Three-channel excitation current acquisition circuit supporting MODBUSRTU communication

Abstract

The utility model discloses a kind of three-way excitation current collector circuit of supporting MODBUS RTU communication, including supply power circuit module, hall sensor circuit module, signal conditioning circuit module, filter circuit module, microcontroller circuit module and isolated RS485 interface circuit module;The output end of hall sensor circuit module is connected signal conditioning circuit module, signal conditioning circuit module output end connects filter circuit module, filter circuit module output end connects microcontroller circuit module, microcontroller circuit module connects isolated RS485 interface circuit module, and isolated RS485 interface circuit module is used for external upper computer or control system equipment.The circuit simple structure, high speed, high isolation, can realize multiple sampling and support MODBUS RTU communication, and it is suitable for measuring and monitoring excitation current equipment in motor, generator and other electrical equipment.

Description

Technical Field

[0001] This utility model belongs to the technical field of excitation current acquisition circuit, specifically relating to a three-channel excitation current acquisition circuit that supports MODBUS RTU communication. Background Technology

[0002] The excitation system is the core control system of a synchronous motor; the excitation current directly affects the motor's reactive power output and voltage stability; and accurate monitoring of the excitation current is crucial for the safety of the power system.

[0003] Traditional acquisition methods have many limitations: analog signal transmission is susceptible to interference; point-to-point connection methods have poor scalability; and data recording and analysis capabilities are very limited.

[0004] Regarding the development of industrial communication protocols: the Modbus protocol has become an industry standard; the RS485 interface physical layer is widely used, featuring strong anti-interference capabilities and multiple nodes; and the rapid development of industrial automation has driven the application of Modbus RTU. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a three-channel excitation current acquisition circuit that supports MODBUS RTU communication. This circuit features a simple structure, high speed, high isolation, and the ability to perform multiple samplings and support MODBUS RTU communication. It is suitable for measuring and monitoring excitation current in electrical equipment such as motors and generators.

[0006] This utility model is achieved through the following technical solution:

[0007] A three-channel excitation current acquisition circuit supporting MODBUS RTU communication includes a power supply circuit module, a Hall sensor circuit module, a signal conditioning circuit module, a filter circuit module, a microcontroller circuit module, and an isolated RS485 interface circuit module. The output terminal of the Hall sensor circuit module is connected to the signal conditioning circuit module, the output terminal of the signal conditioning circuit module is connected to the filter circuit module, the output terminal of the filter circuit module is connected to the microcontroller circuit module, and the microcontroller circuit module is connected to the isolated RS485 interface circuit module. The isolated RS485 interface circuit module is used to connect to an external host computer or control system equipment. The power supply circuit module is used to supply power to the Hall sensor circuit module, the signal conditioning circuit module, the filter circuit module, the microcontroller circuit module, and the isolated RS485 interface circuit module.

[0008] In the above technical solution, the power supply circuit module includes: a switching power supply chip U1, an LDO chip P1, and a precision power supply chip P3. The +5.0V power supply terminal of the switching power supply chip U1 is connected to the Hall sensor circuit module and the signal conditioning circuit module. The +5.0V power supply terminal of the switching power supply chip U1 is connected to the input terminal of the LDO chip P1 and the input terminal of the precision power supply chip P3. The +3.3V power supply terminal of the LDO chip P1 is connected to the microcontroller circuit module for power supply. The +3.3VREF power supply terminal of the precision power supply chip P3 is connected to the reference voltage terminal of the ADC of the microcontroller circuit module.

[0009] In the above technical solution, the Hall sensor circuit module includes: Hall sensor T1, Hall sensor T2 and Hall sensor T3.

[0010] In the above technical solution, the signal conditioning circuit module includes: corresponding sub-components U2A, U3A, and U6A of operational amplifiers U2, U3, and U6; the signal output terminal of Hall sensor T1 is connected to U2A; the signal output terminal of Hall sensor T2 is connected to U3A; the signal output terminal of Hall sensor T3 is connected to U6A; and the signal output terminals of U2A, U3A, and U6A are connected to the filter circuit module.

