A high-precision weighing and communication circuit with integrated temperature compensation function

Abstract

This utility model discloses a high-precision weighing communication circuit with integrated temperature compensation function, including a microcontroller module, a weighing module, an RS485 communication module, a temperature compensation module, and a power supply module. The weighing module, RS485 communication module, temperature compensation module, and power supply module are all connected to the microcontroller module. The RS485 communication module is equipped with a self-resetting fuse for overcurrent protection and a TVS diode for electrostatic discharge protection. The temperature compensation module has a temperature-sensitive chip with a reserved interface for temperature compensation to improve weighing accuracy. The power supply module has a dual LDO and single LDO switching interface adapted to different input voltages. This utility model achieves high-precision weighing while stably transmitting data via the RS485 interface. It also features temperature compensation expansion capabilities, overcurrent / electrostatic discharge protection, and adaptability to various power input scenarios.

Description

Technical Field

[0001] This utility model relates to the field of weighing communication technology, specifically to a high-precision weighing communication circuit with integrated temperature compensation function. Background Technology

[0002] Weighing technology serves as a core support for material measurement, industrial control, and consumer trade. The performance of its circuit system directly determines the accuracy, stability, and reliability of the weighing results. As application scenarios expand from traditional static weighing (such as platform scales and weighbridges) to dynamic weighing (such as belt scales and vehicle scales), high-precision weighing (such as laboratory analytical balances), and weighing in harsh environments (such as chemical, metallurgical, and mining industries), the technical requirements for weighing circuits have evolved from simply "precise data acquisition" to a comprehensive requirement encompassing "interference resistance, low power consumption, miniaturization, and intelligence."

[0003] The existing weighing circuits have the following shortcomings: 1. Weighing data is easily affected by temperature, and there is a lack of integrated temperature compensation modules; 2. The communication interface has weak anti-interference capabilities and no overcurrent / static discharge protection.

[0004] 3. The power module has poor compatibility and cannot adapt to different input voltage scenarios. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a high-precision weighing communication circuit with integrated temperature compensation function, strong anti-interference ability and power compatibility.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A high-precision weighing and communication circuit with integrated temperature compensation function is characterized in that it includes a microcontroller module, a weighing module, an RS485 communication module, a temperature compensation module, and a power supply module; the weighing module, RS485 communication module, temperature compensation module, and power supply module are all connected to the microcontroller module.

[0008] The weighing module includes a weighing sensor for weight data acquisition and an ADC conversion chip for weight data transmission.

[0009] The RS485 communication module includes a level conversion chip for converting single-ended signals to RS485 differential signals, a self-resetting fuse for overcurrent protection of the RS485 interface, and a TVS diode for electrostatic discharge protection of the RS485 interface.

[0010] The temperature compensation module includes a temperature-sensitive chip with a reserved interface for convenient temperature compensation and improved weighing accuracy.

[0011] The power module is equipped with a dual LDO and single LDO switching interface adapted to different input voltages.

[0012] The microcontroller module is equipped with a microcontroller for overall circuit control.

[0013] In some embodiments, the differential signal on the weighing sensor is filtered by an RC filter circuit and then connected to the differential input terminal of the ADC conversion chip. Both the weighing sensor and the ADC conversion chip are connected to the power module, and decoupling filter circuits are provided on the connecting lines. The ADC conversion chip is connected to the microcontroller through its output interface.

[0014] In some embodiments, the temperature-sensitive chip is connected to the microcontroller via pins thereon, and the temperature-sensitive chip is also provided with a filter capacitor to stabilize the power supply voltage of the temperature-sensitive chip.

[0015] In some embodiments, the RS485 communication module further includes an RS485 interface J3. The level conversion chip is connected to the microcontroller through its enable input / output pin and to the RS485 interface J3 through its differential bus pin. Each differential bus is provided with a resistor and the self-resetting fuse, and each line connected to the RS485 interface J3 is provided with a pull-down resistor and the TVS diode.

[0016] In some embodiments, the rated current of the resettable fuse is 200mA, providing overcurrent protection for the RS485 interface.

[0017] In some embodiments, the power module includes a power input interface J2, a first LDO chip, and a second LDO chip. The power input interface J2 is connected to the input ports of the first LDO chip and the second LDO chip, respectively. The output interface of the first LDO chip is connected to the weighing module and the temperature compensation module for power supply. The output interface of the second LDO chip is connected to the microcontroller module and the RS485 module for power supply. Both the input and output terminals of the first LDO chip and the second LDO chip are provided with decoupling filter circuits.

[0018] In some embodiments, a dual-LDO and single-LDO switching interface JP1 is provided between the output terminal of the first LDO chip and the output terminal of the second LDO chip. When the input voltage is less than 9V, the single-LDO power supply can be switched by shorting the JP1 interface to adapt to different input voltages.

