Temperature Acquisition System and Its Intelligent Diagnosis Method

Abstract

The present invention provides a temperature acquisition system and an intelligent diagnosis method thereof. The temperature acquisition system includes: a diagnosis control circuit, a constant current source circuit, a temperature sensor, an interface connection circuit, and a temperature acquisition circuit. The interface connection circuit is connected to the temperature sensor, the constant current source circuit, and the diagnosis control circuit. The constant current source circuit and the temperature acquisition circuit are also connected to the diagnosis control circuit. The constant current source circuit is used to provide a constant current source to the temperature sensor through the interface connection circuit. The temperature acquisition circuit is used to collect the measured voltage value of the temperature sensor through the interface connection circuit and transmit it to the diagnosis control circuit. The diagnosis control circuit controls the connection of the interface connection circuit and is used to perform intelligent diagnosis based on the voltage value across the first resistor and the measured voltage value and obtain temperature data. The present invention can improve the accuracy of temperature detection, prevent false alarms, has high safety, and low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature detection, and particularly relates to a temperature acquisition system and an intelligent diagnosis method thereof. Background Art

[0002] The temperature of a device is an important indicator reflecting the performance of the device. With the continuous development of industry, the temperature measurement range is getting wider and the accuracy requirement is getting higher. In vehicle equipment, in order to ensure the normal and stable operation of the vehicle system, real-time detection of the temperature of vehicle equipment is an important indicator reflecting the safety condition of the vehicle. The vehicle temperature acquisition device includes motor stator temperature acquisition, axle box temperature acquisition, and gearbox temperature acquisition. Improving the resolution and accuracy of temperature acquisition can effectively improve the service life and safety of the equipment.

[0003] In the prior art, temperature acquisition mostly adopts a discrete device solution, including a reference current source, temperature acquisition, temperature reception, and control circuits. However, the signal chain is relatively long, there are many devices, the external environment interference is large, and some devices may fail, inevitably resulting in misjudgment and misoperation. For the integrated device solution, some current analog-to-digital converters (ADCs) currently have an adjustable constant current source output, and various temperature acquisitions are supported externally. However, the device cost is high, the number of channels supported by the integrated chip is small, and channel switching will extend the acquisition cycle, which is not practical for mass-produced products. Summary of the Invention

[0004] The present invention provides a temperature acquisition system and an intelligent diagnosis method thereof to solve the problems that there are many existing temperature acquisition devices, prone to misjudgment and misoperation, and high cost.

[0005] Based on the above object, an embodiment of the present invention provides a temperature acquisition system, including: a diagnosis control circuit, a constant current source circuit, a temperature sensor, an interface connection circuit, and a temperature acquisition circuit; the interface connection circuit is connected to the temperature sensor, the constant current source circuit, and the diagnosis control circuit, and the constant current source circuit and the temperature acquisition circuit are also connected to the diagnosis control circuit; the diagnosis control circuit controls the connection of the interface connection circuit, the constant current source circuit provides a constant current source to the temperature sensor through the interface connection circuit, the interface connection circuit at least includes a first resistor grounded, the temperature acquisition circuit acquires the measured voltage value of the temperature sensor through the interface connection circuit and transmits it to the diagnosis control circuit, and the diagnosis control circuit performs intelligent diagnosis according to the voltage value across the first resistor and the measured voltage value and obtains temperature data.

[0006] Optionally, the interface connection circuit further includes: a first switch, a second switch, and a second resistor. The constant current source circuit is connected to the temperature sensor by connecting the series-connected first switch and the second resistor. The second switch is connected in parallel with the input end of the temperature acquisition circuit. One end of the first resistor is connected to the temperature sensor, and the other end is grounded.

[0007] Optionally, the interface connection circuit further includes: a first diode, a second diode, a third diode, and a fourth diode; the cathode of the first diode is connected between the first resistor and the temperature sensor, the cathode of the second diode is connected between the second resistor and the temperature sensor, the cathode of the third diode is connected to the first end of the second switch, the cathode of the fourth diode is connected to the second end of the second switch, and the anodes of the first diode, the second diode, the third diode, and the fourth diode are grounded.

[0008] Optionally, the temperature acquisition circuit includes: a third resistor, a fourth resistor, a first capacitor, a second capacitor, and a third capacitor; the temperature sensor includes at least a first interface and a second interface; the first end of the third resistor is connected to the first interface, the second end of the third resistor is connected to the diagnostic control circuit and grounded through the second capacitor; the first end of the fourth resistor is connected to the second interface, the second end of the fourth resistor is connected to the diagnostic control circuit and grounded through the third capacitor; a first capacitor is connected between the second end of the third resistor and the second end of the fourth resistor.

