Field device

Abstract

The field device (1) includes: a housing portion (30) having an amplifier shielding chamber (30A) into which an analog signal transmission portion (40) for transmitting an analog signal output from a detector can be inserted; a signal conversion portion (50) disposed inside the amplifier shielding chamber (30A) for converting the analog signal into a digital signal; and a connector (60) disposed inside the amplifier shielding chamber (30A) and detachably connecting the analog signal transmission portion (40) and the signal conversion portion (50).

Description

Technical Field

[0001] The present invention relates to a field device.

[0002] This application claims priority based on a Japanese patent application with an application date of October 29, 2020 and an application number of Japanese Patent Application No. 2020-181674, the content of which is incorporated herein by reference. Background Art

[0003] As one type of field device, a vortex flowmeter described in Japanese Patent Application Laid-Open No. 2002-107192 is known. The vortex flowmeter includes a container having a cylindrical side wall and a partition wall provided at the central portion of the side wall. The interior of the container is divided by the side wall and the partition wall into a terminal box chamber and an amplifier chamber. A terminal box portion having a signal terminal portion and a power supply terminal portion is provided in the terminal box chamber. An amplifier portion that processes an input signal and a power supply input is provided in the amplifier chamber.

[0004] However, in order not to be affected by noise such as power supply noise, an amplifier shielding chamber is formed in the amplifier chamber. A signal line that transmits, for example, an analog signal that is a detection result of a detection unit is accommodated in the amplifier shielding chamber. Conventionally, the signal line is screwed to a substrate disposed in the amplifier shielding chamber. If the signal line is screwed to the substrate, not only a space for disposing a screw in the amplifier shielding chamber but also a space for screwing the screw need to be ensured. Therefore, the amplifier shielding chamber becomes large, and the design freedom of the outside of the amplifier shielding chamber is limited.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-107192 Summary of the Invention

[0008] (1) A field device according to an embodiment of the present invention includes: a housing portion having an amplifier shielding chamber into which an analog signal transmission portion that transmits an analog signal output from a detector can be inserted; a signal conversion portion disposed inside the amplifier shielding chamber and that converts the analog signal into a digital signal; and a connector disposed inside the amplifier shielding chamber and that detachably connects the analog signal transmission portion and the signal conversion portion.

[0009] (2) The field device according to (1) above may have: a communication hole that communicates the inside and outside of the amplifier shielding chamber; a substrate portion having a main body portion disposed inside the housing portion and outside the amplifier shielding chamber and an insertion portion extending from the main body portion and inserted into the inside of the amplifier shielding chamber through the communication hole; and an amplifier shielding plate that closes the communication hole through which the substrate portion passes.

[0010] (3) The field device according to (2) above may be such that the amplifier shielding plate and the substrate portion are threadedly fixed to the housing portion outside the amplifier shielding chamber together.

[0011] (4) The field device according to (2) or (3) above may be such that the housing portion includes a partition wall portion facing a plate surface on one side of the insertion portion and a circumferential wall portion protruding from the partition wall portion, surrounding the periphery of the insertion portion, and having the communication hole formed in a part thereof, and the field device has a second substrate portion that is placed on an open end edge of the circumferential wall portion on the side opposite to the partition wall portion, faces a plate surface on the other side of the insertion portion, and has a shielding pattern formed thereon, and the amplifier shielding chamber is formed by the partition wall portion, the circumferential wall portion, the second substrate portion, and the amplifier shielding plate.

[0012] (5) For the field device according to any one of (1) to (4) above, the analog signal transmission portion may include a second connector that detachably connects a first portion connected to the detector and a second portion inserted into the inside of the housing portion outside the housing portion.

[0013] (6) The field device according to (4) above may be such that the housing portion includes a cylindrical housing body, a first shield installed on one end side of the housing body, and a second shield installed on the other end side of the housing body.

[0014] (7) The field device according to (4) above may be such that the housing body is made of metal, and the first shield and the second shield are made of resin.

