Field device adapter for wireless data transmission

Abstract

The invention relates to a field device adapter (6) for wireless data transmission, comprising at least: an adapter housing (7); an adapter electronics unit (14) arranged in the adapter housing (7), the adapter electronics unit (14) comprising a first supply circuit (15a) introduced into a first connection line (25) in order to provide a first supply voltage from a loop current (I) flowing in the first connection line (25), and a second supply circuit (15b) introduced into a second connection line (26) in order to provide a second supply voltage from a loop current (I) flowing in the second connection line (25), wherein the adapter electronics unit (14) further comprises a HART modem (17) and a wireless module (19) having an antenna for transmission and / or reception, and the adapter electronics unit is configured such that the first supply circuit (15a) supplies the first supply voltage to the HART modem (17) and the second supply circuit (15b) supplies the second supply voltage to the wireless module (19).

Description

TECHNICAL FIELD

[0001] The present invention relates to a field device adapter for wireless data transmission and to a system for capturing and / or setting process variables of automation technology. BACKGROUND

[0002] In automation engineering, in particular in process automation, field devices for determining, optimizing and / or influencing process variables are widely used. Sensors, such as level measuring devices, flow meters, pressure and temperature measuring devices, conductivity measuring devices, etc. are used to capture corresponding process variables, such as level, flow, pressure, temperature and conductivity, etc. Actuators, such as for example valves or pumps, etc. are used to influence process variables. Thus, the flow of a fluid in a pipe section or the level in a container can be changed by means of an actuator. In principle, field devices refer to all devices that are used in a process and supply or process process-related information. In the context of the present invention, field devices also refer to remote I / Os (electrical interfaces), radio adapters and / or generally devices arranged at the field level.

[0003] The Endress+Hauser company produces and sells various such field devices.

[0004] Two-wire field devices connected to a superior unit (e.g. a control unit PLC) via a two-wire line are still very common in a large number of existing automation systems. Two-wire field devices are designed such that the measured values or control values as primary process variables are transmitted in analog form as 4-20 mA signals via a two-wire line or two-wire cable, i.e. are transferred. The HART protocol superimposes a frequency signal on the analog current signal of 4-20 mA as a digital two-wire signal for data transmission, in particular has proven successful for transmitting all other data. According to the HART protocol, data transmission exists between 1200 Hz and 2200 Hz with a switching, wherein the lower frequency represents a logic "1" and the higher frequency represents a logic "0". In this way, the analog current signal, which changes slowly, is not affected by the frequency superimposition, so that analog and digital communication are combined together by HART.

[0005] However, in increasingly digital processes, it is desirable that data can not only be transferred via a two-wire line, i.e. only by wire, but also wirelessly. This can either wirelessly transmit data to a database, e.g. a cloud database, and make the data available in the database, or wirelessly transmit data between a field device and a mobile control unit, e.g. in order to parameterize the field device in a wireless manner via a mobile control device. SUMMARY

[0006] It is therefore the object of the present application to propose a possibility by means of which existing field devices, which are actually designed exclusively for line-bound data transmission, can be retrofitted for wireless data transmission.

[0007] This object is achieved by a field device adapter for wireless data transmission and an automation technology system according to the application.

[0008] The field device adapter for wireless data transmission according to the application comprises at least:

[0009] - an adapter housing having a first end and a second end, wherein the first end has a first connection element and a second connection element for electrically connecting to a field device electronics unit of a field device, and the second end has a third connection element and a fourth connection element for electrically connecting a two-wire line;

