CN116989911A - High-precision multichannel Pt100 sensor temperature detection device and calibration method - Google Patents
High-precision multichannel Pt100 sensor temperature detection device and calibration method Download PDFInfo
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- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
- G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
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Abstract
The invention discloses a high-precision multi-channel Pt100 sensor temperature detection device and a calibration method, wherein the detection device comprises a data preprocessing unit, an analog-to-digital conversion unit, a main control unit, a communication unit, a touch screen and a power management unit for supplying power to the device, wherein the data preprocessing unit converts a Pt100 sensor signal into a voltage signal, the voltage signal is transmitted to the main control unit through the analog-to-digital conversion unit, and the main control unit is responsible for processing, calibrating and converting a sampling value and transmitting the sampling value to the touch screen through the communication unit, so that acquisition and display of Pt100 sensor data are realized; the calibration method comprises the following steps: temperature conversion and data calibration. The invention has high accuracy, has a calibration function, and can realize the acquisition and display of eight-channel Pt100 temperature sensor data; the device has high detection precision, and the temperature measurement deviation of each channel is less than or equal to 0.1 ℃.
Description
Technical Field
The invention relates to the field of sensing detection, in particular to a high-precision multichannel Pt100 sensor temperature detection device and a calibration method.
Background
The temperature parameter is a key parameter of an industrial production field, and the accuracy of measurement is critical to economic and technical indexes such as safe production, product quality, energy conservation and the like of a factory. The Pt100 platinum resistor is one of the most widely used temperature measuring sensors at present, and converts the external temperature change into the resistance change by utilizing the resistance thermal effect principle, so that a user can obtain the current environment temperature by calculating the Pt100 resistance, and the temperature measuring sensor has the characteristics of high precision, good stability, reliable performance and the like. At present, the special Pt100 detection device on the market has the defects of few types, low measurement precision, poor accuracy, few detection channels and the like.
Disclosure of Invention
The invention provides a high-precision multi-channel Pt100 sensor temperature detection device and a calibration method, which aim to overcome the defects existing in the prior art.
The invention is realized by the following technical scheme:
a high-precision multichannel Pt100 sensor temperature detection device comprises a data preprocessing unit group, an analog-to-digital conversion unit, a main control unit, a communication unit, a touch screen and a power management unit for supplying power to the device, wherein the data preprocessing unit group, the analog-to-digital conversion unit, the main control unit, the communication unit and the touch screen are sequentially connected; the data preprocessing unit group consists of a plurality of data preprocessing units, and the data preprocessing units are connected with the Pt100 sensor, convert the resistance change of the Pt100 sensor into a voltage signal and input the voltage signal to the analog-to-digital conversion unit; the analog-to-digital conversion unit converts the voltage signal input by the data preprocessing unit into a digital signal and transmits the digital signal to the main control unit; and the main control unit reads the data input by the analog-to-digital conversion unit, finishes processing, calibration and conversion of the sampling value, and finishes data interaction with the touch screen through the communication unit.
In the above technical scheme, the data preprocessing unit converts the Pt100 resistance change into a voltage signal of 0-10 v.
In the above technical solution, the analog-to-digital conversion unit supports eight-channel analog signal acquisition, and is connected with the main control unit through a parallel data interface.
In the technical scheme, the communication unit adopts an RS-485 communication mode.
In the above technical scheme, the touch screen is an industrial serial screen.
In the above technical solution, the power management unit includes five voltages of +24v, +12v, +5v, +3.3v, and +1.9v.
A calibration method of a high-precision multichannel Pt100 sensor temperature detection device comprises the following steps:
temperature conversion
Establishing a Pt100 sensor resistance temperature comparison array;
(II) data calibration
Creating a theoretical resistance temperature comparison array;
(ii) creating a measured resistance temperature control array;
(iii) making differences in one-to-one correspondence between elements in the theoretical resistance temperature and the actually measured resistance temperature comparison array, and obtaining an error value array;
(iv) establishing a fitting curve by using the actually measured resistance temperature control array and the error value array to obtain a fitting equation;
(v) at R t In the calculation of the value, the resistance R is measured t And adding a calibration value error on the basis, and performing temperature conversion to obtain a final detection temperature value.
