Circuit board with voltage or current sampling function and digital display meter

Abstract

The utility model provides a circuit board with a voltage or current sampling function and a digital display meter, and relates to the technical field of digital display meters. The circuit board comprises a circuit board body, and a pin header connector, a wiring terminal strip and a first sampling circuit which are integrated on the circuit board body. According to the circuit board, the first sampling circuit can be designed to be a voltage sampling circuit or a current sampling circuit according to functions required to be provided by the circuit board, so that the circuit board has a voltage sampling function or a current sampling function, and therefore, only the first sampling circuit on the circuit board body needs to be configured and selected; therefore, the circuit board can have a voltage or current sampling function without producing various different circuit board bodies in the production process, so that the requirements of producing and managing multiple versions of circuit boards respectively for circuit boards with different functions are effectively reduced, the complexity of material production and management and the production cost are reduced, and the production efficiency is improved. And meanwhile, the requirement of the miniaturized meter type design of the digital display meter can be met.

Description

Technical Field

[0001] This application relates to the field of digital display technology, and in particular to a circuit board with voltage or current sampling function and a digital display. Background Technology

[0002] With the continuous development of electronic and automation technologies, digital displays have become an indispensable part of modern power measurement equipment. Especially in industrial, residential, and commercial fields, three-phase voltage / current digital displays are widely used in power monitoring and measurement.

[0003] In related technologies, voltage and current sampling circuits are configured as backup circuits in three-phase voltage / current digital displays. However, in these displays, the voltage and current sampling circuits do not operate simultaneously; instead, one circuit is selected based on the actual functional requirements of the display. The voltage and current sampling circuits are typically arranged on two separate circuit boards, or simultaneously on a single, larger circuit board. Using two separate circuit boards ensures circuit stability but requires configuring part numbers for each board and may necessitate the use of two different meter cases, increasing material management workload and production complexity. Using a single, larger circuit board simplifies material management but increases overall product production costs and fails to meet the requirements of miniaturized meter designs.

[0004] Therefore, in the existing design of three-phase voltage / current digital display meters, the complexity of material production and management, the high production cost, and the difficulty in adapting to the needs of miniaturized meter design have become urgent problems to be solved. Utility Model Content

[0005] This application provides a circuit board and digital display meter with voltage or current sampling function, which can effectively reduce the complexity of material production and management, reduce production costs, and meet the needs of miniaturized meter design.

[0006] In a first aspect, embodiments of this application provide a circuit board with voltage or current sampling function, including: a circuit board body, and a pin header connector, a terminal block, and a first sampling circuit disposed on the circuit board body;

[0007] The first sampling circuit is a voltage sampling circuit or a current sampling circuit;

[0008] The first end of the first sampling circuit is electrically connected to the output end of the three-phase AC power through the terminal block, the second end of the first sampling circuit is electrically connected to the first end of the pin header connector, and the second end of the pin header connector is electrically connected to the controller through the second sampling circuit;

[0009] When the first sampling circuit is the voltage sampling circuit, the first sampling circuit is located on the first side of the circuit board body, and the controller detects the voltage parameters of the three-phase AC power through the voltage sampling circuit and the second sampling circuit;

[0010] When the first sampling circuit is the current sampling circuit, the first sampling circuit is located on the second side of the circuit board body, and the controller detects the current parameters of the three-phase AC power through the current sampling circuit and the second sampling circuit.

[0011] This application provides a circuit board with voltage or current sampling function. The circuit board includes a circuit board body, a pin header connector, a terminal block, and a first sampling circuit integrated on the circuit board body. The input terminal of the first sampling circuit is electrically connected to the output terminal of a three-phase AC power supply through the terminal block. The output terminal of the first sampling circuit is electrically connected to the first end of the pin header connector, and the second end of the pin header connector is electrically connected to a controller through a second sampling circuit. The first sampling circuit can be designed as a voltage sampling circuit or a current sampling circuit according to the functions required by the circuit board, so that the circuit board has voltage sampling function or current sampling function. It eliminates the need to produce multiple different circuit board bodies during the production process. Only the configuration selection of the first sampling circuit on the circuit board body is required, which effectively reduces the need to produce and manage multiple versions of circuit boards separately and effectively reduces the complexity of material production and management. In addition, if a voltage sampling circuit needs to be set on the circuit board body, the voltage sampling circuit can be set on the first side of the circuit board body; if a current sampling circuit needs to be set on the circuit board body, the current sampling circuit can be set on the second side of the circuit board body, which helps to reduce the area of ​​the circuit board body, thereby reducing the space occupied by the circuit board and meeting the needs of miniaturized form factor design.

[0012] In some embodiments, the pin header connector includes three first pin header groups and one second pin header group;

[0013] The terminal block includes three terminal groups;

[0014] The three first pin groups and the three terminal groups correspond one-to-one with the three phase lines of the three-phase AC power supply, and the pins in the second pin group are grounded.

[0015] In some embodiments, the voltage sampling circuit includes three first voltage sampling units and one second voltage sampling unit;

[0016] The three first voltage sampling units, the three first pin groups, and the three terminal groups correspond one-to-one with the three phase lines of the three-phase AC power, and the second voltage sampling unit corresponds to the neutral line of the three-phase AC power.

[0017] In some embodiments, the first voltage sampling unit includes a plurality of first voltage sampling resistors connected in series;

[0018] The first first voltage sampling resistor connected in series is electrically connected to the first end of the terminal group corresponding to the first voltage sampling unit, and the last first voltage sampling resistor connected in series is electrically connected to the first end of the first pin group corresponding to the first voltage sampling unit.

[0019] The first end of the terminal block is also electrically connected to the output end of the phase line corresponding to the terminal block.

[0020] In some embodiments, the second voltage sampling unit includes a second voltage sampling resistor;

[0021] The first end of the second voltage sampling resistor is electrically connected to the second end of the target terminal group, and the second end of the second voltage sampling resistor is grounded; wherein, the target terminal group is any one of the three terminal groups.

[0022] In some embodiments, the current sampling circuit includes three current sampling units;

[0023] The three current sampling units, the three first pin groups, and the three terminal groups correspond one-to-one with the three phase lines of the three-phase AC power.

