AUTOMATION FIELD DEVICE

Abstract

Disclosed is a field device comprising: a connection terminal; field device electronics; an internal interface for connecting an electronic module; the electronic module having at least one electronic component for realizing an additional functionality; a capacitor, which is designed to provide an additional first auxiliary energy amount to the component if the component of the electronic module has an energy demand exceeding the main power; a battery, which is designed to provide a second auxiliary energy amount to the at least one component if the at least one component of the electronic module has an energy demand exceeding the main power and the first auxiliary energy amount, wherein the battery provides the second auxiliary energy amount to the component only if the main power and the first auxiliary energy amount are not sufficient for the energy supply of the component.

Claims

1-13. (canceled)

14. An automated Namur field device, comprising: a connecting terminal for connecting a two-wire line; field device electronics which are provided with maximum operating power via the connecting terminal through the two-wire line, wherein the field device electronics are configured to perform a main functionality of the field device, including a measurement or limit value detection; an internal interface provided by the field device electronics for connecting an electronics module; an electronics module having at least one electronic component for realizing an additional functionality, wherein the at least one electronic component of the electronics module is connected to the field device electronics for data transmission via the internal interface, and the internal interface of the at least one electronic component also provides a main power; a capacitor associated with the electronics module and configured such that the capacitor is charged via the internal interface and, in the event that the at least one component of the electronics module has an energy demand exceeding the main power, the at least one component provides additional first auxiliary energy; and a battery associated with the electronics module, designed such that the battery, in the event that the at least one component of the electronics module requires an energy demand exceeding the main power and the first auxiliary energy, provides second auxiliary energy to the at least one component, wherein the capacitor and the battery are coordinated such that the battery provides the at least one component with the second auxiliary energy only if the main power and the first auxiliary energy are not sufficient for the energy supply of the at least one component.

15. The automated field device according to claim 14, wherein the at least one component includes a radio module which is set up to communicate data wirelessly, and wherein the at least second auxiliary energy supplies the radio module with energy only in the event of a transmit or receive process.

16. The automated field device according to claim 14, further comprising: a current limiting circuit which is connected at an input to the internal interface and at an output to the at least one component of the electronics module, and is designed to limit a current which flows via the internal interface to a specific current value.

17. The automated field device according to claim 16, wherein the capacitor and the battery are arranged between the output of the current limiting circuit and the at least one component and are coordinated with one another such that the battery of the at least one component provides the second auxiliary energy only when an output voltage at the output of the current limiting circuit drops below a specific value.

18. The automated field device according to claim 17, further comprising: a regulator in a connection between the battery and the output of the current limiting circuit which regulates a battery voltage to a value which is less than a specific value at the output of the current limiting circuit.

19. The automated field device according to claim 18, further comprising: a blocking element in the form of a diode or as an integral component of the regulator in the connection between the battery and the output of the current limiting circuit which is designed to prevent a current flow from the output of the current limiting circuit to the battery.

20. The automated field device according to claim 14, wherein the capacitor comprises a plurality of ceramic capacitors, and the capacitor has a size in the range of 500 μF to 2 mF.

21. The automated field device according to claim 16, wherein the battery and the capacitor are connected to one another in parallel at the output of the current limiting circuit.

22. The automated field device according to claim 14, wherein the battery is designed in accordance with the standard IEC 60086-4, issue date Sep. 3, 2014 and/or the standard IEC 60079-11, issue date Jun. 30, 2011, such that the battery is designed for use in an explosive area.

23. The automated field device according to claim 14, wherein the internal interface for data transmission is designed as a UART interface.

24. The automated field device according to claim 15, wherein the radio module can be set up for wireless data transmission in accordance with one of the following standards or protocols or a modified variant thereof: Bluetooth or Bluetooth Low Energy; 6 LoWPAN; 6TiSCH; and Wireless HART.

25. The automated field device according to claim 14, further comprising: a field device housing in which the field device electronics and the electronics module are arranged.

26. The automated field device according to claim 14, further comprising: a field device housing in which the field device electronics are arranged, wherein the electronics module is arranged outside on the field device housing.

