Thermal resistor module verification device

Abstract

The invention provides a thermal resistance module verification device, which comprises a precision resistor connected with a channel to be verified of a multi-channel thermal resistance input module and generating a voltage through a constant current source configured by the multi-channel thermal resistance input module; the voltage sampling module is used for collecting the sampling voltage on the precision resistor; the micro-processing module is used for acquiring a constant current value of the constant current source based on the sampling voltage and the precision resistor, and calculating a voltage value corresponding to the thermal resistance to be output based on the constant current value and the thermal resistance to be output; the voltage output module is used for outputting the voltage value to the multi-channel thermal resistance input module. Through a resistance box aggregation mode, a plurality of groups of thermistor values can be simultaneously output at one time, and the resistance values of the plurality of groups of thermistors can be simultaneously adjusted according to needs, so that module verification is efficiently and rapidly completed. The verification of each channel of the thermal resistance input module is realized based on the voltage signal, and the verification accuracy is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of calibration devices, and more particularly to a calibration device for a thermal resistance module. Background Art

[0002] An efficient thermal resistance calibration device proposed in Chinese Patent Application No. CN202211039447.0 includes a zero-degree constant temperature box with calibration insertion holes. Above the zero-degree constant temperature box, there is a calibration support plate. The calibration support holes are arranged through the calibration support plate. Resistance clamping devices are respectively arranged on the hole walls of the calibration support holes. A support plate lifting device is also connected between the top end of the zero-degree constant temperature box and the calibration support plate. The calibration support plate is used to load and support multiple thermal resistances, and together with the support plate lifting device, each thermal resistance is inserted into the zero-degree constant temperature box through the calibration insertion holes, realizing batch calibration of thermal resistances, thereby improving the calibration efficiency. During the insertion process of the thermal resistance, it is firmly clamped through the cooperation of the resistance clamping device to maintain the stability of the thermal resistance inserted into the zero-degree constant temperature box, avoid collision with the hole wall of the calibration insertion hole, help protect the thermal resistance from deformation caused by collision, and also help ensure the accuracy of the calibration work.

[0003] Currently, the calibration of thermal resistance modules in various power plants still adopts the traditional method. Using a signal generator to output a resistance value can only calibrate a group of thermal resistance values at a time. This patent intends to adopt the method of aggregating resistance boxes. Multiple groups of thermistors are installed in the resistance box, and multiple groups of thermistor resistance values can be output simultaneously at one time, and the resistance values of multiple groups of thermistors can be adjusted simultaneously according to needs, completing the module calibration efficiently and quickly. In the prior art, using a signal generator to output a resistance value can only calibrate a group of thermal resistance values at a time, and it is impossible to output and adjust multiple groups of thermistor resistance values simultaneously, resulting in low calibration efficiency and unable to meet the requirements of rapid calibration. Due to the possible lack of high-precision voltage signal implementation and accurate current detection mechanism in the prior art, this limits the calibration accuracy of each channel of the thermal resistance input module, and may lead to inaccurate calibration results. Limited channel selection: The multi-channel thermal resistance input module in the prior art may not have the option of multiple channel numbers, limiting the flexibility of user selection and the applicable range. Therefore, we make improvements on this and propose a calibration device for a thermal resistance module. Summary of the Invention

[0004] The object of the present invention is to address the problems raised in the existing background technology. To achieve the above object of the invention, the present invention provides the following technical solution: A calibration device for a thermal resistance module, comprising a resistance box and a precision resistor, wherein the precision resistor is connected to the channel to be calibrated of a multi-channel thermal resistance input module, and a voltage is generated by a constant current source configured in the multi-channel thermal resistance input module itself; the current range of the constant current source is 0.1 mA to 10 mA, and the constant current source module is provided with a reference voltage source, a shunt, and an error amplifier, and the error amplifier compares the voltage drop on the current detection element with the reference voltage to generate an error signal;

[0005] The multi-channel thermal resistance input module is connected to a voltage sampling module, the voltage sampling module is used to collect the sampled voltage on the precision resistor, the sampling accuracy of the voltage sampling module is 16-bit ADC, and the sampling rate is 1000 SPS. The voltage sampling module is connected to a microprocessing module, and the microprocessing module is used to obtain the constant current value of the constant current source based on the sampled voltage and the precision resistor, and calculate the voltage value corresponding to the thermal resistance to be output based on the constant current value and the thermal resistance to be output;

[0006] The microprocessing module uses a microcontroller or a DSP processor. The microprocessing module is connected to a voltage output module, and the output accuracy of the voltage output module is 0.01% FS. The voltage output module is used to output the voltage value to the multi-channel thermal resistance input module.