In the above technical solution, the specific resistance temperature control array is: setting up a Pt100 sensor resistance temperature control array at 0.01 ℃ at intervals within the range of-100 ℃ to 100 ℃,
Buf[T n ]＝{R -100.00 ，R -99.99 ，R -99.98 ...R n ...R 99.98 ，R 99.99 ，R 100.00 }，
T n ∈(-100.00℃，100.00℃)，
wherein R is n Refers to the temperature T n The theoretical output resistance of Pt 100.
In the above technical scheme, the measured resistance temperature control array is calibrated by a FLUKE 754 process signal calibrator, standard signals of the calibrator are input into a detection device at intervals of 10 ℃ between-100 ℃ and 100 ℃, and the temperature and resistance control array Buf2[ T ] is recorded 2 ]＝{R -100.00 ，R -90.00 ，R -80.00 ，R -70.00 ...R t ...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 2 ∈(-100.00℃，100.00℃)。
In the above technical solution, the fitting equation uses the elements in the measured resistance temperature control array as the abscissa and the elements in the error value array as the ordinate, and a quadratic fitting curve is made to obtain the fitting equation error=k 2 *R t 2 +k 1 *R t +k 0 Wherein k is 2 、k 1 、k 0 Is a constant coefficient, R t The measured resistance value, error, is the deviation value.
The beneficial effects of the invention are as follows:
aiming at a four-wire Pt100 temperature sensor common in the market, the invention provides an eight-channel high-precision Pt100 resistance measuring circuit, and a temperature conversion and calibration method is designed aiming at the detecting circuit, so that the high-precision detection of the temperature of the Pt100 sensor is realized; the device has high accuracy, has a calibration function, and can realize the acquisition and display of 8-channel Pt100 temperature sensor data; the device has high detection precision, and the temperature measurement deviation of each channel is less than or equal to 0.1 ℃.
Drawings
FIG. 1 is a schematic diagram of a high-precision, multi-channel Pt100 sensor temperature detection device of the present invention;
FIG. 2 is a schematic circuit diagram of a data preprocessing unit according to the present invention;
FIG. 3 is a schematic circuit diagram of an analog-to-digital conversion unit of the present invention;
FIG. 4 is a schematic circuit diagram of a communication unit according to the present invention;
FIG. 5 is a schematic circuit diagram of a power management unit according to the present invention;
FIG. 6 is a flow chart of data processing in the calibration method of the present invention;
FIG. 7 is a flow chart of a data calibration algorithm in the calibration method of the present invention.
Wherein:
1 data preprocessing Unit group
11 operational amplifier
2A/D conversion unit
21 analog-to-digital conversion chip
3 main control unit
4 communication unit
41 serial port chip 42 isolation chip
5 touch screen
6 Power management Unit
61 II power chip 62I power chip
63 III power chip
7Pt100 sensor.
Other relevant drawings may be made by those of ordinary skill in the art from the above figures without undue burden.
Detailed Description
In order to make the technical scheme of the invention better understood by those skilled in the art, the technical scheme of the high-precision multi-channel Pt100 sensor temperature detection device and the calibration method of the invention are further described below by specific embodiments in combination with the attached drawings of the specification.
Example 1
As shown in fig. 1, a high-precision, multi-channel Pt100 sensor temperature detection apparatus includes:
the data preprocessing unit group 1 consists of eight data preprocessing units, wherein the eight data preprocessing units are respectively connected with the Pt100 sensor 7, and are responsible for preprocessing signals of the Pt100 sensor 7, converting resistance change into 4.097 v-9.418 v analog voltage signal change and inputting the analog voltage signal change into the analog-to-digital conversion unit 2;
the analog-to-digital conversion unit 2 supports eight-channel analog signal acquisition, converts 4.097 v-9.418 v analog voltage signals input by the data preprocessing unit into digital signals, is connected with the main control unit 3 through a parallel data interface, and transmits the digital signals to the main control unit 3;
the main control unit 3 is the core of the detection device, reads the digital signal input by the analog-to-digital conversion unit 2 through a parallel data interface, completes the processing, calibration and conversion of a sampling value, obtains the current temperature value of the Pt100 sensor 7, and completes the data interaction with the touch screen 5 through the communication unit 4;
the communication unit 4 adopts an RS-485 communication mode and is responsible for data interaction between the main control unit 3 and the touch screen 5;
touch screen 5 for real-time display of temperature values of eight-channel Pt100 sensor 7
The power management unit 6 is responsible for supplying power to the data preprocessing unit group 1, the analog-digital conversion unit 2, the main control unit 3, the communication unit 4 and the touch screen 5.
