High-precision temperature sampling circuit and temperature testing device for PT1000 platinum resistance

Abstract

The utility model discloses a kind of high-precision temperature sampling circuit and temperature testing device for PT1000 platinum resistance, including bridge balance circuit and differential amplifier circuit.The utility model makes whole bridge stable and smooth by bridge balance circuit, and make the linear relationship of current and voltage of PT100 resistance and PT1000 resistance;PT1000 resistance and first sampling resistance are connected in series as temperature sampling circuit, to collect the temperature of PT1000 resistance, and output corresponding temperature sampling signal;PT100 resistance and second sampling resistance are connected in series as temperature compensation circuit to collect the temperature of PT100 resistance, and output corresponding temperature compensation signal;Differential amplifier circuit carries out linear compensation and differential amplification processing to temperature sampling signal and temperature compensation signal according to reference voltage, output high-precision temperature sampling signal, to realize hardware compensation PT1000 resistance temperature, improve the accuracy of temperature sampling, to reduce temperature measurement error.

Description

TECHNICAL FIELD

[0001] The utility model relates to temperature measurement technical field especially relates to a kind of high-precision temperature sampling circuit and temperature testing device for PT1000 platinum resistance. BACKGROUND

[0002] PT1000 platinum resistance is a kind of thermistor, its temperature and resistance value are proportional to non-linear correlation, is widely used in temperature measurement field, and the precision of its temperature acquisition is associated with the performance of measured product.The traditional PT1000 temperature acquisition is powered to PT1000 first, then the resistance value thereof is calculated by current, so as to push out temperature according to the temperature resistance value table of PT1000, then part of interference quantity is eliminated by software method, to improve the accuracy of temperature sampling.But, only by software method is corrected, and software program is more complex, and in the subsequent software program updating process, the problem of abnormal correction is prone to occur, in addition, because the resistance value of PT1000 and temperature are proportional to non-linear correlation, and PT1000 is easily disturbed by the change of ambient temperature, and the accuracy of temperature sampling is affected, leading to temperature measurement error is large. INVENTION CONTENTS

[0003] The utility model aims to solve the above-mentioned problem and designs a kind of high-precision temperature sampling circuit for PT1000 platinum resistance.

[0004] The utility model realizes the above-mentioned purpose by the following technical scheme:

[0005] The high-precision temperature sampling circuit for PT1000 platinum resistance includes:

[0006] Bridge balance circuit, the bridge balance circuit includes PT1000 resistance, PT100 resistance, first sampling resistance and second sampling resistance, the PT1000 resistance and the first sampling resistance are connected in series as temperature sampling circuit, the temperature sampling circuit is used to collect the temperature of the PT1000 resistance and output corresponding temperature sampling signal;The PT100 resistance and the second sampling resistance are connected in series as temperature compensation circuit, the temperature sampling circuit is connected in parallel with the temperature compensation circuit, and the temperature compensation circuit is used to collect the temperature of the PT100 resistance and output corresponding temperature compensation signal;

[0007] Difference amplification circuit, the power supply end of the difference amplification circuit is used to access reference voltage, the first input end of the difference amplification circuit is connected with the temperature sampling circuit, the second input end of the difference amplification circuit is connected with the temperature compensation circuit, and the difference amplification circuit is used to linear compensation and difference amplification processing according to the reference voltage to the temperature sampling signal and temperature compensation signal, and output high-precision temperature sampling signal.

[0008] The utility model discloses still propose a temperature testing device, temperature testing device includes the high accuracy temperature sampling circuit of PT1000 platinum resistance of above.

[0009] The utility model discloses beneficial effect lies in:

[0010] The high accuracy temperature sampling circuit for PT1000 platinum resistance adopts bridge balance circuit to make the whole bridge stable and smooth, and make the current and voltage of PT100 resistance and PT1000 resistance form a linear relationship;The bridge balance circuit includes PT1000 resistance, PT100 resistance, first sampling resistance and second sampling resistance, connects PT1000 resistance and first sampling resistance in series as temperature sampling circuit to collect the temperature of PT1000 resistance, and exports corresponding temperature sampling signal;Connect PT100 resistance and second sampling resistance in series as temperature compensation circuit to collect the temperature of PT100 resistance, and export corresponding temperature compensation signal;Temperature sampling circuit and temperature compensation circuit are connected in parallel;Difference amplification circuit carries out linear compensation and difference amplification processing to temperature sampling signal and temperature compensation signal according to reference voltage, exports high accuracy temperature sampling signal, thereby realizes the hardware compensation of PT1000 resistance temperature, improves the accuracy of temperature sampling, to reduce temperature measurement error. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is the overall block diagram of the high accuracy temperature sampling circuit for PT1000 platinum resistance of the utility model;

[0012] In the drawing: R1-first sampling resistance, R2-second sampling resistance, OP1-first operational amplifier, OP2-second operational amplifier, OP3-third operational amplifier, OP4-fourth operational amplifier. DETAILED DESCRIPTION

[0013] To make the purpose, technical scheme and advantage of the embodiments of the utility model more clear, the technical scheme in the embodiments of the utility model will be described clearly and completely below with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the utility model.