[0010] - an adapter electronics unit arranged in the adapter housing, which adapter electronics unit connects the first connection element to the third connection element by means of a first electrical connection line and the second connection element to the fourth connection element by means of a second electrical connection line, wherein the adapter electronics unit comprises a first power supply circuit, preferably unregulated or not regulated and installed in the first connection line, in order to provide a first supply voltage from the loop current flowing in the first connection line, and a second power supply circuit (15b), preferably unregulated or not regulated and installed in the second connection line, in order to provide a second supply voltage from the loop current flowing in the second connection line, wherein the adapter electronics unit further comprises a HART modem based on the HART protocol, which is connected to the second connection line at least via a tapping point arranged in the second connection line and is configured to tap a modulated two-wire signal onto the loop current and convert it into a signal, preferably a UART signal, and / or to convert a supplied signal, preferably a UART signal, into a two-wire signal and modulate the converted signal onto the loop current via the tapping point, wherein the adapter electronics unit further comprises a wireless module having an antenna for transmitting and / or receiving, and is configured to transmit a signal, preferably a UART signal, converted and supplied by the HART modem, as a wireless signal, and / or to receive a wireless signal converted into a two-wire signal by the HART modem and to supply this two-wire signal as a signal, preferably a UART signal, to the HART modem, wherein the adapter electronics unit is configured such that the first power supply circuit supplies the first supply voltage to the HART modem and the second power supply circuit (15b) supplies the second supply voltage to the wireless module, the first and the second power supply circuit preferably being independent of one another.

[0011] According to the application, a field device adapter with two internal power supply circuits is proposed, wherein one of the two power supply circuits supplies the HART modem with energy and the other of the two power supply circuits supplies the wireless module with energy.

[0012] For example, data can be transmitted via the field device adapter to a cloud database. For the purposes of the present application, a cloud database is understood to be a database which a user can contact via the Internet. In this case, the database can be provided with an application, for example for visualizing the data stored in the database. The user can access the database application, and thus the data, via the Internet from his device, for example a PC or a mobile terminal.

[0013] Via the wireless adapter connected to the field device, it is also possible to operate a "proprietary" field device which actually has no wireless module.

[0014] An advantageous embodiment of the field device adapter according to the application provides that the adapter electronics unit also has a galvanic isolation which galvanically isolates the HART mode from the wireless module and via which the HART modem and the wireless module at least transfer signals.

[0015] A further advantageous improvement of the field device adapter according to the application provides that the HART modem (17) is configured as a primary or secondary master in accordance with the HART protocol.

[0016] A further advantageous improvement of the field device adapter according to the application provides that the adapter electronics unit also has at least one communication resistor which is installed in the first connection line between the first power supply circuit and the third connection element.

[0017] An alternative improvement of the field device adapter according to the application provides that the adapter electronics unit (14) also has at least one communication resistor (18) which is installed in the second connection line (26) between the second power supply circuit (15b) and the fourth connection element (lib).

[0018] A further advantageous improvement of the field device adapter according to the application provides that the wireless module is also configured to transmit and / or receive radio signals in accordance with one of the following wireless protocols:

[0019] - a Bluetooth protocol or a variant derived therefrom,

[0020] - a 6LoWPAN protocol,

[0021] - a WirelessHART protocol, and / or

[0022] - a 6TiSCH protocol.

[0023] According to another advantageous improvement of the field device adapter of the invention, the adapter electronics also have EMC measures designed to protect at least the first and / or second power supply circuits from EMC interference.

[0024] According to another advantageous improvement of the field device adapter of the invention, the adapter electronics also have explosion-proof measures, said explosion-proof measures including current-limiting explosion-proof measures and / or voltage-limiting measures. Specifically, this improvement may specify that the voltage-limiting measures include at least one current shunt regulator, particularly a higher current shunt regulator, connected in parallel with the first and / or second power supply circuits, and / or the current-limiting measures include at least one resistor connected between the first power supply circuit (15a) and the HART modem and / or connected between the second power supply circuit and the wireless module.

[0025] According to a further advantageous improvement of the field device adapter of the invention, the first end of the adapter housing (7) is further designed such that the first end is a closed end, so that the field device adapter and the field device form two separate mechanical units.

[0026] According to the alternative improvement of the field device adapter of the present invention, the first end of the adapter housing is further designed such that the field device adapter can be mechanically connected to the field device, preferably to the cable sleeve connection of the field device, and particularly preferably to the M20 cable sleeve connection of the field device, so that the field device adapter and the field device form a mechanically connected unit.

