Temperature acquisition device and method based on multichannel PT100 thermal resistance measurement

Abstract

The invention provides a temperature acquisition device and method based on multichannel PT100 thermal resistance measurement, and belongs to the technical field of temperature acquisition, and the device comprises: each conditioning module is used for forming a Wheatstone bridge with a corresponding PT thermal resistor so as to measure the resistance value of the PT thermal resistor and output a voltage signal; each switch module is used for connecting the corresponding conditioning module with the ADC sampling module when the switch module is switched on and disconnecting the corresponding conditioning module with the ADC sampling module when the switch module is switched off; the ADC sampling module is used for collecting the voltage signals output by the conditioning modules and preprocessing the voltage signals; the control module is used for controlling the switch-on or switch-off of each switch module in a polling scanning mode and calculating the environment temperature; and one switch module is in a conducting state at the same moment. According to the scheme of the invention, the efficiency and accuracy of temperature acquisition of multi-channel PT thermal resistance measurement can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of temperature acquisition, and in particular to a temperature acquisition device and method based on multi-channel PT thermal resistance measurement. Background Art

[0002] In the industrial production process, temperature is one of the important parameters that need to be measured and controlled. In temperature measurement, PT (Platinum) thermal resistors are widely used. They do not require external power supply and are easy to use. They have the advantages of simple structure, easy production, wide measurement range, high accuracy and convenient remote transmission of output signals.

[0003] In the production process of nuclear power, thermal power and other power plants, there are many points that need to measure and control temperature, and there is a great demand for temperature acquisition devices that measure multi-channel PT thermal resistors. Existing devices generally use a design of 1 PT thermal resistor + 1 ADC (Analog-to-Digital Converter) chip. Multi-channel PT resistance measurement devices require the use of multiple ADC chips, and the efficiency and accuracy of temperature acquisition are low.

[0004] Therefore, how to improve the efficiency and accuracy of temperature acquisition of multi-channel PT thermal resistor measurement has become a problem to be solved. Summary of the invention

[0005] The purpose of the present application is to provide a temperature acquisition device and method based on multi-channel PT thermal resistor measurement, which can solve the problem of low efficiency and accuracy of temperature acquisition of multi-channel PT thermal resistor measurement in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a temperature acquisition device based on multi-channel PT thermal resistor measurement, connected to at least one PT thermal resistor, the device comprising: at least one conditioning module, at least one switch module, an ADC sampling module and a control module; Each conditioning module is used to form a Wheatstone bridge with a corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor and output a voltage signal; Each switch module is used to connect the corresponding conditioning module with the ADC sampling module when it is turned on, and disconnect the corresponding conditioning module from the ADC sampling module when it is turned off; ADC sampling module, used to collect the voltage signals output by each conditioning module and pre-process each voltage signal; The control module is used to control each switch module to be turned on or off in a polling scanning manner and calculate the ambient temperature; at the same time, one switch module is in the on state.

[0007] In a possible implementation manner of the first aspect, each conditioning module includes: a first resistor, a second resistor, and a third resistor; The first resistor, the second resistor and the third resistor are connected in series, the first end of the first resistor is connected to the first end of the PT thermal resistor and the first input end of the switch module, the series node of the first resistor and the second resistor is connected to the power supply voltage, the series node of the second resistor and the third resistor is connected to the second input end of the switch module, the first end of the third resistor is connected to the second end of the PT thermal resistor, and the third end of the PT thermal resistor is grounded.

[0008] In a possible implementation manner of the first aspect, each switch module includes an optical MOS relay switch; The first input end of the optical MOS relay switch is connected to the first output end of the conditioning module, the second input end of the optical MOS relay switch is connected to the second output end of the conditioning module, the first output end of the optical MOS relay switch is connected to the first input end of the ADC sampling module, and the second output end of the optical MOS relay switch is connected to the second input end of the ADC sampling module.