[0024] In some embodiments, the first end of the current sampling unit is electrically connected to the first end of the terminal block corresponding to the current sampling unit, the second end of the current sampling unit is electrically connected to the second end of the terminal block corresponding to the current sampling unit, the third end of the current sampling unit is electrically connected to the first end of the first pin group corresponding to the current sampling unit, and the fourth end of the current sampling unit is electrically connected to the second end of the first pin group corresponding to the current sampling unit.

[0025] The first end of the terminal block is also electrically connected to the output end of the phase line corresponding to the terminal block.

[0026] In a second aspect, embodiments of this application provide a digital display meter, including a housing and a main circuit board disposed within the housing, as well as a circuit board disposed within the housing as described in the first aspect or any one of the first aspects above;

[0027] The main circuit board integrates a controller and a second sampling circuit.

[0028] In some embodiments, when the first sampling circuit in the circuit board is a voltage sampling circuit, the second sampling circuit includes three first sampling units;

[0029] The three first sampling units correspond one-to-one with the three first pin groups of the pin header connector on the circuit board;

[0030] The first sampling unit includes a first resistor, a second resistor, a first capacitor, and a second capacitor;

[0031] The first end of the first resistor is electrically connected to the first end of the first pin group corresponding to the first sampling unit, and the first end of the second resistor is electrically connected to the second end of the first pin group corresponding to the first sampling unit. Both the second end of the first resistor and the second end of the second resistor are grounded.

[0032] The first terminal of the first capacitor is electrically connected to the first terminal of the first resistor and the controller, the first terminal of the second capacitor is electrically connected to the first terminal of the second resistor and the controller, and the second terminals of the first capacitor and the second capacitor are both grounded.

[0033] In some embodiments, when the first sampling circuit in the circuit board is a current sampling circuit, the second sampling circuit includes three second sampling units;

[0034] The three second sampling units correspond one-to-one with the three first pin groups of the pin header connector on the circuit board;

[0035] The second sampling unit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor, and a fourth capacitor;

[0036] The first end of the third resistor is electrically connected to the first end of the first pin group corresponding to the second sampling unit, the first end of the fourth resistor is electrically connected to the second end of the first pin group corresponding to the second sampling unit, and the second ends of the third resistor and the fourth resistor are both grounded.

[0037] The first end of the fifth resistor is electrically connected to the first end of the third resistor, and the second end of the fifth resistor is electrically connected to the controller;

[0038] The first end of the sixth resistor is electrically connected to the first end of the fourth resistor, and the second end of the sixth resistor is electrically connected to the controller;

[0039] The first terminal of the third capacitor is electrically connected to the second terminal of the fifth resistor, the first terminal of the fourth capacitor is electrically connected to the second terminal of the sixth resistor, and the second terminals of both the third capacitor and the fourth capacitor are grounded.

[0040] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0041] Figure 1 This is a circuit block diagram of a circuit board with voltage or current sampling function provided in an embodiment of this application.

[0042] Figure 2 This is a circuit block diagram of a circuit board with voltage sampling function provided in an embodiment of this application.

[0043] Figure 3 This is a circuit block diagram of a circuit board with current sampling function provided in an embodiment of this application.

[0044] Figure 4 A circuit block diagram of another circuit board with voltage sampling function provided in this application embodiment.

[0045] Figure 5 A circuit block diagram of another circuit board with current sampling function provided in this application embodiment.

[0046] Figure 6 This is a circuit diagram of a pin header connector provided in an embodiment of this application.

[0047] Figure 7 This is a circuit diagram of a voltage sampling circuit provided in an embodiment of this application.

[0048] Figure 8 This is a circuit diagram of a current sampling circuit provided in an embodiment of this application.

[0049] Figure 9 This is a circuit schematic diagram of a controller provided in an embodiment of this application.

[0050] Figure 10 This is a circuit diagram of a second sampling circuit provided in an embodiment of this application.

[0051] Figure 11 A circuit diagram of another second sampling circuit provided in an embodiment of this application.

[0052] Explanation of reference numerals in the attached figures:

[0053] 10. Circuit board;

[0054] 11. Terminal block; 12. First sampling circuit; 13. Pin header connector;

[0055] 111. Terminal block assembly;

[0056] 121. Voltage sampling circuit; 122. Current sampling circuit;

[0057] 1211, First voltage sampling unit; 1212, Second voltage sampling unit;

[0058] 1221. Current sampling unit;

[0059] 131. First row of needles; 132. Second row of needles;

[0060] 20. Three-phase alternating current;

[0061] 31. Second sampling circuit; 32. Controller;

[0062] 311. First sampling unit; 312. Second sampling unit. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0065] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0066] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0067] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0068] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, "connection" or "joining" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by a partition, such as a connection fixed by screws, bolts, or other partitions; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0069] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0070] Figure 1 This is a circuit block diagram of a circuit board with voltage or current sampling function provided in an embodiment of this application. Figure 1 As shown, the circuit board 10 includes a circuit board body, a terminal block 11, a first sampling circuit 12, and a pin header connector 13 disposed on the circuit board body.

[0071] The first sampling circuit 12 is either a voltage sampling circuit 121 or a current sampling circuit 122.

[0072] The first end of the first sampling circuit 12 is electrically connected to the output end of the three-phase AC power 20 through the terminal block 11. The second end of the first sampling circuit 12 is electrically connected to the first end of the pin header connector 13. The second end of the pin header connector 13 is electrically connected to the controller 32 through the second sampling circuit 31.

[0073] When the first sampling circuit 12 is a voltage sampling circuit 121, the first sampling circuit 12 is located on the first side of the circuit board body, and the controller 32 detects the voltage parameters of the three-phase AC power 20 through the voltage sampling circuit 121 and the second sampling circuit 31.

[0074] When the first sampling circuit 12 is a current sampling circuit 122, the first sampling circuit 12 is located on the second side of the circuit board body, and the controller 32 detects the current parameters of the three-phase AC power 20 through the current sampling circuit 122 and the second sampling circuit 31.