[0027] In another advantageous improvement of the field device adapter according to the invention, the first and / or second power supply circuits each have at least one current shunt regulator, particularly a higher current shunt regulator, or each have at least one diode, preferably at least one Zener diode in each case, said at least one Zener diode being designed to have a fixed value for the first or second power supply voltage.

[0028] The present invention also relates to a system for an automated technique for capturing and / or setting process variables, the system having:

[0029] - The first double-wire line is used to transmit loop current using a modulated double-wire signal;

[0030] - A field device for automation technology, having a field device housing having at least one housing opening, wherein the field device further includes a field device electronics unit disposed within the field device housing, the field device electronics unit being designed to transmit data in the form of two-wire signals, particularly process variables, the two-wire signals being particularly two-wire signals based on the HART protocol;

[0031] - An improved field device adapter based on the previously described. Attached Figure Description

[0032] The invention will be explained in more detail with reference to the following figures. They are shown below:

[0033] Figure 1 A schematic representation of a two-wire field device, as can be found in many existing automation systems, which allows data to be transmitted via wired means through a two-wire line.

[0034] Figure 2 Schematic representation of the field device adapter according to the present invention.

[0035] Figure 3 A schematic representation of a field device adapter mechanically attached to a field device, forming a unit whereby the field device and the field device adapter are mechanically connected.

[0036] Figure 4 : A schematic representation of field devices and field device adapters, each forming a separate unit and electrically connected to each other via connection lines. Detailed Implementation

[0037] Figure 1 A schematic diagram illustrates a two-wire field device including a metal housing 2, within which a field device electronics unit 4 is arranged. The field device electronics unit 4 is designed with connection terminals 13, through which a two-wire line 12 is electrically connected. The field device electronics unit 4, and thus the field device 1, is connected to a higher-level unit 31 via the two-wire line. Figure 1 Not shown separately, this allows for wired communication of data with the higher-level unit 31. In this case, measured or control values, which are the main process variables, are transmitted analogously via two-wire line 12 in the form of a 4-20mA current signal, while all other data are transmitted in the form of a digital two-wire signal according to the HART standard.

[0038] To enable the dual-wire line 12 from outside the housing 2 to make electrical contact with the field device electronics unit 4 arranged inside the housing 2, the metal housing 2 has a housing opening 3. A cable sealing sleeve 5 is introduced into the housing opening 3 so that the dual-wire line 12 can be introduced into the housing 2 through the cable sealing sleeve 5. The cable sealing sleeve 5 is preferably in the form of a PG cable sealing sleeve, that is, a cable sealing sleeve with large-diameter steel conduit threads conforming to the DIN EN 62444 standard published in May 2014. The cable sealing sleeve 5 can be, for example, in the form of an M20 PG cable sealing sleeve, that is, having an outer diameter of 20 mm.

[0039] Figure 2 A schematic representation of a field device adapter 6 according to the invention is shown. The field device adapter 6 has an adapter housing 7 with an adapter chamber 10. The adapter housing 7 is designed such that the field device adapter 6 can be mechanically secured at a first end 8 to a cable seal 5 of the field device 1, particularly to a PG cable seal. For this purpose, the first end 8 of the adapter housing preferably has an M20 thread, via which the adapter can be mechanically screwed to the cable seal of the field device. In particular, the first end 8 can be designed such that it can be connected to a PG cable seal of the field device conforming to the standard DIN EN62444 published in May 2014, having an M20 thread.

[0040] For electrical contact, the field device adapter 6 has first and second connection elements 16a and 16b at its first end 8. The first and second connection elements 16a and 16b may each include an electrical connection or connection line for electrical connection to the field device electronics unit 4. Specifically, the connection may be made via a two-wire line 27.

[0041] At the second end 9, opposite the first end 8, the adapter housing 7 is designed such that the two-wire line 12 for data transmission to the field device adapter 6 can be electrically connected via third and fourth connecting elements 11a, 11b. For the electrical connection of the two-wire line 12, the third and fourth connecting elements 11a and 11b may include, for example, connecting terminals.