[0015] (8) The field device according to (4) above may further include a terminal box to which external wiring introduced through an introduction hole formed in the housing portion is connected. The inside of the housing portion may be separated by the partition wall portion into an amplifier chamber and a terminal box chamber. The first substrate portion and the second substrate portion may be disposed in the amplifier chamber, and the terminal box may be disposed in the terminal box chamber.

[0016] (9) The field device according to (4) above may be such that the main body portion is connected to the terminal box via connection terminals passing through the partition wall portion.

[0017] (10) The field device according to (4) above, wherein, it is possible that a third connector is provided on the second substrate portion, and the insertion portion is connected to the analog signal transmission portion via the first connector inside the amplifier shielding chamber and is connected to the second substrate portion via the third connector.

[0018] (11) The field device according to (10) above, the shielding pattern may be a portion other than the third connector, and is formed into an annular portion at least for the open end of the circumferential wall portion and the front end portion of the amplifier shielding plate to abut.

[0019] (12) The field device according to (11) above, the front end portion of the amplifier shielding plate may have a length equal to the thickness of the circumferential wall portion.

[0020] (13) The field device according to (5) above, it is possible that a communication hole communicating with the amplifier shielding chamber is formed in the frame portion, and a connection substrate portion detachably connected with the second connector is arranged at the lower end opening of the communication hole.

[0021] (14) The field device according to (13) above, the first part may be a flexible sensor wire with one end connected to the detector, the other end provided with the second connector and connected to the connection substrate portion.

[0022] (15) The field device according to (13) above, the second part may be a circuit board with one end connected to the connection substrate portion, the other end provided with the first connector and connected to the signal conversion portion.

[0023] (16) The field device according to any one of (1) to (15) above, the detector may include a piping portion for fluid flow and a detection portion for detecting the flow rate or flow of the fluid.

[0024] (17) The field device according to (16) above, it is possible that the detection portion is formed in a rod shape and is inserted into a through hole penetrating the piping portion.

[0025] (18) The field device according to (17) above, it is possible that the detection portion is arranged inside the piping portion, and a stress detection element for measuring the flow rate or flow of the fluid is provided inside the detection portion.

[0026] (19) The field device according to the above (18) may be such that the stress detection element detects the alternating lift force acting on the vortex street generator of the detection unit, measures the frequency of the Karman vortex street, and measures the flow velocity or flow rate of the fluid based on this frequency.

[0027] (20) The field device according to the above (18) may be such that the detection signal output from the stress detection element is transmitted to the signal conversion unit via the analog signal transmission unit.

[0028] According to one embodiment of the present invention, a field device capable of miniaturizing an amplifier shield room can be provided.

[0029] Other features and aspects of the present invention will become apparent from the accompanying drawings and the detailed description of the embodiments below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of a field device showing one embodiment.

[0031] Figure 2 is a sectional configuration view of a field device showing one embodiment.

[0032] Figure 3 is Figure 2 a view as seen from the arrow of line A shown.

[0033] Figure 4 is a perspective view of an amplifier shield room showing the state after removing the second substrate portion in one embodiment.

[0034] Figure 5 is Figure 3 a sectional view taken along line V - V shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Embodiments of the present invention will be described with reference to preferred embodiments. Those skilled in the art can complete numerous alternative methods using the teachings of the present invention, and the present invention is not limited to the preferred embodiments described herein.

[0036] One embodiment of the present invention is to provide a field device capable of miniaturizing an amplifier shield room.

[0037] The field device according to one embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the following, first, an overview of one embodiment of the present invention will be described, and then the detailed content of one embodiment of the present invention will be described.