[0011] In the above technical solution, the filtering circuit module includes: corresponding sub-components U2B, U3B, and U6B of operational amplifiers U2, U3, and U6; the signal output terminal of the signal conditioning circuit module U2A is connected to the signal input terminal of U2B; the signal output terminal of the signal conditioning circuit module U3A is connected to the signal input terminal of U3B; and the signal output terminal of the signal conditioning circuit module U6A is connected to the signal input terminal of U6B.

[0012] In the above technical solution, the U2B, U3B and U6B of the filter circuit module all have two-stage low-pass filters and clamping diodes.

[0013] In the above technical solution, the microcontroller circuit module includes: a microcontroller chip U4, and the output terminals of the filter circuit module U2B, U3B and U6B are respectively connected to the microcontroller chip U4.

[0014] In the above technical solution, the microcontroller chip U4 is model GD32F130F8P6TR, and the three signal lines (RS485DE, RS485D, RS485R) of the isolated RS485 interface circuit module are connected to the microcontroller chip U4.

[0015] In the above technical solution, the isolated RS485 interface circuit module includes: an isolated RS485 chip U5, a transient suppression diode connected between output terminal A and output terminal B of the isolated RS485 chip U5, a pull-up resistor connected to output terminal A, and a pull-down resistor connected to output terminal B.

[0016] The advantages and beneficial effects of this utility model are as follows:

[0017] This invention allows for flexible configuration of multiple excitation current monitoring points, supports the Modbus RTU communication protocol, operates on 8-30VDC power, and has an isolation voltage level of 2000VAC. It can achieve a range of 1000 meters at 100Kbps and 200 meters at 1Mbps. It is suitable for various applications involving real-time monitoring of the excitation current of generators or motors and transmitting data to a host computer or control system via the Modbus RTU protocol. It features small size, easy installation, low cost, strong anti-interference capability, high precision, and high reliability in excitation current acquisition. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a three-channel excitation current acquisition circuit that supports MODBUS RTU communication.

[0019] Figure 2 This is the circuit diagram of the power supply circuit module.

[0020] Figure 3 This is the circuit diagram of the Hall sensor circuit module.

[0021] Figure 4 This is the circuit diagram of the signal conditioning circuit module.

[0022] Figure 5 This is the circuit diagram of the filter circuit module.

[0023] Figure 6 This is a circuit diagram of a microcontroller circuit module.

[0024] Figure 7 This is the circuit diagram of an isolated RS485 interface circuit module.

[0025] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.

[0027] This invention designs a three-channel excitation current acquisition circuit that supports MODBUS RTU communication. See attached diagram. Figure 1 The circuit includes a power supply circuit module 1, a Hall sensor circuit module 2, a signal conditioning circuit module 3, a filter circuit module 4, a microcontroller circuit module 5, and an isolated RS485 interface circuit module 6.

[0028] The Hall sensor circuit module is used to detect the excitation current in electrical equipment such as motors or generators. The output of the Hall sensor circuit module is connected to a signal conditioning circuit module, which in turn is connected to a filter circuit module. The filter circuit module's output is connected to a microcontroller circuit module, which is then connected to an isolated RS485 interface circuit module. This isolated RS485 interface circuit module is used to connect to an external host computer or control system device. The power supply circuit module provides power to the Hall sensor circuit module, signal conditioning circuit module, filter circuit module, microcontroller circuit module, and isolated RS485 interface circuit module. During operation, the weak voltage signal measured by the Hall sensor circuit module is fed into the conductor. After conditioning by the signal conditioning circuit module and filtering by the filter circuit module, the signal is sent to the microcontroller circuit module. The ADC within the microcontroller circuit module converts the analog signal into a digital signal. This digital signal undergoes a series of calculations, per-unit CRC checks, and other processing by the microcontroller to form a MODBUS RTU data packet. This data packet includes the terminal address, three circuit data streams, and a CRC check value. This data packet is then transmitted to the host computer or control system device via the isolated RS485 interface circuit module.