[0009] Optionally, the temperature acquisition circuit further includes a first inductor and a second inductor. The first inductor is connected in series between the third resistor and the first interface, and the second inductor is connected in series between the fourth resistor and the second interface.

[0010] Optionally, the constant current source circuit includes: an operational amplifier, a buffer, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; the inverting input terminal of the operational amplifier is grounded through the fifth resistor and connected to the output terminal of the operational amplifier through the seventh resistor. The non-inverting input terminal of the operational amplifier is connected to a voltage source through the sixth resistor and connected to the output terminal of the buffer through the eighth resistor. The output terminal of the operational amplifier is connected to one end of the ninth resistor, and the other end of the ninth resistor serves as the output terminal of the constant current source circuit. The input terminal of the buffer is connected to the other end of the ninth resistor.

[0011] Optionally, the temperature acquisition system further includes a constant current source diagnostic circuit. The input terminal of the constant current source diagnostic circuit is connected in parallel across the two ends of the ninth resistor, and the output terminal of the constant current source diagnostic circuit is connected to the diagnostic control circuit.

[0012] Based on the same inventive concept, an embodiment of the present invention further provides an intelligent diagnosis method for a temperature acquisition system, including: obtaining a measured voltage value of a temperature sensor collected by a temperature acquisition circuit; detecting whether the interface connection circuit and the temperature acquisition circuit are abnormal according to the voltage value across the grounding resistor in the interface connection circuit and the measured voltage value; and obtaining temperature data according to the measured voltage value when it is detected that the voltage value across the grounding resistor and the measured voltage value are normal.

[0013] Optionally, detecting whether the interface connection circuit and the temperature acquisition circuit are abnormal according to the voltage value across the grounding resistor in the interface connection circuit and the measured voltage value includes: if the voltage value across the grounding resistor and the measured voltage value are normal, determining that the interface connection circuit and the temperature acquisition circuit are normal; if the voltage value across the grounding resistor is normal and the measured voltage value is 0, determining that the temperature acquisition circuit is short-circuited; if the voltage value across the grounding resistor is normal and the measured voltage value is abnormal, determining that the temperature acquisition circuit is open-circuited; and if the voltage values across the grounding resistor and the measured voltage value are both abnormal, determining that the temperature acquisition circuit and the interface connection circuit are simultaneously short-circuited or open-circuited.

[0014] Optionally, the intelligent diagnosis method further includes: performing multiple temperature acquisitions using the temperature acquisition circuit to obtain corresponding multiple temperature data; removing deviation data from the multiple temperature data, and filtering out abnormal temperature data using a hold filter algorithm; and performing smoothing filtering on the remaining multiple temperature data to obtain final temperature data.

[0015] The beneficial effects of the present invention are as follows. As can be seen from the above description, a temperature acquisition system and its intelligent diagnosis method provided by an embodiment of the present invention, the temperature acquisition system includes: a diagnosis control circuit, a constant current source circuit, a temperature sensor, an interface connection circuit, and a temperature acquisition circuit; the interface connection circuit is connected to the temperature sensor, the constant current source circuit, and the diagnosis control circuit, and the constant current source circuit and the temperature acquisition circuit are connected to the diagnosis control circuit; the diagnosis control circuit controls the connection of the interface connection circuit, the constant current source circuit provides a constant current source to the temperature sensor through the interface connection circuit, the interface connection circuit at least includes a first resistor grounded, the temperature acquisition circuit acquires the measured voltage value of the temperature sensor through the interface connection circuit and transmits it to the diagnosis control circuit, and the diagnosis control circuit performs intelligent diagnosis based on the voltage value across the first resistor and the measured voltage value and obtains temperature data, which can improve the accuracy of temperature detection, achieve error-free output of the temperature acquisition device, and at the same time effectively solve some misjudgments and misoperations in the temperature acquisition process, improve the reliability and safety of the system and equipment, have a low cost, and also enhance the economy of the system and equipment and the practicality of interface generality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic structural diagram of the temperature acquisition system in the embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the specific circuit structure of the constant current source circuit in the embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of the specific circuit structure of the four-wire interface connection of the temperature acquisition circuit in the embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of the system calibration process in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions, and advantages of the present disclosure clearer and more understandable, the following will further describe the present disclosure in detail with reference to specific embodiments and the accompanying drawings.