[0038] 〔Overview〕

[0039] The vortex flowmeter disclosed in Japanese Patent Application Laid-Open No. 2002-107192 is a measuring instrument that measures the flow velocity and flow rate by measuring the frequency of the Karman vortex street generated from a vortex street generating body placed in a pipeline. As a detection method for the vortex street frequency, there is a stress detection method in which a stress detection element is arranged above or inside the vortex street generating body to detect the alternating lift force acting on the vortex street generating body, thereby measuring the frequency of the Karman vortex street. The sensor analog signal from the stress detection element is transmitted from the detector to the converter through a sensor wire. The analog signal transmitted to the converter is converted into a digital signal in the amplifier shielding chamber. In the amplifier shielding chamber, external noise and power supply noise are shielded by the metal container of the converter and the amplifier shielding plate.

[0040] In the past, the sensor wire that detected the alternating lift force acting on the vortex street generating body by the stress detection element and transmitted the detected sensor analog signal was directly screwed and fixed to the substrate of the amplifier shielding chamber. In the case of ensuring the shielding property of external electrical noise through this structure, the area of the amplifier shielding chamber including the screwed and fixed connection part becomes larger, and the degree of freedom in substrate design is limited.

[0041] Moreover, since the sensor wire is fixed to the substrate, the converter cannot be removed from the main body and the orientation of the converter cannot be changed without entering the inside of the converter to remove the sensor wire, resulting in poor maintainability.

[0042] One embodiment of the present invention is an embodiment in which the amplifier shielding chamber is miniaturized by connecting the sensor wire with a connector inside the converter in a field device. And one embodiment of the present invention is an embodiment in which a relay part is provided between the detector and the converter, and the sensor wire is connected with a connector outside the converter, so that the converter can be disassembled and the orientation of the converter can be changed without entering the inside of the converter.

[0043] 〔Embodiment〕

[0044] Figure 1 FIG. is a perspective view of a field device 1 showing one embodiment. Figure 2 FIG. is a sectional structure view of a field device 1 showing one embodiment.

[0045] As Figure 1 shown, the field device 1 includes a pipe detector 2 (detector) and a converter 3. As Figure 2 shown, the pipe detector 2 includes a pipe part 4 and a detection part 20.

[0046] Among them, in the following description, there is content where an XYZ rectangular coordinate system is set, and the positional relationship of each component is described with reference to this XYZ rectangular coordinate system. The X-axis direction is the direction of fluid flow in the piping detector 2. The Z-axis direction is the direction in which the converter 3 is connected to the piping detector 2 in a direction orthogonal to the above X-axis direction. The Y-axis direction is the direction orthogonal to the above X-axis direction and the above Z-axis direction.

[0047] As Figure 1 shown, the piping section 4 is formed in a cylindrical shape extending in the X-axis direction. At both ends of the piping section 4, there are flanges 5 (not shown) that can be connected to external piping. A plurality of connection holes 5a in the circumferential direction of the central axis of the piping section 4 are formed at intervals on the flanges 5. On the circumferential surface of the piping section 4, a base portion 6 is erected in the Z-axis direction. The bracket 10 that supports the converter 3 is connected to the upper surface of the base portion 6.

[0048] As Figure 2 shown, the detection section 20 is formed in a rod shape. The detection section 20 extends from the upper surface of the base portion 6 in the Z-axis direction toward the piping section 4 and is inserted through the through hole 7 of the piping section 4. The fixing block 13 that fixes the detection section 20 is screwed and fixed to the upper surface of the base portion 6 via bolts 13a.

[0049] A stress detection element 21 is provided inside the detection section 20. The stress detection element 21 detects the alternating lift acting on the vortex shedding body of the detection section 20 disposed inside the piping section 4, measures the frequency of the Karman vortex street, and measures the fluid flow rate and flow rate by this frequency. Among them, the detection section 20 may further include sensors that detect not only the flow rate and flow rate but also various physical quantities such as temperature, humidity, pressure, vibration, acceleration, and rotational speed.

[0050] The detection signal (analog signal) output from the detection section 20 (stress detection element 21) is transmitted to the converter 3 via the analog signal transmission section 40. The bracket 10 includes a pair of legs 11 that straddle the fixing block 13 in the Y-axis direction and a support portion 12 that is supported by the pair of legs 11 and supports the converter 3. The pair of legs 11 are screwed and fixed to the upper surface of the base portion 6 via bolts 11a.