[0007] As a preferred technical solution of the present invention, multiple groups of thermistors are installed in the resistance box. A calibration input port and a voltage output port are provided on the front side of the resistance box, and the calibration input port and the voltage output port adopt RS-232, RS-485, USB or Ethernet interfaces.

[0008] As a preferred technical solution of the present invention, the microprocessing module is connected to a calibration control button circuit, and a power control button is provided on the side of the resistance box. The power control button is connected to a storage battery circuit provided in the resistance box.

[0009] As a preferred technical solution of the present invention, an indicator light assembly is provided on the resistance box. The indicator light assembly includes a calibration operation indicator light, a qualified indicator light, and an alarm indicator light. The qualified indicator light is provided on the right side of the calibration operation indicator light, and the alarm indicator light is provided on the right side of the qualified indicator light.

[0010] As a preferred technical solution of the present invention, the microprocessing module is connected to a calibration data display circuit, and the calibration data display is connected to the microprocessing module circuit.

[0011] As a preferred technical solution of the present invention, the output range of the voltage output module is 0 - 5V, the output accuracy is 0.005% FS, and the load capacity is ≥10 mA.

[0012] As a preferred technical solution of the present invention, the number of channels of the multi-channel thermal resistance input module is 4 channels, 8 channels, 10 channels, or 12 channels.

[0013] As a preferred technical solution of the present invention, the target verification R of the microprocessing module check The voltage value formula is

[0014] where the two known resistors and voltages are (R1, V1) and (R2, V2), and R check is the preset thermal resistance value to be output, that is, the target verification value, and R1 < R check < R2.

[0015] As a preferred technical solution of the present invention, a calibration circuit board is provided inside the resistance box. A PID temperature controller is provided on the calibration circuit board. The PID temperature controller is circuit-connected to the microprocessor unit MCU, and the microprocessor unit MCU is circuit-connected to a low-pass filter.

[0016] As a preferred technical solution of the present invention, circuit connection copper sheets are provided on the back side of the calibration circuit board. The circuit connection copper sheets connect the PID temperature controller, the microprocessor unit MCU, and the low-pass filter.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In the solution of the present invention: Through the resistance box aggregation method, multiple groups of thermistor values can be output simultaneously at one time, and the resistance values of multiple groups of thermistors can be adjusted simultaneously as needed, thereby efficiently and quickly completing module calibration. The calibration of each channel of the thermal resistance input module is realized based on voltage signals, effectively improving the calibration accuracy. The number of channels of the multi-channel thermal resistance input module is 4 channels, 8 channels, 10 channels, or 12 channels, and the appropriate number of channels can be selected according to actual needs. The microprocessing module is circuit-connected to the calibration control button, and a power control button is provided on the side of the resistance box, which is convenient for operation and control. An indicator light assembly is provided on the resistance box, including a calibration operation indicator light, a qualified indicator light, an alarm indicator light, and a calibration data display connected to the microprocessing module circuit, making the calibration process more intuitive and understandable. A calibration circuit board is provided inside the resistance box, and a PID temperature controller is provided on the calibration circuit board, which is circuit-connected to the microprocessor unit MCU to ensure stable temperature control. The microprocessor unit MCU is circuit-connected to a low-pass filter, which can optimize the signal quality and improve the calibration accuracy. Description of the Drawings

[0018] Figure 1 Logic block diagram provided by the present invention;

[0019] Figure 2 Structural schematic diagram provided by the present invention;

[0020] Figure 3 Structural schematic diagram of the calibration circuit board provided by the present invention;

[0021] Figure 4 Partial structural schematic diagram provided by the present invention;

[0022] Figure 5 Top view structural schematic diagram of the calibration circuit board provided by the present invention;

[0023] Figure 6 Structural schematic diagram of the circuit connection copper sheet provided by the present invention.

