Automation field equipment

Abstract

The invention relates to an automation field device (1), comprising: a housing (2) enclosing an interior space (3); a sensor and / or actuator element (4) arranged on the housing (2); an electronic circuit (5) arranged in the housing (2) for operating the sensor and / or actuator element (4), wherein the electronic circuit (5) has at least one circuit board (5a) with a preferably circular outer contour and a plurality of spring contacts (5c) in an edge region (5b), wherein the inner contour of the housing and the edge contour of the first circuit board (5a) are adapted to one another so that the first circuit board (5a) ) can be introduced into the housing (2) through a main plane (E), wherein the main plane is implemented to be arranged orthogonally to a longitudinal axis (L), the longitudinal axis extending through an interior space (3) of the housing (2), and the spring contact (5c) is arranged on the first circuit board (5a) and is implemented to hold at least the first circuit board (5a) in this position in the interior space (3), and furthermore, an electrical connection is generated between the first circuit board (5a) and the housing (2) so as to discharge interference currents from the first circuit board (5a) to the housing (2) via the spring contact (5c).

Description

Technical Field

[0001] The present invention relates to automation field devices. Background Art

[0002] Known in the prior art are field devices used in industrial plants. In process automation technology and manufacturing automation technology, field devices are often used. In principle, so-called field devices refer to all devices that are used near the process and deliver or process process-related information. Field devices are used to record and / or influence process variables. Used to record process variables are measuring devices or sensors. For example, these are used for pressure and temperature measurement, conductivity measurement, flow measurement, etc., and record the corresponding process variables, pressure, temperature, conductivity, pH value, material level, flow, etc. Actuators are used to influence process variables. For example, these actuators are pumps or valves, which can affect the flow of liquids in pipes or pipelines or the material level in containers. In addition to the measuring devices and actuators mentioned above, so-called field devices also include remote I / O, radio adapters, and devices that are usually arranged at the field level.

[0003] The Endress+Hauser Group of companies produces and sells a large number of these field devices.

[0004] Typically, the housing of the field device is made of a conductive material, in particular metal. In this case, the grounding of the field device electronics located in the housing can occur via the housing wall. Typically, the ground connection uses screws and / or clamps. This assumes a metallized area (edge ​​metallization) or a grounding lug on the circuit board. These are relatively complex to implement in the production of the field device. Summary of the invention

[0005] Starting from the above considerations, it is an object of the present invention to provide a grounding of the field device electronics in the field device housing which is as simple as possible.

[0006] This object is achieved according to the invention by an automation field device as claimed in claim 1 .

[0007] The automation field device of the present invention comprises:

[0008] - a housing enclosing an interior space, the cross section of which is preferably a circular inner contour;

[0009] - a sensor and / or actuator element, arranged at the housing, for setting and / or recording a process variable;

[0010] - an electronic circuit, arranged in a housing for operating sensor and / or actuator elements, wherein the electronic circuit has at least one circuit board with a preferably circular outer contour and a plurality of spring contacts in an edge region, wherein the inner contour of the housing and the edge contour of the first circuit board are adapted to one another so that the first circuit board can be introduced into the housing via a main plane, in which it is embodied to rest orthogonally to a longitudinal axis extending through an interior space of the housing, and the spring contacts are arranged on the first circuit board and are embodied to hold at least the first circuit board in this position in the interior space, and furthermore an electrical connection is produced between the first circuit board and the housing in order to conduct interference currents from the first circuit board to the housing via the spring contacts.

[0011] According to the invention, an automated field device is provided, in which case grounding is achieved via a spring contact. This offers the advantage that no screw / terminal connection is required and thus work steps in the production of the field device can be omitted. Another advantage compared to the terminal / screw variant is that the circuit board can be produced at lower cost, since edge metallization is no longer required. Other advantages include that tolerances in the housing or circuit board can be accommodated via the spring travel of the spring contact and / or that in the event of vibrations of the field device hardly any friction occurs in the contact area, since the spring can accommodate most of the vibrations via the spring travel.

[0012] An advantageous embodiment of the automation field device according to the invention provides that the spring contacts are arranged substantially rotationally symmetrically in an edge region of the first printed circuit board.

[0013] Another advantageous embodiment of the automation field device of the present invention provides that the electronic circuit includes at least one other circuit board electrically connected to the first circuit board, and wherein the first circuit board (5a) also includes electronic components, which are implemented to implement EMC measures, in particular EMC filtering measures and / or EMC emission measures.