[0075] The circuit board body is the main part of the circuit board, and the circuit board body integrates a pin header connector 13, a terminal block 11 and a first sampling circuit 12.

[0076] The pin header connector 13 is used to connect to the first sampling circuit 12 and the second sampling circuit 31. The first end of the pin header connector 13 is the input end of the pin header connector 13, and the second end of the pin header connector 13 is the output end of the pin header connector 13.

[0077] Terminal block 11 is used to connect the output terminal of three-phase AC power 20. The three-phase AC power 20 is connected to the circuit board through terminal block 11 to provide the voltage or current signal to be measured to the first sampling circuit 12 on the circuit board.

[0078] Figure 2 This is a circuit block diagram of a circuit board with voltage sampling function provided in an embodiment of this application. Figure 2 As shown, when the digital display is a three-phase voltage digital display, the first sampling circuit 12 is a voltage sampling circuit 121, and the controller 32 detects the phase voltage of each phase of the three-phase AC power 20 through the voltage sampling circuit 121 and the second sampling circuit 31.

[0079] Figure 3 This is a circuit block diagram of a circuit board with current sampling function provided in an embodiment of this application. Figure 3 As shown, when the digital display is a three-phase current digital display, the first sampling circuit 12 is a current sampling circuit 122, and the controller 32 detects the line current of each phase of the three-phase AC power 20 through the current sampling circuit 122 and the second sampling circuit 31.

[0080] The circuit board is designed to have either voltage sampling or current sampling functionality. When used in a three-phase digital voltage display meter, the circuit board needs to have voltage sampling functionality. In this case, a voltage sampling circuit 121 is provided on the first side of the circuit board to enable voltage sampling. When used in a three-phase digital current display meter, the circuit board needs to have current sampling functionality. In this case, a current sampling circuit 122 is provided on the second side of the circuit board to enable current sampling.

[0081] It should be noted that the first and second sides of the circuit board body are arranged opposite to each other, that is, the first side of the circuit board body is the front side of the circuit board body, and the second side of the circuit board body is the back side of the circuit board body, or the first side of the circuit board body is the back side of the circuit board body, and the second side of the circuit board body is the front side of the circuit board body.

[0082] When this circuit board is used for a three-phase voltage / current digital display meter, the first sampling circuit 12 on the circuit board body is either a voltage sampling circuit 121 or a current sampling circuit 122. The circuit board body will not have both a voltage sampling circuit 121 and a current sampling circuit 122 at the same time.

[0083] Since the voltage sampling circuit 121 and the current sampling circuit 122 on the circuit board body are alternately selected, the circuit board can have voltage sampling function or current sampling function by setting either the voltage sampling circuit 121 or the current sampling circuit 122 on the circuit board body. This eliminates the need to produce multiple different circuit board bodies during the manufacturing process; only the first sampling circuit 12 on the existing circuit board body needs to be configured and selected. This effectively reduces the need to separately produce and manage multiple versions of the circuit board, and significantly reduces the complexity of material production and management. Furthermore, if the voltage sampling circuit 121 needs to be set on the circuit board body, it can be located on the first side of the circuit board body; if the current sampling circuit 122 needs to be set on the circuit board body, it can be located on the second side of the circuit board body. This helps to reduce the area of ​​the circuit board body, thereby reducing the space occupied by the circuit board and meeting the requirements of miniaturized form factor design.

[0084] It should be noted that regardless of whether the first sampling circuit 12 on the circuit board body is a voltage sampling circuit 121 or a current sampling circuit 122, the installation positions of the terminal block 11 and the pin connector 13 on the circuit board body remain fixed, so that the opening position and size of the corresponding terminal block 11 on the digital display meter housing remain unchanged, thereby allowing the three-phase voltage digital display meter and the three-phase current digital display meter to use the same housing.

[0085] This application provides a circuit board with voltage or current sampling function. The circuit board includes a circuit board body, a pin header connector, a terminal block, and a first sampling circuit integrated on the circuit board body. The input terminal of the first sampling circuit is electrically connected to the output terminal of a three-phase AC power supply through the terminal block. The output terminal of the first sampling circuit is electrically connected to the first end of the pin header connector, and the second end of the pin header connector is electrically connected to a controller through a second sampling circuit. The first sampling circuit can be designed as a voltage sampling circuit or a current sampling circuit according to the functions required by the circuit board, so that the circuit board has voltage sampling function or current sampling function. It eliminates the need to produce multiple different circuit board bodies during the production process. Only the configuration selection of the first sampling circuit on the circuit board body is required, which effectively reduces the need to produce and manage multiple versions of circuit boards separately and effectively reduces the complexity of material production and management. In addition, if a voltage sampling circuit needs to be set on the circuit board body, the voltage sampling circuit can be set on the first side of the circuit board body; if a current sampling circuit needs to be set on the circuit board body, the current sampling circuit can be set on the second side of the circuit board body, which helps to reduce the area of ​​the circuit board body, thereby reducing the space occupied by the circuit board and meeting the needs of miniaturized form factor design.

[0086] Figure 4 A circuit block diagram of another circuit board with voltage sampling function provided in this application embodiment. Figure 5 A circuit block diagram of another circuit board with current sampling function provided in this application embodiment. (See diagram below.) Figure 4 and Figure 5 As shown, in some embodiments, the pin header connector 13 includes three first pin header groups 131 and one second pin header group 132.

[0087] Among them, the pin header connector 13 is a common electronic connector used for electrical connections on electronic circuit boards. The pin header connector consists of a row of metal pins and is usually soldered onto the circuit board to make electrical connections with other components.

[0088] It should be noted that the pin header connector 13 can be a double-row pin header connector or a single-row pin header connector; this embodiment does not specifically limit it in this regard.

[0089] Figure 6 This is a circuit diagram of a pin header connector provided for an embodiment of this application. Figure 6 As shown, pin header connector J2 is the same as pin header connector 13. Pin header connector 13 is a double-row connector and has 8 pins, that is, pin header connector 13 has 8 pins.