[0024] Labels in the figure:

[0025] 1. Precision resistor; 2. Voltage sampling module; 3. Microprocessing module; 4. Voltage output module; 5. Resistance box; 6. Thermistor; 7. Calibration input port; 8. Voltage output port; 9. Power control button; 10. Calibration control button; 11. Indicator light assembly; 1101. Calibration operation indicator light; 1102. Qualified indicator light; 1103. Alarm indicator light; 12. Calibration data display; 13. Calibration circuit board; 14. PID temperature controller; 15. Microprocessor unit MCU; 16. Low-pass filter; 17. Circuit connection copper sheet. Specific implementation manners

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0027] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed present invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other. It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] Embodiment 1: Please refer to Figures 1-6, A thermal resistance module calibration device, including a resistance box 5 and a precision resistor 1. The precision resistor 1 is connected to the channel to be calibrated of the multi-channel thermal resistance input module, and a voltage is generated through the constant current source configured in the multi-channel thermal resistance input module itself. The current range of the constant current source is 0.1 mA to 10 mA. The constant current source module is provided with a reference voltage source, a shunt, and an error amplifier. The error amplifier compares the voltage drop on the current detection element with the reference voltage to generate an error signal;

[0029] The multi-channel thermal resistance input module is connected to the voltage sampling module 2. The voltage sampling module 2 is used to collect the sampling voltage on the precision resistor 1. The sampling accuracy of the voltage sampling module 2 is 16-bit ADC, and the sampling rate is 1000 SPS. The voltage sampling module 2 is connected to the microprocessing module 3. The microprocessing module 3 is used to obtain the constant current value of the constant current source based on the sampling voltage and the precision resistor 1, and calculate the voltage value corresponding to the thermal resistance to be output based on the constant current value and the thermal resistance to be output;

[0030] The microprocessing module 3 uses a microcontroller or a DSP processor. The microprocessing module 3 is connected to the voltage output module 4. The output accuracy of the voltage output module 4 is 0.01% FS. The voltage output module 4 is used to output the voltage value to the multi-channel thermal resistance input module.

[0031] Multiple groups of thermistors 6 are installed in the resistance box 5. A calibration input port 7 and a voltage output port 8 are arranged on the front side of the resistance box 5. The calibration input port 7 and the voltage output port 8 adopt RS-232, RS-485, USB or Ethernet interfaces.

[0032] The microprocessing module 3 is circuit-connected to the calibration control button 10. A power control button 9 is arranged on the side of the resistance box 5. The power control button 9 is circuit-connected to the storage battery arranged in the resistance box 5.

[0033] An indicator light assembly 11 is arranged on the resistance box 5. The indicator light assembly 11 includes a calibration operation indicator light 1101, a qualified indicator light 1102, and an alarm indicator light 1103. The qualified indicator light 1102 is arranged on the right side of the calibration operation indicator light 1101, and the alarm indicator light 1103 is arranged on the right side of the qualified indicator light 1102.

[0034] The microprocessing module 3 is circuit-connected to the calibration data display 12. The calibration data display 12 is circuit-connected to the microprocessing module 3.

[0035] The output range of the voltage output module 4 is 0 - 5V, the output accuracy is 0.005% FS, and the load capacity: ≥10 mA.

[0036] The number of channels of the multi-channel thermal resistance input module is 4 channels, 8 channels, 10 channels, 12 channels.

[0037] Target verification R of the microprocessing module 3 check The voltage value formula of

[0038] where the two known resistors and voltages are R1, V1 and R2, V2, and R check is the preset resistance value of the thermal resistor to be output, that is, the target verification value, and R1 < R check < R2.

[0039] The calibration circuit board 13 is arranged inside the resistor box 5. The PID temperature controller 14 is arranged on the calibration circuit board 13. The PID temperature controller 14 is circuit-connected to the microprocessor unit MCU15, and the microprocessor unit MCU15 is circuit-connected to the low-pass filter 16. The circuit connection copper sheet 17 is arranged on the back side of the calibration circuit board 13. The circuit connection copper sheet 17 connects the PID temperature controller 14, the microprocessor unit MCU15 and the low-pass filter 16.