[0015] It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0016] In the description of the utility model, it needs to be understood that the orientation or position relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right" and the like is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship commonly placed when the utility model product is used, or is the orientation or position relationship commonly understood by the person skilled in the art, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the utility model.

[0017] In addition, the terms "first", "second" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0018] In the description of the utility model, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "arrange", "connect" and the like should be understood in a broad sense, for example, "connect" can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through an intermediate medium, or the communication inside two elements. For the person skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0019] The specific embodiment of the utility model will be described in detail below in combination with the drawings.

[0020] As shown in the drawings, the high-precision temperature sampling circuit for PT1000 platinum resistance comprises: Figure 1

[0021] The bridge balance circuit comprises a PT1000 resistance, a PT100 resistance, a first sampling resistance R1 and a second sampling resistance R2, the PT1000 resistance and the first sampling resistance R1 are connected in series as a temperature sampling circuit, the temperature sampling circuit is used for collecting the temperature of the PT1000 resistance and outputting a corresponding temperature sampling signal; the PT100 resistance and the second sampling resistance R2 are connected in series as a temperature compensation circuit, the temperature compensation circuit is used for collecting the temperature of the PT100 resistance and outputting a corresponding temperature compensation signal, and the temperature sampling circuit and the temperature compensation circuit are connected in parallel;

[0022] ​A differential amplification circuit, a power supply end of the differential amplification circuit is used to access a reference voltage, a first input end of the differential amplification circuit is connected with the temperature sampling circuit, a second input end of the differential amplification circuit is connected with the temperature compensation circuit, the differential amplification circuit is used to perform linear compensation and differential amplification processing on the temperature sampling signal and the temperature compensation signal according to the reference voltage, and output a high-precision temperature sampling signal.

[0023] In an embodiment, the PT1000 resistor, the PT100 resistor, the first sampling resistor R1 and the second sampling resistor R2 are high-precision resistors.

[0024] In an embodiment, the differential amplification circuit comprises a first operational amplifier OP1, a second operational amplifier OP2, a third operational amplifier OP3 and a fourth operational amplifier OP4, an output end of the first operational amplifier OP1 is connected with the second operational amplifier OP2 and the third operational amplifier OP3 respectively, an input end of the second operational amplifier OP2 is connected with the temperature sampling circuit, an input end of the third operational amplifier OP3 is connected with the temperature compensation circuit, a first input end of the fourth operational amplifier OP4 is connected with the second operational amplifier OP2, and a second input end of the fourth operational amplifier OP4 is connected with the third operational amplifier OP3.

[0025] In the embodiment, the PT100 resistor is a heating platinum resistor, and the PT100 resistor is arranged beside the PT1000 resistor. Since the temperature change of the PT1000 resistor will affect the PT100 resistor, the temperature sampling signal can be compensated by using the temperature compensation signal. Specifically, a bridge balance circuit is composed of the PT1000 resistor, the PT100 resistor, the first sampling resistor R1 and the second sampling resistor R2, a VCC end of the bridge balance circuit is connected with a PWM power supply, so that the whole bridge is stably balanced, and the current and voltage of the PT100 resistor and the PT1000 resistor form a linear relationship. The PT1000 resistor, the PT100 resistor, the first sampling resistor R1 and the second sampling resistor R2 all need to be selected as high-precision resistors, so as to reduce the temperature measurement error.

[0026] In the embodiment, the differential amplification circuit linearly compensates the temperature sampling signal and the temperature compensation signal according to the reference voltage, and outputs a high-precision temperature sampling signal after differential amplification processing. The differential amplification circuit includes a first operational amplifier OP1, a second operational amplifier OP2, a third operational amplifier OP3 and a fourth operational amplifier OP4. It can be understood that the reference voltage is used as a compensation value to compensate the temperature sampling signal, so that the nonlinear curve is transformed into a linear curve. Then, after differential amplification operation is performed on the temperature sampling signal and the temperature compensation signal, a high-precision temperature sampling signal is output through the OUT terminal, so that the hardware compensation of the PT1000 resistance temperature is realized, the accuracy of temperature sampling is improved, and the temperature measurement error is reduced.