[0022] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second" and similar terms used in the embodiments of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] An embodiment of the present invention provides a temperature acquisition system. As Figure 1 shown, the temperature acquisition system includes: a diagnostic control circuit 11, a constant current source circuit 12, a temperature sensor 13, an interface connection circuit 14, and a temperature acquisition circuit 15. The interface connection circuit 14 is connected to the temperature sensor 13, the constant current source circuit 12, and the diagnostic control circuit 11. The constant current source circuit 12 and the temperature acquisition circuit 15 are also connected to the diagnostic control circuit 11. The diagnostic control circuit 11 controls the connection of the interface connection circuit 14. The constant current source circuit 12 provides a constant current source to the temperature sensor 13 through the interface connection circuit 14. The interface connection circuit 14 at least includes a first resistor R1 grounded. The temperature acquisition circuit 15 acquires the measured voltage value of the temperature sensor 13 through the interface connection circuit 14 and transmits it to the diagnostic control circuit 11. The diagnostic control circuit 11 performs intelligent diagnosis based on the voltage value across the first resistor R1 and the measured voltage value and obtains temperature data. Among them, one end of the first resistor R1 is connected to the temperature sensor 13, and the other end is grounded to GND.

[0024] The constant current source circuit 12 is used to provide a constant current source to the subsequent temperature sensor 13 through the interface connection circuit 14. The circuit configuration is as Figure 2As shown, the constant current source circuit 12 includes: an operational amplifier N1, a buffer N2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9; the inverting input terminal of the operational amplifier N1 is grounded through the fifth resistor R5 and connected to the output terminal of the operational amplifier N1 through the seventh resistor R7, the non-inverting input terminal of the operational amplifier N1 is connected to a voltage source through the sixth resistor R6 and connected to the output terminal of the buffer N2 through the eighth resistor R8, the output terminal of the operational amplifier N1 is connected to one end of the ninth resistor R9, the other end of the ninth resistor R9 serves as the output terminal of the constant current source circuit, and the input terminal of the buffer N2 is connected to the other end of the ninth resistor R9.

[0025] The constant current source circuit 12 here is different from the traditional Howland constant current source. In the Howland constant current source, the inverting input terminal of the operational amplifier N1 is grounded through the fifth resistor R5 and at the same time connected to the output terminal of the operational amplifier N1 through the seventh resistor R7; the non-inverting input terminal of the operational amplifier N1 is connected to a voltage source through the sixth resistor R6 and directly connected to the output terminal through the eighth resistor R8. In the Howland constant current source, when the eighth resistor R8 is large enough, a constant current can be output, but if the eighth resistor R8 is too large, the circuit speed will be reduced, and there is current flowing into the non-inverting input terminal of the operational amplifier N1 at the output terminal, which will cause a certain error. In the embodiment of the present invention, by connecting an inverter or a buffer N2 in series behind the eighth resistor R8, it can be ensured that all the current flows backward to the temperature sensor PTC as the load. The output current of the constant current source circuit in the embodiment of the present invention is only controlled by the input voltage provided by the voltage source, and it is an ideal constant current source circuit.

[0026] If R8 / R6 = R7 / R5 = k, then the output current of the constant current source circuit 12 is:

[0027]

[0028] The temperature acquisition system further includes a constant current source diagnostic circuit 16. The input end of the constant current source diagnostic circuit 16 is connected in parallel across both ends of the ninth resistor R9, and the output end of the constant current source diagnostic circuit 16 is connected to the diagnostic control circuit 16. When current flows normally through the temperature sensor 13, there is a voltage V across both ends of the ninth resistor R9, and V = *R9. The constant current source circuit 12 can be specifically designed according to the actual current source parameters. To prevent leakage current from causing problems with the acquisition accuracy, the backend of the constant current source circuit 12 needs to be set to high impedance. The diagnostic control circuit 11 also calculates the current value flowing across both ends of the ninth resistor R9 based on the voltage across both ends of the ninth resistor R9 collected by the constant current source diagnostic circuit 16 and compares it with the designed value for actual application. Through multiple samplings, an accurate current error coefficient is obtained, and the measured voltage value of the temperature sensor 13 collected by the temperature acquisition circuit 15 is calculated according to this current error coefficient, and finally the temperature data of the temperature sensor 13 is obtained, improving the detection accuracy. If the diagnostic shows that the constant current source value is too high and exceeds the range, the diagnostic value is inaccurate, and a fault alarm can be set for indication. The current output by the constant current source circuit 12 flows backward into the interface connection circuit 14 and the temperature sensor 13 to facilitate temperature acquisition.