[0051] The support portion 12 is formed in a bottomed cylindrical shape that opens in the Z-axis direction. The mounting cylinder portion 31d provided on the converter 3 is inserted into the support portion 12 and is screwed and fixed to the support portion 12 via bolts 12a. The bottom of the support portion 12 is penetrated in the Z-axis direction, and a holding member 12b that holds the analog signal transmission section 40 is provided in this penetration portion.

[0052] In the mounting cylinder part 31d, a communication hole 31c is formed which communicates with the amplifier shield room 30A into which the analog signal transmission part 40 is inserted. A connection substrate part 57 to which a second connector 43 described below is detachably connected is disposed at the lower end opening of the communication hole 31c. Among them, a holding member for holding the analog signal transmission part 40 or a sealing member for sealing the communication hole 31c may also be provided in the communication hole 31c.

[0053] The converter 3 includes a housing part 30, and the housing part 30 has an amplifier shield room 30A into which the analog signal transmission part 40 is inserted. A signal conversion part 50 for converting an analog signal into a digital signal and a connector 60 for detachably connecting the analog signal transmission part 40 and the signal conversion part 50 are disposed in the amplifier shield room 30A.

[0054] The housing part 30 includes a cylindrical housing body 31 extending in the Y-axis direction, a first shield 32 mounted on one end side (-Y side) of the housing body 31, and a second shield 33 mounted on the other end side (+Y side) of the housing body 31. A partition wall part 31a is provided at a substantially middle position in the Y-axis direction inside the housing body 31. Among them, in the housing part 30, the housing body 31 may be made of a material capable of at least blocking electrical noise, for example, it may be made of metal. The first shield 32 and the second shield 33 may be made of resin.

[0055] In the housing part 30, the space on the left side (-Y side) of the partition wall part 31a becomes an amplifier room, and a first substrate part 51, a second substrate part 52, a third substrate part, a fourth substrate part 54 and a display device 55 are disposed. A window part 32a for exposing the display surface of the display device 55 is provided on the first shield 32. The display device 55 is a liquid crystal display screen or an OLED display screen, etc., and displays, for example, the flow rate or flow of a fluid.

[0056] In the housing part 30, the space on the right side (+Y side) of the partition wall part 31a becomes a terminal box room, and a terminal box 56 is disposed. Unillustrated external wiring introduced through an external wiring introduction hole 34 formed in the housing body 31 is connected to the terminal box 56. The external wiring includes a power line and a signal line. Among them, when the field device 1 does not operate by external power supply, a power supply or a wireless communication device may also be disposed in the terminal box room.

[0057] The signal conversion unit 50 is connected to the analog signal transmission unit 40 via the connector 60, and converts the analog signal into a digital signal. Among them, if the signal conversion unit 50 is inside the amplifier shielding chamber 30A, it may also be provided on the first substrate portion 51 (the following insertion portion 51B) or the second substrate portion 52. And the signal conversion unit 50 may not be encapsulated as a module. For example, it may be a signal conversion circuit provided on the first substrate portion 51 or the second substrate portion 52. That is, either the first substrate portion 51 or the second substrate portion 52 may include the signal conversion unit 50.

[0058] The first substrate portion 51 has a main body portion 51A inside the housing portion 30 and disposed outside the amplifier shielding chamber 30A, and an insertion portion 51B extending from the main body portion 51A and inserted into the inside of the amplifier shielding chamber 30A through the communication hole 31b1 (refer to the following Figure 3 ). Inside the amplifier shielding chamber 30A, the insertion portion 51B is connected to the analog signal transmission unit 40 via the connector 60, and is connected to the second substrate portion 52 via the connector 61.