[0090] Specifically, in the pin header connector 13, two pin headers form a pin header group. The first and third pin headers of the pin header connector 13 form a second pin header group 132 of the pin header connector 13, that is, pin 1 and pin 3 of the pin header connector 13 are the first and second ends of the second pin header group 132, respectively; the second and fourth pin headers of the pin header connector 13 form a first pin header group 131 of the pin header connector 13, that is, pin 2 and pin 4 of the pin header connector 13 are the first and second ends of a second pin header group 132, respectively; the sixth and eighth pin headers of the pin header connector 13 form another first pin header group 131 of the pin header connector 13, that is, pin 6 and pin 8 of the pin header connector 13 are the first and second ends of another second pin header group 132, respectively; the fifth and seventh pin headers of the pin header connector 13 form yet another first pin header group 131 of the pin header connector 13, that is, pin 5 and pin 7 of the pin header connector 13 are the first and second ends of yet another second pin header group 132, respectively.

[0091] like Figure 4 and Figure 5 As shown, the terminal block 11 includes three terminal groups 111.

[0092] The terminal block 11 is used for electrical connection with the three-phase AC power supply 20.

[0093] It should be noted that the terminal block 11 has 6 terminals. Two terminals in the terminal block 11 form a terminal group 111. The first and second terminals of the terminal block 11 form one terminal group 111, the third and fourth terminals of the terminal block 11 form another terminal group 111, and the fifth and sixth terminals of the terminal block 11 form yet another terminal group 111.

[0094] The three first pin groups 131 and the three terminal groups 111 correspond one-to-one with the three phase lines of the three-phase AC power supply 20, and the pins in the second pin group 132 are grounded.

[0095] Among them, the three phase lines of the three-phase AC power supply 20 are phase A, phase B and phase C of the three-phase AC power supply 20.

[0096] It should be noted that phases A, B, and C of the three-phase AC power supply 20 correspond to a first row of pins 131 and a terminal block 111, respectively.

[0097] For example, the three first pin groups 131 are first pin group A, first pin group B and first pin group C respectively, and the three terminal groups 111 are terminal group A, terminal group B and terminal group C respectively. The A of the three-phase AC power 20 corresponds to the first pin group A and terminal group A, the B of the three-phase AC power 20 corresponds to the first pin group B and terminal group B, and the C of the three-phase AC power 20 corresponds to the first pin group C and terminal group C.

[0098] In this embodiment, using the pins in the second pin group 132 of the pin header connector 13 for grounding, i.e., the first and third pins of the pin header connector 13 for grounding, can ensure that the grounding connection of the first sampling circuit 12 is more stable and reliable, while also helping to reduce grounding impedance, thereby reducing noise and electromagnetic interference, and improving signal quality and stability.

[0099] like Figure 4 As shown, in some embodiments, the voltage sampling circuit 121 includes three first voltage sampling units 1211 and one second voltage sampling unit 1212.

[0100] The three first voltage sampling units 1211, the three first pin groups 131, and the three terminal groups 111 correspond one-to-one with the three phase lines of the three-phase AC power 20, and the second voltage sampling unit 1212 corresponds to the neutral line of the three-phase AC power 20.

[0101] It should be noted that phases A, B and C of the three-phase AC power 20 each correspond to a first voltage sampling unit 1211, and each first voltage sampling unit 1211 corresponds to a first pin group 131 and a terminal group 111.

[0102] For example, the three first voltage sampling units 1211 are respectively the first voltage sampling unit A, the first voltage sampling unit B, and the first voltage sampling unit C. The A of the three-phase AC power 20 corresponds to the first voltage sampling unit A, the first pin header group A, and the terminal group A. The B of the three-phase AC power 20 corresponds to the first voltage sampling unit B, the first pin header group B, and the terminal group B. The C of the three-phase AC power 20 corresponds to the first voltage sampling unit C, the first pin header group C, and the terminal group C.

[0103] It should be noted that the second voltage sampling unit 1212 corresponds to the N phase of the three-phase AC power supply 20.

[0104] In this embodiment, the first voltage sampling unit 1211 is used to sample the voltage of the phase line of the corresponding three-phase AC power 20, and the second voltage sampling unit 1212 is used to sample the voltage of the N-phase of the three-phase AC power 20. The output terminals of the first voltage sampling unit 1211 and the second voltage sampling unit 1212 are both connected to the controller 32 through the pin header connector 13 and the second sampling circuit 31, so that the controller 32 can obtain the phase voltage corresponding to the three phase lines of the three-phase AC power 20 respectively.

[0105] In some embodiments, the first voltage sampling unit 1211 includes a plurality of first voltage sampling resistors connected in series.

[0106] The first voltage sampling resistor connected in series is electrically connected to the first end of the terminal group 111 corresponding to the first voltage sampling unit 1211, and the last voltage sampling resistor connected in series is electrically connected to the first end of the first pin group 131 corresponding to the first voltage sampling unit 1211.

[0107] The first end of the terminal block 111 is also electrically connected to the output end of the corresponding phase line of the terminal block 111.

[0108] The number of first voltage sampling resistors in the first voltage sampling unit 1211 can be determined by the user according to actual needs, and this embodiment does not impose specific limitations on this.

[0109] For example, the first voltage sampling unit 1211 includes six first voltage sampling resistors connected in series.

[0110] Figure 7 This is a circuit diagram of a voltage sampling circuit provided in an embodiment of this application. Figure 7 As shown, the first voltage sampling unit A includes a first A-phase voltage sampling resistor RA1, a second A-phase voltage sampling resistor RA2, a third A-phase voltage sampling resistor RA3, a fourth A-phase voltage sampling resistor RA4, a fifth A-phase voltage sampling resistor RA5, and a sixth A-phase voltage sampling resistor RA6 connected in series. The first A-phase voltage sampling resistor RA1 is also electrically connected to the first terminal of terminal block A, and the sixth A-phase voltage sampling resistor RA6 is also electrically connected to the first terminal of the first pin header group A. The first terminal of terminal block A is also electrically connected to the output terminal of phase A of the three-phase AC power supply 20. Wherein, CTA+ represents the first terminal of the first pin header group A, IA* represents the first terminal of terminal block A, and LA represents the output terminal of phase A of the three-phase AC power supply 20.