[0029] In the embodiment of the present invention, the temperature sensor 13 is preferably a positive temperature coefficient (PTC) thermistor. Of course, the temperature sensor 13 can also be a negative temperature coefficient thermistor NTC. The external wiring method of the temperature sensor 13 has two-wire system, three-wire system and four-wire system. Hereinafter, the four-wire system will be taken as an example for illustration. The temperature sensor 13 includes a total of 4 interfaces, namely a first interface 1, a second interface 2, a third interface 3 and a fourth interface 4.

[0030] Such as Figure 3As shown, the interface connection circuit 14 further includes: a first switch K1, a second switch K2, and a second resistor R2. The constant current source circuit 12 is connected to the temperature sensor 13 by connecting the series-connected first switch K1 and the second resistor R2 in series. The second switch K2 is connected in parallel with the input end of the temperature acquisition circuit 15. One end of the first resistor R1 is connected to the temperature sensor 13, and the other end is grounded to GND. Specifically, both ends of the second switch K2 are respectively connected to the first interface 1 and the second interface 2 of the temperature sensor 13. The first resistor R1 is connected to the fourth interface 4 of the temperature sensor 13. One end of the second resistor R2 is connected to the third interface 3 of the temperature sensor 13. The first switch K1 is used to control the input of the constant current source circuit 12; the second switch K2 is used to control the opening and closing of the temperature acquisition channel. Connecting the second resistor R2 in series can provide overcurrent protection to prevent the internal circuit from being burned due to excessive external interference; the first resistor R1 is grounded to GND to form a current loop. Under normal circumstances, the first switch K1 is closed and the second switch K2 is open for normal temperature acquisition; during self-check, the first switch K1 is open and the second switch K2 is closed, disconnecting the output of the constant current source circuit 12, sending the power supply VCC to the acquisition channel, closing the acquisition channel, and performing self-check on the interface connection circuit 14. The VCC voltage range can be adjusted according to the acquisition range of the backend. The first switch K1 and the second switch K2 can be adjusted according to actual applications, and analog switches or relays can be selected.

[0031] The interface connection circuit 14 further includes: a first diode V1, a second diode V2, a third diode V3, and a fourth diode V4; the cathode of the first diode V1 is connected between the second resistor R2 and the temperature sensor 13, the cathode of the second diode V2 is connected between the first resistor R1 and the temperature sensor 13, the cathode of the third diode V3 is connected to the first end of the second switch K2, the cathode of the fourth diode V4 is connected to the second end of the second switch K2, and the anodes of the first diode V1, the second diode V2, the third diode V3, and the fourth diode V4 are grounded. The first diode V1, the second diode V2, the third diode V3, and the fourth diode V4 all play a role in surge protection. To prevent errors caused by excessive leakage current, the clamping voltage value cannot be too small.

[0032] Continue to refer to Figure 3, the temperature acquisition circuit 15 includes: a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and a third capacitor C3. The temperature sensor 13 includes at least a first interface 1 and a second interface 2; a first end of the third resistor R3 is connected to the first interface 1, a second end of the third resistor R3 is connected to the diagnostic control circuit 11, and is grounded to GND through the second capacitor C2; a first end of the fourth resistor R4 is connected to the second interface 2, a second end of the fourth resistor R4 is connected to the diagnostic control circuit 11, and is grounded to GND through the third capacitor C3; a first capacitor C1 is connected between the second end of the third resistor R3 and the second end of the fourth resistor R4. The cathode of the third diode V3 and the first end of the second switch K2 are connected to the first interface 1 of the temperature sensor 13, and the cathode of the fourth diode V4 and the second end of the second switch K2 are connected to the second interface 2 of the temperature sensor 13. The third resistor R3, the fourth resistor R4, the first capacitor C1, the second capacitor C2, and the third capacitor C3 together form an RC filter circuit: the third resistor R3, the fourth resistor R4, the second capacitor C2, and the third capacitor C3 therein perform common-mode interference filtering; the third resistor R3, the fourth resistor R4, the first capacitor C1, the second capacitor C2, and the third capacitor C3 perform differential-mode interference filtering, and the specific bandwidth can be adjusted according to the actual application of the backend.