[0059] Outside the amplifier shielding chamber 30A, the second substrate portion 52 is connected to the main body portion 51A of the first substrate portion 51 via the connector 62. And the main body portion 51A is connected to the terminal box 56 via the connection terminal 63 penetrating the partition wall portion 31a. The analog signal transmitted by the analog signal transmission unit 40 is converted into a digital signal in the amplifier shielding chamber 30A, and is transmitted to the terminal box 56 via the second substrate portion 52, the connector 62, the main body portion 51A, and the connection terminal 63. Further, the digital signal transmitted to the terminal box 56 is transmitted to, for example, an external device via a signal line (not shown) connected to the terminal box 56.

[0060] Figure 3 is Figure 2 the view observed from the arrow of line A as shown. Figure 4 is a perspective view of the amplifier shielding chamber 30A showing the state after removing the second substrate portion 52 according to an embodiment. Figure 5 is Figure 3 the cross-sectional view taken along line V - V as shown.

[0061] As Figure 5 shown, the amplifier shielding chamber 30A is formed by the partition wall portion 31a and the circumferential wall portion 31b provided on the housing body 31, the second substrate portion 52, and the amplifier shielding plate 80.

[0062] The partition wall portion 31a faces the plate surface on one side (+Y side) of the insertion portion 51B. The circumferential wall portion 31b protrudes from the partition wall portion 31a toward the -Y side, as Figure 3As shown, it surrounds the periphery of the insertion portion 51B and a communication hole 31b1 is formed in a part thereof. As described above, the insertion portion 51B of the first substrate portion 51 passes through the communication hole 31b1. As Figure 4 shown, the amplifier shielding plate 80 closes the communication hole 31b1 through which the insertion portion 51B of the first substrate portion 51 passes. The amplifier shielding plate 80 may be made of a material that blocks electrical noise, for example, a metal plate.

[0063] As Figure 5 shown, the second substrate portion 52 is placed on the opening end edge of the circumferential wall portion 31b on the side opposite to the partition wall portion 31a and faces the plate surface on the other side (-Y side) of the insertion portion 51B. A shielding pattern 52a is formed on the second substrate portion 52. The shielding pattern 52a is a part other than the connector 61 and may be formed at least as an annular portion where the opening end of the circumferential wall portion 31b and the front end portion 81 of the amplifier shielding plate 80 abut. Among them, Figure 5 as shown, the shielding pattern 52a is also formed on the -Y side surface of the second substrate portion 52 to cover the area inside the above-mentioned annular portion, but the portion covering the area inside the annular portion may also be formed inside (inner layer) the second substrate portion 52.

[0064] The amplifier shielding plate 80 has a front end portion 81 bent inwardly of the amplifier shielding chamber 30A and a fixing portion 82 bent outwardly of the amplifier shielding chamber 30A. The front end portion 81 abuts against the shielding pattern 52a of the second substrate portion 52 and is also at the same ground potential as the circumferential wall portion 31b (the frame body 31) that abuts against the shielding pattern 52a. And, in order to make the front end portion 81 have the same noise blocking function as the circumferential wall portion 31b, the front end portion 81 has a length equal to the thickness of the circumferential wall portion 31b. Among them, the front end portion 81 of the amplifier shielding plate 80 may also be bent outwardly of the amplifier shielding chamber 30A.

[0065] The fixing portion 82 and the first substrate portion 51 are screwed and fixed to the frame body 31 outside the amplifier shielding chamber 30A via a bolt 73. A bolt base portion 31a1 for torsionally fastening the bolt 73 is formed on the partition wall portion 31a. As Figure 3 shown, the first substrate portion 51 is screwed and fixed near the amplifier shielding chamber 30A via a bolt 73 and is also screwed and fixed to the frame body 31 via a bolt 72 disposed substantially diagonally to the bolt 73. That is, the first substrate portion 51 is screwed and fixed to the frame body 31 by two bolts 72 and 73.

[0066] Among them, near the bolt 73 of the frame body 31, there is formed Figure 2The second bolt base portion 31e to which the support rod 70 that supports the third substrate portion 53 and the fourth substrate portion 54 is threadedly connected as shown. A pair of bolt base portions 31e are provided separately in the X-axis direction.

