Measuring device with multiple antennas

Abstract

Measuring device (100) for process automation, comprising: a multiple antenna (2) for receiving a first signal from a remotely located first transmitter having a first frequency and a second signal from a remotely located second transmitter having a second frequency different from the first frequency; a first receiving branch (6) with a first radio module (13) for processing the first signal; a second receiving branch (7) with a second radio module (16) for processing the second signal; a measuring instrument housing (1); wherein the multiple antenna (2) is mounted outside the measuring instrument housing.

Description

Field of the invention

[0001] The invention relates to process automation. In particular, the invention relates to a measuring device for process automation and uses of the measuring device. background

[0002] In process automation, field devices are used to determine measured variables. These include, in particular, level measuring devices, point level detectors, flow meters, and pressure measuring devices. These measuring devices can be equipped with a radio module, via which they can send measurement data to a remote receiver and receive parameter data from this receiver, which can be used to program the measuring device. These measuring devices can also be equipped with a satellite navigation module, via which the position of the measuring device can be determined.

[0003] Especially in cases where the measuring device housing is metallic, the antennas of the radio modules are preferably located outside the measuring device housing to ensure the best possible radio connection. The antennas are connected via cables to the radio modules located inside the measuring device housing. In explosion-proof devices, the cables and feedthroughs are protected against sparking.

[0004] WO 2016 / 205 295 A1 describes an integrated wireless communication measurement and monitoring system with multiple antennas arranged in the sensor housing.

[0005] US 2010 / 0 091 752 A1 describes a high-frequency circuit, a high-frequency component and a communication device for using multiple frequency bands. Summary of the invention

[0006] It is an object of the invention to provide a measuring device for process automation which has a simplified structure.

[0007] This object is achieved by the features of claim 1. Further developments of the invention emerge from the subclaims and the following description.

[0008] A first aspect of the invention relates to a measuring device for process automation, which has a first receiving branch with a first radio module for processing a first received signal and a second receiving branch with a second radio module for processing a second received signal. The frequencies of the two received signals can be different. A multiple antenna is provided which receives both signals. According to one embodiment of the invention, the multiple antenna is connected to the two receiving branches via one or more crossover networks, and the crossover network(s) is / are configured to ensure that the first signal is transmitted essentially only to the first receiving branch and the second signal is transmitted essentially only to the second receiving branch.

[0009] The first radio module could be, for example, a satellite navigation module (GPS, GLONASS, etc.) or a short-range communication module, such as a Bluetooth module. The second radio module could be, for example, a Wi-Fi module.

[0010] The first receiving branch can further comprise a second crossover network for selectively transmitting the first signal to the first radio module or to a third radio module of the first receiving branch. The first radio module could then be, for example, a satellite navigation module, and the third radio module a Bluetooth module.

[0011] The radio modules can of course also be configured to transmit measurement data via the multiple antenna. According to this embodiment, the measuring device is also configured to transmit a transmission signal at either the first frequency (in this case, the transmission signal is generated by the first radio module or the third radio module) or the second frequency (in this case, the transmission signal is generated by the second radio module) via the multiple antenna.

[0012] According to a further embodiment of the invention, the measuring device comprises a measuring device housing, wherein the multiple antenna is mounted outside the measuring device housing. In particular, the multiple antenna can be arranged several meters away from the measuring device housing. It can also be provided that the multiple antenna is removably attached to the measuring device housing or integrated therein.

[0013] A further aspect of the invention relates to the use of a measuring device described above and below for level measurement or limit level measurement.

[0014] Another aspect concerns the use of a measuring device for pressure measurement as described above and below.

[0015] A further aspect of the invention relates to the use of a measuring device described above and below for flow measurement.

[0016] Embodiments of the invention are described below with reference to the figures. The representations in the figures are schematic and not to scale. Where the same reference numerals are used in the following description of the figures, they denote identical or similar elements. Short description of the characters Fig. 1 shows a measuring device housing for, for example, a level radar according to a first embodiment of the invention in the open state. Fig. 2 shows the measuring device housing of the Fig. 1 in closed position. Fig. 3 shows a circuit arrangement of a measuring device according to an embodiment of the invention. Detailed description of embodiments

[0017] Fig. Figure 1 shows a measuring device housing 100 according to a first embodiment of the invention, which can be used, for example, for a level radar. An antenna 2 is attached to the outside of the measuring device housing. The antenna 2 is connected to the electronics 3 of the measuring device via the antenna cable 4.

[0018] Fig. 2 shows the measuring device housing of the Fig. 1 in the closed position. Antenna 2 can receive and transmit signals of different frequencies simultaneously, allowing the measuring device to operate with a single multiple antenna. This represents a significant cost savings.

[0019] The measuring device is capable of sending and receiving signals of various radio standards. Examples include Bluetooth, mobile radio, and GPS (Global Positioning System) signals, or, more generally, satellite navigation signals. The measuring device may have a metal housing, and the multiple antenna is connected via cable 4 to the measuring device electronics 3 located inside the housing. Since only a single multiple antenna is used, only one antenna cable 4, one antenna mount 17, and one antenna 2 are required.

