Digital weighing device and weighing method based on two-wire Ethernet communication

Abstract

The invention relates to the field of weighing and metering, in particular to a digital weighing device based on two-wire Ethernet communication, which comprises a pressure sensing unit, an analog circuit unit, a digital circuit unit and a shell. And the analog circuit unit and the digital circuit unit are arranged in the shell. And the pressure sensing unit is fixed on the shell, is mechanically connected to the weighing container after penetrating through the shell, and is electrically connected to the analog circuit unit. The analog circuit unit is further connected to the digital circuit unit. The invention further comprises a weighing method. According to the invention, the Ethernet data can be exchanged only by two cables, and a long bridging distance is provided, so that networking and installation of new equipment are facilitated, modernized transformation based on existing wiring is also facilitated, and a low-cost and high-benefit scheme is realized. In the fields of high-speed communication, safety operation in potential explosion areas, long cable installation and the like, only two cables need to be specially modified, and therefore the cost advantage is achieved. The system also has the capability of collecting and analyzing a large amount of data.

Description

Technical Field

[0001] The invention relates to the field of weighing and metering, in particular to a digital weighing device and a weighing method based on two-wire Ethernet communication. Background Art

[0002] The development of sensor technology is relatively mature. Traditional digital sensors use integrated A / D conversion circuits, digital signal transmission and digital filtering technology to improve measurement accuracy and working reliability. However, traditional digital transmission technology has poor anti-interference ability and large transmission delay, making it impossible to feedback measurement results in real time. It also requires special cables and is complicated to install. Summary of the invention

[0003] The object of the present invention is to provide a digital weighing device and weighing method based on two-wire Ethernet communication, mainly to solve the problems existing in the above-mentioned prior art.

[0004] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is to provide a digital weighing device based on two-wire Ethernet communication, characterized in that it comprises a pressure sensing unit, an analog circuit unit, a digital circuit unit and a housing; The analog circuit unit and the digital circuit unit are arranged in the housing; the pressure sensing unit is fixed on the housing and mechanically connected to the weighing container after passing through the housing, and electrically connected to the analog circuit unit; the analog circuit unit is further connected to the digital circuit unit; A load is placed in the weighing container, causing the pressure sensing unit to undergo mechanical deformation; the analog circuit unit converts the mechanical deformation into an analog electrical signal, and then converts it into a digital electrical signal and transmits it to the digital circuit unit; the digital circuit unit processes the digital electrical signal to generate weighing information, and sends it through a digital transmission interface; the digital transmission interface is a two-wire Ethernet communication interface.

[0005] Furthermore, the pressure sensing unit includes an elastomer and a piezoelectric conversion module; a weighing container mounting interface is provided on the elastomer for transmitting the pressure from the load; the piezoelectric conversion module is fixed on the elastomer, deforms along with the elastomer, and stimulates the analog electrical signal related to the pressure.

[0006] Furthermore, the weighing container mounting interface is a plurality of transverse holes arranged in parallel to each other, or a plurality of vertical holes arranged in parallel to each other; the transverse holes or the vertical holes match the shape of the weighing container; the weighing container is connected to the elastomer by being inserted into the transverse holes or the vertical holes.

[0007] Furthermore, the elastic body has a rectangular shape; a hole is opened in the center of the rectangle, and the piezoelectric conversion module is embedded and installed.

[0008] Furthermore, a limiting module is provided below the elastic body to limit the maximum deformation of the elastic body; the limiting module is fixed on the housing.

[0009] Furthermore, the piezoelectric conversion module is circular in shape and is embedded in the elastic body; a nickel sheet and a strain gauge are symmetrically fixedly installed on the outer edge of the circle; the nickel sheet and the strain gauge are electrically connected to the analog circuit unit respectively.