[0067] As Figure 2 shown, the analog signal transmission unit 40 includes a first portion 41 connected to the detection unit 20, a second portion 42 inserted inside the housing portion 30, and a second connector 43 that detachably connects the first portion 41 and the second portion 42 outside the housing portion 30. The first portion 41 is, for example, connected to the stress detection element 21 at one end, and a second connector 43 is provided at the other end and connected to the flexible sensor wire of the connection substrate portion 57. The first portion 41 is held on the bracket 10 via the holding member 12b.

[0068] The second portion 42 is, for example, connected to the connection substrate portion 57 at one end, and a connector 60 is provided at the other end and connected to the circuit board of the signal conversion unit 50. The second portion 42 can be a rigid substrate or a flexible substrate.

[0069] The second connector 43 is disposed in the space surrounded by the support portion 12 of the bracket 10 and the mounting cylinder portion 31d of the housing portion 30 (housing body 31). According to this structure, by removing the bolt 12a and pulling out the mounting cylinder portion 31d from the support portion 12, the second connector 43 can be accessed.

[0070] As Figure 3 shown, in the field device 1 having the above structure, the analog signal transmission unit 40 that transmits the analog signal is detachably connected to the signal conversion unit 50 via the connector 60 in the amplifier shield room 30A. Therefore, it is not necessary to arrange screws inside the amplifier shield room 30A, and the amplifier shield room 30A can be miniaturized. As a result, the external space of the amplifier shield room 30A becomes larger, and the design freedom outside the amplifier shield room 30A is improved.

[0071] Thus, according to the field device 1 of the present embodiment described above, it includes: a housing portion 30 having an amplifier shield room 30A into which the analog signal transmission unit 40 that transmits the analog signal output from the pipe detector 2 can be inserted; a signal conversion unit 50 disposed inside the amplifier shield room 30A and converting the analog signal into a digital signal; and a connector 60 disposed inside the amplifier shield room 30A and detachably connecting the analog signal transmission unit 40 and the signal conversion unit 50. Thereby, the amplifier shield room 30A can be miniaturized.

[0072] And, as Figure 3As shown, in the present embodiment, inside the housing portion 30, a communication hole 31b1 that communicates the inside and the outside of the amplifier shield room 30A is formed in the amplifier shield room 30A, and a first substrate portion 51 and an amplifier shield plate 80 are provided. The first substrate portion 51 has a main body portion 51A disposed inside the housing portion 30 and outside the amplifier shield room 30A, and an insertion portion 51B that extends from the main body portion 51A and is inserted into the inside of the amplifier shield room 30A through the communication hole 31b1. The amplifier shield plate 80 closes the communication hole 31b1 through which the first substrate portion 51 passes. According to this structure, the substrate portion (insertion portion 51B) disposed inside the amplifier shield room 30A and the substrate portion (main body portion 51A) disposed outside the amplifier shield room 30A are integrated, thereby reducing the number of components. Also, by providing the amplifier shield plate 80 to the communication hole 31b1, the shielding property of the amplifier shield room 30A can be maintained.

[0073] Also, in the present embodiment, the amplifier shield plate 80 and the first substrate portion 51 are threadedly fixed to the housing portion 30 together outside the amplifier shield room 30A. According to this structure, the first substrate portion 51 and the amplifier shield plate 80 can be integrally fastened by bolts 73, reducing the number of bolts provided outside the amplifier shield room 30A and improving the design freedom outside the amplifier shield room 30A.

