POWER-OVER-ETHERNET-BASED FIELD DEVICE USED IN AUTOMATION TECHNOLOGY

Abstract

The application discloses a power-over-Ethernet-based field device comprising a field device housing, an Ethernet connection so that the field device is suppliable with energy and can exchange data with the network, a voltage converter electronics for converting a voltage applied to the Ethernet connection to an operating voltage, and a field device electronics, which is supplied the operating voltage, and which serves for registering a process variable and communicating the registered process variable in the form of process data via the Ethernet connection, wherein the voltage converter electronics has a first means to heat the interior of the field device housing to a first threshold temperature and which contributes to converting the voltage applied to the Ethernet connection into the operating voltage so that the field device electronics can register the process variable and communicate the registered process variable in the form of process data via the Ethernet connection.

Claims

1-12. (canceled)

13. A power-over-Ethernet-based field device of automation technology comprising: a field device housing; an Ethernet connection arranged on the field device housing for connecting the field device to an Ethernet-based network, so that the field device is suppliable via the Ethernet connection with energy and can exchange data with the network; a voltage converter electronics for converting a voltage applied to the Ethernet connection to an operating voltage; and a field device electronics, which is supplied the operating voltage, and which serves for registering a process variable and communicating the registered process variable in the form of process data via the Ethernet connection, wherein the voltage converter electronics has at least a first means, which is adapted in a first operating state to heat the interior of the field device housing to a first threshold temperature and which, furthermore, contributes in a second operating state to converting the voltage applied to the Ethernet connection into the operating voltage so that the field device electronics can register the process variable in the second operating state and communicate the registered process variable in the form of process data via the Ethernet connection.

14. The power-over-Ethernet-based field device as claimed in claim 13, wherein the first means includes a transformer, which is adapted in such a manner that it serves in the first operating state at least partially for heating the interior of the field device housing to the first threshold temperature and serves, furthermore, in the second operating state for voltage conversion so that the field device electronics in the second operating state can register the process variable and communicate the registered process variable in the form of process data via the Ethernet connection.

15. The power-over-Ethernet-based field device as claimed in claim 13, wherein the first means includes at least one resistance element, which is adapted such that in the first operating state it at least partially serves for heating the interior of the field device housing to the first threshold temperature and, in the second operating state for voltage conversion so that the field device electronics in the second operating state can register the process variable and communicate the registered process variable in the form of process data via the Ethernet connection.

16. The power-over-Ethernet-based field device as claimed in claim 13, wherein the voltage converter electronics is adapted to not supply the field device electronics with energy in the first operating state.

17. The power-over-Ethernet-based field device as claimed in claim 13, wherein the voltage converter electronics is adapted to supply the field device electronics with energy in the second operating state.

18. The power-over-Ethernet-based field device as claimed in claim 17, wherein the field device electronics and/or the voltage converter electronics are/is adapted such that essentially a constant power is available to the field device electronics in the second operating state.

19. The power-over-Ethernet-based field device as claimed in claim 18, wherein the first means for heating is controlled such that a total power, which is consumed via the Ethernet connection, is, and remains, essentially constant and the power required for operation is available to the field device electronics, so that the field device electronics can register the process variable and communicate the registered process variable in the form of process data via the Ethernet connection.

20. The power-over-Ethernet-based field device as claimed in claim 13, wherein the first threshold temperature is selected from a range from 30 C. to 70 C.

21. The power-over-Ethernet-based field device as claimed in claim 13, wherein the first means is further adapted to heat the interior of the field device housing up to a second threshold temperature.

22. The power-over-Ethernet-based field device as claimed in claim 21, wherein the field device electronics and/or the voltage converter electronics are/is further adapted such that in a temperature range between the first and second threshold temperatures the total power consumed via the Ethernet connection serves partially for operating the field device electronics, so that the field device electronics can register the process variable and communicate the registered process variable in the form of process data via the Ethernet connection and the remaining power serves for heating the interior of the field device housing by means of the first means.

23. The power-over-Ethernet-based field device as claimed in claim 22, wherein the second threshold temperature is selected from a range from 5 C. to 25 C.