[0111] like Figure 7As shown, the second voltage sampling unit B includes a first B-phase voltage sampling resistor RB1, a second B-phase voltage sampling resistor RB2, a third B-phase voltage sampling resistor RB3, a fourth B-phase voltage sampling resistor RB4, a fifth B-phase voltage sampling resistor RB5, and a sixth B-phase voltage sampling resistor RB6 connected in series. The first B-phase voltage sampling resistor RB1 is also electrically connected to the first terminal of the terminal block B, and the sixth B-phase voltage sampling resistor RB6 is also electrically connected to the first terminal of the first pin header B. The first terminal of the terminal block B is also electrically connected to the output terminal of the B phase of the three-phase AC power supply 20. Wherein, CTB+ represents the first terminal of the first pin header B, IB* represents the first terminal of the terminal block B, and LB represents the output terminal of the B phase of the three-phase AC power supply 20.

[0112] like Figure 7 As shown, the third voltage sampling unit C includes a first C-phase voltage sampling resistor RC1, a second C-phase voltage sampling resistor RC2, a third C-phase voltage sampling resistor RC3, a fourth C-phase voltage sampling resistor RC4, a fifth C-phase voltage sampling resistor RC5, and a sixth C-phase voltage sampling resistor RC6 connected in series. The first C-phase voltage sampling resistor RC1 is also electrically connected to the first terminal of the terminal block C, and the sixth C-phase voltage sampling resistor RC6 is also electrically connected to the first terminal of the first pin header C. The first terminal of the terminal block C is also electrically connected to the output terminal of the C-phase of the three-phase AC power supply 20. Wherein, CTC+ represents the first terminal of the first pin header C, IC* represents the first terminal of the terminal block C, and LC represents the output terminal of the C-phase of the three-phase AC power supply 20.

[0113] In this embodiment, the first voltage sampling unit is a resistor divider sampling unit, and all resistors in the first voltage sampling unit are 1206 chip resistors, which helps to reduce the space occupied by the first voltage sampling unit.

[0114] In some embodiments, the second voltage sampling unit 1212 includes a second voltage sampling resistor.

[0115] The first end of the second voltage sampling resistor is electrically connected to the second end of the target terminal block, and the second end of the second voltage sampling resistor is grounded.

[0116] The second end of the target terminal block is also electrically connected to the output end of the neutral line of the three-phase AC power 20. The target terminal block is any one of the three terminal blocks 111.

[0117] It should be noted that the target terminal group is terminal group A, terminal group B, or terminal group C. The second terminal of the target terminal group among the three terminal groups 111 is electrically connected to the output terminal of the neutral line of the three-phase AC power 20, and the second terminals of the other terminal groups 111 besides the target terminal group are left floating.

[0118] For example, the target terminal block is terminal block C. In this case, the second terminal of terminal block C is electrically connected to the output terminal of the N phase of the three-phase AC power supply 20 and the first terminal of the second voltage sampling resistor, respectively. The second terminal of the second voltage sampling resistor is grounded, and the second terminals of terminal block A and terminal block B are left floating.

[0119] like Figure 7 As shown, the second voltage sampling resistor is the N-phase voltage sampling resistor RN1. The first end of the N-phase voltage sampling resistor RN1 is electrically connected to the second end of the terminal block C. The second end of the terminal block C is also electrically connected to the N-phase output terminal of the three-phase AC power supply 20. The second end of the N-phase voltage sampling resistor RN1 is grounded.

[0120] In this embodiment, the resistance of the N-phase voltage sampling resistor RN1 is 0Ω.

[0121] In some embodiments, the current sampling circuit 122 includes three current sampling units 1221.

[0122] The three current sampling units 1221, the three first row of pin groups 131, and the three terminal groups 111 correspond one-to-one with the three phase lines of the three-phase AC power supply 20.

[0123] It should be noted that phases A, B and C of the three-phase AC power 20 each correspond to a current sampling unit 1221, and each current sampling unit 1221 corresponds to a first row of pins 131 and a terminal block 111.

[0124] For example, the three current sampling units 1221 are current sampling unit A, current sampling unit B and current sampling unit C, respectively. The A of the three-phase AC power 20 corresponds to current sampling unit A, first pin group A and terminal group A, the B of the three-phase AC power 20 corresponds to current sampling unit B, first pin group B and terminal group B, and the C of the three-phase AC power 20 corresponds to current sampling unit C, first pin group C and terminal group C.

[0125] In this embodiment, the current sampling unit 1221 is used to sample the current of the phase line of the corresponding three-phase AC power 20. The output terminals of the current sampling unit 1221 are all connected to the controller 32 through the pin header connector 13 and the second sampling circuit 31, so that the controller 32 can obtain the line current corresponding to the three phase lines of the three-phase AC power 20 respectively.

[0126] In some embodiments, the first end of the current sampling unit 1221 is electrically connected to the first end of the terminal group 111 corresponding to the current sampling unit 1221, the second end of the current sampling unit 1221 is electrically connected to the second end of the terminal group 111 corresponding to the current sampling unit 1221, the third end of the current sampling unit 1221 is electrically connected to the first end of the first pin group 131 corresponding to the current sampling unit 1221, and the fourth end of the current sampling unit 1221 is electrically connected to the second end of the first pin group 131 corresponding to the current sampling unit 1221.

[0127] The first end of the terminal block 111 is also electrically connected to the output end of the corresponding phase line of the terminal block 111.

[0128] Among them, the current sampling unit 1221 is a current transformer.

[0129] Figure 8 This is a circuit diagram of a current sampling circuit provided in an embodiment of this application. Figure 8 As shown, current sampling unit A is a current transformer CT1. The first terminal of current transformer CT1 is electrically connected to the first terminal of terminal block A, the second terminal of current transformer CT1 is electrically connected to the second terminal of terminal block A, the third terminal of current transformer CT1 is electrically connected to the first terminal of the first pin header group A, and the fourth terminal of current transformer CT1 is electrically connected to the second terminal of the first pin header group A. The first terminal of terminal block A is also electrically connected to the output terminal of phase A of the three-phase AC power supply 20. Wherein, CTA+ represents the first terminal of the first pin header group A, CTA- represents the second terminal of the first pin header group A, IA* represents the first terminal of terminal block A, and IA represents the second terminal of terminal block A.