[0074] Also, as Figure 5 shown, in the present embodiment, the housing portion 30 includes a partition wall portion 31a facing one side plate surface of the insertion portion 51B, and a circumferential wall portion 31b that protrudes from the partition wall portion 31a, surrounds the periphery of the insertion portion 51B, and has a communication hole 31b1 formed in a part thereof. The field device has a second substrate portion 52, which is placed on the open end edge of the circumferential wall portion 31b on the side opposite to the partition wall portion 31a, faces the other side plate surface of the insertion portion 51B, and has a shielding pattern 52a formed thereon. The amplifier shield room 30A is formed by the partition wall portion 31a, the circumferential wall portion 31b, the second substrate portion 52, and the amplifier shield plate 80. According to this structure, the second substrate portion 52 and the amplifier shield plate 80 can be combined with the partition wall portion 31a and the circumferential wall portion 31b of the housing portion 30 to form a small-sized amplifier shield room 30A.

[0075] Also, as Figure 2 shown, in the present embodiment, the analog signal transmission unit 40 includes a first portion 41 connected to the detection unit 20, a second portion 42 inserted into the inside of the housing portion 30, and a second connector 43 that detachably connects the first portion 41 and the second portion 42 outside the housing portion 30. According to this structure, the converter 3 can be removed from the pipe detector 2 (bracket 10) without entering the inside of the converter 3, and the orientation of the converter 3 can be changed.

[0076] The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above embodiments. The various shapes and combinations of the respective structural components shown in the above embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

[0077] For example, in the above embodiment, the structure in which the substrate portion (insertion portion 51B) inside the amplifier shielding chamber 30A and the substrate portion (main body portion 51A) outside the amplifier shielding plate 80 are integrated has been described, but the substrate portion inside the amplifier shielding chamber 30A may also be separated from the substrate portion outside the amplifier shielding plate 80. In this case, the communication hole 31b1 of the circumferential wall portion 31b may not be provided either. That is, the circumferential wall portion 31b may be formed to cover (surround) the entire circumference of the amplifier shielding chamber 30A. In this case, the substrate portion (insertion portion 51B) inside the amplifier shielding chamber 30A may be fixed by connecting to the second substrate portion, or may be fixed by other fixing methods.

[0078] Moreover, in the above embodiment, for example, the connection of the frame portion 30 to the field device 1 of the pipe detector 2 has been described, but since the analog signal transmission portion 40 is made detachable from the frame portion 30 by the connector 60, the field device 1 may have a structure including at least the frame portion 30, and is not limited to a structure connected to the pipe detector 2 or other detectors. For example, a pressure transmitter or a temperature transmitter may also include the above frame portion 30.

[0079] In this specification, terms indicating directions such as front, rear, upper, lower, left, right, vertical, horizontal, longitudinal, transverse, row, and column all refer to these directions in the device of the present invention. Therefore, these terms in the specification of the present invention should be interpreted relatively in the device of the present invention.

[0080] The expression "configured to..." is used to indicate a configuration, element, or part of a device configured to achieve the functions of the present invention.

[0081] Moreover, expressions showing functional limitations in the claims should include all structures that can be used to achieve the functions included in the present invention.

[0082] The term "unit" is used to indicate a part of a structure element, unit, hardware, or software written to achieve a desired function. A typical example of hardware is a device or a circuit, but is not limited to these.

[0083] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other changes can be made within the scope not departing from the gist of the present invention. The present invention is not limited by the above description, but only by the appended claims.

Claims

1. A field device, characterized in that, Comprising: A housing portion having an amplifier shielding chamber into which an analog signal transmission portion for transmitting an analog signal output from a detector can be inserted; A signal conversion portion disposed within the amplifier shielding chamber and configured to convert the analog signal into a digital signal; A first connector disposed within the amplifier shielding chamber and configured to detachably connect the analog signal transmission portion and the signal conversion portion; A communication hole that communicates the interior of the amplifier shielding chamber with the exterior; A first substrate portion having a main body portion disposed inside the housing portion and outside the amplifier shielding chamber and an insertion portion extending from the main body portion and inserted into the interior of the amplifier shielding chamber through the communication hole; An amplifier shielding plate that closes the communication hole through which the first substrate portion passes; 2. The field device according to claim 1, wherein: The amplifier shielding plate and the first substrate portion are threadedly fixed to the housing portion outside the amplifier shielding chamber.