[0040] Embodiment 2, a thermal resistor module calibration device. The constant current source module is a key component in the multi-channel thermal resistor input module. Its main function is to provide a stable and accurate current source for each channel to be calibrated during the calibration process. This characteristic is crucial for ensuring the accuracy of thermal resistor measurement because the resistance value change of the thermal resistor is calculated by measuring the voltage drop across it under a known current.

[0041] The constant current source module works based on the feedback control principle. Its core components include a reference voltage source, a current detection element, including a shunt or a high-precision resistor, an error amplifier, and a power output stage. The specific working principle is as follows: Reference voltage source: Provides a stable reference voltage, which is the basis for the output current magnitude of the constant current source.

[0042] Current detection element: Connected in series in the output circuit to detect the actual output current value. When current passes through it, a voltage drop proportional to the current is generated on it. Error amplifier: Compares the voltage drop on the current detection element with the reference voltage to generate an error signal. If the actual current is less than the set value, the error signal is positive; otherwise, the error signal is negative.

[0043] Power output stage: Adjusts its output current according to the output signal of the error amplifier to reduce the error signal. When the error signal is zero, it means that the actual output current reaches the set value, and at this time the constant current source is in a stable state.

[0044] Working process of the constant current source module:

[0045] Initialization: When the multi-channel thermoresistor input module starts to work, the constant current source module is initialized first. This includes setting the voltage value of the reference voltage source, calibrating the current detection element, and initializing the parameters of the error amplifier and the power output stage.

[0046] Setting the current value: According to the calibration requirements, a set current value is sent to the constant current source module through an external control interface such as a digital interface or an analog signal. This value is stored in the internal register of the constant current source module as the reference for subsequent current control.

[0047] Starting the constant current output: After receiving the start signal, the constant current source module starts to output current. Initially, since the output current may not be zero and is unstable, the error amplifier will detect a large error signal and drive the power output stage to adjust its output current.

[0048] Closed-loop control: As the current is stably output, the voltage drop across the current detection element gradually approaches the reference voltage set by the reference voltage source. The error amplifier continuously compares these two voltage values and outputs a corresponding control signal to the power output stage to maintain the constancy of the output current. This process is a closed-loop control process, which can ensure that the current remains stable during the calibration process.

[0049] Calibration process: During the calibration process of the multi-channel thermoresistor input module, each channel to be calibrated is sequentially connected to the output terminal of the constant current source module. Since the constant current source module provides a stable current source, the resistance value change can be accurately calculated by measuring the voltage drop across the thermoresistor, thus achieving high-precision calibration.

[0050] End and reset: When all channels are calibrated, the constant current source module receives an end signal. At this time, the module stops outputting current and is ready to enter the next calibration cycle or enter the standby state. When needed, the constant current source module can be restored to its initial state through a reset operation.

[0051] The main function of voltage sampling module 2 is to perform high-precision and real-time acquisition of the voltage across precision resistor 1. Since the voltage across precision resistor 1 is proportional to the current passing through it and the resistance value according to Ohm's law V = IR, this voltage sampling value is crucial for subsequent calculation of the resistance value change of the thermoresistor. Voltage sampling module 2 usually uses a high-precision analog-to-digital converter ADC as the core component to convert the analog voltage signal into a digital signal for subsequent processing. In addition, to ensure the accuracy and stability of sampling, voltage sampling module 2 may also include a signal conditioning circuit, a filtering circuit, and a protection circuit.

[0052] The specific working principle of voltage sampling module 2 is as follows:

[0053] Signal Conditioning: First, the analog voltage signal on the precision resistor 1 undergoes preprocessing through a signal conditioning circuit, including amplification, buffering, and offset adjustment, to ensure that the signal meets the input requirements of the ADC.

[0054] Filtering: To eliminate noise and interference, the conditioned voltage signal is smoothed through a filtering circuit. Common filtering methods include low-pass filtering and band-pass filtering.