[0029] The connection relationships of each circuit module are described in detail below.

[0030] like Figure 2As shown, the power supply circuit module includes: a switching power supply chip U1, an LDO chip P1, and a precision power supply chip P3. The switching power supply chip U1 is model SGM61412, the LDO chip P1 is model LM1117-3.3, and the precision power supply chip P3 is model TPR3312. The power supply is connected to TVS1 via the positive and negative terminals. The positive terminal (DC+) of the power supply is connected in series with diode D1 and then to pin 3 of the switching power supply chip U1. Pin 3 of U1 is connected to one pin of ceramic capacitors C1 and C2 and resistor R1. The other pin of ceramic capacitors C1 and C2 is connected to GND. Resistors R1 and R2 are connected, and the connection point is connected to pin 5 of U1. The other pin of resistor R2 is connected to GND. Pin 1 of U1 is connected to GND. Capacitor C3 is connected between pins 2 and 6 of U1. Pin 2 of U1 is connected to one end of inductor L1. One end of inductor L1 provides +5.0V power to the Hall sensor circuit module and signal conditioning circuit module. Capacitors C22, C4, C6, and C23 are connected between +5.0V and GND. +5.0V is connected to voltage divider resistor R. 3. Resistor R3 is connected to one end of the parallel connection of resistor R4 and capacitor C24. The other end of the parallel connection of resistor R4 and capacitor C24 is connected to feedback pin 4 of U1 and one end of sampling resistor R5. The other end of resistor R5 is connected to GND. Pin 3 of LDO chip P1 and pin 1 of precision power chip P3 are connected to +5.0V. Pin 1 of LDO chip P1 and pin 3 of precision power chip P3 are connected to GND. Pins 2 and 4 of LDO chip P1 are +3.3V, which power the microcontroller circuit module and are connected to GND via capacitors C7 and C25. Pin 2 of precision power chip P3 is +3.3VREF, which serves as the reference voltage for the ADC of the microcontroller circuit module and is connected to GND via capacitors C6 and C26.

[0031] like Figure 3 As shown, the Hall sensor circuit module includes: Hall sensor T1, Hall sensor T2 and Hall sensor T3. Capacitors C5 and C34, C27 and C36, and C28 and C35 are connected between the positive power supply terminal 1 and the negative power supply terminal 2 of Hall sensors T1, T2 and T3, respectively. Filter capacitors C29, C37 and C38 are connected between the output pin 3 of Hall sensors T1, T2 and T3 and GND, respectively.

[0032] like Figure 4As shown, the signal conditioning circuit module includes: operational amplifiers U2, U3, and U6, sub-components U2A, U3A, and U6A; an indirect resistor R26 between pins 1 and 2 of U2A; an indirect resistor R17 between pin 2 of U2A and GND; the signal output terminal of Hall sensor T1 from the Hall sensor circuit module is connected to pin 3 of U2A and resistor R25 via resistor R18, with the other pin of resistor R25 grounded; an indirect resistor R28 between pins 1 and 2 of U3A; an indirect resistor R19 between pin 2 of U3A and GND; and the signal output terminal of Hall sensor T2 from the Hall sensor circuit module. Resistor R20 is connected to pin 3 of U3A and resistor R27, with the other pin of resistor R27 grounded; resistor R30 is connected between pins 1 and 2 of U6A, and resistor R21 is connected between pin 2 of U6A and GND; the signal output terminal of Hall sensor T3 from the Hall sensor circuit module is connected to pin 3 of U6A and resistor R29 via resistor R22, with the other pin of resistor R29 grounded; pins 1 of U2A, U3A, and U6A are signals I1, I2, and I3, respectively, and they are connected to the filter circuit module; decoupling capacitors C18, C61, and C20 are connected between pin 8 of U2A, U3A, and U6A and GND, respectively.

