Automation field device

Abstract

The invention relates to an automation field device (1), having: - a housing (2) which encloses an interior (3); - a sensor and / or actuator element (4) arranged on or in 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 printed circuit board (5.1), wherein the at least one printed circuit board has at least two spring arms formed from the printed circuit board, wherein at least two of the spring arms are formed in a plane of the printed circuit board such that the two spring arms extend outwards at mutually opposite printed circuit board edges of the printed circuit board, and wherein the two opposite spring arms are designed and matched to the interior such that the spring arms generate a clamping force for the printed circuit board introduced into the interior and hold the printed circuit board in the interior, wherein at least one of the spring arms has an electrically conductive coating in order to achieve an electrically conductive connection between the printed circuit board and the housing.

Description

[0001] Field device of automation technology

[0002] The invention relates to a field device for automation technology.

[0003] Field devices are known from the state of the art and are used in industrial plants. They are widely employed in process automation as well as in manufacturing automation. In principle, field devices are defined as all devices used close to the process that provide or process process-relevant information. Thus, field devices are used to acquire and / or influence process variables. Measuring devices, or sensors, are used to acquire process variables. These are used, for example, for pressure and temperature measurement, conductivity measurement, flow measurement, etc., and acquire the corresponding process variables such as pressure, temperature, conductivity, pH value, fill level, flow rate, etc. Actuators are used to influence process variables. These include, for example, pumps or valves that can influence the flow of a liquid in a pipe or the fill level in a container.In addition to the aforementioned measuring instruments and actuators, field devices also include remote I / Os, radio adapters, or generally devices that are located at the field level.

[0004] A large number of such field devices are produced and distributed by the Endress+Hauser Group.

[0005] The housings of field devices are typically made of an electrically conductive material, especially metal. The electronics inside the housing can be grounded via a housing wall. This grounding connection is usually achieved using screws, clamps, and / or metal springs. All these variations are relatively complex to implement in the manufacturing process.

[0006] Based on this, the object of the present invention is to propose the simplest possible grounding of field device electronics in a field device housing. This object is achieved according to the invention by the field device of automation technology according to claim 1.

[0007] The field device for automation technology according to the invention comprises:

[0008] - a housing which encloses an interior space which has a preferably round inner contour in cross-section;

[0009] - a sensor and / or actuator element arranged on or in the housing for setting and / or detecting a process variable;

[0010] - an electronic circuit arranged in the housing for operating the sensor and / or actuator element, wherein the electronic circuit comprises at least one printed circuit board, wherein the at least one printed circuit board has at least two, preferably at least four, spring arms formed from the printed circuit board, wherein at least two of the spring arms are formed in a plane of the printed circuit board such that the two spring arms extend outwards along opposite edges of the printed circuit board, and wherein the two opposite spring arms are designed and adapted to the interior such that the spring arms generate a clamping force for the printed circuit board inserted into the interior of the housing and hold the printed circuit board inserted into the interior, wherein at least one of the spring arms, preferably all spring arms, has an electrically conductive coating at least at their edge region.to achieve an electrically conductive connection between the circuit board and the housing of the field device.

[0011] According to the invention, a field device for automation technology is proposed, comprising a printed circuit board with spring arms that serve as contact springs. The spring arms are implemented using the printed circuit board. For this purpose, a portion of the printed circuit board (spring arms) is designed to behave like a spring (deformation under force) and has a contact surface at its edge.

[0012] An advantageous embodiment of the field device according to the invention can provide that the spring arms are formed in one piece and / or integrally from the printed circuit board. This can be achieved, for example, by milling a corresponding contour into the printed circuit board.

[0013] Another advantageous embodiment of the field device according to the invention can provide that the spring arms are formed in a plane of the circuit board and preferably are not bent out of the plane or do not protrude from the plane.

[0014] A further advantageous embodiment of the field device according to the invention can provide that the spring arms are each formed from a first and a second spring arm part, wherein the first spring arm part adjoins a main area of ​​the printed circuit board and preferably extends outwards at a first angle of approximately 40° to 70° to the edge of the printed circuit board. In particular, the embodiment can provide that the second spring arm part adjoins the first spring arm part and bends towards the edge of the printed circuit board, and / or that the second spring arm part bends towards the edge of the printed circuit board in such a way that the second spring arm part forms an angle of at most 20°, in particular at most 10°, to the edge of the printed circuit board.

[0015] A further advantageous embodiment of the field device according to the invention can provide that the two opposing spring arms are designed such that a span, which represents the difference between the two outermost points of the two spring arms, is a few hundred micrometers, preferably about 500 micrometers, larger than the diameter of the interior of the housing in which the circuit board is placed.

[0016] The invention is explained in more detail with reference to the following drawings. They show:

[0017] Fig. 1: a top view of a printed circuit board for an electrical circuit of a field device for automation technology, and Fig. 2: a cross-section through a field device for automation technology according to the invention.