[0055] Analog-to-Digital Conversion: The filtered voltage signal is fed into a high-precision ADC for analog-to-digital conversion. The ADC converts the continuous analog voltage signal into a discrete digital signal, and its resolution and accuracy determine the accuracy and resolution of the sampled voltage.

[0056] Data Output: The converted digital voltage value is output through a digital interface, which includes SPI and I2C, to the microprocessing module 3 or other processing units for subsequent calculation and analysis.

[0057] Working Process of the Voltage Sampling Module 2

[0058] Initialization: After the system starts or resets, the voltage sampling module 2 first performs initialization. This includes configuring the sampling rate, resolution, and reference voltage parameters of the ADC, as well as calibration and self-check processes to ensure the normal operation of the module.

[0059] Sampling Trigger: According to the requirements of the calibration system, the voltage sampling module 2 triggers the sampling operation at specific time points or periodically. The sampling trigger can be controlled by an external signal, such as a timer interrupt, or internal logic.

[0060] Signal Acquisition and Processing: After the sampling trigger, the voltage sampling module 2 starts to acquire the voltage signal on the precision resistor 1. After signal conditioning and filtering, the voltage signal is fed into the ADC for analog-to-digital conversion. During the conversion process, the ADC continuously samples and quantifies the analog signal until the predetermined number of sampling points or sampling time is reached.

[0061] Data Output: The converted digital voltage value is stored in the internal register of the ADC and output to the microprocessing module 3 through a digital interface. After reading these data, the microprocessing module 3 performs further processing and analysis, such as calculating the resistance change of the thermal resistor.

[0062] Repeated Sampling: According to the requirements of the calibration system, the voltage sampling module 2 repeats the above sampling process to achieve continuous monitoring and real-time acquisition of the voltage on the precision resistor 1.

[0063] Data parameters of the voltage sampling module 2: The sampling rate of the voltage sampling module 2 refers to the number of voltage samples that the voltage sampling module 2 can collect per second. The higher the sampling rate, the faster the response speed to voltage changes, but it will also increase the data processing volume and system burden. The resolution of the voltage sampling module 2 refers to the minimum voltage value that the ADC can distinguish. The higher the resolution, the higher the accuracy of the sampled voltage, but it will also increase the complexity and cost of the ADC.

[0064] Accuracy of the voltage sampling module 2: It refers to the error range between the output voltage of the voltage sampling module 2 and the actual voltage. The higher the accuracy, the better the accuracy of the sampling result. Input range of the voltage sampling module 2: It refers to the range of voltage signals that the voltage sampling module 2 can process. The input range should match the voltage range on the precision resistor 1 to ensure the effectiveness and safety of sampling. Noise level of the voltage sampling module 2: It refers to the magnitude of the noise and interference introduced by the voltage sampling module 2 during the sampling process. The lower the noise level, the higher the signal-to-noise ratio of the sampling result and the smaller the impact on subsequent calculations. Power consumption of the voltage sampling module 2: It refers to the electrical energy consumed by the voltage sampling module 2 during operation. The lower the power consumption, the lower the overall energy consumption and heat dissipation requirements for the system.

[0065] Specific working principle of the microprocessing module 3: The microprocessing module 3, as the core control unit of the multi-channel thermal resistance module calibration device, undertakes important tasks such as data processing, logical judgment, and instruction sending. It realizes the precise control of the constant current source current and the efficient calibration of the thermal resistance value through interaction with the voltage sampling module 2 and the voltage output module 4.

[0066] Data processing: The microprocessing module 3 first receives the digital voltage value from the voltage sampling module 2, which is a quantization representation of the voltage on the precision resistor 1. Combining the known resistance value of the precision resistor 1, usually stored in the memory of the microprocessing module 3, the constant current value of the constant current source can be calculated using the inverse operation of Ohm's law V = IR.

[0067] Logical judgment and calculation: After obtaining the constant current value, the microprocessing module 3 will perform logical judgment and calculation based on the preset target thermal resistance value to be output, that is, the target calibration value. Through an analog circuit or a pre-stored algorithm table, the theoretical voltage value corresponding to the target thermal resistance value under a given current can be quickly calculated.