[0033] like Figure 5As shown, the filter circuit module includes: operational amplifiers U2, U3, and operational amplifiers U6, and their sub-components U2B, U3B, and U6B; the signal output terminal I1 from the signal conditioning circuit module is connected to resistor R23, and then to capacitor C39 and resistor R6 respectively, where the other end of capacitor C39 is grounded, and the other end of resistor R6 is connected to pin 5 of U2B; pins 6 and 7 of U2B are shorted and connected to resistor R9, the other end of resistor R9 is connected to capacitor C14 and pin 3 of diode array D2 respectively, and named output terminal AIN1, which is connected to the microcontroller circuit module, where the other end of capacitor C14 is connected to GNG, pin 1 of diode array D2 is connected to GND, and pin 2 is connected to +3.3VREF from the power supply circuit module; the signal output terminal I2 from the signal conditioning circuit module is connected to resistor R24, and then to capacitor C40 and resistor R7 respectively, where the other end of capacitor C40 is grounded, and the other end of resistor R7 is connected to pin 5 of U3B; U3B Pins 6 and 7 of U6B are shorted and connected to resistor R11. The other end of resistor R11 is connected to capacitor C15 and pin 3 of diode array D3, respectively, and is named output terminal AIN2, which is connected to the microcontroller circuit module. The other end of capacitor C15 is connected to GNG, pin 1 of diode array D3 is connected to GND, and pin 2 is connected to +3.3VREF from the power supply circuit module. The signal output terminal I3 from the signal conditioning circuit module is connected to resistor R31 and then to capacitor C41 and resistor R14. The other end of capacitor C41 is grounded, and the other end of resistor R14 is connected to pin 5 of U6B. Pins 6 and 7 of U6B are shorted and connected to resistor R13. The other end of resistor R13 is connected to capacitor C19 and pin 3 of diode array D4, respectively, and is named output terminal AIN3, which is connected to the microcontroller circuit module. The other end of capacitor C19 is connected to GNG, pin 1 of diode array D4 is connected to GND, and pin 2 is connected to +3.3VREF from the power supply circuit module. Through the above connection structure, the filter circuit modules U2B, U3B and U6B each have two-stage low-pass filters and clamping diodes, namely: a low-pass filter composed of R23, C39 and R9, C14, and a clamping diode D2; a low-pass filter composed of R24, C40 and R11, C15, and a clamping diode D3; and a low-pass filter composed of R31, C41 and R13, C19, and a clamping diode D4.

[0034] like Figure 6As shown, the microcontroller circuit module includes: a microcontroller chip U4, model GD32F130F8P6TR; the output terminals AIN1, AIN2, and AIN3 from the filter circuit module are connected to pins 7, 8, and 9 of the microcontroller chip U4, respectively; pin 1 of the microcontroller chip U4 is connected to GND with a resistor R8; pin 4 of the microcontroller chip U4 is connected to GND with a capacitor C13, and to the +3.3V from the power supply circuit module with a resistor R10; pins 19 and 20 of the microcontroller chip U4 are connected to pins 2 and 3 of J2, respectively; pins 1 and 4 of J2 are connected to +3.3V and GND, respectively; pins 14, 17, and 18 of the microcontroller chip U4 are named RS485DE, RS485D, and RS485R, respectively, and are connected to the isolated RS485 interface circuit module.

[0035] like Figure 7 As shown, the isolated RS485 interface circuit module includes: an isolated RS485 chip U5, model CA-IS2092A; two capacitors C31 and C33 connected between pins 5 and 6 of the isolated RS485 chip U5; pin 6 of U5 connected to +5.0V from the power supply circuit module; and pin 5 of U5 connected to GND; pins 1 and 2, and pins 3 and 4 of the isolated RS485 chip U5 are respectively connected to RS485R, RS485DE, and RS485D from the microcontroller chip U4; and a capacitor connected between pins 7 and 8 of the isolated RS485 chip U5. Pin 7 of U5 is connected to the +3.3V power supply from the power supply circuit module. Two capacitors, C30 and C32, are connected between pins 11 and 12 of the isolated RS485 chip U5. Pin 11 is named +5.0VT, and pin 12 is named GNDT. A capacitor, C12, is connected between pins 10 and 9 of the isolated RS485 chip U5, with pin 10 connected to +5.0VT and pin 9 connected to GNDT. Pins 14 and 15 of the isolated RS485 chip U5 are named A and B as output terminals, connected to a transient voltage suppressor diode (TVS2). Pin A is connected to a pull-up resistor R15, and pin B is connected to a pull-down resistor R16. Pin 13 of the isolated RS485 chip U5 is connected to +5.0VT.