As shown in fig. 2, in this embodiment, the data preprocessing unit is built by using a dual-channel, low-power-consumption operational amplifier 11 with a model AD 822. The a channel of the operational amplifier 11 is a constant current source circuit, and can provide a constant current source of 1mA for the Pt100 sensor 7, and convert a change in the resistance value of the Pt100 sensor 7 into a voltage change. At the temperature of-100 ℃ to 100 ℃, the resistance value of Pt100 is changed to 60.256 to 138.502 omega, so that the voltage of Pt100 after being treated by a constant current source is changed to 60.256mV to 138.502mV. The B channel of the operational amplifier 11 is an amplifying circuit responsible for amplifying the voltage at both ends of the Pt100 sensor 7 by 68 times and converting it into an analog voltage signal of 4.097 to 9.418 v.
The specific circuit connection relation is as follows: the No. 1 pin of the operational amplifier 11 is connected with the No. 2 pin of the Pt100 sensor 7, and the No. 2 pin of the operational amplifier 11 is respectively connected with the No. 3 pin of the Pt100 sensor 7; the resistor R1=5k is respectively connected with the No. 2 pin and GND of the operational amplifier 11; the No. 3 pin of the operational amplifier 11 is connected with +5V, and the No. 4 pin of the operational amplifier 11 is connected with GND; resistor r2=68k, respectively connected to pin No. 5 and GND of operational amplifier 11; the resistor R3=1k is respectively connected with the No. 1 pin of the Pt100 sensor 7 and the No. 5 pin of the operational amplifier 11; resistance r4=1k; the pin 4 of the Pt100 sensor 7 and the pin 6 of the operational amplifier 11 are respectively connected; the resistor R5=68k is respectively connected with the No. 6 pin and the No. 7 pin of the operational amplifier 11; the pin 7 of the operational amplifier 11 is connected with the analog-digital conversion unit 2; pin 8 of op-amp 11 is connected to +12v.
As shown in fig. 3, in the present embodiment, the analog-to-digital conversion unit 2 uses a sixteen-bit eight-channel analog-to-digital conversion chip 21 with a sampling frequency of 510KSPS and a model number of ADS 8568. The ADS8568 analog-to-digital conversion chip 21 supports a parallel fast output interface, and can process ±10v analog voltage signals by configuration. Thus (2)ADS8568 analog-to-digital conversion chip 21 data acquisition accuracy β=20/2 16 V, i.e. β= 0.30517578125mV.
The specific circuit connection relation is as follows: the 37 # pin, the 38 # pin, the 39 # pin, the 40 # pin, the 13 # pin and the 34 # pin of the analog-to-digital conversion chip 21 are connected with a control port of the main control unit 3; the number 34 pin, the number 42 pin, the number 47 pin, the number 49 pin, the number 54 pin, the number 64 pin, the number 59 pin, the number 7 pin and the number 2 pin of the analog-to-digital conversion chip 21 are analog voltage signal input pins which are respectively connected with the output ends of the eight paths of data preprocessing units; the analog-digital conversion chip 21 has parallel data output ports, which are respectively connected with the parallel data input ports of the main control unit 3.
In this embodiment, the main control unit adopts the TMS320F28335 main controller of TI company, and the device has the advantages of low cost, small power consumption, high performance, large data and program storage capacity, etc., and the chip adopts 1.9V power supply inside and 3.3V power supply outside, and the main frequency can reach 150M, so that the high-efficiency operation of floating point number can be realized.
As shown in fig. 4, in this embodiment, the communication unit 4 is composed of a serial port chip 41 with a model number MAX485 and an isolation chip 42 with a model number ISO 7221; the serial port chip 41 of MAX3485 is powered by 5V, and can achieve a transmission rate of up to 2.5 Mbps. The isolation chip 42 of the ISO7221 can effectively isolate signals, improves the anti-interference capability of data transmission through level signal conversion, and effectively ensures the stability of data communication.