[0130] The current sampling unit B is a current transformer CT2. The first terminal of current transformer CT2 is electrically connected to the first terminal of terminal block B, the second terminal of current transformer CT2 is electrically connected to the second terminal of terminal block B, the third terminal of current transformer CT2 is electrically connected to the first terminal of the first pin header group B, and the fourth terminal of current transformer CT2 is electrically connected to the second terminal of the first pin header group B. The first terminal of terminal block B is also electrically connected to the output terminal of phase B of the three-phase AC power supply 20. Wherein, CTB+ represents the first terminal of the first pin header group B, CTB- represents the second terminal of the first pin header group B, IB* represents the first terminal of terminal block B, and IB represents the second terminal of terminal block B.

[0131] The current sampling unit C is a current transformer CT3. The first terminal of current transformer CT3 is electrically connected to the first terminal of terminal block C, the second terminal of current transformer CT3 is electrically connected to the second terminal of terminal block C, the third terminal of current transformer CT3 is electrically connected to the first terminal of the first pin header group C, and the fourth terminal of current transformer CT3 is electrically connected to the second terminal of the first pin header group C. The first terminal of terminal block C is also electrically connected to the output terminal of phase C of the three-phase AC power supply 30. Wherein, CTC+ represents the first terminal of the first pin header group C, CTC- represents the second terminal of the first pin header group C, IC* represents the first terminal of terminal block C, and IC represents the second terminal of terminal block C.

[0132] In addition, this application embodiment also provides a digital display meter, which includes a housing and a main circuit board disposed within the housing, as well as a circuit board as described in the above embodiment disposed within the housing; the main circuit board integrates a controller and a second sampling circuit.

[0133] The main circuit board and the circuit board are both located inside the housing of the digital display. The connection relationship between the controller and the second sampling circuit on the main circuit board, as well as the pin header connector, terminal block and the first sampling circuit on the circuit board, has been described in detail in the above embodiments, and will not be repeated in this embodiment.

[0134] Figure 9 This is a circuit schematic diagram of a controller provided in an embodiment of this application. Figure 9 As shown, the controller is a GB0F924 controller.

[0135] like Figure 4 As shown, in some embodiments, when the first sampling circuit 12 in the circuit board is a voltage sampling circuit 121, the second sampling circuit 31 includes three first sampling units 311, and the three first sampling units 311 correspond one-to-one with the three first pin groups 131 of the pin header connector 13 on the circuit board.

[0136] The first sampling unit 311 includes a first resistor, a second resistor, a first capacitor, and a second capacitor.

[0137] The first end of the first resistor is electrically connected to the first end of the first pin group corresponding to the first sampling unit 311, the first end of the second resistor is electrically connected to the second end of the first pin group corresponding to the first sampling unit 311, and the second ends of the first resistor and the second resistor are both grounded; the first end of the first capacitor is electrically connected to the first end of the first resistor and the controller respectively, the first end of the second capacitor is electrically connected to the first end of the second resistor and the controller respectively, and the second ends of the first capacitor and the second capacitor are both grounded.

[0138] In the case where the first sampling circuit 12 is a voltage sampling circuit 121, the three first sampling units 311 correspond one-to-one with the three first pin groups 131 of the pin header connector 13 on the circuit board.

[0139] For example, the three first sampling units 311 are first sampling unit A, first sampling unit B and first sampling unit C, respectively. First sampling unit A corresponds to first voltage sampling unit A, first pin group A and terminal group A, first sampling unit B corresponds to first voltage sampling unit B, first pin group B and terminal group B, and first sampling unit C corresponds to first voltage sampling unit C, first pin group C and terminal group C.

[0140] Figure 10 This is a circuit schematic diagram of a second sampling circuit provided in an embodiment of this application. Figure 10 As shown, the first sampling unit A includes an eleventh resistor R11, a twelfth resistor R12, an eleventh capacitor C11, and a twelfth capacitor C12. The first terminal of the eleventh resistor R11 is electrically connected to the first terminal of the first pin header A, and the first terminal of the twelfth resistor R12 is electrically connected to the second terminal of the first pin header A. The second terminals of both the eleventh and twelfth resistors R11 are grounded. The first terminal of the eleventh capacitor C11 is electrically connected to both the first terminal of the eleventh resistor R11 and the first terminal of the controller. The first terminal of the twelfth capacitor C12 is electrically connected to both the first terminal of the twelfth resistor R12 and the second terminal of the controller. The second terminals of both the eleventh and twelfth capacitors C12 are grounded. Wherein, CTA+ represents the first terminal of the first pin header A, CTA- represents the second terminal of the first pin header A, the first terminal of the controller is pin 3, and the second terminal of the controller is pin 4.

[0141] like Figure 10 As shown, the first sampling unit B includes a thirteenth resistor R13, a fourteenth resistor R14, a thirteenth capacitor C13, and a fourteenth capacitor C14. The first terminal of the thirteenth resistor R13 is electrically connected to the first terminal of the first pin header group B, and the first terminal of the fourteenth resistor R14 is electrically connected to the second terminal of the first pin header group B. Both the second terminals of the thirteenth and fourteenth resistors R13 are grounded. The first terminal of the thirteenth capacitor C13 is electrically connected to both the first terminal of the thirteenth resistor R13 and the third terminal of the controller. The first terminal of the fourteenth capacitor C14 is electrically connected to both the first terminal of the fourteenth resistor R14 and the fourth terminal of the controller. Both the second terminals of the thirteenth and fourteenth capacitors C14 are grounded. Wherein, CTB+ represents the first terminal of the first pin header group B, CTB- represents the second terminal of the first pin header group B, the third terminal of the controller is pin 5, and the fourth terminal of the controller is pin 6.