[0068] Instruction sending: After calculating the theoretical voltage value, the microprocessing module 3 will generate corresponding control instructions and send them to the voltage output module 4 through a digital interface such as SPI or I2C. The voltage output module 4 adjusts its output voltage according to the received instructions to simulate the voltage output of the target thermal resistance under actual working conditions.

[0069] Working process of the microprocessing module 3

[0070] Initialization: After the system starts up or resets, the microprocessing module 3 first performs initialization, including configuring interface parameters, loading preset values including the resistance value of precision resistor 1, the target resistance value of the thermal resistor, and clearing the internal register.

[0071] Receive sampled data: Receive the digital voltage value sent by the voltage sampling module 2 through the digital interface and store it in the internal register.

[0072] Calculate the constant current value: Using the inverse operation of Ohm's law, calculate the constant current value of the constant current source based on the received voltage value and the known resistance value of precision resistor 1.

[0073] Calculate the theoretical voltage value: According to the preset target verification value of the resistance value of the thermal resistor to be output and the calculated constant current value, quickly calculate the corresponding theoretical voltage value through an algorithm or a look-up table.

[0074] Send control instructions: Convert the calculated theoretical voltage value into control instructions and send them to the voltage output module 4 through the digital interface.

[0075] Loop verification: According to the verification requirements, the microprocessing module 3 will repeat the above process to verify all channels to be verified of the multi-channel thermal resistor input module one by one or simultaneously.

[0076] Result output: After the verification is completed, the microprocessing module 3 can output the verification results such as the deviation between the actual voltage value and the theoretical voltage value, and whether the verification passes through the communication interface to the host computer or the display screen for display.

[0077] Data parameters of the microprocessing module 3

[0078] Calculation accuracy: Refers to the accuracy of the microprocessing module 3 when calculating the constant current value and the theoretical voltage value. High-precision calculation can reduce error accumulation and improve the reliability of the verification results.

[0079] Processing speed: Refers to the time required for the microprocessing module 3 to complete one data processing and instruction sending. Fast processing speed can shorten the verification cycle and improve the verification efficiency.

[0080] Interface type and rate: Refers to the interface type such as SPI, I2C and rate of communication between the microprocessing module 3 and the voltage sampling module 2 and the voltage output module 4. High-rate interfaces can reduce data transmission delay and improve the system response speed.

[0081] Storage capacity: Refers to the capacity of the internal memory of the microprocessing module 3. Sufficient storage capacity can store more preset values and algorithm tables, support more complex verification logics and wider application scenarios.

[0082] Power consumption: It refers to the electrical energy consumption of the microprocessing module 3 during operation. Low-power design helps reduce the overall energy consumption of the system and extend the battery life, which is particularly important in portable devices.

[0083] Calculation and processing by the microprocessing module 3:

[0084] During the calculation and processing, the microprocessing module 3 mainly uses numerical calculation methods and logical judgments. For the calculation of the constant current value, the inverse operation of Ohm's law can be directly applied; for the calculation of the theoretical voltage value, it may be necessary to quickly solve it through algorithms or look-up tables based on the target thermal resistance value and the constant current value. To improve the calculation efficiency and accuracy, the microprocessing module 3 usually adopts optimized algorithms and efficient numerical processing methods to accelerate the calculation process and reduce errors.

[0085] Specific working principle and working process of the voltage output module 4:

[0086] The voltage output module 4 is a key component in the multi-channel thermal resistance calibration device. It receives the calculation result from the microprocessing module 3, that is, the theoretical voltage value, and generates the corresponding analog voltage signal, which is output to the corresponding channel of the multi-channel thermal resistance input module. By precisely controlling the amplitude and stability of the output voltage, the voltage output module 4 can simulate the voltage output of the actual thermal resistance under working conditions, thereby realizing the calibration of the measurement accuracy of the thermal resistance.

[0087] The voltage output module 4 usually includes core components such as a digital-to-analog converter (DAC), a buffer amplifier, a filter circuit, and a protection circuit. The DAC is responsible for converting the digital voltage value sent by the microprocessing module 3 into an analog voltage signal; the buffer amplifier is used to enhance the driving ability of the signal and reduce the attenuation and distortion of the signal during transmission; the filter circuit is used to eliminate noise and interference to ensure the smoothness and stability of the output voltage; the protection circuit is used to prevent damage to the module caused by abnormal situations such as overcurrent and overvoltage.