[0010] Furthermore, the analog circuit unit includes a Wheatstone bridge, a temperature correction module and an analog-to-digital conversion module; the Wheatstone bridge is electrically connected to the pressure sensing unit, detects pressure changes and converts them into the analog electrical signal; the temperature correction module is connected to the output of the Wheatstone bridge, performs temperature correction on the analog electrical signal, and then transmits it to the analog-to-digital conversion unit as input; the analog-to-digital conversion unit converts the analog electrical signal into the digital electrical signal.

[0011] Furthermore, the digital circuit unit includes a digital signal processing module and the digital transmission interface; the digital signal processing module obtains the weighing information from the digital electrical signal and then sends it using the digital transmission interface; the digital transmission interface includes the two-wire Ethernet communication interface and the serial port communication interface.

[0012] Furthermore, a plurality of fixing bolt holes are provided at the bottom of the housing for fixing the weighing device during operation.

[0013] The present invention also discloses a weighing method using the above-mentioned digital weighing device based on two-wire Ethernet communication, which is characterized by comprising the steps of: Step S1, using bolt holes at the bottom of the housing to fix the weighing device on a working platform using bolts; Step S2, fixing the weighing container to the pressure sensing unit through the weighing container mounting interface; Step S3, powering on the analog circuit unit and the digital circuit unit; Step S4, placing the load in the weighing container; Step S5, the analog circuit unit and the digital circuit unit obtain the weighing information of the load; Step S6, sending the weighing information using the digital transmission interface.

[0014] In view of the above technical features, the digital weighing device and weighing method based on two-wire Ethernet communication of the present invention have the following advantages: 1. The present invention only needs two cables to exchange Ethernet data, and has a long bridging distance (the trunk length can reach 1,000 m, and the branch length can reach 200 m), which is not only convenient for new equipment networking and installation, but also convenient for modernization based on existing wiring, realizing a low-cost and high-efficiency solution. In particular, in the field of high-speed communication, the field that requires Ethernet-based communication, the field of safe operation in potential explosion areas, and the field of installation of long cables, only two cables need to be specially modified, thus having a cost advantage.

[0015] 2. The present invention is based on the mature Ethernet protocol, supports a variety of network topologies, supports a variety of different devices and applications, and thus has the ability to collect and analyze large amounts of data, providing a realistic basis for implementing new solutions such as preventive maintenance.

[0016] 3. The present invention also has the advantages of fast dynamic response capability, can accurately capture weight changes, and provide real-time feedback of measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of a preferred embodiment of a digital weighing device based on two-wire Ethernet communication of the present invention; Figure 2 It is an exploded view of a preferred embodiment of the digital weighing device based on two-wire Ethernet communication of the present invention; Figure 3 It is an electrical structure diagram of a preferred embodiment of the digital weighing device based on two-wire Ethernet communication of the present invention; Figure 4 It is a flow chart of a preferred embodiment of a weighing method of a digital weighing device based on two-wire Ethernet communication of the present invention; Figure 5 The present invention is a simplified diagram of the working principle of a preferred embodiment of a weighing method of a digital weighing device based on two-wire Ethernet communication.

[0018] In the figure: 10 - pressure sensing unit, 20 - analog circuit unit, 30 - digital circuit unit, 40 - housing, 50 - sealing plate, 60 - small sealing plate, 70 - product label, 80 - substrate connecting wire; 11-elastic body, 12-piezoelectric conversion module, 13-limiting module, 14-transverse hole, 15-vertical hole; 121-nickel sheet, 122-strain gauge; 131-limiting column, 132-limiting nut; 21-Wheatstone bridge, 22-temperature correction module, 23-analog-to-digital conversion module; 31-digital signal processing module, 32-digital transmission interface, 33-locking nut; 41-Fixing bolt hole. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0020] See also Figure 1 , Figure 2 and Figure 3 The present invention discloses a digital weighing device based on two-wire Ethernet communication. As shown in the figure, a preferred embodiment thereof comprises a pressure sensing unit 10, an analog circuit unit 20, a digital circuit unit 30 and a housing 40.

