CN215064636U - Temperature and pressure measuring circuit - Google Patents
Temperature and pressure measuring circuit Download PDFInfo
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- CN215064636U CN215064636U CN202120599571.7U CN202120599571U CN215064636U CN 215064636 U CN215064636 U CN 215064636U CN 202120599571 U CN202120599571 U CN 202120599571U CN 215064636 U CN215064636 U CN 215064636U
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Abstract
The utility model provides a temperature pressure measurement circuit, include: the device comprises a temperature detection module, a pressure detection module, an AD conversion module and a processor; the input end of the temperature detection module is connected with the output end of the AD conversion module, and the output end of the temperature detection module is connected with a group of analog signal input ends of the AD conversion module; the input end of the pressure detection module is connected with the output end of the AD conversion module, and the output end of the pressure detection module is connected with the other group of analog signal input ends of the AD conversion module; the AD conversion module is also connected with a corresponding pin of the processor. The utility model discloses a AD conversion module of a high accuracy, low-power consumption has integrateed constant current source excitation current circuit, low noise instrumentation amplifier and low noise converting circuit, has simplified the complexity of circuit, makes measuring circuit receive external disturbance littleer, and the precision is higher, has prolonged the live time of battery power supply instrument, has better economic benefits and social.
Description
Technical Field
The utility model relates to a measure the field, especially relate to a temperature pressure measurement circuit.
Background
The temperature and pressure measuring circuit is used for measuring temperature and pressure and has wide application in the fields of gas metering, refrigeration, heating, petroleum, chemical industry and the like.
Referring to fig. 1, an excitation source of a conventional temperature measurement circuit generally provides a constant voltage source from a TL431 voltage regulator chip Z1, the constant voltage source drives a temperature sensor PT1000 and a comparison resistor R3, voltages are respectively generated on the two resistors, a difference value of the two voltages is amplified by a differential amplifier, the amplified voltage is input to an AD converter to obtain a voltage value, a resistance value is calculated according to the voltage value, and finally a temperature value of the sensor is obtained according to a thermal resistance score table.
Referring to fig. 2, in the conventional pressure measurement circuit, an operational amplifier a1 generates an excitation current source to a pressure sensor, a voltage signal generated at a signal end of the pressure sensor is amplified by the operational amplifier a2 and the operational amplifier A3, and an output voltage is converted into a voltage value by an AD converter, and a pressure value is obtained according to a pressure curve of the pressure sensor.
The above two measurement circuits have the following disadvantages:
1. the sensor driving source of the current temperature and pressure measuring circuit generally comprises an operational amplifier, an operational amplifier chip is easily subjected to external electromagnetic interference and has errors and drifts, so that the measuring precision of the circuit is influenced, and the circuit needs to be manually subjected to zero alignment before delivery;
2. temperature and pressure need two independent driving sources, and the amplifying circuits at the rear ends cannot be integrated, so that the complexity of the circuits is increased, and the maintenance of products at the later stage is not facilitated;
3. by adopting the scheme, the working current of the circuit is larger, so that the service time of the measuring instrument powered by the battery is shorter, and the experience of a user is reduced.
Disclosure of Invention
In view of the above prior art's shortcoming, the utility model aims to provide a temperature and pressure measurement circuit for it needs to carry out manual zero point alignment, the high maintenance that is unfavorable for the later stage product of the complexity of circuit and the great problem of power consumption of operating current to solve before dispatching from the factory among the prior art.
To achieve the above and other related objects, the present invention provides a temperature and pressure measuring circuit, comprising: the device comprises a temperature detection module, a pressure detection module, an AD conversion module and a processor;
the input end of the temperature detection module is connected with the output end of the AD conversion module, and the output end of the temperature detection module is connected with a group of analog signal input ends of the AD conversion module;
the input end of the pressure detection module is connected with the output end of the AD conversion module, and the output end of the pressure detection module is connected with the other group of analog signal input ends of the AD conversion module;
the AD conversion module is also connected with a corresponding pin of the processor.