[0042] Furthermore, the field device adapter 6 has an adapter electronics unit 14 disposed in an adapter compartment. This adapter electronics unit connects a first connection element 16a to a third connection element 11a via a first electrical connection line 25, and connects a second connection element 16b to a fourth connection element 11b via a second electrical connection line 26. A loop current I is fed from the two-wire line 12 to the field device electronics unit 4 via the first electrical connection line 25, and a loop current I is fed back to the two-wire line 12 connected to the field device adapter 6 via the second electrical connection line 26. The adapter electronics unit 14 is thus configured to transmit digital two-wire signals designed according to the HART standard bidirectionally between the two-wire line 12 connected via the third and fourth connection elements and the field device electronics unit 4 connected via the first and second connection elements 16a, 16b.

[0043] For the autonomous power supply of the field device adapter 6, the adapter electronics unit 14 has a first power supply circuit 15a and a second power supply circuit 15b, which respectively provide a first or a second supply voltage. The power supply circuits 15a and 15b are preferably designed to be independent of each other and separated by current isolation 30. The power supply circuits 15a and 15b may each have a Z-diode or a Zener diode, which is mounted in the first or second connection line such that they are each connected in opposite directions to the loop current flowing through the first or second connection line, and in each case, the voltage tap can be used as the supply voltage via the diode.

[0044] Alternatively, the first and / or second power supply circuits 15a and 15b may each have at least one current shunt regulator, particularly a higher current shunt regulator, which is designed and installed in the first or second connection line respectively, such that it generates a first or second power supply voltage that can be fixed.

[0045] The adapter electronics unit 14 also includes: a wireless module 19 with an antenna for transmitting or receiving radio signals; and a HART modem 17 for converting digital two-wire signals. According to the invention, the wireless module 19 is powered by one of two power supply circuits, while the HART modem 17 is powered by the other. Figure 2 In the exemplary embodiment shown, the first power supply circuit 15a supplies a first power supply voltage to the HART modem 17, while the second power supply circuit 15b supplies a second power supply voltage to the wireless module 19.

[0046] The radio unit 19 is designed to transmit radio signals in particular according to the Bluetooth protocol or its variants, the 6LoWPAN protocol, the wireless HART protocol, and / or the 6TiSCH protocol.

[0047] In order to enable the splitting of digital two-wire signals transmitted on the connected two-wire line 12 or to modulate the digital two-wire signals onto the loop current I, the adapter electronics 14 has a split point 23 installed in the second connection line 26. This split point 23 is preferably installed between the second power supply circuit 15b and the fourth connection element 11b installed in the second connection line 26. Furthermore, the adapter electronics 14 is designed so that the wireless module 19 and the HART modem 17 can communicate with each other, for example, via a UART interface 33. In this way, radio signals received by the wireless module 19 can be transmitted to the HART modem 17 via the UART interface 33 and converted by the HART modem 17 into corresponding digital two-wire signals, which can then be modulated onto the loop current via the split point 23. The digital two-wire signals transmitted on the loop current can also be split at the split point 23 by the HART modem and converted into UART signals by the HART modem 17, which are then transmitted to the wireless module 19 via the UART interface 33, and these signals are transmitted as radio signals through the wireless module 19.

[0048] In order to form two power supply circuits that are independent of each other and located in different connection lines, the adapter electronics unit can have current isolation, through which only data between the wireless module and the HART modem is transmitted.

[0049] In order to enable the adapter electronics unit 14 to tap the digital two-wire signal or modulate it onto the loop current I via the tap 23, a communication resistor 18 is also provided in the first electrical connection line 25. In this case, the communication resistor 18 can be installed in the first electrical connection line 25, between the first power supply circuit 15a and the third connection element 11a.

[0050] Alternatively, the communication resistor 18 can also be installed in the second connection line 26, between the second power supply circuit and the fourth connection element. Figure 2 In this example, a dashed resistor is used. Needless to say, in this case, there is no communication resistor in the first connection line 25.