[0033] The temperature acquisition circuit 15 further includes a first inductor L1 and a second inductor L2. The first inductor L1 is connected in series between the third resistor R3 and the first interface 1, and the second inductor L2 is connected in series between the fourth resistor R4 and the second interface 2. The first inductor L1 and the second inductor L2 can play a role in suppressing high-frequency interference.

[0034] For other wire systems, some circuit interfaces can be combined in the case of a four-wire system. For example, in a two-wire system, the third interface 3 and the first interface 1 of the temperature sensor 13 in the four-wire system can be connected together, that is, one end of the second resistor R2 and the first end of the second switch K2 share an interface; the second interface 2 and the fourth interface 4 are connected together, that is, the second end of the second switch K2 and one end of the first resistor R1 share an interface. For a three-wire system, only the first interface 1 and the third interface 3 of the temperature sensor 13 in the four-wire system need to be connected together.

[0035] The temperature acquisition system according to an embodiment of the present invention includes: a diagnostic control circuit 11, a constant current source circuit 12, a temperature sensor 13, an interface connection circuit 14, and a temperature acquisition circuit 15; the interface connection circuit 14 is connected to the temperature sensor 13, the constant current source circuit 12, and the diagnostic control circuit 11, and the constant current source circuit 12 and the temperature acquisition circuit 15 are also connected to the diagnostic control circuit 11; the diagnostic control circuit 11 controls the connection of the interface connection circuit 14, the constant current source circuit 12 provides a constant current source to the temperature sensor 13 through the interface connection circuit 14, the interface connection circuit 14 at least includes a first resistor R1 grounded, the temperature acquisition circuit 15 acquires the measured voltage value of the temperature sensor 13 through the interface connection circuit 14 and transmits it to the diagnostic control circuit 11, and the diagnostic control circuit 11 performs intelligent diagnosis based on the voltage value across the first resistor R1 and the measured voltage value and obtains temperature data, which can improve the accuracy of temperature detection, achieve error-free output of the temperature acquisition device, effectively solve some misjudgments and misoperations in the temperature acquisition process, improve the reliability and safety of the system and equipment, have a low cost, and also enhance the economy of the system and equipment and the practicality of interface generality.

[0036] Based on the same inventive concept, an embodiment of the present invention further provides an intelligent diagnosis method for a temperature acquisition system, which is applied to the aforementioned diagnostic control circuit 11, as Figure 4 shown, and includes:

[0037] Step S11: Obtain the measured voltage value of the temperature sensor 13 acquired by the temperature acquisition circuit 15.

[0038] Taking the temperature sensor 13 as a thermistor as an example, when the temperature acquisition system performs normal temperature acquisition, the constant current source circuit 12 outputs current to the temperature sensor 13 and is grounded to GND through the first resistor R1 to form a current loop. The thermistor generates heat and its resistance value changes accordingly. The measured voltage value across the thermistor is acquired by the temperature acquisition circuit 15 and transmitted to the diagnostic control circuit 11, and the diagnostic control circuit 11 obtains this measured voltage value.

[0039] Step S12: Detect whether the interface connection circuit 14 and the temperature acquisition circuit 15 are abnormal according to the voltage value across the grounding resistor in the interface connection circuit 14 and the measured voltage value.

[0040] The grounding resistance is the aforementioned first resistor R1. In the embodiment of the present invention, if only the wiring of the temperature acquisition circuit 15 is disconnected, the voltage value across the grounding resistance in the current loop of the constant current source circuit 12 is normal, and the measured voltage value of the temperature sensor 13 is abnormal; if the wiring of the constant current source circuit 12 is disconnected or the wiring of the constant current source circuit 12 and the wiring of the temperature acquisition circuit 15 are disconnected simultaneously, both the measured voltage value of the temperature sensor 13 and the voltage value across the grounding resistance in the current loop of the constant current source circuit 12 are abnormal. If the wiring of the temperature acquisition circuit 15 is short-circuited, the resistance value of the temperature sensor 13 acquired is 0, that is, the measured voltage value of the temperature sensor 13 is 0. At this time, the voltage value across the grounding resistance in the current loop of the constant current source circuit 12 is normal, and the measured voltage value of the temperature sensor 13 is abnormal. If the wiring of the constant current source circuit 12 is short-circuited or the wiring of the constant current source circuit 12 and the wiring of the temperature acquisition circuit 15 are short-circuited simultaneously, no current flows through the temperature sensor 13. At this time, both the measured voltage value of the temperature sensor 13 and the voltage value across the grounding resistance in the current loop of the constant current source circuit 12 are abnormal. In practical applications, the disconnection and short-circuit states are not distinguished, and it can be judged by whether the minimum resistance value of the temperature sensor 13 is exceeded.