[0142] like Figure 10 As shown, the first sampling unit C includes a fifteenth resistor R15, a sixteenth resistor R16, a fifteenth capacitor C15, and a sixteenth capacitor C16. The first terminal of the fifteenth resistor R15 is electrically connected to the first terminal of the first pin header group C, and the first terminal of the sixteenth resistor R16 is electrically connected to the second terminal of the first pin header group C. Both the second terminals of the fifteenth and sixteenth resistors R15 are grounded. The first terminal of the fifteenth capacitor C15 is electrically connected to both the first terminal of the fifteenth resistor R15 and the fifth terminal of the controller. The first terminal of the sixteenth capacitor C16 is electrically connected to both the first terminal of the sixteenth resistor R16 and the sixth terminal of the controller. Both the second terminals of the fifteenth and sixteenth capacitors C16 are grounded. Wherein, CTC+ represents the first terminal of the first pin header group C, CTC- represents the second terminal of the first pin header group C, the fifth terminal of the controller is the 7th pin of the controller, and the sixth terminal of the controller is the 8th pin of the controller.

[0143] In this embodiment, when the first sampling circuit 12 is a voltage sampling circuit 121, the voltage signal is divided by a resistor and then connected to the controller 32 through the pin header connector 13 and the three first sampling units 311. The controller 32 measures the phase voltage of each phase of the three-phase AC power 20.

[0144] like Figure 5 As shown, in some embodiments, when the first sampling circuit 12 in the circuit board is a current sampling circuit 122, the second sampling circuit 31 includes three second sampling units 312, and the three second sampling units 312 correspond one-to-one with the three first pin groups 131 of the pin header connector 13 on the circuit board.

[0145] The second sampling unit 312 includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor, and a fourth capacitor.

[0146] The first end of the third resistor is electrically connected to the first end of the first pin group corresponding to the second sampling unit; the first end of the fourth resistor is electrically connected to the second end of the first pin group corresponding to the second sampling unit; the second ends of both the third and fourth resistors are grounded; the first end of the fifth resistor is electrically connected to the first end of the third resistor; the second end of the fifth resistor is electrically connected to the controller; the first end of the sixth resistor is electrically connected to the first end of the fourth resistor; the second end of the sixth resistor is electrically connected to the controller; the first end of the third capacitor is electrically connected to the second end of the fifth resistor; the first end of the fourth capacitor is electrically connected to the second end of the sixth resistor; the second ends of both the third and fourth capacitors are grounded.

[0147] In the case where the first sampling circuit 12 is a current sampling circuit 122, the three second sampling units 312 correspond one-to-one with the three first pin groups 131 of the pin header connector 13 on the circuit board.

[0148] For example, the three second sampling units 312 are second sampling unit A, second sampling unit B and second sampling unit C, respectively. Second sampling unit A corresponds to current sampling unit A, first pin group A and terminal group A, second sampling unit B corresponds to current sampling unit B, first pin group B and terminal group B, and second sampling unit C corresponds to current sampling unit C, first pin group C and terminal group C.

[0149] Figure 11 A circuit schematic diagram of another second sampling circuit provided in an embodiment of this application. (See diagram below.) Figure 11 As shown, the second sampling unit A includes a 35th resistor R35, a 46th resistor R46, a 51st resistor R51, a 56th resistor R56, a 33rd capacitor C33, and a 36th capacitor C36. The first end of the 35th resistor R35 is electrically connected to the first end of the first pin group A; the first end of the 46th resistor R46 is electrically connected to the second end of the first pin group A; and the second ends of both the 35th and 46th resistors are grounded. The first end of the 51st resistor R51 is electrically connected to the first end of the 35th resistor R35; and the second end of the 51st resistor R51 is electrically connected to the first end of the controller. The first end of the 56th resistor R56 is electrically connected to the first end of the 46th resistor R46; and the second end of the 56th resistor R56 is electrically connected to the second end of the controller. The first end of the 33rd capacitor C33 is electrically connected to the second end of the 51st resistor R51; and the first end of the 36th capacitor C36 is electrically connected to the second end of the 56th resistor R56; and the second ends of both the 33rd and 36th capacitors are grounded. Wherein, CTA+ represents the first end of the first row of pins A, CTA- represents the second end of the first row of pins A, the first end of the controller is the third pin of the controller, and the second end of the controller is the fourth pin of the controller.

[0150] like Figure 11As shown, the second sampling unit B includes a 36th resistor R36, a 47th resistor R47, a 52nd resistor R52, a 57th resistor R57, a 34th capacitor C34, and a 37th capacitor C37. The first end of the 36th resistor R36 is electrically connected to the first end of the first pin group B; the first end of the 47th resistor R47 is electrically connected to the second end of the first pin group B; and the second ends of both the 36th and 47th resistors are grounded. The first end of the 52nd resistor R52 is electrically connected to the first end of the 36th resistor R36; and the second end of the 52nd resistor R52 is electrically connected to the third end of the controller. The first end of the 57th resistor R57 is electrically connected to the first end of the 47th resistor R47; and the second end of the 57th resistor R57 is electrically connected to the fourth end of the controller. The first end of the 34th capacitor C34 is electrically connected to the second end of the 52nd resistor R52; and the first end of the 37th capacitor C37 is electrically connected to the second end of the 57th resistor R57; and the second ends of both the 34th and 37th capacitors are grounded. Wherein, CTB+ represents the first end of the first row of pins B, CTB- represents the second end of the first row of pins B, the third end of the controller is the fifth pin of the controller, and the fourth end of the controller is the sixth pin of the controller.

[0151] like Figure 11 As shown, the second sampling unit C includes a 37th resistor R37, a 48th resistor R48, a 53rd resistor R53, a 58th resistor R58, a 35th capacitor C35, and a 38th capacitor C38. The first end of the 37th resistor R37 is electrically connected to the first end of the first pin group C; the first end of the 48th resistor R48 is electrically connected to the second end of the first pin group C; and the second ends of both the 37th and 48th resistors R37 and R48 are grounded. The first end of the 53rd resistor R53 is electrically connected to the first end of the 37th resistor R37; and the second end of the 53rd resistor R53 is electrically connected to the fourth end of the controller. The first end of the 58th resistor R58 is electrically connected to the first end of the 48th resistor R48; and the second end of the 58th resistor R58 is electrically connected to the fifth end of the controller. The first end of the 35th capacitor C35 is electrically connected to the second end of the 53rd resistor R53; and the first end of the 38th capacitor C38 is electrically connected to the second end of the 58th resistor R58; and the second ends of both the 35th and 38th capacitors C35 and C38 are grounded. Wherein, CTC+ represents the first end of the first row of pins C, CTC- represents the second end of the first row of pins C, the fourth end of the controller is the 7th pin of the controller, and the fifth end of the controller is the 8th pin of the controller.