In an embodiment of the present invention, the temperature detecting module includes a temperature sensor PT1, a diode D1, a plurality of resistors and a plurality of capacitors;
the positive end of the diode D1 is connected with an excitation current output end of the AD conversion module, the negative end of the diode D1 is connected with one ends of the temperature sensor PT1, the capacitor C3 and the resistor R1, the other end of the resistor R1 is connected with one end of the capacitor C4, the other end of the temperature sensor PT1 is connected with the other end of the capacitor C3, one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R2 is connected with the other end of the capacitor C4, two ends of the capacitor C4 are further connected with a group of analog signal input ends of the AD conversion module, and the other end of the resistor R3 is connected with a positive reference voltage input pin of the AD conversion module.
In an embodiment of the present invention, the pressure detecting module includes a pressure sensor PR1, a diode D2, a plurality of resistors and a plurality of capacitors;
the positive terminal of the diode D2 is connected to the other excitation current output terminal of the AD conversion module, the negative terminal of the diode D2 is connected to the first pin of the pressure sensor PR1, one end of the capacitor C7 and one end of the resistor R6, the other end of the capacitor C7 is connected to one end of the resistor R7, the third pin of the pressure sensor PR1 and the positive reference voltage input pin of the AD conversion module, the other end of the resistor R7 is connected to the second pin of the pressure sensor PR1, one end of the capacitor C5 and one end of the resistor R5, the fourth pin of the pressure sensor PR1 is connected to the other end of the resistor R6, the other end of the capacitor C5 and one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C6, the other end of the resistor R5 is connected to the other end of the capacitor C6, and both ends of the capacitor C6 are also connected to the other set of analog signal input terminals of the AD conversion module.
In an embodiment of the present invention, the AD conversion module includes an AD conversion chip U1, a resistor R8, and a plurality of capacitors;
one excitation current output end of the AD conversion chip U1 is connected with the input end of the temperature detection module, the other excitation current output end is connected with the input end of the pressure detection module,
one group of analog signal input ends of the AD conversion chip U1 are connected with the output end of the temperature detection module, the other group of analog signal input ends are connected with the output end of the pressure detection module,
the positive reference voltage input pin of the AD conversion chip U1 is connected with the input ends of the temperature detection module and the pressure detection module, and is also connected with one end of a resistor R8 and one end of a capacitor C8, the other ends of the resistor R8 and the capacitor C8 are grounded,
the negative reference voltage input pin and the ground pin of the AD conversion chip U1 are grounded,
the digital power supply pin of the AD conversion chip U1 is connected with a first voltage, the analog power supply pin is connected with a second voltage, the second voltage is also connected with one end of a capacitor C1 and a capacitor C2, the other end of the capacitor C1 and the other end of the capacitor C2 are grounded,
the serial clock input pin, the chip selection pin, the serial data input pin and the serial data output pin of the AD conversion chip U1 are respectively connected with corresponding pins of the processor.
In an embodiment of the present invention, the temperature and pressure measuring circuit further includes a power module, the power module includes a first voltage converter and a second voltage converter, wherein the first voltage converter outputs a first voltage, and the second voltage converter outputs a second voltage.
As described above, the utility model discloses a temperature pressure measurement circuit has following beneficial effect: the AD conversion module with high precision and low power consumption is adopted, and a constant current source exciting current circuit, a low-noise instrument amplifier and a low-noise conversion circuit are integrated, so that the complexity of the circuit is simplified, the measuring circuit is less interfered by the outside, the precision is higher, the service time of the battery power supply instrument is prolonged, and the AD conversion module has better economic benefit and social benefit.
Drawings
Fig. 1 shows a schematic wiring diagram of a temperature measuring circuit disclosed in the prior art of the present invention.
Fig. 2 shows a schematic wiring diagram of a pressure measurement circuit disclosed in the prior art of the present invention.
Fig. 3 is a block diagram of the overall structure disclosed in the embodiment of the present invention.
Fig. 4 is a schematic wiring diagram of the temperature detection module disclosed in the embodiment of the present invention.
Fig. 5 is a schematic wiring diagram of the pressure detection module disclosed in the embodiment of the present invention.
Fig. 6 is a schematic wiring diagram of the AD conversion module disclosed in the embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and only the components related to the present invention are shown in the drawings rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
Referring to fig. 3-6, the present invention provides a temperature and pressure measuring circuit, including: the device comprises a temperature detection module, a pressure detection module, an AD conversion module and a processor.