[0041] Therefore, in step S12, if the voltage value across the grounding resistance and the measured voltage value are normal, it is determined that the interface connection circuit 14 and the temperature acquisition circuit 15 are normal; if the voltage value across the grounding resistance is normal and the measured voltage value is 0, it is determined that the temperature acquisition circuit 15 is short-circuited; if the voltage value across the grounding resistance is normal and the measured voltage value is abnormal, it is determined that the temperature acquisition circuit 15 is open-circuited; if both the voltage value across the grounding resistance and the measured voltage value are abnormal, it is determined that there is a simultaneous short-circuit or open-circuit fault in the temperature acquisition circuit 15 and the interface connection circuit 14.

[0042] When the measured voltage value of the temperature sensor measured by the temperature acquisition circuit 15 has a large difference compared with the normal value, in the case of multi-channel applications, a multiplexer can be selected to switch the output of the constant current source circuit, and the current loop can be re-detected for faults.

[0043] Step S13: When it is detected that the voltage value across the grounding resistance and the measured voltage value are normal, obtain temperature data according to the measured voltage value.

[0044] To avoid poor contact caused by external environmental interference, train jitter, or other actions, or false triggering caused by other actions, the embodiments of the present invention also introduce a software calibration function. Optionally, the temperature acquisition circuit is used to perform multiple temperature acquisitions to obtain a corresponding plurality of temperature data; deviation data is removed from the plurality of temperature data, and the abnormal temperature data is filtered using a hold filter algorithm; the remaining plurality of temperature data is smoothed to obtain the final temperature data. That is, multiple filtering processes are required during the temperature acquisition calculation: first, the temperature is acquired multiple times according to the actual sampling period, then the deviation values are removed according to the number of samples, generally based on the maximum and minimum values, and finally, the average sampling value is calculated according to the remaining number of samples. In some cases with large interference, a sampling hold filter algorithm is also introduced, that is, the previous sampling value and the current sampling value are balanced according to a coefficient to avoid false alarms triggered by large interference in a short period. The embodiments of the present invention also introduce constant current source calibration. In a multi-channel application scenario, a multiplexer can be selected to switch the output of the constant current source circuit to improve the board integration and reduce the system cost. At this time, the calibration and control of the constant current source are crucial. Constant current source calibration introduces system calibration on the constant current source diagnostic circuit. By collecting the voltage across the ninth resistor R9, which is the output conditioning resistor of the constant current source, the current value flowing through both ends of the ninth resistor R9 is calculated and compared with the actual application design value. Through multiple samplings, an accurate current error coefficient is obtained and introduced into the calculation of the subsequent temperature acquisition to improve the detection accuracy. If the deviation is large, it is necessary to re-detect whether there is a fault in the current loop.

[0045] The above describes specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0046] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the concept of the present disclosure, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments of the present application as described above. For the sake of brevity, they are not provided in detail.

[0047] One or more embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application shall be included within the scope of protection of the present disclosure.