3. The field device according to claim 1 or 2, wherein: The housing portion includes a partition wall portion facing one side plate surface of the insertion portion and a circumferential wall portion protruding from the partition wall portion, surrounding the periphery of the insertion portion, and having the communication hole formed in a part thereof; The field device has a second substrate portion that is placed on an open end edge of the circumferential wall portion on the side opposite to the partition wall portion, faces the other side plate surface of the insertion portion, and has a shielding pattern formed thereon; The amplifier shielding chamber is formed by the partition wall portion, the circumferential wall portion, the second substrate portion, and the amplifier shielding plate.

4. The field device according to claim 1 or 2, wherein: The analog signal transmission portion includes a second connector that detachably connects a first portion connected to the detector and a second portion inserted into the interior of the housing portion outside the housing portion.

5. The field device according to claim 3, wherein: The housing portion includes a cylindrical housing body, a first shield installed on one end side of the housing body, and a second shield installed on the other end side of the housing body.

6. The field device according to claim 5, wherein: The housing body is made of metal; The first shield and the second shield are made of resin.

7. The field device according to claim 3, wherein: Further comprising a terminal box to which external wiring introduced through an introduction hole formed in the housing portion is connected; The interior of the housing portion is separated by the partition wall portion into an amplifier chamber and a terminal box chamber; The first substrate portion and the second substrate portion are disposed in the amplifier chamber; The terminal box is disposed in the terminal box chamber.

8. The field device according to claim 7, wherein: The main body portion is connected to the terminal box via connection terminals passing through the partition wall portion.

9. The field device according to claim 3, wherein: A third connector is provided on the second substrate portion. The insertion part is connected to the analog signal transmission part via the first connector inside the amplifier shielding chamber, and is connected to the second substrate part via the third connector.

10. The field device according to claim 9, wherein, The shielding pattern is a part other than the third connector, and is formed as an annular part for at least the open end of the circumferential wall part and the front end part of the amplifier shielding plate to abut against.

11. The field device according to claim 10, wherein, The front end part of the amplifier shielding plate has a length equal to the thickness of the circumferential wall part.

12. The field device according to claim 1 or 2, wherein, The detector includes a piping part through which fluid flows and a detection part for detecting the flow rate or flow volume of the fluid.

13. The field device according to claim 12, wherein, The detection part is formed in a rod shape and is inserted into a through hole penetrating the piping part.

14. The field device according to claim 13, wherein, The detection part is arranged inside the piping part, and a stress detection element for measuring the flow rate or flow volume of the fluid is provided inside the detection part.

15. The field device according to claim 14, wherein, The stress detection element detects the alternating lift force acting on the vortex shedding body of the detection part, measures the frequency of the Karman vortex street, and measures the flow rate or flow volume of the fluid according to this frequency.

16. The field device according to claim 14, wherein, The detection signal output from the stress detection element is transmitted to the signal conversion part via the analog signal transmission part.

17. A field device, characterized in that, Comprising: A housing part having an amplifier shielding chamber into which an analog signal transmission part for transmitting an analog signal output from a detector can be inserted; A signal conversion part arranged inside the amplifier shielding chamber and converting the analog signal into a digital signal; A first connector arranged inside the amplifier shielding chamber and detachably connecting the analog signal transmission part and the signal conversion part; The analog signal transmission part includes a second connector that detachably connects a first part connected to the detector and a second part inserted inside the housing part outside the housing part, A communication hole communicating with the amplifier shielding chamber is formed in the housing part, And a connection substrate part for detachably connecting the second connector is arranged at the lower end opening of the communication hole.

18. The field device according to claim 17, wherein, The first part is a flexible sensor wire with one end connected to the detector and the other end provided with the second connector and connected to the connection substrate part.

19. The field device according to claim 17, wherein, The second part is a circuit board with one end connected to the connection substrate part and the other end provided with the first connector and connected to the signal conversion part.

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