[0009] In a possible implementation of the first aspect, the ADC sampling module includes an instrumentation amplifier; The in-phase input terminal of the instrument amplifier is connected to the first output terminal of each switch module, the inverting input terminal of the instrument amplifier is connected to the second output terminal of each switch module, the output terminal of the instrument amplifier is connected to the input terminal of the control module, and the instrument amplifier is used to amplify the voltage signal output by each conditioning module.

[0010] In a possible implementation of the first aspect, the ADC sampling module also includes an A / D converter; the input end of the A / D converter is connected to the output end of the instrument amplifier, the output end of the A / D converter is connected to the input end of the control module, and the A / D converter is used to convert the amplified voltage signals into digital signals.

[0011] In a possible implementation of the first aspect, the ADC sampling module also includes a photoelectric isolator; the input end of the photoelectric isolator is connected to the output end of the A / D converter, and the output end of the photoelectric isolator is connected to the input end of the control module, and the photoelectric isolator is used to isolate the digital signal output by the A / D converter and the input signal of the control module.

[0012] In a second aspect, an embodiment of the present application provides a temperature acquisition system based on multi-channel PT thermal resistor measurement, the system comprising: a temperature acquisition device based on multi-channel PT thermal resistor measurement according to any one of the first aspects, a temperature collection node, and a host computer; A temperature collection device is used to collect temperature data and upload the collected multiple temperature data to the temperature collection node; The temperature collection node is used to collect multiple temperature data collected by the temperature collection device and forward the collected temperature data to the upper computer; The host computer is used to store and display the collected temperature data.

[0013] In a third aspect, an embodiment of the present application provides a temperature acquisition method based on multi-channel PT thermal resistor measurement, which is implemented based on a temperature acquisition device based on multi-channel PT thermal resistor measurement in any one of the first aspects, and the method includes: Based on each conditioning module, a Wheatstone bridge is formed with the corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor; Based on each switch module, when the switch module is turned on, the corresponding conditioning module is connected to the ADC sampling module, and when the switch module is turned off, the corresponding conditioning module is disconnected from the ADC sampling module; Based on the ADC sampling module, the voltage signals output by each conditioning module are collected, and each voltage signal is pre-processed; Based on the control module, each switch module is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal; at the same time, one switch module is in the on state.

[0014] In a possible implementation of the third aspect, the ADC sampling module includes an instrument amplifier, an A / D converter, and a photoelectric isolator; the voltage signals output by each conditioning module are collected based on the ADC sampling module, and each voltage signal is preprocessed, including: Based on the instrument amplifier, the voltage signals output by each conditioning module are collected and amplified; based on the A / D converter, the amplified voltage signals are converted into digital signals; based on the optoelectronic isolator, the digital signal output by the A / D converter and the input signal of the control module are isolated.

[0015] In a possible implementation of the third aspect, based on the control module, each switch module is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal, including: Based on the polling scanning mode of the control module, a switch module is controlled to be turned on at the same time, and the resistance value of each PT thermal resistor is calculated according to each voltage signal, and the corresponding ambient temperature is obtained by reverse calculation according to each resistance value.

[0016] In the present application scheme, each conditioning module and the corresponding PT thermal resistor form a Wheatstone bridge to measure the resistance value of the PT thermal resistor and output a voltage signal; each switch module connects the corresponding conditioning module to the ADC sampling module when turned on, and disconnects the corresponding conditioning module from the ADC sampling module when turned off; the ADC sampling module collects the voltage signals output by each conditioning module and pre-processes each voltage signal; the control module controls each switch module to be turned on or off in a polling scanning manner, and calculates the ambient temperature, and only one switch module is in the on state at the same time.

[0017] The present application does not require the use of multiple ADC sampling modules, but only requires one ADC sampling chip to collect the temperatures corresponding to multiple PT thermistors, thereby improving the efficiency and accuracy of temperature collection of multi-channel PT thermistor measurements, and has strong ease of use and practicality.