Referring to fig. 6, the AD conversion module includes an AD conversion chip U1, a resistor R8, and a plurality of capacitors; the model of the AD conversion chip U1 in this embodiment is AD7793, and a high-precision constant-current source excitation current circuit, a low-noise instrument amplifier, and a low-noise 24-bit AD conversion circuit are integrated in the AD7793, and these integrated functions simplify the circuit structure, improve the measurement precision, reduce the power consumption, make the measurement circuit less interfered by the outside, and realize the service time of the measurement instrument powered by the battery.
The fourth pin of the AD conversion chip U1 is an excitation current output terminal, and the eleventh pin is another excitation current output terminal, where the fourth pin is connected to the input terminal of the temperature detection module, and the eleventh pin is connected to the input terminal of the pressure detection module.
The fifth pin and the sixth pin of the AD conversion chip U1 are a set of analog signal input terminals, and the seventh pin and the eighth pin are another set of analog signal input terminals, wherein the fifth pin and the sixth pin are connected to the output terminal of the temperature detection module, and the seventh pin and the eighth pin are connected to the output terminal of the pressure detection module.
In the embodiment, the tenth pin is grounded, the ninth pin is connected with the input ends of the temperature detection module and the pressure detection module, and the excitation current output by the AD conversion chip U1 flows through the temperature detection module and the pressure detection module and then generates a reference voltage through the resistor R8, so that the sensor signal and the reference voltage are generated by the same excitation current, thereby avoiding errors caused by drift of the excitation current.
The first pin of the AD conversion chip U1 is a serial clock input pin, the third pin is a chip select terminal, the sixteenth pin is a serial data input terminal, and the fifteenth pin is a serial data output terminal, which are respectively connected to corresponding pins of the processor.
A thirteenth pin of the AD conversion chip U1 is an analog power supply pin and is connected with the second voltage; the fourteenth pin is a digital power pin and is connected to the first voltage. In this embodiment, two filter capacitors are further connected between the thirteenth pin and the ground, so that the working power supply of the chip is more stable.
It should be noted that the model adopted by the processor in this embodiment is MSP430F415, and other suitable models may be selected in actual use, which is not described herein again.
Referring to fig. 4, the temperature detecting module includes a temperature sensor PT1, a diode D1, a plurality of resistors and a plurality of capacitors;
an excitation current output by the AD conversion chip U1 is input to the temperature sensor PT1 through the diode D1, and a high-precision excitation current is provided for the temperature sensor PT 1. The voltage values at two ends of the temperature sensor PT1 are input to a fifth pin and a sixth pin of an AD conversion chip U1 through a resistor R1 and a resistor R2, digital voltage values are obtained through AD conversion in the chip, the resistance value of the temperature sensor PT1 at the moment can be obtained according to the digital voltage values and the output excitation current values, and then the temperature value is obtained according to a thermal resistance dial gauge. The model of the temperature sensor selected in this embodiment is PT 1000.
Referring to fig. 5, the pressure detection module includes a pressure sensor PR1, a diode D2, a plurality of resistors, and a plurality of capacitors.
The other excitation current output by the AD conversion chip U1 is input to the first pin of the pressure sensor PR1 through the diode D2, meanwhile, the ninth pin of the AD conversion chip U1 outputs the reference voltage to the three pins of the pressure sensor PR1, high-precision excitation current is provided for the pressure sensor PR1, a voltage value related to a pressure value is output to the second pin and the fourth pin of the pressure sensor PR1, the voltage value is input to the seventh pin and the eighth pin of the AD conversion chip U1 through the resistor R4 and the resistor R5, a digital voltage value is obtained through AD conversion inside the chip, and the current pressure value can be calculated according to the digital voltage value and a pressure curve of the pressure sensor.
The utility model discloses a temperature pressure measurement circuit still includes power module, and power module includes first voltage converter and second voltage converter, and wherein, first voltage converter output first voltage, second voltage converter output second voltage.
To sum up, the utility model discloses a temperature pressure measurement circuit has following beneficial effect: the AD conversion module with high precision and low power consumption is adopted, and a constant current source exciting current circuit, a low-noise instrument amplifier and a low-noise conversion circuit are integrated, so that the complexity of the circuit is simplified, the measuring circuit is less interfered by the outside, the precision is higher, the service time of the battery power supply instrument is prolonged, and the AD conversion module has better economic benefit and social benefit. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (5)
1. A temperature and pressure measurement circuit, comprising: the device comprises a temperature detection module, a pressure detection module, an AD conversion module and a processor;
the input end of the temperature detection module is connected with the output end of the AD conversion module, and the output end of the temperature detection module is connected with a group of analog signal input ends of the AD conversion module;
the input end of the pressure detection module is connected with the output end of the AD conversion module, and the output end of the pressure detection module is connected with the other group of analog signal input ends of the AD conversion module;
the AD conversion module is also connected with a corresponding pin of the processor.