[0021] The analog circuit unit 20 and the digital circuit unit 30 are arranged in the housing 40, and the pressure sensing unit 10 is fixed on the housing 40, and passes through the housing 40 and is mechanically connected to the weighing container. The sealing plate 50 is installed on the housing 40, and is used to enclose the analog circuit unit 20 and the digital circuit unit 30 in the housing 40. A product label 70 is also installed on the housing 40. The pressure sensing unit 10 is electrically connected to the analog circuit unit 20. The analog circuit unit 20 is electrically connected to the digital circuit unit 30 through the substrate connecting line 80. A digital transmission interface 32 is set on the digital circuit unit 30 to send weighing information. A plurality of fixing bolt holes 41 are set at the bottom of the housing 40, which are used to cooperate with bolts to fix the weighing device on the working plane to ensure the accuracy of weighing.

[0022] The pressure sensing unit 10 includes an elastic body 11, a piezoelectric conversion module 12 and a limit module 13. The weighing container installation interface is arranged on the elastic body 11, which is a plurality of mutually parallel horizontal holes 14 and a plurality of mutually parallel vertical holes 15. Among them, the horizontal hole 14 is used to install the weighing bracket, and the vertical hole 15 is used to install the weighing pan. A cross bar is arranged on one side of the weighing bracket, and the diameter and length of the cross bar match the cross hole 14. During installation, the cross bar on the weighing bracket is inserted into the cross hole 14. When the load is placed on the weighing bracket, the cross bar transfers the pressure to the elastic body 11 through the cross hole 14, causing the elastic body 11 to deform. Similarly, a vertical bar is arranged at the bottom of the weighing pan, and the diameter and length of the vertical bar match the vertical hole 15. During installation, the vertical bar on the weighing pan is inserted into the vertical hole 15. When the load is placed on the weighing pan, the vertical bar transfers the pressure to the elastic body 11 through the vertical hole 15, causing the elastic body 11 to deform. When the elastic body 11 is deformed, the piezoelectric conversion module 12 fixed thereon is deformed together. The mechanical deformation of the piezoelectric conversion module 12 changes its electrical characteristics, and stimulates an analog electrical signal related to pressure in the analog circuit unit 20 .

[0023] The shape of the elastic body 11 is rectangular. The shape of the piezoelectric conversion module 12 is circular. A hole is opened in the center of the rectangular elastic body 11, and its size matches the outer diameter of the piezoelectric conversion module 12. The piezoelectric conversion module 12 is embedded and installed in the opening. A small sealing plate 60 is installed on the elastic body 11 to enclose the piezoelectric conversion module 12 in the elastic body 11. On the left and right outer edges of the circular shape of the piezoelectric conversion module 12, a nickel sheet 121 and a strain gauge 122 are symmetrically fixedly installed. The nickel sheet 121 and the strain gauge 122 are electrically connected to the analog circuit unit 20 respectively. When the piezoelectric conversion module 12 is deformed, the nickel sheet 121 and the strain gauge 122 will be pulled up or compressed accordingly, but the electrical properties of the nickel sheet 121 and the strain gauge 122 will change differently when they are deformed. At the same time, the change in the electrical properties of the strain gauge 122 has the characteristic of regular change with its deformation. Therefore, the analog circuit unit 20 can generate an analog electrical signal related to the magnitude of the pressure according to the change in the electrical properties. Below the elastomer 11, a limit module 13 is provided, which includes a limit column 131 and a limit nut 132. The function of the limit module 13 is to limit the maximum deformation of the elastomer 11, thereby protecting the elastomer 11 from always working in its elastic deformation area. The limit column 131 is fixed to the housing 40 by the limit nut 132. The distance between the limit column 131 and the elastomer 11 can be adjusted by the limit nut. When the elastomer 11 is deformed by the pressure of the load and moves downward to reach its maximum stroke in the design, the bottom end of the elastomer 11 fits against the upper end of the limit column 131, thereby preventing the elastomer 11 from continuing to deform. At this time, the weighing device reaches its maximum range.