24. A use of a Power-over-Ethernet-based field device, the field device including: a field device housing; an Ethernet connection arranged on the field device housing for connecting the field device to an Ethernet-based network, so that the field device is suppliable via the Ethernet connection with energy and can exchange data with the network; a voltage converter electronics for converting a voltage applied to the Ethernet connection to an operating voltage; and a field device electronics, which is supplied the operating voltage, and which serves for registering a process variable and communicating the registered process variable in the form of process data via the Ethernet connection, wherein the voltage converter electronics has at least a first means, which is adapted in a first operating state to heat the interior of the field device housing to a first threshold temperature and which, furthermore, contributes in a second operating state to converting the voltage applied to the Ethernet connection into the operating voltage so that the field device electronics can register the process variable in the second operating state and communicate the registered process variable in the form of process data via the Ethernet connection, wherein the use is in an environment with, externally surrounding the field device housing, a temperature, which lies below the first threshold temperature and/or the second threshold temperature, wherein the first threshold temperature is in the range from 30 C. to 70 C., and wherein the second threshold temperature is in the range from 5 C. to 25 C.

Description

[0024] The invention will now be explained in greater detail based on the appended drawing, the figures of which show as follows:

[0025] FIG. 1a a schematic block diagram of a first example of an embodiment of a PoE field device of the invention,

[0026] FIG. 1b a schematic block diagram of a second example of an embodiment of the PoE field device of the invention.

[0027] FIG. 1a shows a block diagram of a first example of a PoE field device 1 of the invention. The PoE field device 1 includes a field device housing 2, in which a voltage converter electronics 5 and a field device electronics 6 are arranged. Field device housing 2 includes an external Ethernet connection 3, via which the PoE field device 1 is connectable with a PoE-capable Ethernet cable 11 to an Ethernet-network 4. Via the PoE-capable Ethernet cable 11, the field device 1 is, in the connected state, supplied with energy. For this, there is provided (not shown in FIG. 1a) an energy supply unit (PSE), which is likewise connected with the Ethernet network 4.

[0028] Voltage converter electronics 5 is, in principle, adapted in a first operating state to heat the interior of the field device housing 2 and in a second operating state to convert the voltage applied to the Ethernet connection 3 into an operating voltage. For this, the voltage converter electronics 5 shown in FIG. 1a includes a transformer 7, which serves both for voltage conversion as well as also for heating the interior of the field device housing 2. In order to control the transformer 7 corresponding to the desired function, thus, heating or converting, the voltage converter electronics 5 includes, furthermore, a control circuit 10. Control circuit 10 is adapted to control the transformer 7 in the first operating state in such a manner that it has a poor efficiency, in order to be able to heat the interior above the first threshold temperature. Furthermore, the voltage converter electronics 5 is adapted to control the transformer 7 in the second operating state in such a manner that such is operated at an essentially optimal working point and, thus, also has a best possible efficiency, in order to convert the voltage applied to the Ethernet connection 3 into the operating voltage. For this, a driver unit 9 can be provided, which drives the transformer 7. The driver unit 9 can be so influenced by the control circuit 10 that the efficiency of the transformer 7 is high or low, corresponding to the particular operating mode.

[0029] In the case, in which a resistance is used for heating instead of the transformer 7, the control circuit 10 then controls the resistance 8, which serves for the heating. Used as resistance for heating can be either a resistance component of the voltage converter electronics 5 or of the field device electronics 6. By way of example, the resistance element for heating in FIG. 1a is arranged between the transformer 7 and the control circuit 10, i.e. after the transformer. It can, however, also be arranged between the Ethernet connection 3 and the transformer 7, i.e. in front of the transformer, as shown in FIG. 1b.

[0030] Control circuit 10 is also adapted to register an internal temperature reigning in the field device housing 2, and, based on the internal temperature, to switch between the first and second operating states. For this, the control circuit 10 or the field device electronics 6 can include a temperature sensor element 12, for example, a platinum temperature sensor. Temperature sensor element 12 can be embodied as a separate element in the voltage converter electronics 5, or field device electronics 6, or be formed by an element, which must unavoidably be present in the voltage converter electronics 5, or the field device electronics 6, as the case may be.