[0014] Furthermore, another advantageous embodiment of the automation field device of the present invention provides that the first circuit board has a plurality of layers, at least one of which comprises a substantially continuous copper layer, so that the first circuit board divides the interior space into an EMC shielding area and a non-EMC shielding area. Of course, despite the at least one continuous copper layer, contacts from one surface to another surface (e.g. in the form of through-holes and / or micro-vias) may be present in the circuit board, and in particular the continuous copper layer may also have contacts from one surface to another surface.

[0015] Another advantageous embodiment of the automation field device of the present invention stipulates that the field device also includes a field device interface, preferably a plug connector, particularly preferably an M12 plug connector, which is installed in a housing for data communication, wherein the field device interface also has an electrical grounding contact, and the first circuit board is connected to the field device interface via the electrical grounding contact to discharge interference current. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention will now be explained in more detail based on the accompanying drawings, in which:

[0017] Figure 1a is a plan view of a first circuit board for an electronic circuit of a field device,

[0018] Figure 1b is a side view of the first circuit board for the electronic circuit of the field device shown in FIG. 1 , and

[0019] Figure 2 is a cross section of an automation field device of the present invention. DETAILED DESCRIPTION

[0020] Figure 1a A plan view of a first circuit board 5a is shown, which is used as part of an electronic circuit 5 of a field device 1 of automation technology. The first circuit board 5a is implemented to implement EMC measures, in particular EMC filtering measures and / or EMC emission measures. For this purpose, the first circuit board 5a can have an EMC filter, which is implemented in the form of two EMC chokes, for example. The first circuit board 5a has a circular outer contour, which is adapted to the inner space 3 of the housing 2 of the field device 1 in such a way that the first circuit board 5a can be introduced into the inner space 3 laterally. In addition, the first circuit board 5a includes a plurality of rotationally symmetrically arranged spring contacts 5c in the edge region 5b. In this case, the spring contacts 5c are implemented so that they have a (right-angled) trapezoidal cross section. The spring contacts 5c are arranged in the edge region 5b of the first circuit board 5a in such a way that the columns bent outward protrude beyond the edge of the circuit board. In this way, on the one hand, the first circuit board 5a can be positioned at this position after it is introduced into the inner space 3 of the housing 2, and on the other hand, interference signals can be discharged to the housing wall via the spring contacts 5c. Due to the rotationally symmetrical arrangement of the spring contacts 5 c , interfering currents can be discharged relatively evenly via the housing wall.

[0021] In order to be able to use the first circuit board 5a to achieve a separation between an EMC shielding ("Faraday cage") area and a non-shielding EMC area, the first circuit board 5a can have a plurality of circuit board layers 5f to 5i, wherein at least one circuit board layer 5g is implemented in the form of a continuous copper conductor layer. In addition, the first circuit board 5a can have through holes and / or micro through holes for electrical contact between the layer surfaces.

[0022] Figure 2 The invention shows an automated field device 1, which comprises a housing 2, which encloses an inner space 3, the cross section of which has a circular inner contour. In addition, the field device 1 also comprises: a sensor and / or actuator element 4, which is arranged at the housing 2 for setting and / or recording process variables; and an electronic circuit 5 located in the inner space 3, which is implemented to operate the sensor and / or actuator element 4. According to the invention, the electronic circuit 5 comprises a first circuit board 5a, which can be implemented as described above. The first circuit board 5a has a main plane ( Figure 1b and Figure 2 The main plane is arranged orthogonally to the longitudinal axis. Figure 2 . The first circuit board 5a is held in the interior space 3 by spring contacts 5c arranged in the edge region 5b, in particular by outwardly bent bars of the spring contacts 5c. In addition, interference currents are discharged from the first circuit board 5a to the housing 2 by the spring contacts 5c, in particular by outwardly bent bars of the spring contacts 5c. In addition, the orthogonal orientation of the first circuit board 5a relative to the longitudinal axis of the interior space divides the housing 2 into two areas or chambers, namely a first non-EMC shielding area and a second EMC shielding area. In this case, the non-EMC shielding area is preferably located in the upper part of the field device 1. In this part of the field device 1, the housing 2 also includes a cover, in which or on which a display 11 is mounted. The display 11 is electrically connected to the electronic circuit 5, for example via a plug-in connection 12 via a circuit board 10 for driving the display.