[0024] The analog circuit unit 20 includes a Wheatstone bridge 21, a temperature correction module 22 and an analog-to-digital conversion module 23. The two input ends of the Wheatstone bridge 21 are electrically connected to the nickel sheet 121 and the strain gauge 122 in the pressure sensing unit 10, respectively. Under the action of pressure, the difference in electrical characteristics between the nickel sheet 121 and the strain gauge 122 causes the Wheatstone bridge 21 to lose balance, thereby generating an analog electrical signal at the output end. The temperature correction module 22 takes the analog electrical signal output by the Wheatstone bridge 21 as input, performs temperature correction on the analog electrical signal according to the ambient temperature, and then sends the corrected analog electrical signal to the analog-to-digital conversion unit 23. The analog-to-digital conversion unit 23 converts the analog electrical signal into a digital electrical signal, which can be further processed by the subsequent digital circuit unit 30.

[0025] The digital circuit unit 30 includes a digital signal processing module 31 and a digital transmission interface 32. The digital signal processing module 31 is responsible for calculating the weighing information based on the digital electrical signal. The digital transmission interface 32 is installed on the housing 40 through a locking nut 33, and it includes two types: a two-wire Ethernet communication interface and a serial communication interface, which are used to send the weighing information to a remote device. The two-wire Ethernet adopts the unified technology of twisted pair communication and power supply, which is a further development of Ethernet network data transmission at the physical level. The physical layer only needs two cables to exchange Ethernet data. The network topology of the two-wire Ethernet supports flexible design to achieve a compact layout. It can be directly connected to a standard Ethernet, so there is no need to arrange a trunk line. In this embodiment, when the weighing information is sent based on the two-wire Ethernet, its encoding method complies with the PROFINET communication protocol, that is, the PROFINET protocol is carried on the two-wire Ethernet, which is used to send the weighing information over a long distance, and the scene where the weighing information is transmitted through the serial communication interface is generally used for short-range communication.

[0026] See also Figure 4 and Figure 5 The present invention also provides a weighing method using the above-mentioned digital weighing device based on two-wire Ethernet communication, a preferred embodiment of which comprises the steps of: Step S10, fixing the weighing device.

[0027] Use the bolt holes at the bottom of the housing to fix the weighing device to the work platform with bolts.

[0028] Step S20, connecting a weighing container.

[0029] The weighing container can be a weighing hanger or a weighing pan. The weighing hanger is fixedly connected to the elastic body in the pressure sensing unit through the horizontal hole in the weighing container mounting interface. The weighing pan is fixedly connected to the elastic body in the pressure sensing unit through the vertical hole in the weighing container mounting interface.

[0030] Step S30, turning on the power supply.

[0031] The analog circuit unit and the digital circuit unit are powered on and enter a working state.

[0032] Step S40, placing a load in a weighing container.

[0033] The weight of the load is transmitted to the elastic body through the weighing rack or the weighing pan in the form of pressure through the weighing container mounting interface, causing the elastic body to deform.

[0034] Step S50, obtaining the weighing information of the load.

[0035] When the elastic body is deformed by external force, the nickel sheet and strain gauge attached to the elastic body also follow the deformation, and their electrical characteristics change. The analog circuit unit uses the unbalanced Wheatstone bridge to convert the force signal into a millivolt analog electrical signal, which is then converted into a digital electrical signal after temperature characteristic correction and transmitted to the digital circuit unit. The digital circuit unit processes the digital electrical signal to generate weighing information.

[0036] Step S60, sending weighing information.

[0037] The digital circuit unit sends the weighing information through the digital transmission interface 32: the data may be PROFINET compliant data sent through a two-wire Ethernet, or the data in other formats may be sent through a serial communication interface (eg RS232).