Claims

1. A temperature acquisition system, characterized in that, The temperature acquisition system includes: a diagnostic control circuit, a constant current source circuit, a temperature sensor, an interface connection circuit, and a temperature acquisition circuit; the interface connection circuit is connected to the temperature sensor, the constant current source circuit, and the diagnostic control circuit, and the constant current source circuit and the temperature acquisition circuit are also connected to the diagnostic control circuit; the diagnostic control circuit controls the connection of the interface connection circuit, the constant current source circuit provides a constant current source to the temperature sensor through the interface connection circuit, the interface connection circuit at least includes a first resistor grounded, the temperature acquisition circuit acquires the measured voltage value of the temperature sensor through the interface connection circuit and transmits it to the diagnostic control circuit, and the diagnostic control circuit performs intelligent diagnosis based on the voltage value across the first resistor and the measured voltage value and obtains temperature data; The interface connection circuit further includes: a first switch, a second switch, and a second resistor, and the temperature acquisition circuit includes: a third resistor, a fourth resistor, a first capacitor, a second capacitor, and a third capacitor, and the temperature sensor at least includes a first interface and a second interface; The temperature acquisition circuit further includes a first inductor and a second inductor, the first inductor is connected in series between the third resistor and the first interface, and the second inductor is connected in series between the fourth resistor and the second interface; The third resistor, the fourth resistor, the first capacitor, the second capacitor, and the third capacitor together form an RC filter circuit: among them, the third resistor, the fourth resistor, the second capacitor, and the third capacitor perform common-mode interference filtering; For other wiring systems, some line interfaces can be combined in the four-wire system. In the two-wire system, the third interface and the first interface of the temperature sensor in the four-wire system can be connected together, that is, one end of the second resistor and the first end of the second switch share an interface; the second interface and the fourth interface are connected together, that is, the second end of the second switch and one end of the first resistor share an interface. In the three-wire system, only the first interface and the third interface of the temperature sensor in the four-wire system need to be connected together; The constant current source circuit includes: an operational amplifier, a buffer, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; the inverting input terminal of the operational amplifier is grounded through the fifth resistor and connected to the output terminal of the operational amplifier through the seventh resistor, the non-inverting input terminal of the operational amplifier is connected to a voltage source through the sixth resistor and connected to the output terminal of the buffer through the eighth resistor, the output terminal of the operational amplifier is connected to one end of the ninth resistor, the other end of the ninth resistor serves as the output terminal of the constant current source circuit, and the input terminal of the buffer is connected to the other end of the ninth resistor.

2. The temperature acquisition system according to claim 1, characterized in that, The constant current source circuit is connected to the temperature sensor by connecting the series-connected first switch and the second resistor in series, the second switch is connected in parallel with the input terminal of the temperature acquisition circuit, and one end of the first resistor is connected to the temperature sensor and the other end is grounded.

3. The temperature acquisition system according to claim 2, characterized in that, The interface connection circuit further includes: a first diode, a second diode, a third diode, and a fourth diode; the cathode of the first diode is connected between the second resistor and the temperature sensor, the cathode of the second diode is connected between the first resistor and the temperature sensor, the cathode of the third diode is connected to the first end of the second switch, the cathode of the fourth diode is connected to the second end of the second switch, and the anodes of the first diode, the second diode, the third diode, and the fourth diode are grounded.

4. The temperature acquisition system according to claim 1, characterized in that, The first end of the third resistor is connected to the first interface, the second end of the third resistor is connected to the diagnostic control circuit and grounded through the second capacitor; the first end of the fourth resistor is connected to the second interface, the second end of the fourth resistor is connected to the diagnostic control circuit and grounded through the third capacitor; a first capacitor is connected between the second end of the third resistor and the second end of the fourth resistor.

5. An intelligent diagnosis method for a temperature acquisition system according to any one of claims 1-4, characterized in that, The method includes: Obtaining the measured voltage value of the temperature sensor collected by the temperature acquisition circuit; Detecting whether the interface connection circuit and the temperature acquisition circuit are abnormal according to the voltage value across the grounding resistor in the interface connection circuit and the measured voltage value; Obtaining temperature data according to the measured voltage value when it is detected that the voltage value across the grounding resistor and the measured voltage value are normal.

6. The intelligent diagnosis method for a temperature acquisition system according to claim 5, characterized in that, The detecting whether the interface connection circuit and the temperature acquisition circuit are abnormal according to the voltage value across the grounding resistor in the interface connection circuit and the measured voltage value includes: If the voltage value across the grounding resistor and the measured voltage value are normal, determining that the interface connection circuit and the temperature acquisition circuit are normal; If the voltage value across the grounding resistor is normal and the measured voltage value is 0, determining that the temperature acquisition circuit is short-circuited; If the voltage value across the grounding resistor is normal and the measured voltage value is abnormal, determining that the temperature acquisition circuit is open-circuited; If the voltage values across the grounding resistor and the measured voltage value are both abnormal, determining that the temperature acquisition circuit and the interface connection circuit have simultaneous short-circuit or open-circuit faults.

7. The intelligent diagnosis method for a temperature acquisition system according to claim 5, characterized in that, The method further includes: Performing multiple temperature acquisitions using the temperature acquisition circuit to obtain corresponding multiple temperature data; Eliminating deviation data from the multiple temperature data and filtering out abnormal temperature data using a hold filtering algorithm; Performing smoothing filtering on the remaining multiple temperature data to obtain the final temperature data.

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