2. The temperature and pressure measurement circuit of claim 1, wherein: the temperature detection module comprises a temperature sensor PT1, a diode D1, a plurality of resistors and a plurality of capacitors;
the positive end of the diode D1 is connected with an excitation current output end of the AD conversion module, the negative end of the diode D1 is connected with one ends of the temperature sensor PT1, the capacitor C3 and the resistor R1, the other end of the resistor R1 is connected with one end of the capacitor C4, the other end of the temperature sensor PT1 is connected with the other end of the capacitor C3, one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R2 is connected with the other end of the capacitor C4, two ends of the capacitor C4 are further connected with a group of analog signal input ends of the AD conversion module, and the other end of the resistor R3 is connected with a positive reference voltage input pin of the AD conversion module.
3. The temperature and pressure measurement circuit of claim 1, wherein: the pressure detection module comprises a pressure sensor PR1, a diode D2, a plurality of resistors and a plurality of capacitors;
the positive terminal of the diode D2 is connected to the other excitation current output terminal of the AD conversion module, the negative terminal of the diode D2 is connected to the first pin of the pressure sensor PR1, one end of the capacitor C7 and one end of the resistor R6, the other end of the capacitor C7 is connected to one end of the resistor R7, the third pin of the pressure sensor PR1 and the positive reference voltage input pin of the AD conversion module, the other end of the resistor R7 is connected to the second pin of the pressure sensor PR1, one end of the capacitor C5 and one end of the resistor R5, the fourth pin of the pressure sensor PR1 is connected to the other end of the resistor R6, the other end of the capacitor C5 and one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C6, the other end of the resistor R5 is connected to the other end of the capacitor C6, and both ends of the capacitor C6 are also connected to the other set of analog signal input terminals of the AD conversion module.
4. The temperature and pressure measurement circuit of claim 1, wherein: the AD conversion module comprises an AD conversion chip U1, a resistor R8 and a plurality of capacitors;
one excitation current output end of the AD conversion chip U1 is connected with the input end of the temperature detection module, the other excitation current output end is connected with the input end of the pressure detection module,
one group of analog signal input ends of the AD conversion chip U1 are connected with the output end of the temperature detection module, the other group of analog signal input ends are connected with the output end of the pressure detection module,
the positive reference voltage input pin of the AD conversion chip U1 is connected with the input ends of the temperature detection module and the pressure detection module, and is also connected with one end of a resistor R8 and one end of a capacitor C8, the other ends of the resistor R8 and the capacitor C8 are grounded,
the negative reference voltage input pin and the ground pin of the AD conversion chip U1 are grounded,
the digital power supply pin of the AD conversion chip U1 is connected with a first voltage, the analog power supply pin is connected with a second voltage, the second voltage is also connected with one end of a capacitor C1 and a capacitor C2, the other end of the capacitor C1 and the other end of the capacitor C2 are grounded,
the serial clock input pin, the chip selection pin, the serial data input pin and the serial data output pin of the AD conversion chip U1 are respectively connected with corresponding pins of the processor.
5. The temperature and pressure measurement circuit of claim 1, wherein: the temperature and pressure measuring circuit further comprises a power module, wherein the power module comprises a first voltage converter and a second voltage converter, the first voltage converter outputs a first voltage, and the second voltage converter outputs a second voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120599571.7U CN215064636U (en) | 2021-03-24 | 2021-03-24 | Temperature and pressure measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120599571.7U CN215064636U (en) | 2021-03-24 | 2021-03-24 | Temperature and pressure measuring circuit |
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| Publication Number | Publication Date |
|---|---|
| CN215064636U true CN215064636U (en) | 2021-12-07 |
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| CN202120599571.7U Active CN215064636U (en) | 2021-03-24 | 2021-03-24 | Temperature and pressure measuring circuit |
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| CN (1) | CN215064636U (en) |
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- 2021-03-24 CN CN202120599571.7U patent/CN215064636U/en active Active
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