[0038] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A digital weighing device based on two-wire Ethernet communication, characterized in that: It includes a pressure sensing unit, an analog circuit unit, a digital circuit unit and a housing; The analog circuit unit and the digital circuit unit are arranged in the housing; the pressure sensing unit is fixed on the housing and mechanically connected to the weighing container after passing through the housing, and electrically connected to the analog circuit unit; the analog circuit unit is further connected to the digital circuit unit; A load is placed in the weighing container, causing the pressure sensing unit to undergo mechanical deformation; the analog circuit unit converts the mechanical deformation into an analog electrical signal, and then converts it into a digital electrical signal and transmits it to the digital circuit unit; the digital circuit unit processes the digital electrical signal to generate weighing information, and sends it through a digital transmission interface; the digital transmission interface is a two-wire Ethernet communication interface.

2. The digital weighing device based on two-wire Ethernet communication according to claim 1, characterized in that: The pressure sensing unit includes an elastomer and a piezoelectric conversion module; a weighing container mounting interface is provided on the elastomer for transmitting the pressure from the load; the piezoelectric conversion module is fixed on the elastomer, deforms along with the elastomer, and stimulates the analog electrical signal related to the pressure.

3. The digital weighing device based on two-wire Ethernet communication according to claim 2, characterized in that: The weighing container installation interface is a plurality of mutually parallel transverse holes, or a plurality of mutually parallel vertical holes; the transverse holes or the vertical holes match the shape of the weighing container; the weighing container is connected to the elastomer by being inserted into the transverse holes or the vertical holes.

4. The digital weighing device based on two-wire Ethernet communication according to claim 2, characterized in that: The elastic body is in the shape of a rectangle; a hole is opened in the center of the rectangle, and the piezoelectric conversion module is embedded and installed.

5. The digital weighing device based on two-wire Ethernet communication according to claim 4, characterized in that: A limiting module is also arranged below the elastic body to limit the maximum deformation of the elastic body; the limiting module is fixed on the housing.

6. The digital weighing device based on two-wire Ethernet communication according to claim 2, characterized in that: The piezoelectric conversion module is circular in shape and is embedded in the elastic body; a nickel sheet and a strain gauge are symmetrically fixedly installed on the outer edge of the circle; the nickel sheet and the strain gauge are electrically connected to the analog circuit unit respectively.

7. The digital weighing device based on two-wire Ethernet communication according to claim 1, characterized in that: The analog circuit unit comprises a Wheatstone bridge, a temperature correction module and an analog-to-digital conversion module; the Wheatstone bridge is electrically connected to the pressure sensing unit to detect pressure changes and convert them into the analog electrical signal; the temperature correction module is connected to the output of the Wheatstone bridge to perform temperature correction on the analog electrical signal and then transmit it to the analog-to-digital conversion unit as input; The analog-to-digital conversion unit converts the analog electrical signal into the digital electrical signal.

8. The digital weighing device based on two-wire Ethernet communication according to claim 1, characterized in that: The digital circuit unit includes a digital signal processing module and the digital transmission interface; the digital signal processing module obtains the weighing information from the digital electrical signal and then sends it using the digital transmission interface; the digital transmission interface includes the two-wire Ethernet communication interface and the serial communication interface.

9. The digital weighing device based on two-wire Ethernet communication according to claim 1, characterized in that: A plurality of fixing bolt holes are arranged at the bottom of the housing for fixing the weighing device during operation.

10. A weighing method using the digital weighing device based on two-wire Ethernet communication as claimed in claim 1, characterized in that: Contains steps: Step S1, using bolt holes at the bottom of the housing to fix the weighing device on a working platform using bolts; Step S2, fixing the weighing container to the pressure sensing unit through the weighing container mounting interface; Step S3, powering on the analog circuit unit and the digital circuit unit; Step S4, placing the load in the weighing container; Step S5, the analog circuit unit and the digital circuit unit obtain the weighing information of the load; Step S6, sending the weighing information using the digital transmission interface.

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