio module (9), wherein the radio module (9) is configured such that it forms at least one first radio channel (91) and one second radio channel (92), wherein the first radio channel (91) is configured for a reading access and the second radio channel (92) for a writing access to the field device (1), characterized in that the second radio channel (92) is deactivated in a basic state of the field device (1) i.e., write access to the field device (1) is disabled, and the field device (1) has a switching element at least partially realized as hardware, wherein the switching element is configured such that the second radio channel (92) can be activated.

2. The automation technology field device (1) according to claim 1, characterized in that the switching element is configured such that the second radio channel (92) can be deactivated.

3. The automation technology field device (1) according to any one of the preceding claims, characterized in that the switching element is coupled to a timer such that the second radio channel (92) is automatically deactivated after a predeterminable time after an activation has elapsed.

4. The field device (1) according to any one of the preceding claims, characterized in that the switching element has an operating member (11) formed as hardware.

5. The field device (1) according to patent claim 4, characterized in that the operating member (11) is configured and arranged such that an actuation is possible only when the radio module (9) is removed from the field device (1).

6. The field device (1) according to any one of the preceding claims 4 or 5, characterized in that the radio module (9) is indirectly or directly mechanically anchored, and the operating member (11) is disposed on a side facing into a housing interior, such that the operating member (11) is accessible only after the anchoring of the radio module (9) has been disconnected and it has been removed from the housing (3) of the field device (1).

7. The field device (1) according to any one of the preceding claims, characterized in that the radio module (9) is integrated into a display and / or operating module (7).

8. The field device (1) according to any one of the preceding patent claims, characterized in that the operating member (11) is configured as a switch or button coupled to an electronic control system of the radio module (9) such that the second radio channel (92) can be activated and / or deactivated.

9. The field device (1) according to any one of the preceding claims, characterized in that the field device (1) has an independent communication channel that enables a reading access to diagnostic data.

10. The field device (1) according to any one of the preceding claims, characterized in that the second radio channel (92) is configured exclusively for a writing access to a parameter memory of the field device (1).

11. The field device (1) according to any one of the preceding claims, characterized in that the field device (1) can be mechanically locked and secured against unauthorized operation.