[0019] In some embodiments, the microcontroller module is also connected to a program burning interface J1, which is used to download and debug programs via a programmer.

[0020] In some embodiments, when PCB space is insufficient, it is not necessary to set up a program programming interface J1. The pins of the programming interface on the microcontroller can be directly exposed on the edge of the PCB or in the available space in the form of PADs.

[0021] In some embodiments, the microcontroller uses the WB32L003 chip; the ADC conversion chip uses the XM24LPLUS chip; and the level conversion chip in the RS485 communication module uses the SN65LBC184D chip.

[0022] The beneficial effects of this utility model are as follows:

[0023] This invention incorporates an integrated temperature compensation module, which enhances the temperature stability of weighing data and thus improves the accuracy of the weighing data. A self-resetting fuse is installed at the RS485 interface for overcurrent protection, and a TVS diode is used for electrostatic discharge protection, providing strong anti-interference capabilities. The power module features a dual LDO and single LDO switching interface to adapt to different input voltages, resulting in higher compatibility.

[0024] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some schematic diagrams of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a block diagram showing the module connection of this utility model;

[0027] Figure 2 This is a circuit diagram of the weighing module in this utility model;

[0028] Figure 3 This is the circuit diagram of the temperature compensation module in this utility model;

[0029] Figure 4 This is a circuit schematic diagram of the RS485 communication module in this utility model;

[0030] Figure 5 This is a circuit diagram of the power supply module in this utility model;

[0031] Figure 6 This is the circuit schematic diagram of the microcontroller module in this utility model. Detailed Implementation

[0032] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0033] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0034] The names of the messages or information exchanged between the multiple devices in this embodiment of the invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0035] Example: Figure 1-6 As shown:

[0036] A high-precision weighing and communication circuit with integrated temperature compensation function includes a microcontroller module, a weighing module, an RS485 communication module, a temperature compensation module, and a power supply module; the weighing module, RS485 communication module, temperature compensation module, and power supply module are all connected to the microcontroller module.

[0037] In this embodiment, the microcontroller module includes a microcontroller U1, which uses a WB32L003 chip and is responsible for the overall circuit control. The weighing module includes a weighing sensor CN1 and an ADC conversion chip U3 for the acquisition and transmission of weight data. The ADC conversion chip U3 uses an XM24LPLUS chip and is responsible for processing the weighing signal acquired by the weighing sensor. The RS485 communication module includes a level conversion chip U2, a resettable fuse, and a TVS diode. The level conversion chip U2 converts single-ended signals to RS485 differential signals, the resettable fuse provides overcurrent protection for the RS485 interface, and the TVS diode provides electrostatic discharge protection for the RS485 interface, thus realizing RS485 communication. Bus anti-interference communication ensures data transmission; level conversion chip U2 uses SN65LBC184D chip; temperature compensation module includes temperature-sensitive chip U6 with reserved interface, temperature-sensitive chip U6 uses XM24L+ chip for temperature compensation, improving the stability of weighing data; power module includes power input interface J2, first LDO chip U4 and second LDO chip U5, both first LDO chip U4 and second LDO chip U5 use HT7550 chip, first LDO chip U4 provides +5VA power and second LDO chip U5 provides +5VD power.

[0038] Specifically: such as Figure 2-6 The microcontroller U1 is connected to the SCLK and DOUT pins of the ADC converter chip U3 via its PC3 and PC4 pins, respectively. It is connected to the SCL, SDA, and ALERT pins of the temperature-sensitive chip U6 via its PC5, PC6, and PB4 pins, respectively. It is connected to the RE, DI, and RO pins of the level conversion chip U2 via its PD4, PD5, and PD6 pins, respectively. The power input interface J2 is connected to an external power supply. The first LDO chip U4 supplies power to the weighing module and the temperature compensation module U6, and the second LDO chip U5 supplies power to the microcontroller module U1 and the RS485 communication module.

[0039] In this embodiment, the differential signal on the weighing sensor CN1 is filtered by the RC filter circuit and then connected to the differential input terminal of the ADC conversion chip U3. Both the weighing sensor CN1 and the ADC conversion chip U3 are connected to the power module, and decoupling filter circuits are provided on the connected lines. The ADC conversion chip U3 is connected to the microcontroller module through its output interface.

[0040] Specifically: such as Figure 2The S- pin on the load cell CN1 is connected to the AINN pin on the ADC converter chip U3 through series resistors R3 and R4. The S+ pin on the load cell CN1 is connected to the AINP pin on the ADC converter chip U3 through series resistors R5 and R6. The E- pin on the load cell CN1 is grounded, and the E+ pin is connected to the +5VA power supply. The VVREFP and AVDD pins on the ADC converter chip U3 are both connected to the +5VA power supply, and the AGND pin is grounded.