[0051] In order for the adapter electronics 14 to transmit digital two-wire signals to the field device 1, the HART modem 17 is preferably configured as an auxiliary host. Thus, for example, the field device 1 can be wirelessly parameterized via radio signals received by the wireless module 19 of the field device adapter 6 and converted into corresponding digital two-wire signals by the HART modem 17.

[0052] Alternatively, HART modem 17 can also be configured as the primary host. This may be useful, for example, if there is only one upper-level unit 31 without HART communication devices, and therefore no other primary hosts exist. In this case, for example, to parameterize field devices, adapter electronics 14 can communicate with field device electronics 4 via two-wire line 27 using HART.

[0053] Furthermore, the adapter electronics unit 14 may have EMC measures 29, which are designed to protect at least the first and / or second power supply circuits 15a, 15b from EMC interference. The EMC measures may, in particular, include one or more suppressor diodes connected in parallel with at least the first or second power supply circuit. Depending on the connection line in which the communication resistor is arranged, the suppressor diodes are connected in parallel with the power supply circuit and the communication resistor located in the power supply line.

[0054] Additionally or alternatively, the adapter electronics 14 may also have explosion-proof measures 28, 32. These may in particular include current-limiting explosion-proof measures 32 and / or voltage-limiting explosion-proof measures 28. For example, current-limiting explosion-proof measures may include resistors that have been installed in the line between the first power supply circuit and the HART modem 22a and / or in the line between the second power supply circuit and the wireless module 22b for the corresponding voltage supply. Voltage-limiting explosion-proof measures may include at least one current shunt regulator, particularly a higher current shunt regulator, connected in parallel with the first and / or second power supply circuits 15a, 15b.

[0055] Figure 3 A schematic representation of field device 1 is shown, with field device adapter 6 mechanically attached to field device 1 at its first end 8, forming a mechanically connected unit between field device 1 and field device adapter 6. For example... Figure 3 As shown, the field device adapter 6 can be arranged such that it lies between the housing opening 3 of the field device 1 and the cable seal 5, which actually belongs to the housing opening of the field device. In this case, the adapter housing 7 is designed so that the cable seal 5 can be secured to or screwed onto a correspondingly designed second end 9. For example, the second end 9 can also be in the form of a PG cable seal with an M20 thread conforming to the DIN EN 62444 standard published in May 2014.

[0056] Alternatively, the field device adapter 6 can also be designed such that the adapter housing 7 serves as a cable seal, so that a separate cable seal is not required when the adapter housing 7 is installed on the field device 1.

[0057] In both cases, the field device 1 and the field device adapter mechanically attached to the housing opening 3 of the field device 1 form a mechanically connected unit.

[0058] On the contrary, Figure 4 A schematic representation of field device 1 and field device adapter 6 is shown. In each case, field device 1 and field device adapter 6 form separate mechanical units and are electrically connected to each other via a connection line, particularly a second two-wire line 27. Because field device adapter 6 is electrically connected to field device 1 only via connection line 27 rather than via a mechanical connection, field device adapter 6 can be flexibly placed in the automation system, thereby allowing for a quasi-independent installation location from field device 1.

[0059] List of reference numerals

[0060] 1. Field equipment for automation technology

[0061] 2. Field equipment housing

[0062] 3. Shell opening

[0063] 4 Field Equipment Electronic Unit

[0064] 5 Cable sealing sleeve

[0065] 6 Field device adapters

[0066] 7. Adapter housing

[0067] 8. First end of the adapter housing

[0068] 9. The second end of the adapter housing

[0069] 10 Adapter Room

[0070] 11a Third connecting element

[0071] 11b Fourth connecting element

[0072] 12 (First) Double-track line

[0073] 13 Connection terminals for field devices

[0074] 14 Adapter Electronics Unit

[0075] 15a First power supply circuit for feeding a HART modem

[0076] 15b A second power supply circuit for feeding the wireless module

[0077] 16a First connecting element

[0078] 16b Second connecting element

[0079] 17 HART Modems

[0080] 18 Communication Resistors

[0081] 19 Wireless Module

[0082] 20 Mechanical connection elements, such as M20 threads for mechanically connecting an adapter to a cable sleeve of a field device.