[0018] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a schematic block diagram of the overall structure of a temperature acquisition device 100 based on multi-channel PT thermal resistance measurement provided in an embodiment of the present application; Figure 2 is a schematic block diagram of the overall structure of an 8-channel temperature acquisition system provided in an embodiment of the present application; Figure 3 It is a schematic block diagram of the specific structure of the temperature acquisition device based on multi-channel PT thermal resistance measurement provided by an embodiment of the present application; Figure 4 It is a schematic block diagram of the overall structure of a temperature acquisition system based on multi-channel PT thermal resistance measurement provided by an embodiment of the present application; Figure 5 It is a schematic diagram of the steps of the temperature acquisition method based on multi-channel PT thermal resistance measurement provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0022] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0023] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0024] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0025] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0026] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0027] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0028] In the present application specification, unless otherwise specified, directional words such as "up, down, left, right" generally refer to the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of the application is usually placed when in use.

[0029] In the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] In the industrial production process, temperature is one of the important parameters that need to be measured and controlled. In temperature measurement, PT thermal resistors are widely used. No external power supply is required for measurement, and it is easy to use. It has the advantages of simple structure, easy production, wide measurement range, high accuracy, and convenient remote transmission of output signals.

[0031] PT100 is a platinum thermal resistor. The 100 after PT means that its resistance is 100Ω at 0℃ and about 138.5Ω at 100℃. The resistance value of PT100 will increase at an approximately uniform rate as the temperature rises. By measuring the resistance value of the thermal resistor, the corresponding temperature value can be calculated. Using this feature, a temperature acquisition device for multi-channel PT100 thermal resistor measurement can be designed.

[0032] In the production process of nuclear power, thermal power and other power plants, there are many points that need to measure and control temperature. The demand for temperature acquisition devices using multi-channel PT100 thermal resistors is very large. The manufacturing cost of existing devices is high and cannot meet project requirements.

[0033] PT100 thermal resistor is made of platinum material, and its resistance value is relatively high. Existing methods require an external current source, such as a constant current source circuit, for power supply compensation to ensure the accuracy of temperature measurement. However, the constant current source circuit is expensive, and the output accuracy of the constant current source circuit is greatly affected by the ambient temperature, and the stability is poor, which affects the accuracy and stability of PT100 thermal resistor measurement.

[0034] Existing devices generally adopt a design method of 1 PT100 thermal resistor + 1 ADC chip. A multi-channel PT100 resistance measurement device needs to use multiple ADC chips, which are expensive, resulting in a high overall manufacturing cost of the device. At the same time, the efficiency and accuracy of temperature acquisition are low. Therefore, how to improve the efficiency and accuracy of temperature acquisition of multi-channel PT thermal resistor measurement has become a problem to be solved.

[0035] In response to the above-mentioned defects, an embodiment of the present application provides a temperature acquisition device based on multi-channel PT thermistor measurement, wherein each conditioning module and the corresponding PT thermistor form a Wheatstone bridge to measure the resistance value of the PT thermistor and output a voltage signal; each switch module connects the corresponding conditioning module to the ADC sampling module when turned on, and disconnects the corresponding conditioning module from the ADC sampling module when turned off; the ADC sampling module acquires the voltage signals output by each conditioning module and pre-processes each voltage signal; the control module controls each switch module to be turned on or off in a polling scanning manner, and calculates the ambient temperature, and only one switch module is in the on state at the same time.

[0036] The present application does not require the use of multiple ADC sampling modules, but only requires one ADC sampling chip to collect the temperatures corresponding to multiple PT thermistors, thereby improving the efficiency and accuracy of temperature collection of multi-channel PT thermistor measurements, and has strong ease of use and practicality.

[0037] The overall structure of the temperature acquisition device based on multi-channel PT thermal resistance measurement provided by the embodiment of the present application is introduced below through specific embodiments.

[0038] See also Figure 1 , Figure 1 1 is a schematic block diagram of the overall structure of a temperature acquisition device 100 based on multi-channel PT thermal resistance measurement provided by an embodiment of the present application. Figure 1 As shown, the device 100 is connected to at least one PT thermal resistor, and the device 100 includes: at least one conditioning module (111~11n), at least one switch module (121~12n), an ADC sampling module 130 and a control module 140.

[0039] The number of PT thermal resistors, conditioning modules and switch modules (121-12n) is preferably 8, and may also be any positive integer less than 8.