[0088] II. Working process

[0089] Receiving instructions: The voltage output module 4 first receives the control instructions and theoretical voltage value from the microprocessing module 3 through digital interfaces such as SPI and I2C.

[0090] Digital-to-analog conversion: The received digital voltage value is sent to the DAC for analog-to-digital conversion to generate the corresponding analog voltage signal.

[0091] Signal amplification and filtering: The converted analog voltage signal is amplified by the buffer amplifier to enhance its driving ability; then it is smoothed through the filter circuit to eliminate noise and interference.

[0092] Output voltage: The analog voltage signal that has been amplified and filtered is output to the corresponding channels of the multi-channel thermistor input module, simulating the voltage output of an actual thermistor in the working state.

[0093] Monitoring and feedback: Some voltage output modules 4 also have a monitoring function, which can detect the amplitude and stability of the output voltage in real time and feed the detection results back to the microprocessing module 3 for further processing or adjustment.

[0094] Cyclic verification: According to the verification requirements, the voltage output module 4 will repeat the above process to verify all the channels to be verified of the multi-channel thermistor input module one by one or simultaneously.

[0095] The voltage output module 4 simulates the voltage output of an actual thermistor in the working state by precisely controlling the amplitude and stability of the output voltage. First, the microprocessing module 3 calculates the theoretical voltage value according to the resistance value of the thermistor to be verified, the preset current value, and Ohm's law. Then, this theoretical voltage value is sent to the voltage output module 4. The voltage output module 4 receives and processes this value, converts it into an analog voltage signal through the DAC, and outputs it to the corresponding channels of the multi-channel thermistor input module after amplification and filtering. In this way, the multi-channel thermistor input module can receive a voltage signal similar to that of an actual thermistor in the working state, thus completing the verification process.

[0096] Experimental example:

[0097] In order to verify the performance of the thermistor module verification device of the present invention, the following experimental example was designed. This experiment aims to demonstrate the superiority of the present invention by comparing the efficiency, accuracy, and ease of use of the traditional single-channel verification device and the multi-channel thermistor input module verification device of the present invention.

[0098] The experimental equipment includes:

[0099] 1. The thermistor module verification device of the present invention; 2. Traditional single-channel thermistor verification device; 3. Standard thermistor module; 4. Digital multimeter; 5. Timer; 6. Computer;

[0100] Experimental steps:

[0101] 1. Use the thermistor module verification device of the present invention and the traditional single-channel thermistor verification device to verify the same set of standard thermistor modules respectively.

[0102] 2. Record the time required for the two devices to complete the verification.

[0103] 3. Use a digital multimeter to measure and record the output voltage values of the two devices to verify their accuracy.

[0104] 4. Operate the two devices and record the convenience during the operation process.

[0105] 5. Repeat the above steps to ensure the reliability of the data.

[0106] Experimental data:

[0107] 1. Verification efficiency:

[0108] The device of the present invention: Verifies 4 channels at a time, with each channel taking 2 seconds.

[0109] Traditional device: Single-channel verification, with each channel taking 8 seconds.

[0110] 2. The verification accuracy is measured by the stability of the output voltage:

[0111] The device of the present invention: The output voltage fluctuation is less than 0.005% FS.

[0112] Traditional device: The output voltage fluctuation is about 0.01% FS.

[0113] 3. Ease of use:

[0114] The device of the present invention: Has intuitive indicator lights and a display, and is easy to operate.

[0115] Traditional device: Lacks intuitive indication and is relatively complex to operate.

[0116] Analysis of experimental results:

[0117] It can be seen from the experimental data that the calibration device for thermal resistance modules of the present invention is significantly higher than the traditional single-channel device in terms of calibration efficiency, and can complete the calibration work of multiple channels in a shorter time. In terms of accuracy, the voltage output stability of the device of the present invention is also better than that of the traditional device. In addition, the ease of use of the device of the present invention has also been improved, and the operation is more convenient.