[0083] 21 Bidirectional Current-Isolated Data Transmission Unit

[0084] 22a and 22b are circuits used for power supply.

[0085] 23 tap points

[0086] 25 First electrical connection line

[0087] 26 Second electrical connection line

[0088] 27. For the connecting line, the second double-line line is preferred.

[0089] 28. Pressure limiting and explosion-proof measures, especially for higher current shunt regulators.

[0090] 29 EMC Measures

[0091] 30 Current isolation

[0092] 31. Higher-level unit, for example, control system.

[0093] 32. Current limiting and explosion-proof measures, especially for resistors.

[0094] 33 interfaces, especially the UART interface

[0095] I loop current

Claims

1. A field device adapter (6) for wireless data transmission, said field device adapter (6) having at least: - Adapter housing (7) having a first end (8) and a second end (9), wherein the first end (8) has a first connecting element (16a) and a second connecting element (16b) for electrically connecting to the field device electronics unit (4) of the field device (1), and the second end (9) has a third connecting element (11a) and a fourth connecting element (11b) for electrically connecting to the two-wire line (12); - An adapter electronic unit (14), which is disposed in the adapter housing (7), the adapter housing connecting the first connecting element (16a) to the third connecting element (11a) via a first electrical connection line (25), and connecting the second connecting element (16b) to the fourth connecting element (11b) via a second electrical connection line (26), wherein the adapter electronic unit (14) comprises: A first power supply circuit (15a) is installed in the first electrical connection line (25) to provide a first power supply voltage from the loop current (I) flowing in the first electrical connection line (25); And a second power supply circuit (15b), which is installed in the second electrical connection line (26) to provide a second power supply voltage from the loop current (I) flowing in the second electrical connection line (26), wherein the adapter electronics unit (14) further includes a HART modem (17) based on the HART protocol, which is connected to the second electrical connection line at least by means of a tap (23) arranged in the second electrical connection line and is configured to tap a modulated two-wire signal onto the loop current (I) and convert it into a signal, and / or convert the supplied signal into a two-wire signal and modulate the converted two-wire signal onto the loop via the tap (23). In the current (I), the adapter electronics unit further includes a wireless module (19) having an antenna for transmitting and / or receiving, and configured to transmit, and / or receive, a signal converted and supplied by the HART modem (17) as a wireless signal, and / or receive a wireless signal converted by the HART modem (17) as a two-wire signal, and supply the two-wire signal as a signal to the HART modem, wherein the adapter electronics unit is configured such that the first power supply circuit (15a) supplies the first power supply voltage to the HART modem (17), and the second power supply circuit (15b) supplies the second power supply voltage to the wireless module (19).

2. The field device adapter according to claim 1, wherein, The first power supply circuit (15a) is unadjusted or not regulated.

3. The field device adapter according to claim 1, wherein, The second power supply circuit (15b) is unregulated or not regulated.

4. The field device adapter according to claim 1, wherein, The HART modem (17) is configured to convert a modulated two-wire signal into a UART signal, and / or convert a UART signal into a two-wire signal.

5. The field device adapter according to claim 1, wherein, The adapter electronics are configured to transmit UART signals as wireless signals and / or receive wireless signals that are converted into two-wire signals by the HART modem (17), and supply the wireless signals as UART signals to the HART modem.

6. The field device adapter according to claim 1, wherein, The first power supply circuit (15a) supplies the first power supply voltage to the HART modem (17), and the second power supply circuit (15b) supplies the second power supply voltage to the wireless module (19). The first power supply circuit and the second power supply circuit are independent of each other.