[0040] In some embodiments, each conditioning module (111-11n) is used to form a Wheatstone bridge with a corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor and output a voltage signal. The control module 140 uses the Wheatstone bridge to calculate the resistance value of the PT thermal resistor. Each switch module (121-12n) is used to connect the corresponding conditioning module (111-11n) to the ADC sampling module 130 when turned on, and disconnect the corresponding conditioning module (111-11n) from the ADC sampling module 130 when turned off.

[0041] The PT thermal resistor may be a platinum thermal resistor such as PT100 and PT1000. The Wheatstone bridge is a circuit for accurately measuring resistance values, which has a simple structure and good stability.

[0042] In some embodiments, the ADC sampling module 130 is used to collect the voltage signals output by each conditioning module (111-11n) and pre-process each voltage signal. The control module 140 is used to control each switch module (121-12n) to turn on or off in a polling scanning manner and calculate the ambient temperature.

[0043] Among them, the control module 140 uses a round-robin scanning method, and only scans one switch module at a time, and scans in a cycle in sequence. At the same time, only one switch module is in the on state, and the other switch modules are in the off state. The final calculation is the ambient temperature corresponding to the PT thermal resistor corresponding to the switch module in the on state.

[0044] See also Figure 2 , Figure 2 8-channel temperature acquisition system provided by the embodiment of the present application. Figure 1 and Figure 2 , an 8-channel temperature acquisition system (i.e., a temperature acquisition device 100) is connected to 8 PT100 resistors. The system includes: 8 conditioning circuits (1-8), 8 optical MOS relay switches (1-8), an ADC sampling circuit, and a controller.

[0045] In one embodiment, taking channel 1 as an example, the PT100 thermal resistor adopts a three-wire connection mode, and the two ends of the PT100 thermal resistor are respectively connected to A1 and B1, and B1 and C1 are short-circuited. During the normal operation of the temperature acquisition device 100, the eight PT100 thermal resistor measurement channels can be measured simultaneously without affecting each other.

[0046] Among them, the optical MOS relay has a fast switch-on speed and low on-resistance, and its influence on the resistance test of the PT100 thermal resistor can be ignored.

[0047] See also Figure 3 , Figure 3 1 is a schematic block diagram of the specific structure of the temperature acquisition device 100 based on multi-channel PT thermal resistance measurement provided by the embodiment of the present application. Figure 3 As shown, each conditioning module (111-118) includes: a first resistor R1, a second resistor R2 and a third resistor R3.

[0048] In one embodiment, in the conditioning module 111, the first resistor R1, the first resistor R2, and the third resistor R3 are connected in series. The first end of the first resistor R1 is connected to the first end (A1) of the PT thermal resistor and the first input end of the switch module 121, the series node of the first resistor R1 and the first resistor R2 is connected to the power supply voltage (which can be a 10V DC voltage), and the series node of the first resistor R2 and the third resistor R3 is connected to the second input end of the switch module 121. The first end of the third resistor R3 is connected to the second end (B1) of the PT thermal resistor, and the third end (C1) of the PT thermal resistor is grounded.

[0049] Please continue to see Figure 3 According to an embodiment of the present application, each switch module (121-128) includes a photo MOS relay switch (K1-K8).

[0050] In one embodiment, the first input end of the optical MOS relay switch (K1-K8) is connected to the first output end of the conditioning module (111-118), and the second input end of the optical MOS relay switch (K1-K8) is connected to the second output end of the conditioning module (111-118). The first output end of the optical MOS relay switch (K1-K8) is connected to the first input end of the ADC sampling module 130, and the second output end of the optical MOS relay switch (K1-K8) is connected to the second input end of the ADC sampling module 130.

[0051] In one embodiment, the controller uses a polling scanning method to control the on and off of the optical MOS relay switches K1~K8, ensuring that only one switch is in the on state at the same time, realizing time-sharing multiplexing of 8-channel PT100 thermal resistors with 1 ADC chip, reducing the manufacturing cost of the device.