Description

[0032] The invention is explained in more detail based upon the following drawing. The following is shown:

[0033] FIG. 1: an embodiment of an automated field device according to the invention.

[0034] FIG. 1 shows an embodiment of an automated field device 1 according to the invention. The field device 1 shown in FIG. 1 is a Namur field device which, for example, is designed as a limit level switch in accordance with the standard DIN en 60947-5-6 (issue date: December 2000). Namur field devices 1 of this type are supplied with energy by means of a load-independent loop current I via a two-wire line 3 so that, in addition to transmitting measured values, the two-wire line 3 also supplies power to the field device 1, i.e., no separate or additional power supply unit is provided for supplying energy.

[0035] In order to perform a main functionality, for example the detection of a specific limit level and transmission of the limit level in the form of a measured value, the field device has field device electronics 4 located inside a field device housing 13. For this purpose, the field device electronics 4 can have a sensor unit 14 which is used for detecting a process variable, in particular for detecting the limit level.

[0036] The sensor unit 14 can detect the process variable at a measurement rate f.sub.M and provide a process variable signal dependent thereupon, which signal is converted by the field device electronics to an output signal that can be output.

[0037] The generated process variable signal only knows two states which are transmitted by the two-wire line 3; on the one hand, the state that the limit level is reached, and on the other hand, the state that the limit level is (still) not reached. Correspondingly, the field device electronics 4 are set up to output a current value of greater than 2.1 mA as an output signal via the two-wire line 3 if the measured values detected by the sensor unit indicate that the limit level is not yet reached, and to output a current value of less than 1.2 mA as an output signal via the two-wire line if the detected measured values indicate that the limit level is reached.

[0038] In order for the field device electronics 4 to be able to communicate the output signal via the two-wire line 3, a connecting terminal 2 is available for connecting the two-wire line 3. Furthermore, the field device electronics 4 are provided via the two-wire line 3 connected to the connecting terminal 2 with a maximum operating power Pmax used to supply energy to all components, in particular the sensor unit 14, which are needed for performing the main functionality, in particular detecting the limit level and communicating a corresponding current value.

[0039] Furthermore, the field device electronics 4 have an internal interface 5 which is designed such that an electronics module 7 can be connected for realizing or performing an additional functionality. In this case, the internal interface 5 can be configured as a UART interface (Universal Asynchronous Receiver Transmitter) with regard to the data transmission between the electronics module 7 and the field device electronics 4. In addition to the data transmission, the internal interface 5 is further designed to provide the electronics module 7 with a main power Phaupt. In this case, the field device electronics 4 are designed to provide an internal voltage Uintern and an internal current Imax, which serve to supply the electronics module 7, at the internal interface. The field device electronics 4 are preferably designed such that a maximum internal voltage Uintern of approximately 3 V is available at the internal interface 5.

[0040] To realize a radio functionality as an additional functionality, the field device 1 has an electronics module 6 with a radio unit 7 arranged within the field device housing 13. In this case, the radio unit 7 can be set up for wireless data transmission in accordance with one of the following standards or protocols or a modified variant thereof: [0041] Bluetooth or Bluetooth Low Energy; [0042] 6 LoWPAN; [0043] 6TiSCH; or [0044] Wireless HART.

[0045] In order to be able to provide sufficient energy to a transmit or receive process of the radio unit, the electronics module 6 further has a capacitor 8 which provides the radio unit 7 with a first auxiliary energy Ehilf1. The capacitor 8 may, for example, have a value in the range of 800 μF to 1.6 mF. Furthermore, the capacitor 8 is preferably in the form of a capacitor. The capacitor is connected in such a way that it is charged by the field device electronics 4 via the internal interface 5 and, in the event that the radio unit 7 has an energy demand exceeding the main power Phaupt during the transmit or receive process, additionally provides the radio unit 7 with the first auxiliary energy Philf1. For example, the capacitor may be connected to the radio unit 7 by a first electrode 8a and to ground by a second electrode 8b. It goes without saying that the capacitor 8 can also be formed by a plurality of capacitors which are connected accordingly. In order to minimize the space required for the capacitor 8 on the electronics module 6, the capacitor 8 is preferably formed from a plurality of ceramic capacitors, each of which has a single capacitance of 100 μF and is connected in such a way that a capacitance value in the range from 500 μF to 2 mF, preferably in the range from 800 μF to 1.6 mF, results.