[0018] Figure 1 shows a top view of a printed circuit board 5.1, which serves as part of an electrical circuit 5 of a field device for automation technology 1. The printed circuit board 5.1 has four spring arms 5.2, which are designed to insert the printed circuit board 5.1 into an interior space 3 of a housing 2 of a field device for automation technology 1 (to be described in more detail below) and to clamp it there by means of the spring arms 5.2. The spring arms 5.2 are formed in a plane of the printed circuit board 5.1 and are preferably not bent out of or protrude from this plane. The spring arms 5.2 are formed in one piece and / or integrally from the printed circuit board 5.1. For example, the spring arms 5.2 can be milled from the material of the printed circuit board 5.1. Alternatively, the spring arms 5.2 can also be produced by stamping or similar processes. To generate a clamping force by means of which the printed circuit board 5.1 is held in place, the spring arms 5.2 are formed by means of a single piece and / or by a material bond.In the housing 3, where the printed circuit board is held, two spring arms 5.2 are configured such that the two spring arms 5.2 are located on opposite sides or edges 5.4 of the printed circuit board and extend outwards beyond the actual side edge of the printed circuit board 5.1. The two opposite spring arms 5.2 are configured such that the span, which represents the difference between the two outermost points of the spring arms, is several hundred micrometers, preferably approximately 500 micrometers, larger than the diameter of the interior of the housing into which the printed circuit board is to be placed.

[0019] The spring arms 5.2 also have an electrically conductive coating 5.5, at least in their edge regions, by which the circuit board 5.1 is clamped in the interior 3 of the housing 2. The electrically conductive coating 5.5 establishes an electrically conductive connection between the circuit board 5.1 and the housing of the field device, for example to enable grounding of the electrical circuit via the housing.

[0020] The spring arms 5.2 are preferably formed from two spring arm parts 5.6, 5.7. A first spring arm part 5.6 connects, preferably integrally and / or materially bonded, to a main area 5.8 of the printed circuit board 5.1 or to the actual printed circuit board edge 5.4, and a second spring arm part 5.7 connects in turn to the first spring arm part 5.6. The actual printed circuit board edge 5.4 is understood here to be the edge or contour of the printed circuit board that the printed circuit board would have if it did not have spring arms.

[0021] The first spring arm part 5.6 is preferably designed such that at least the first spring arm part 5.6 projects outwards at an angle ai in the range of approximately 40° to 70° to the actual circuit board edge 5.4.

[0022] Additionally, the second spring arm section 5.7 can be bent towards the printed circuit board edge 5.4 relative to the first spring arm section 5.6. Preferably, the second spring arm section 5.7 is bent towards the printed circuit board edge 5.4 such that it forms an angle 02 of a maximum of 20°, and in particular a maximum of 10°, towards the printed circuit board edge 5.4.

[0023] Figure 2 shows a field device 1 according to the invention for automation technology, comprising a housing 2 enclosing an interior space 3 which has a round inner contour in cross-section. The field device 1 further comprises a sensor and / or actuator element 4 arranged on the housing 2 for setting and / or detecting a process variable, and an electronic circuit 5 located in the interior space 3, which is configured to operate the sensor and / or actuator element 4.

[0024] The electronic circuit 5 comprises at least one printed circuit board 5.1, which is configured as described above. The printed circuit board 5.1 is arranged with a main plane in which it is formed parallel to a longitudinal axis through the housing. The opposing spring arms 5.2 of the printed circuit board 5.1 and the clamping force they generate hold the printed circuit board 5.1 in the interior 3 of the housing 2 without any additional fastening means. Simultaneously, the electrical connection between the printed circuit board 5.1, and thus the electrical circuit 5, and the housing 2, as described above, is established. Reference numerals: Field device of automation technology; Housing; Interior; Sensor and / or actuator element; Electronic circuit; Printed circuit board; Spring arms; (Actual) sides or edges of the printed circuit board; Electrically conductive coating; First spring arm section; Second spring arm section; Main area of ​​the printed circuit board

Claims

Patent claims 1. Field device of automation technology (1 ), comprising: - a housing (2) which encloses an interior space (3) which has a preferably round inner contour in cross-section; - a sensor and / or actuator element (4) arranged on or in the housing (2) for setting and / or detecting 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) comprises at least one printed circuit board (5.1), wherein the at least one printed circuit board (5.1) comprises at least two, preferably at least four, spring arms (5.2) formed from the printed circuit board, wherein at least two of the spring arms (5.2) are formed in a plane of the printed circuit board such that the two spring arms extend outwards along opposite edges of the printed circuit board and wherein the two opposite spring arms are designed and adapted to the interior such that the spring arms generate a clamping force for the printed circuit board inserted into the interior of the housing and hold the printed circuit board inserted into the interior in the interior, wherein at least one of the spring arms, preferably all spring arms, has an electrically conductive coating at least on its edge region in order to achieve an electrically conductive connection between the printed circuit board and the housing of the field device.

2. Field device of automation technology according to claim 1, wherein the spring arms are formed in one piece and / or materially bonded from the printed circuit board.

3. Field device of automation technology according to one or more of the preceding claims, wherein the spring arms are formed in a plane of the circuit board and preferably are not bent out of the plane or do not protrude from the plane.

4. Field device of automation technology according to one or more of the preceding claims, wherein the spring arms are each formed from a first and a second spring arm part, wherein the first spring arm part connects to a main area of ​​the circuit board and preferably extends outwards at a first angle in the range of approximately 40° to 70° to the edge of the circuit board.

5. Field device of automation technology according to the preceding claim, wherein the second spring arm part connects to the first spring arm part and bends towards the edge of the circuit board.

6. Field device of automation technology according to the preceding claim, wherein the second spring arm part bends towards the circuit board edge in such a way that the second spring arm part forms an angle of a maximum of 20°, in particular a maximum of 10° towards the circuit board edge.

7. Field device of automation technology according to one or more of the preceding claims, wherein the two opposing spring arms are designed such that a span representing the difference between the two outermost points of the two spring arms is greater by a few hundred micrometers, preferably by about 500 micrometers, than a diameter of the interior of the housing in which the circuit board is placed.

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