[0052] According to an embodiment of the present application, the ADC sampling module 130 includes an instrumentation amplifier U1 or other operational amplifiers.

[0053] In one embodiment, the in-phase input terminal (+) of the instrument amplifier U1 is connected to the first output terminal of each switch module (121-128), the inverting input terminal (-) of the instrument amplifier U1 is connected to the second output terminal of each switch module (121-128), and the output terminal of the instrument amplifier U1 is connected to the input terminal of the control module (controller) 140. The instrument amplifier U1 is used to amplify the voltage signal output by each conditioning module (111-118).

[0054] In one embodiment, an independent Wheatstone bridge circuit can be designed for each channel PT100 thermal resistor, and the voltage signal output by the Wheatstone bridge circuit is input to the instrument amplifier U1 after passing through the optical MOS relay switch. The instrument amplifier U1 itself has a high common mode rejection ratio and strong anti-interference ability. By connecting an external gain resistor to the instrument amplifier U1, the voltage signal output by the Wheatstone bridge is amplified so that the voltage signal is within the full-scale measurement range of the ADC chip.

[0055] According to one embodiment of the present application, the ADC sampling module 130 further includes an A / D converter 134. The input end of the A / D converter 134 is connected to the output end of the instrumentation amplifier U1, and the output end of the A / D converter 134 is connected to the input end of the control module 140. Each amplified voltage signal is an analog signal, and the A / D converter 134 is used to convert each amplified voltage signal into a digital signal.

[0056] According to one embodiment of the present application, the ADC sampling module 130 further includes a photoelectric isolator 132. The input end of the photoelectric isolator 132 is connected to the output end of the A / D converter 134, and the output end of the photoelectric isolator 132 is connected to the input end of the control module 140. The photoelectric isolator 132 is used to isolate the digital signal output by the A / D converter 134 and the input signal of the control module 140.

[0057] See also Figure 4 , Figure 4 2 is a schematic block diagram of the overall structure of a temperature acquisition system 200 based on multi-channel PT thermal resistance measurement provided by an embodiment of the present application. Figure 4 As shown, the system 200 includes: a temperature acquisition device 100 based on multi-channel PT thermal resistance measurement, a temperature collection node 210 and a host computer 220.

[0058] In one embodiment, the temperature collection device 100 is used to collect temperature data and upload the collected temperature data to the temperature collection node 210. The temperature collection node 210 is used to collect the temperature data collected by the temperature collection device and forward the collected temperature data to the host computer 220. The host computer 220 is used to store and display the collected temperature data.

[0059] See also Figure 5 , Figure 5 1 is a schematic diagram of the steps of the temperature acquisition method based on multi-channel PT thermal resistor measurement provided by the embodiment of the present application. The method is implemented using a temperature acquisition device 100 based on multi-channel PT thermal resistor measurement, such as Figure 5 As shown, the method may include the following steps: S501, based on each conditioning module (111-11n), a Wheatstone bridge is formed with the corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor.

[0060] In one embodiment, Figure 3 As shown, the three resistors of each conditioning module (111-118) and the corresponding PT thermal resistor (1-8) form a Wheatstone bridge, and then the resistance value of the PT thermal resistor is calculated based on the controller 140.

[0061] S502 , based on each switch module ( 121 - 12n ), when the corresponding conditioning module ( 111 - 11n ) is turned on, the corresponding conditioning module ( 111 - 11n ) is connected to the ADC sampling module 130 , and when the corresponding conditioning module ( 111 - 11n ) is turned off, the corresponding conditioning module ( 111 - 11n ) is disconnected from the ADC sampling module 130 .

[0062] S503 , collecting voltage signals output by each conditioning module ( 111 - 11 n ) based on the ADC sampling module 130 , and preprocessing each voltage signal.