[0046] The electronics module 6 furthermore has a current limiting circuit 10 which is set up to limit the current flow via the internal interface 5 to a maximum current value Imax, for example approximately 0.8 mA. By limiting the current, a maximum main power provided by the field device electronics via the internal interface is limited to a maximum value, for example approx. 2.4 mW (=Uintern*Imax=3 V*0.8 mA). The current limiting circuit 10 is also electrically connected in such a way that an input 10a is connected to the internal interface 5, and an output of the current limiting circuit 10b is connected to the first electrode 8a and the radio unit 7 so that a voltage U with a predetermined value, for example a value of less than 3 V, preferably a value from the range 2.5 to less than 3 V, is present at the output of the current limiting circuit 10b.

[0047] Also provided according to the invention is a battery 9 which is associated with the electronics module 6 and is preferably part of the electronics module 6. In this case, the battery 9 is designed such that, in the event that the radio module 7 briefly, for example during a transmit or receive process, has an energy demand exceeding the main power Phaupt and the first auxiliary energy Ehilf1, it provides the radio module 7 with a second auxiliary energy Ehilf2. In this case, the electronics module 6 is designed such that the battery 9 provides the radio module 7 with the second auxiliary energy Philf2 only when the main power Phaupt and the first auxiliary energy Ehilf1 are not sufficient for supplying energy to the at least one component 7. This can be realized, for example, by the battery 9 being continuously connected to the output of the current limiting circuit 10b by a regulator 11 which regulates a battery voltage Ubatterie to a value smaller than the voltage at the output of the current limiting circuit 10b, so that the battery 9 provides the second auxiliary energy Ehilf2 only when the voltage U at the output of the current limiting circuit 10b drops due to an increased energy demand by the radio module. Due to the fact that the voltage for the radio module is set to a higher value than the battery voltage downstream of the regulator Ubatterie, the battery automatically supports the energy supply of the radio module when the output voltage U drops.

[0048] In order to prevent an undesired current flow in the direction of the battery 9, it can furthermore be provided that a blocking element 12, for example a diode, is inserted between the regulator 11 and the output of the current limiting circuit 10b. Alternatively, the blocking element 12 can also be designed as an integral component of the regulator 11.

[0049] The wiring of the radio module according to the invention makes it possible to intercept energy peaks from a momentarily or temporarily increased energy demand. In this case, the auxiliary energy of the battery Ehilf 2 is used only when more energy is required internally than by the two-wire line or than is available or can be provided to the capacitor so that there is not a permanent drain on the battery.

LIST OF REFERENCE SIGNS

[0050] 1 Automated field device [0051] 2 Terminal [0052] 3 Two-wire line [0053] 4 Field device electronics [0054] 5 Internal interface [0055] 6 Electronics module [0056] 7 Electronic component, in particular radio unit [0057] 8 Capacitor [0058] 8a First electrode [0059] 8b Second electrode [0060] 9 Battery [0061] 10 Current limiting circuit [0062] 10a Input of current limiting circuit [0063] 10b Output of current limiting circuit [0064] 11 Regulator [0065] 12 Blocking element [0066] 13 Field device housing [0067] 14 Sensor unit [0068] Ehilf1 First auxiliary energy provided by the capacitor [0069] Ehilf2 Second auxiliary energy provided by the battery [0070] I Current supplied to the field device through the two-wire line [0071] Imax Maximum internal current available for supplying the electronics module [0072] U Output voltage at the current limiting circuit [0073] Uintern Voltage at the internal interface [0074] UBatterie Voltage at the battery or optionally between the regulator and blocking element [0075] P max Maximum operating power provided by the two-wire line to the field device [0076] Phaupt Main power provided via the internal interface