[0118] In summary, the calibration device for thermal resistance modules of the present invention performs excellently in terms of efficiency, accuracy, and ease of use, can effectively improve the calibration work efficiency and accuracy of thermal resistance modules, reduce the operation difficulty at the same time, and has high practical value.

[0119] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above respective embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or substitution to the present invention; and all technical solutions and their improvements that do not deviate from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. A thermal resistor module calibration device, comprising a resistor box (5) and a precision resistor (1), characterized in that: The precision resistor (1) is connected to a channel to be calibrated of a multi-channel thermal resistor input module, and generates a voltage via a constant current source configured in the multi-channel thermal resistor input module itself; the current range of the constant current source is 0.1 mA to 10 mA, and the constant current source module is provided with a reference voltage source, a shunt, and an error amplifier, and the error amplifier compares the voltage drop on the current detection element with the reference voltage to generate an error signal; The multi-channel thermal resistor input module is connected to a voltage sampling module (2), the voltage sampling module (2) is used to collect a sampled voltage on the precision resistor (1), the sampling accuracy of the voltage sampling module (2) is 16-bit ADC, and the sampling rate is 1000 SPS, the voltage sampling module (2) is connected to a microprocessing module (3), the microprocessing module (3) is used to obtain a constant current value of the constant current source based on the sampled voltage and the precision resistor (1), and calculate a voltage value corresponding to the thermal resistor to be output based on the constant current value and the thermal resistor to be output; The microprocessing module (3) adopts a microcontroller or a DSP processor. The microprocessing module (3) is connected to a voltage output module (4). The output accuracy of the voltage output module (4) is 0.01% FS. The voltage output module (4) is used to output the voltage value to the multi-channel thermal resistance input module.

2. A thermal resistance module calibration device according to claim 1, characterized in that: A plurality of groups of thermistors (6) are installed in the resistance box (5), and a calibration input port (7) and a voltage output port (8) are arranged on the front side of the resistance box (5), wherein the calibration input port (7) and the voltage output port (8) adopt RS-232, RS-485, USB or Ethernet interfaces.

3. A thermal resistance module calibration device according to claim 2, characterized in that: The microprocessor module (3) is connected to a verification control button (10) circuit, a power control button (9) is provided on the side of the resistor box (5), and the power control button (9) is connected to a battery circuit provided in the resistor box (5).

4. A thermal resistance module calibration device according to claim 3, characterized in that: The resistance box (5) is provided with an indicator light assembly (11), the indicator light assembly (11) comprising a verification operation indicator light (1101), a qualified indicator light (1102) is provided on the right side of the verification operation indicator light (1101), and an alarm indicator light (1103) is provided on the right side of the qualified indicator light (1102).

5. A thermal resistance module calibration device according to claim 4, characterized in that: The microprocessing module (3) is connected to the circuit of the verification data display (12), and the verification data display (12) is connected to the circuit of the microprocessing module (3).

6. A thermal resistance module calibration device according to claim 5, characterized in that: The output range of the voltage output module (4) is 0-5V, the output accuracy is 0.005% FS, and the load capacity is ≥10mA.

7. A thermal resistance module calibration device according to claim 6, characterized in that: The multi-channel thermal resistor input module has 4 channels, 8 channels, 10 channels, and 12 channels.

8. A thermal resistance module calibration device according to claim 7, characterized in that: The target verification R of the microprocessing module (3) check The voltage value formula is: The two known resistances and voltages are (R1, V1) and (R2, V2), R check is the preset thermal resistance value to be output, that is, the target calibration value, and R1 <R check <R2。 9. A thermal resistance module calibration device according to claim 8, characterized in that: A calibration circuit board (13) is arranged inside the resistance box (5), a PID temperature controller (14) is arranged on the calibration circuit board (13), the PID temperature controller (14) is connected to a microprocessor unit MCU (15) circuit, and the microprocessor unit MCU (15) is connected to a low-pass filter (16) circuit.

10. A thermal resistance module calibration device according to claim 9, characterized in that: A circuit connection copper sheet (17) is provided on the back side of the verification circuit board (13), and the circuit connection copper sheet (17) connects the PID temperature controller (14), the microprocessor unit MCU (15) and the low-pass filter (16).

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