[0020] Alternatively to the embodiment of the Fig. 1 and Fig. 2, the antenna can also be located away from the actual measuring device. The distance between the antenna and the measuring device can be, for example, 10 m or more. In particular, the antenna can be designed to be removable so that it can be easily replaced.

[0021] The measuring device can have explosion protection, in which case the individual antenna cable 4 and its lead-through through the measuring device housing are protected against sparking to the outside.

[0022] In particular, the measuring device can be designed as a field device using two-wire technology, four-wire technology, according to the HART standard, the Fieldbus Foundation standard, or the Profibus PA standard. The device with the multiple antenna can also be an evaluation device that communicates with one or more measuring devices and receives measurement data from them.

[0023] It is also possible for the multiple antenna to be located inside the housing, for example, on the circuit board of the measuring device's electronics. Additional antennas are not required.

[0024] Fig. Figure 3 shows the structure of a measuring device in circuit diagram form. The antenna 2 is connected to a first crossover network 5 via the signal line or antenna line 4. This may be a power splitter / combiner, for example, in the form of a miniature circuit.

[0025] The Power Splitter / Combiner 5 not only distributes the received radio signals to the individual receive paths; it also prevents the power from the first receive path from affecting the second receive path during transmission. This is particularly important because the first receive path may transmit at high power while the second path transmits at very low power. The sensitivity in the second receive path can be very high under certain circumstances, and this could damage the radio module.

[0026] The filters and diplexers prevent the radio modules from "seeing" frequencies outside their normal operating range. These could disrupt reception or even destroy the radio modules.

[0027] The filters should be designed so that the desired frequencies receive as little attenuation as possible and the undesired frequencies receive as much attenuation as possible. The transition between low and high attenuation should be as steep as possible.

[0028] The Power Splitter / Combiner 5 only splits the received power. This results in a reduction in the system's sensitivity. However, the Power Splitter / Combiner can also contain a filter.

[0029] The power splitter / combiner 5 transmits the signal received by the antenna either via the signal line 6 (first reception branch) to a second frequency divider 8, for example in the form of a diplexer, or via the second signal line 7 (second reception branch) via (optionally) a bandpass filter 15 to the wireless radio module 16, which evaluates the received signal.

[0030] If, however, the received signal is transmitted to the diplexer 8 via the second signal line, the diplexer then transmits the signal either via line 9 and the SAW filter 11 to the GNSS module 13 (the “first” radio module) or via the signal line 10 and the bandpass filter 12 to the Bluetooth module 14 (the “second” radio module).

[0031] For example, the diplexer 8 preferentially transmits frequencies in the GNSS frequency band and / or the Bluetooth frequency band to the upper signal path 9 and frequencies in the UMTS, DCS, or GSM frequency band to the lower signal path 10. The first diplexer 5 ensures that frequencies in the GSM band, DCS band, or UMTS band are preferably transmitted to the second reception path 7. These frequencies will typically be between 850 and 2100 MHz.

[0032] The circuit can be designed as an integrated circuit to which the signal line 4 is connected.

[0033] Additionally, it should be noted that "comprising" and "having" do not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered limitations.

Claims

[1] Measuring device (100) for process automation, comprising: a multiple antenna (2) for receiving a first signal from a remotely located first transmitter having a first frequency and a second signal from a remotely located second transmitter having a second frequency different from the first frequency; a first receiving branch (6) with a first radio module (13) for processing the first signal; a second receiving branch (7) with a second radio module (16) for processing the second signal; a measuring device housing (1); wherein the multiple antenna (2) is mounted outside the measuring device housing. [2] Measuring device according to claim 1, wherein the first radio module (13) is a satellite navigation module or a Bluetooth module. [3] Measuring device according to one of the preceding claims, wherein the second radio module (16) is a WLAN module. [4] Measuring device according to one of the preceding claims, further comprising: a first frequency divider (5) connecting the first and second receiving branches to the multiple antenna for selectively transmitting the first signal to the first receiving branch and the second signal to the second receiving branch [5] Measuring device according to one of the preceding claims, wherein the first receiving branch (6) has a second frequency divider (8) for selectively transmitting the first signal to the first radio module (13) or a third radio module (14) of the first receiving branch. [6] Measuring device according to one of the preceding claims, wherein the multiple antenna (2) is arranged several meters away from the measuring device housing (1). [7] Measuring device according to one of claims 1 to 5, wherein the multiple antenna (2) is removably attached to the measuring device housing (1). [8] Measuring device according to one of the preceding claims, wherein the measuring device (100) is arranged to transmit a third signal with optionally the first frequency or the second frequency via the multiple antenna (2). [9] Use of a measuring device (100) according to one of claims 1 to 8 for level measurement or limit level measurement. [10] Use of a measuring device (100) according to one of claims 1 to 8 for pressure measurement. [11] Use of a measuring device (100) according to one of claims 1 to 8 for flow measurement.

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