[0152] In this embodiment, when the first sampling circuit 12 is a current sampling circuit 122, the current signal is sampled by the current transformer and then connected to the controller 32 through the pin header connector 13 and the three second sampling units 312. The controller 32 measures the line current of each phase of the three-phase AC power 20.

[0153] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A circuit board with voltage or current sampling function, characterized in that, The circuit board includes a circuit board body, and a pin header connector, a terminal block, and a first sampling circuit disposed on the circuit board body; The first sampling circuit is a voltage sampling circuit or a current sampling circuit; The first end of the first sampling circuit is electrically connected to the output end of the three-phase AC power through the terminal block, the second end of the first sampling circuit is electrically connected to the first end of the pin header connector, and the second end of the pin header connector is electrically connected to the controller through the second sampling circuit; When the first sampling circuit is the voltage sampling circuit, the first sampling circuit is located on the first side of the circuit board body, and the controller detects the voltage parameters of the three-phase AC power through the voltage sampling circuit and the second sampling circuit; When the first sampling circuit is the current sampling circuit, the first sampling circuit is located on the second side of the circuit board body, and the controller detects the current parameters of the three-phase AC power through the current sampling circuit and the second sampling circuit.

2. A circuit board with voltage or current sampling function according to claim 1, characterized in that, The pin header connector includes three first pin header groups and one second pin header group; The terminal block includes three terminal groups; The three first pin groups and the three terminal groups correspond one-to-one with the three phase lines of the three-phase AC power supply, and the pins in the second pin group are grounded.

3. A circuit board with voltage or current sampling function according to claim 2, characterized in that, The voltage sampling circuit includes three first voltage sampling units and one second voltage sampling unit; The three first voltage sampling units, the three first pin header groups, and the three terminal blocks correspond one-to-one with the three phase lines of the three-phase AC power, and the second voltage sampling unit corresponds to the neutral line of the three-phase AC power.

4. A circuit board with voltage or current sampling function according to claim 3, characterized in that, The first voltage sampling unit includes a plurality of first voltage sampling resistors connected in series; The first first voltage sampling resistor connected in series is electrically connected to the first end of the terminal group corresponding to the first voltage sampling unit, and the last first voltage sampling resistor connected in series is electrically connected to the first end of the first pin group corresponding to the first voltage sampling unit. The first end of the terminal block is also electrically connected to the output end of the phase line corresponding to the terminal block.

5. A circuit board with voltage or current sampling function according to claim 3, characterized in that, The second voltage sampling unit includes a second voltage sampling resistor; The first end of the second voltage sampling resistor is electrically connected to the second end of the target terminal group, and the second end of the second voltage sampling resistor is grounded; wherein, the target terminal group is any one of the three terminal groups.

6. A circuit board with voltage or current sampling function according to claim 2, characterized in that, The current sampling circuit includes three current sampling units; The three current sampling units, the three first pin groups, and the three terminal groups correspond one-to-one with the three phase lines of the three-phase AC power.

7. A circuit board with voltage or current sampling function according to claim 6, characterized in that, The first end of the current sampling unit is electrically connected to the first end of the terminal group corresponding to the current sampling unit, the second end of the current sampling unit is electrically connected to the second end of the terminal group corresponding to the current sampling unit, the third end of the current sampling unit is electrically connected to the first end of the first pin group corresponding to the current sampling unit, and the fourth end of the current sampling unit is electrically connected to the second end of the first pin group corresponding to the current sampling unit. The first end of the terminal block is also electrically connected to the output end of the phase line corresponding to the terminal block.

8. A digital display meter, characterized in that, It includes a housing and a main circuit board disposed within the housing, as well as a circuit board with voltage or current sampling function as described in any one of claims 1 to 7 disposed within the housing; The main circuit board integrates a controller and a second sampling circuit.

9. A digital display meter according to claim 8, characterized in that, In the case that the first sampling circuit in the circuit board is a voltage sampling circuit, the second sampling circuit includes three first sampling units; The three first sampling units correspond one-to-one with the three first pin groups of the pin header connector on the circuit board; The first sampling unit includes a first resistor, a second resistor, a first capacitor, and a second capacitor; The first end of the first resistor is electrically connected to the first end of the first pin group corresponding to the first sampling unit, and the first end of the second resistor is electrically connected to the second end of the first pin group corresponding to the first sampling unit. Both the second end of the first resistor and the second end of the second resistor are grounded. The first terminal of the first capacitor is electrically connected to the first terminal of the first resistor and the controller, the first terminal of the second capacitor is electrically connected to the first terminal of the second resistor and the controller, and the second terminals of the first capacitor and the second capacitor are both grounded.

10. A digital display meter according to claim 8, characterized in that, In the case that the first sampling circuit in the circuit board is a current sampling circuit, the second sampling circuit includes three second sampling units; The three second sampling units correspond one-to-one with the three first pin groups of the pin header connector on the circuit board; The second sampling unit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor, and a fourth capacitor; The first end of the third resistor is electrically connected to the first end of the first pin group corresponding to the second sampling unit, the first end of the fourth resistor is electrically connected to the second end of the first pin group corresponding to the second sampling unit, and the second ends of the third resistor and the fourth resistor are both grounded. The first end of the fifth resistor is electrically connected to the first end of the third resistor, and the second end of the fifth resistor is electrically connected to the controller; The first end of the sixth resistor is electrically connected to the first end of the fourth resistor, and the second end of the sixth resistor is electrically connected to the controller; The first terminal of the third capacitor is electrically connected to the second terminal of the fifth resistor, the first terminal of the fourth capacitor is electrically connected to the second terminal of the sixth resistor, and the second terminals of both the third capacitor and the fourth capacitor are grounded.

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