[0041] Three grounded capacitors, C6, C18, and C7, are connected in parallel between the E+ pin and the VVREFP pin on the ADC converter chip U3 and the +5VA power supply connection point. Two grounded capacitors, C19 and C8, are connected in parallel on the power line after the AVDD pin on the ADC converter chip U3 and the +5VA power supply connection point. The above parallel capacitors constitute a decoupling filter circuit.

[0042] There are two parallel grounded circuits connected in the circuit between resistors R3 and R4. One circuit is connected to capacitor C1 and then directly grounded. The other circuit is connected to capacitor C3 and then connected to the circuit between resistors R5 and R6, and then connected to capacitor C2 and grounded.

[0043] There are also two parallel grounding circuits between resistor R4 and the AINN pin on the ADC converter chip U3. One circuit is connected to capacitor C4 and then directly grounded. The other circuit is connected to capacitor C17 and then connected to the circuit between resistor R6 and the AINP pin on the ADC converter chip U3. After that, capacitor C5 is connected and then grounded. The above resistor + capacitor filtering circuit forms the RCRC filtering circuit.

[0044] In this embodiment, the temperature-sensitive chip is connected to the microcontroller module and can be used for temperature compensation. The temperature-sensitive chip is also equipped with a filter capacitor to stabilize the power supply voltage of the temperature-sensitive chip.

[0045] Specifically: such as Figure 3 The temperature-sensitive chip U6 is connected to the PC5, PC6 and PB4 pins of the microcontroller U1 via its SCL, SDA and ALERT pins, respectively. The V+ pin of the temperature-sensitive chip U6 is led out and connected to the +5VA power supply through a series resistor R8, and the other is connected to the ground through a series capacitor C20 and the ADDO pin of the temperature-sensitive chip U6. The capacitor C20 is used for filtering to stabilize the power supply voltage of the temperature-sensitive chip.

[0046] In this embodiment, the RS485 communication module also includes an RS485 interface J3. The level conversion chip U2 is connected to the microcontroller module through its enable input / output pin and to the RS485 interface J3 through its differential bus pin. Each differential bus is equipped with a resistor and a resettable fuse, and the lines connected to the RS485 interface J3 are equipped with pull-down resistors and TVS diodes.

[0047] Specifically: such as Figure 4 As shown, the level conversion chip U2 is connected to the RS485 interface J3 via a resistor R2 and a resettable fuse FR1 connected in series through its differential bus A pin. The level conversion chip U2 is also connected to the RS485 interface J3 via a resistor R1 and a resettable fuse FR2 connected in series through its differential bus B pin. A parallel resistor R10 and a TVS diode D2 are connected between resistor R1 and the resettable fuse FR2, and then grounded. A parallel resistor R9 and a TVS diode D1 are connected between resistor R2 and the resettable fuse FR1, and then connected to the +5VD power supply. One path of the VCC pin on the level conversion chip U2 is connected to the +5VD power supply, and the other path is connected in series with a capacitor C12 and then grounded. A resistor R11 is connected to the line connecting the RE pin on the level conversion chip U2 and the DIR pin on the microcontroller U1, and then grounded. The DE pin on the level conversion chip U2 is also connected to the RE pin.

[0048] In this embodiment: as Figure 4 The rated current of both resettable fuses FR1 and FR2 is 200mA, providing overcurrent protection for the RS485 interface.

[0049] In this embodiment: the power input interface J2 is connected to the input ports of the first LDO chip and the second LDO chip respectively; the output interface of the first LDO chip is connected to the weighing module and the temperature compensation module; the output interface of the second LDO chip is connected to the microcontroller module and the RS485 module; and decoupling filter circuits are provided at the input and output terminals of both the first LDO chip and the second LDO chip.

[0050] Specifically: such as Figure 5Pin 2 of the power input interface J2 is grounded. One lead of pin 1 is connected to the input port IN of the first LDO chip, and the other lead is connected to the input port IN of the second LDO chip. A parallel capacitor C13 and C23 are connected before the input port IN of the first LDO chip, and a parallel capacitor C14 and C24 are connected before the input port IN of the second LDO chip. The output port OUT of the first LDO chip is connected to a +5VA power supply, and the output port OUT of the second LDO chip is connected to a +5VD power supply. A parallel capacitor C15 and C25 are connected on the output line of the first LDO chip, and a parallel capacitor C16 and C26 are connected on the output line of the second LDO chip. The other ends of all the parallel capacitors are grounded.

[0051] In this embodiment, a dual-LDO and single-LDO switching interface JP1 is provided between the output terminal of the first LDO chip and the output terminal of the second LDO chip. When the input voltage is less than 9V, the single-LDO power supply can be switched by shorting the JP1 interface to adapt to different input voltages.

[0052] In this embodiment, as Figure 6 The microcontroller module is also connected to a program burning interface J1, which is used to download and debug programs via a programmer.