[0023] The field device 1 further comprises a field device interface 9, via which the electronic circuit 5 of the field device 1 is connected to a two-wire, three-wire or four-wire line, depending on the embodiment, in order to communicate data, in particular measurement and / or actuation values, between the circuit and the superordinate unit. The field device interface 9 can, for example, be implemented in the form of a plug connector, such as an M12 plug connector interface. In addition, the field device interface 9 can have an electrical ground contact 9a, via which the first circuit board 5a is connected to the field device interface 9, in order to exclude interference currents. The ground contact 9a can be implemented as part of the field device interface 9. Alternatively, grounding can also occur via the housing 2 and the process connector 13, via which the field device 1 is fastened to, for example, a tank or a container.

[0024] like Figure 2 As shown in , the electronic circuit 5 can be formed by a plurality of other circuit boards 5d, wherein the circuit boards 5a, 5d are plugged into each other via plug connections 12 and are thus in electrical contact with each other. In order to achieve a space-saving construction as much as possible, the circuit boards 5a, 5d can be tilted or rotated relative to each other. For example, Figure 2 As shown in FIG. 1 , two other circuit boards 5 d may extend orthogonally from the first circuit board 5 a , on which another circuit board 5 d is mounted at an end away from the first circuit board 5 a .

[0025] Reference numerals list

[0026] 1 Automated field equipment

[0027] 2. Housing

[0028] 3. Internal Space

[0029] 4 Sensor and / or actuator elements

[0030] 5 Electronic Circuits

[0031] 5a First circuit board

[0032] 5b Edge area of ​​the first circuit board

[0033] 5c Spring contact

[0034] 5d Other circuit boards

[0035] 5e Electronic components for EMC measures

[0036] 5f to 5i circuit board layers

[0037] 5g copper conductor layer

[0038] 7 EMC shielding area

[0039] 8 Unshielded EMC zone

[0040] 9 Field device interface, especially M12 interface

[0041] 9a Electrical ground contact for field device interface

[0042] 10 Display driver circuit board

[0043] 11 Display

[0044] 12 Electrical plug-in connections

[0045] 13 Process connector

[0046] E A plane in which the first circuit board is implemented

[0047] L is the longitudinal axis extending through the interior space of the housing.

Claims

1. An automated field device (1), comprising: - a housing (2) enclosing an interior space (3) having a circular inner profile in cross section; a sensor and / or actuator element (4) which is arranged at the housing (2) for setting and / or recording a process variable; - an electronic circuit (5) arranged in the housing (2) for operating the sensor and / or actuator element (4), wherein the electronic circuit (5) has at least one first circuit board (5a) with a circular outer contour and a plurality of spring contacts (5c) in an edge region (5b), wherein the inner contour of the housing and the edge contour of the first circuit board (5a) are adapted to one another so that the first circuit board (5a) can be introduced into the housing (2) via a main plane (E), wherein the main plane is designed to lie orthogonally to a longitudinal axis (L) extending through an interior space (3) of the housing (2), and the spring contacts (5c) are arranged on the first circuit board (5a) and are designed to hold at least the first circuit board (5a) in the interior space (3), and furthermore to produce an electrical connection between the first circuit board (5a) and the housing (2) in order to discharge interference currents from the first circuit board (5a) to the housing (2) via the spring contacts (5c). 2 . The field device according to claim 1 , wherein the spring contact ( 5 c ) is arranged substantially rotationally symmetrically in an edge region ( 5 b ) of the first printed circuit board ( 5 a ).

3. A field device according to claim 1, wherein the electronic circuit (5) includes at least one other circuit board (5d) electrically connected to the first circuit board (5a), and wherein the first circuit board (5a) also includes electronic components (5e), ​​which are implemented to implement EMC measures.

4. The field device according to claim 3, wherein the electronic component (5e) is embodied to implement EMC filtering measures and / or EMC emission measures.

5. A field device according to one of claims 1 to 4, wherein the first circuit board (5a) has a plurality of layers (5f-5i), at least one of which comprises a substantially continuous copper layer (5g), so that the first circuit board (5a) divides the internal space (3) into an EMC shielding area (7) and a non-EMC shielding area (8).

6. The field device according to one of claims 1 to 4 further comprises a field device interface (9), which is installed in the housing (2) for data communication, wherein the field device interface (9) also has an electrical grounding contact (9a), and the first circuit board (5a) is connected to the field device interface (9) via the electrical grounding contact to discharge interference current.

7. The field device according to claim 6, wherein the field device interface (9) is a plug connector.

8. The field device according to claim 7, wherein the field device interface (9) is an M12 plug connector.

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