[0036] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0038] The present invention has been described above by way of example. It should be noted that, without departing from the core of the present invention, any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort fall within the protection scope of the present invention.

Claims

1. A three-channel excitation current acquisition circuit supporting MODBUS RTU communication, characterized in that: The system includes a power supply circuit module, a Hall sensor circuit module, a signal conditioning circuit module, a filter circuit module, a microcontroller circuit module, and an isolated RS485 interface circuit module. The output of the Hall sensor circuit module is connected to the signal conditioning circuit module, the output of the signal conditioning circuit module is connected to the filter circuit module, the output of the filter circuit module is connected to the microcontroller circuit module, and the microcontroller circuit module is connected to the isolated RS485 interface circuit module. The isolated RS485 interface circuit module is used to connect to an external host computer or control system equipment. The power supply circuit module is used to supply power to the Hall sensor circuit module, the signal conditioning circuit module, the filter circuit module, the microcontroller circuit module, and the isolated RS485 interface circuit module.

2. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 1, characterized in that: The power supply circuit module includes: a switching power supply chip U1, an LDO chip P1, and a precision power supply chip P3. The +5.0V power supply terminal of the switching power supply chip U1 is connected to the Hall sensor circuit module and the signal conditioning circuit module. The +5.0V power supply terminal of the switching power supply chip U1 is connected to the input terminal of the LDO chip P1 and the input terminal of the precision power supply chip P3. The +3.3V power supply terminal of the LDO chip P1 is connected to the microcontroller circuit module for power supply. The +3.3VREF power supply terminal of the precision power supply chip P3 is connected to the reference voltage terminal of the ADC of the microcontroller circuit module.

3. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 1, characterized in that: The Hall sensor circuit module includes: Hall sensor T1, Hall sensor T2 and Hall sensor T3.

4. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 3, characterized in that: The signal conditioning circuit module includes: corresponding sub-components U2A, U3A, and U6A of operational amplifiers U2, U3, and U6; the signal output terminal of Hall sensor T1 is connected to U2A; the signal output terminal of Hall sensor T2 is connected to U3A; the signal output terminal of Hall sensor T3 is connected to U6A; and the signal output terminals of U2A, U3A, and U6A are connected to the filter circuit module.

5. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 4, characterized in that: The filtering circuit module includes: corresponding sub-components U2B, U3B, and U6B of operational amplifiers U2, U3, and U6; the signal output terminal of signal conditioning circuit module U2A is connected to the signal input terminal of U2B; the signal output terminal of signal conditioning circuit module U3A is connected to the signal input terminal of U3B; and the signal output terminal of signal conditioning circuit module U6A is connected to the signal input terminal of U6B.

6. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 5, characterized in that: The filter circuit modules U2B, U3B, and U6B each have two-stage low-pass filters and clamping diodes.

7. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 6, characterized in that: The microcontroller circuit module includes a microcontroller chip U4, and the output terminals of the filter circuit modules U2B, U3B and U6B are respectively connected to the microcontroller chip U4.

8. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 7, characterized in that: The microcontroller chip U4 model is GD32F130F8P6TR. The three signal lines of the isolated RS485 interface circuit module are connected to the microcontroller chip U4.

9. The three-channel excitation current acquisition circuit supporting MODBUS RTU communication according to claim 1, characterized in that: The isolated RS485 interface circuit module includes: an isolated RS485 chip U5, a transient suppression diode connected between output terminal A and output terminal B of the isolated RS485 chip U5, a pull-up resistor connected to output terminal A, and a pull-down resistor connected to output terminal B.

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