[0053] Specifically, the SWCLK / PD1 pin and SWDIO / PC7 pin on the microcontroller U1 are connected to pins 2 and 3 on the interface J1, respectively; pin 1 on the interface J1 is connected to the +5VD power supply, pin 4 is grounded, and pin 5 is connected to the nRST pin on the microcontroller.

[0054] In some embodiments, when PCB space is insufficient, it is not necessary to set up a program programming interface J1. The pins of the programming interface on the microcontroller U1 can be directly exposed on the edge of the PCB or in the available space in the form of PADs.

[0055] In this embodiment, as Figure 6 Two circuits are connected to the nRST pin on the microcontroller U1. One circuit is connected to the +5VD power supply in series with resistor R7, and the other circuit is connected to ground in series with capacitor C11. The VCAP pin on the microcontroller U1 is connected to ground in series with two parallel capacitors C9 and C21. One circuit on the VDD pin on the microcontroller U1 is connected to ground in series with two parallel capacitors C10 and C22, and the other circuit is directly connected to the +5VD power supply.

[0056] This circuit enables high-precision weighing and stable data transmission via an RS485 interface. It also features temperature compensation expansion capabilities, overcurrent / static discharge protection, and adaptability to various power input scenarios, making it suitable for industrial weighing, warehouse metering, and other fields.

[0057] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A high-precision weighing and communication circuit with integrated temperature compensation function, characterized in that, It includes a microcontroller module, a weighing module, an RS485 communication module, a temperature compensation module, and a power supply module; the weighing module, RS485 communication module, temperature compensation module, and power supply module are all connected to the microcontroller module. The weighing module includes a weighing sensor for weight data acquisition and an ADC conversion chip for weight data transmission. The RS485 communication module includes a level conversion chip for converting single-ended signals to RS485 differential signals, a self-resetting fuse for overcurrent protection of the RS485 interface, and a TVS diode for electrostatic discharge protection of the RS485 interface. The temperature compensation module includes a temperature-sensitive chip with a reserved interface for convenient temperature compensation and improved weighing accuracy. The power module is equipped with dual LDO and single LDO switching interfaces adapted to different input voltages; The microcontroller module is equipped with a microcontroller for overall circuit control.

2. The high-precision weighing communication circuit with integrated temperature compensation function according to claim 1, characterized in that, The differential signal from the weighing sensor is filtered by an RC filter circuit and then input to the differential input terminal of the ADC conversion chip. Both the weighing sensor and the ADC conversion chip are connected to the power module, and decoupling filter circuits are provided on the connecting lines. The ADC conversion chip is connected to the microcontroller through its output interface.

3. The high-precision weighing communication circuit with integrated temperature compensation function according to claim 1, characterized in that, The temperature-sensitive chip is connected to the microcontroller through its pins, and the temperature-sensitive chip is also equipped with a filter capacitor to stabilize the power supply voltage of the temperature-sensitive chip.

4. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 1, characterized in that, The RS485 communication module also includes an RS485 interface J3. The level conversion chip is connected to the microcontroller through its enable input / output pin and to the RS485 interface J3 through its differential bus pin. Each differential bus is equipped with a resistor and a resettable fuse, and each line connected to the RS485 interface J3 is equipped with a pull-down resistor and a TVS diode.

5. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 4, characterized in that, The self-resetting fuse has a rated current of 200mA, providing overcurrent protection for the RS485 interface.

6. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 1, characterized in that, The power module includes a power input interface J2, a first LDO chip, and a second LDO chip. The power input interface J2 is connected to the input ports of the first LDO chip and the second LDO chip, respectively. The output interface of the first LDO chip is connected to the weighing module and the temperature compensation module for power supply. The output interface of the second LDO chip is connected to the microcontroller module and the RS485 module for power supply. Both the input and output terminals of the first LDO chip and the second LDO chip are equipped with decoupling filter circuits.

7. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 6, characterized in that, A dual-LDO and single-LDO switching interface JP1 is provided between the output terminals of the first LDO chip and the second LDO chip. When the input voltage is less than 9V, the power supply can be switched to single LDO by shorting the JP1 interface to adapt to different input voltages.

8. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 1, characterized in that, The microcontroller module is also connected to a program burning interface J1, which is used to download and debug programs via a programmer.

9. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 8, characterized in that, When PCB space is insufficient, there is no need to set up the program programming interface J1. The pins of the programming interface on the microcontroller can be directly exposed on the edge of the PCB or in the available space in the form of PADs.

10. A high-precision weighing communication circuit with integrated temperature compensation function according to claim 8, characterized in that, The microcontroller uses the WB32L003 chip; the ADC conversion chip uses the XM24LPLUS chip; and the level conversion chip in the RS485 communication module uses the SN65LBC184D chip.

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