7. The field device adapter according to claim 1, wherein, The adapter electronics unit (14) also has a current isolation (30) that isolates the HART modem (17) from the wireless module (19), and the HART modem (17) and the wireless module (19) transmit at least the signal via the current isolation (30).

8. The field device adapter according to claim 7, wherein, The HART modem (17) and the wireless module (19) transmit at least UART signals via the current isolation (30).

9. The field device adapter according to any one of claims 1-8, wherein, The HART modem (17) is configured as a primary or secondary host according to the HART protocol.

10. The field device adapter according to any one of claims 1-8, wherein, The adapter electronics unit (14) also has at least one communication resistor (18) which is installed in the first electrical connection line (25) between the first power supply circuit (15a) and the third connection element (11a).

11. The field device adapter according to any one of claims 1-8, wherein, The adapter electronics unit (14) also has at least one communication resistor (18), which is installed in the second electrical connection line (26) between the second power supply circuit (15b) and the fourth connection element (11b).

12. The field device adapter according to any one of claims 1-8, wherein, The wireless module is also configured to transmit and / or receive the wireless signals according to one of the following wireless protocols: - Bluetooth protocol or its derivatives, -6LoWPAN protocol, - WirelessHART protocol, and / or -6TiSCH protocol.

13. The field device adapter according to any one of claims 1-8, wherein, The adapter electronics unit (14) also has EMC measures (29) designed to protect at least the first power supply circuit and / or the second power supply circuit from EMC interference.

14. The field device adapter according to any one of claims 1-8, wherein, The adapter electronic unit (14) also has explosion-proof measures, wherein the explosion-proof measures include current-limiting explosion-proof measures (32) and / or voltage-limiting measures (28).

15. The field device adapter according to claim 14, wherein, The voltage limiting measure (28) includes at least one current shunt regulator, which is connected in parallel with the first power supply circuit and / or the second power supply circuit.

16. The field device adapter according to claim 15, wherein, The voltage limiting measure (28) includes a shunt regulator with higher current.

17. The field device adapter according to claim 14, wherein, The current limiting explosion protection measure (32) includes at least one resistor connected between the first power supply circuit (15a) and the HART modem (17) and / or connected between the second power supply circuit and the wireless module (19).

18. The field device adapter according to any one of claims 1-8, wherein, The first end (8) of the adapter housing (7) is further designed such that the first end is a closed end, so that the field device adapter (6) and the field device (1) form two separate mechanical units.

19. The field device adapter according to any one of claims 1-8, wherein, The first end (8) of the adapter housing (7) is further designed such that the field device adapter (6) can be mechanically connected to the field device (1), such that the field device adapter (6) and the field device (1) form a mechanically connected unit.

20. The field device adapter according to claim 19, wherein, The field device adapter (6) can be mechanically connected to the cable sheath connection (5) of the field device (1).

21. The field device adapter according to claim 20, wherein, The field device adapter (6) can be mechanically connected to the M20 cable seal of the field device (1).

22. The field device adapter according to any one of claims 1-8, wherein, The first power supply circuit and / or the second power supply circuit each have at least one current shunt regulator, or each has at least one diode.

23. The field device adapter according to claim 22, wherein, The first power supply circuit and / or the second power supply circuit each have a higher current shunt regulator in each case.

24. The field device adapter according to claim 22, wherein, The first power supply circuit and / or the second power supply circuit each have at least one Zener diode, which is designed to have a fixed value for the first or second power supply voltage.

25. A system for an automation technique of capturing and / or setting process variables, the system comprising: - First double-wire line (12), the first double-wire line (12) is used to transmit loop current (I) using the modulated double-wire signal; - An automation field device (1) having a field device housing (2) having at least one housing opening (3), wherein the field device (1) further includes a field device electronics unit (4) arranged within the field device housing (2), the field device electronics unit being designed to transmit data in the form of two-wire signals; - The field device adapter (6) according to any one of claims 1-24.

26. The system according to claim 25, wherein, The field device electronics unit is designed to transmit the process variables in the form of two-wire signals based on the HART protocol.

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