[0031] The first operating state is characterized by the feature that the internal temperature lies below the first threshold temperature. In this operating state, the control circuit controls the transformer in such a manner that such essentially serves completely for heating. This means that in the first operating state, the field device electronics is essentially not supplied with energy by the voltage converter electronics. Because of the heating, it is assured that components, which are qualified at the first threshold temperature, are not operated below this threshold temperature.

[0032] The second operating state is characterized by the feature that, from the beginning, the internal temperature lies above the first threshold temperature. In this operating state, the control circuit 10 controls the transformer 7 in such a manner that such serves for converting the voltage into the operating voltage. Furthermore, the control circuit 10 in the second operating state can also drive the transformer 7 partially for heating. Thus, for example, it can be provided that the total power provided via the Ethernet connection 3, for example, 3.84 W, when the PoE field device 1 is classified in the lowest class, is divided by the control circuit 10 in such a manner that the field device electronics 6 receives an essentially constant power required for functioning and a remaining power fraction is used for heating the field device interiors by the transformer 7. This means that the control 10 of the transformer 7 occurs dynamically. In this way, the field device electronics 6 can work as desired in the second operating state and register a process variable and communicate the process variable in the form of process data via the Ethernet connection 3.

[0033] In the case, in which the PoE field device 1 is a type 2 PD device having an integrated Data Link Layer of the IEEE802.3-2015 standard, the control circuit 10 can also be embodied in such a manner that such performs a dynamic change of the classification in the ongoing operation of the PoE field device 1, so that the power provided to the Ethernet connection 3 is increased. This can be performed, for example, when the internal temperature lies significantly below the first threshold temperature and, thus, the heating of the field device interiors would last inacceptably long. Control circuit 10 can then be adapted in such a manner that it starts the PoE field device with a higher power class, e.g. about 13 W instead of 3.84 W, and after reaching the first threshold temperature, starts the PoE field device in a lower power class.

[0034] Furthermore, the control circuit 10 can be adapted in such a manner that upon reaching a second threshold temperature the transformer 7 serves exclusively for converting the voltage applied on the Ethernet connection 3 into the operating voltage.

[0035] The control unit 10 can, furthermore, be adapted not to supply the field device electronics 6 with electrical current in the first operating state, while in the second operating state the field device electronics 6 is supplied with the needed power. For example, this can be implemented via a switch in the form of a transistor, which is operated by the control unit 10 in the first operating state in such a manner that the field device electronics 6 is electrically isolated from the voltage converter electronics 5 and in the second operating state the field device electronics 6 is electrically connected with the voltage converter electronics 5, so that the field device electronics 6 receives the appropriate power.

[0036] Alternatively, the turning of the field device electronics on- and off could also occur by a signal from the control unit 10 to the driver unit 9, which, in this case, then is adapted in the first operating state to isolate the field device electronics 6 from the voltage converter electronics 5, thus, to turn off the field device, and in the second operating state to connect the field device electronics 6 electrically with the voltage converter electronics 5.

[0037] The PoE field device 1 can, thus, be operated in an environment, which has an ambient temperature, i.e. a temperature externally surrounding the field device housing 2, which is lower than the first threshold temperature. For example, the PoE field device 1 can be operated at an ambient temperature of less than 40 C., wherein the field device 1 is embodied in such a manner that the first threshold temperature is about 40 C. and the second threshold temperature is about 20 C. The operating temperatures, thus, the first and, in given cases, the second threshold temperatures, are, in such case, adaptable to the particular location of use. In principle, the threshold temperatures can be selected as desired, when the PoE field device 1 is correspondingly adapted. Proved to be especially suitable for the first threshold temperature has been a temperature value in the range from 30 C. to 70 C., especially the temperature value of 60 C. Proved especially suitable for the second threshold temperature has been a temperature value in the range from 5 C. to 25 C., especially the temperature value of 20 C.

LIST OF REFERENCE CHARACTERS

[0038] 1 PoE field device of automation technology [0039] 2 field device housing [0040] 3 Ethernet connection [0041] 4 network [0042] 5 voltage converter electronics [0043] 6 field device electronics [0044] 7 transformer [0045] 8 resistance element for heating [0046] 9 driver unit [0047] 10 control circuit [0048] 11 Ethernet cable [0049] 12 temperature sensor element