[0063] According to one implementation of the present application, Figure 3 As shown, the ADC sampling module 130 includes an instrumentation amplifier U1, an A / D converter 134, and an optoelectronic isolator 132. Figure 1 and Figure 3 , based on the ADC sampling module 130, collecting the voltage signals output by each conditioning module (111~11n), and preprocessing each voltage signal, may include the following steps: Based on the instrumentation amplifier U1, the voltage signals output by each conditioning module (111~11n) are collected and amplified. Based on the A / D converter 134, each amplified voltage signal is converted into a digital signal, and based on the photoelectric isolator 132, the digital signal output by the A / D converter 134 and the input signal of the control module 140 are isolated.

[0064] S504, based on the control module 140, each switch module (121~12n) is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal; at the same time, one switch module (121~12n) is in the on state.

[0065] According to an embodiment of the present application, based on the control module 140, each switch module (121-12n) is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal, which may include the following steps: Based on the polling scanning method, the control module 140 controls a switch module (121-12n) to be turned on at the same time, and calculates the resistance value of each PT thermal resistor according to each voltage signal, and reversely infers the corresponding ambient temperature according to each resistance value.

[0066] In one embodiment, the resistance values ​​of the three resistors of each conditioning module (111~11n) are known, and the controller 140 reads the voltage value stored in the internal register of the ADC chip (ADC sampling module 134), and then reversely derives the resistance value of the PT100 thermal resistor based on Kirchhoff's current law and voltage law.

[0067] The 100 after PT means that its resistance is 100Ω at 0℃ and about 138.5Ω at 100℃. The resistance value of PT100 thermal resistor will increase at a nearly uniform rate as the temperature rises. By measuring the resistance value of PT100 thermal resistor, the corresponding temperature value can be calculated.

[0068] In the present application scheme, each conditioning module (111~11n) and the corresponding PT thermal resistor form a Wheatstone bridge to measure the resistance value of the PT thermal resistor and output a voltage signal; each switch module (121~12n) connects the corresponding conditioning module (111~11n) to the ADC sampling module 130 when turned on, and disconnects the corresponding conditioning module (111~11n) from the ADC sampling module 130 when turned off; the ADC sampling module 130 collects the voltage signals output by each conditioning module (111~11n) and pre-processes each voltage signal; the control module 140 controls each switch module (121~12n) to turn on or off in a polling scanning manner, and calculates the ambient temperature, and only one switch module (121~12n) is in the on state at the same time.

[0069] The present application solution does not require the use of multiple ADC sampling modules 130, but only requires one ADC sampling chip to collect the temperatures corresponding to multiple PT thermistors, thereby improving the efficiency and accuracy of temperature collection of multi-channel PT thermistor measurements, and has strong ease of use and practicality.

[0070] In addition, the present application scheme uses a polling scanning method based on the controller to control the on or off of the optical MOS relay switch, ensuring that only one switch is in the on state at the same time, realizing the time-sharing multiplexing of 8-channel PT100 thermal resistors using 1 ADC chip, reducing the manufacturing cost of the device.

[0071] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0072] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0073] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A temperature acquisition device based on multi-channel PT thermal resistance measurement, characterized in that: Connected to at least one PT thermal resistor, the device includes: at least one conditioning module, at least one switch module, an ADC sampling module and a control module; Each conditioning module is used to form a Wheatstone bridge with a corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor and output a voltage signal; Each switch module is used to connect the corresponding conditioning module with the ADC sampling module when it is turned on, and disconnect the corresponding conditioning module from the ADC sampling module when it is turned off; The ADC sampling module is used to collect the voltage signals output by each conditioning module and pre-process each voltage signal; The control module is used to control each switch module to be turned on or off in a polling scanning manner, and calculate the ambient temperature; at the same time, one switch module is in the on state.

2. The temperature acquisition device based on multi-channel PT thermal resistance measurement according to claim 1 is characterized in that: Each conditioning module includes: a first resistor, a second resistor and a third resistor; The first resistor, the second resistor and the third resistor are connected in series, the first end of the first resistor is connected to the first end of the PT thermal resistor and the first input end of the switch module, the series node of the first resistor and the second resistor is connected to the power supply voltage, the series node of the second resistor and the third resistor is connected to the second input end of the switch module, the first end of the third resistor is connected to the second end of the PT thermal resistor, and the third end of the PT thermal resistor is grounded.