[0027] The utility model discloses a high-precision temperature sampling circuit for PT1000 platinum resistance adopts bridge balance circuit to make the whole bridge stable and smooth, and make the current and voltage of PT100 resistance and PT1000 resistance form a linear relationship. The bridge balance circuit includes PT1000 resistance, PT100 resistance, first sampling resistance R1 and second sampling resistance R2. PT1000 resistance and first sampling resistance R1 are connected in series as a temperature sampling circuit to collect the temperature of PT1000 resistance and output corresponding temperature sampling signal. PT100 resistance and second sampling resistance R2 are connected in series as a temperature compensation circuit to collect the temperature of PT100 resistance and output corresponding temperature compensation signal. The temperature sampling circuit and the temperature compensation circuit are connected in parallel. The differential amplification circuit linearly compensates the temperature sampling signal and the temperature compensation signal according to the reference voltage, and outputs a high-precision temperature sampling signal after differential amplification processing. Thus, the hardware compensation of the PT1000 resistance temperature is realized, the accuracy of temperature sampling is improved, and the temperature measurement error is reduced.

[0028] The utility model discloses a high-precision temperature sampling circuit for PT1000 platinum resistance adopts bridge balance circuit to make the whole bridge stable and smooth, and make the current and voltage of PT100 resistance and PT1000 resistance form a linear relationship. The bridge balance circuit includes PT1000 resistance, PT100 resistance, first sampling resistance R1 and second sampling resistance R2. PT1000 resistance and first sampling resistance R1 are connected in series as a temperature sampling circuit to collect the temperature of PT1000 resistance and output corresponding temperature sampling signal. PT100 resistance and second sampling resistance R2 are connected in series as a temperature compensation circuit to collect the temperature of PT100 resistance and output corresponding temperature compensation signal. The temperature sampling circuit and the temperature compensation circuit are connected in parallel. The differential amplification circuit linearly compensates the temperature sampling signal and the temperature compensation signal according to the reference voltage, and outputs a high-precision temperature sampling signal after differential amplification processing. Thus, the hardware compensation of the PT1000 resistance temperature is realized, the accuracy of temperature sampling is improved, and the temperature measurement error is reduced.

[0029] In one embodiment, the temperature testing device includes a precision reference voltage source configured to provide the reference voltage.

[0030] In the embodiment, the temperature testing device includes a precision reference voltage source configured to provide the reference voltage.

[0031] The hardware error elimination method is adopted in the utility model to correct the influence of the PT1000 resistance environmental temperature, so that the resistance value of the PT1000 resistance and the temperature present linear relationship, so as to improve the temperature measurement precision.

[0032] The above only is the preferred embodiment of the utility model, it should be pointed out, for ordinary skilled person in the art, without departing from the technical principle of the utility model, under the premise of, can make a number of improvements and refinements, these improvements and refinements also should be considered as the protection scope of the utility model.

Claims

1. A high precision temperature sampling circuit for a PT1000 platinum resistance, characterized in that, The high-precision temperature sampling circuit for the PT1000 platinum resistance comprises: a bridge balance circuit, which comprises a PT1000 resistance, a PT100 resistance, a first sampling resistance and a second sampling resistance, the PT1000 resistance and the first sampling resistance are connected in series as a temperature sampling circuit, the temperature sampling circuit is used for collecting the temperature of the PT1000 resistance and outputting a corresponding temperature sampling signal; the PT100 resistance and the second sampling resistance are connected in series as a temperature compensation circuit, the temperature compensation circuit is used for collecting the temperature of the PT100 resistance and outputting a corresponding temperature compensation signal, and the temperature sampling circuit and the temperature compensation circuit are connected in parallel; a differential amplification circuit, a power supply end of the differential amplification circuit is used for accessing a reference voltage, a first input end of the differential amplification circuit is connected with the temperature sampling circuit, a second input end of the differential amplification circuit is connected with the temperature compensation circuit, and the differential amplification circuit is used for performing linear compensation and differential amplification processing on the temperature sampling signal and the temperature compensation signal according to the reference voltage, and outputting a high-precision temperature sampling signal.

2. The high precision temperature sampling circuit for PT1000 platinum resistance according to claim 1, characterized in that, The PT1000 resistance, the PT100 resistance, the first sampling resistance and the second sampling resistance are all high-precision resistances.

3. The high precision temperature sampling circuit for PT1000 platinum resistance according to claim 1, characterized in that, The differential amplification circuit comprises a first operational amplifier, a second operational amplifier, a third operational amplifier and a fourth operational amplifier, the output ends of the first operational amplifier are connected with the second operational amplifier and the third operational amplifier respectively, the input end of the second operational amplifier is connected with the temperature sampling circuit, the input end of the third operational amplifier is connected with the temperature compensation circuit, the first input end of the fourth operational amplifier is connected with the second operational amplifier, and the second input end of the fourth operational amplifier is connected with the third operational amplifier.

4. A temperature testing device, characterized by, The temperature testing device comprises the high-precision temperature sampling circuit for the PT1000 platinum resistance according to any one of claims 1-3.

5. The temperature testing device of claim 4, wherein, The temperature testing device comprises a precise reference voltage source, which is used for providing the reference voltage.

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