3. The temperature acquisition device based on multi-channel PT thermal resistance measurement according to claim 1 is characterized in that: Each switch module includes a photo MOS relay switch; The first input end of the optical MOS relay switch is connected to the first output end of the conditioning module, the second input end of the optical MOS relay switch is connected to the second output end of the conditioning module, the first output end of the optical MOS relay switch is connected to the first input end of the ADC sampling module, and the second output end of the optical MOS relay switch is connected to the second input end of the ADC sampling module.

4. The temperature acquisition device based on multi-channel PT thermal resistance measurement according to claim 1 is characterized in that: The ADC sampling module includes an instrument amplifier; The in-phase input terminal of the instrument amplifier is connected to the first output terminal of each switch module, the inverting input terminal of the instrument amplifier is connected to the second output terminal of each switch module, the output terminal of the instrument amplifier is connected to the input terminal of the control module, and the instrument amplifier is used to amplify the voltage signal output by each conditioning module.

5. The temperature acquisition device based on multi-channel PT thermal resistance measurement according to claim 4 is characterized in that: The ADC sampling module also includes an A / D converter; The input end of the A / D converter is connected to the output end of the instrument amplifier, the output end of the A / D converter is connected to the input end of the control module, and the A / D converter is used to convert each amplified voltage signal into a digital signal.

6. The temperature acquisition device based on multi-channel PT thermal resistance measurement according to claim 5 is characterized in that: The ADC sampling module also includes a photoelectric isolator; The input end of the photoelectric isolator is connected to the output end of the A / D converter, and the output end of the photoelectric isolator is connected to the input end of the control module. The photoelectric isolator is used to isolate the digital signal output by the A / D converter and the input signal of the control module.

7. A temperature acquisition system based on multi-channel PT thermal resistance measurement, characterized in that: The system comprises: a temperature acquisition device based on multi-channel PT thermal resistance measurement according to any one of claims 1 to 6, a temperature collection node and a host computer; The temperature collection device is used to collect temperature data and upload the collected multiple temperature data to the temperature collection node; The temperature collection node is used to collect multiple temperature data collected by the temperature collection device and forward the collected temperature data to the host computer; The host computer is used to store and display the collected temperature data.

8. A temperature acquisition method based on multi-channel PT thermal resistance measurement, characterized in that: The temperature acquisition device based on multi-channel PT thermal resistance measurement according to any one of claims 1 to 6 is implemented, and the method comprises: Based on each conditioning module, a Wheatstone bridge is formed with the corresponding PT thermal resistor to measure the resistance value of the PT thermal resistor; Based on each switch module, when the switch module is turned on, the corresponding conditioning module is connected to the ADC sampling module, and when the switch module is turned off, the corresponding conditioning module is disconnected from the ADC sampling module; Based on the ADC sampling module, the voltage signals output by each conditioning module are collected, and each voltage signal is pre-processed; Based on the control module, each switch module is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal; at the same time, one switch module is in the on state.

9. The temperature acquisition method based on multi-channel PT thermal resistance measurement according to claim 8 is characterized in that: The ADC sampling module includes an instrument amplifier, an A / D converter and a photoelectric isolator; The voltage signals output by each conditioning module are collected based on the ADC sampling module, and each voltage signal is pre-processed, including: Based on the instrument amplifier, the voltage signals output by each conditioning module are collected and each voltage signal is amplified; Based on the A / D converter, convert each amplified voltage signal into a digital signal; Based on the photoelectric isolator, the digital signal output by the A / D converter and the input signal of the control module are isolated.

10. The temperature acquisition method based on multi-channel PT thermal resistance measurement according to claim 8, characterized in that: Based on the control module, each switch module is controlled to be turned on or off in a polling scanning manner, and the corresponding ambient temperature is calculated according to each voltage signal, including: Based on the polling scanning mode of the control module, a switch module is controlled to be turned on at the same time, and the resistance value of each PT thermal resistor is calculated according to each voltage signal, and the corresponding ambient temperature is obtained by reverse calculation according to each resistance value.

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