The specific circuit connection relation is as follows: pin 1 and pin 8 of the isolation chip 42 are connected with +3.3v; the number pins 2 and 3 of the isolation chip 42 are respectively connected with SCIA_TX and SCI_RX interfaces of the main control unit 3; the No. 4 pin and the No. 5 pin of the isolation chip 42 are connected with GND; the No. 6 pin and the No. 7 pin of the isolation chip 42 are respectively connected with the No. 4 pin and the No. 3 pin of the serial port chip 41. Pin 1 and pin 2 of serial port chip 41 are connected with +3.3v; c3 =0.1 uf, respectively connected to pin No. 5 and GND of serial port chip 41; c4 =0.1 uf, respectively connected to pins 6 and 7 of the serial port chip 41; the No. 8 pin and the No. 9 pin of the serial port chip 41 are connected with GND; c5 =0.1 uf, respectively connected to pins 10 and 11 of the serial port chip 41; c6 =0.1 uf, respectively connected to pin 12 of the serial chip 41 and GND; the No. 13 pin and the No. 14 pin of the serial port chip 41 are respectively communication interfaces of Tx and Rx of the RS-485; the No. 16 pin of the serial port chip 41 is connected with +3.3v; c7 =0.1 uf, with +3.3v and GND, respectively; c1 =0.1 uf, with +3.3v and GND, respectively; r4=0Ω, respectively connected to pins No. 1 and No. 8 of the isolation chip 42.
In this embodiment, the touch screen 5 adopts a DMT64480S056 industrial serial port screen developed by DWIN (diwen) corporation, the resolution of the serial port screen is 800 x 480, 3.3V/5V power is externally adopted, the touch screen has two communication interfaces of RS232/RS485, and functional modules such as list display, control instruction, numerical value display and data input are integrated internally, so that a user can realize the display of the temperature value of each channel of the detection device through secondary development.
As shown in fig. 5, in the present embodiment, the power management unit 6 includes five voltages of +24v, +12v, +5v, +3.3v, +1.9v. The detection device is powered by +24V, and the No. I power chip 62 with the model number of WRA2412S-3WR2 is responsible for converting +24V into +12V, and the No. II power chip 61 with the model number of 78M05 is responsible for converting +24V into +5V. In addition, in consideration of +3.3V and +1.9V circuit power consumption, the present embodiment employs III power chip 63 of type TPS767D301 from TI company to perform +3.3V, +1.9V voltage conversion. The III power chip 63 with the model number TPS767D301 is a double-circuit power chip, can output two voltages of +3.3V and +1.9V at the same time, and the maximum output current of each channel can reach 1A.
The specific circuit connection relation is as follows: the No. 1 pin and the No. 2 pin of the No. I power chip 62 are respectively connected with GND and +24v; c10 100uf/25v, respectively connected to pins 1 and 2 of the power chip 62; the pins 6 and 8 of the power chip 62 are respectively output to be +/-12 v; pin 7 of the power chip 62 is output GND; c11 100uf/25v connected to pins 6 and 7 of the power chip 62; c12 The power chip is connected with pins 7 and 8 of the power chip 62 respectively, and the power chip is connected with pins 100uf/25 v. The pin 1 and the pin 2 of the power chip 61 are respectively connected with +24v and GND; pin 3 of the power chip 61 of II outputs +5v; c8 The power chip is respectively connected with a No. 1 pin and a No. 2 pin of the No. II power chip 61 in an=10uf/25 v mode; c9 The power chip is connected with pins 2 and 3 of the power chip 61 respectively, and the power chip is connected with pins 10uf/16 v. The III power chip 63 is connected with +5v through a pull-up resistor R5=4.7k; the No. 3 pin, the No. 4 pin, the No. 9 pin and the No. 10 pin of the No. III power chip 63 are connected with GND; pin 11 and pin 12 of the III power chip 63 are connected with +5v; the No. 23 pin and the No. 24 pin of the III power chip 63 output 1.8v voltage, the No. 17 pin, the No. 18 pin and the No. 19 pin output +3.3v voltage.
The working process of the invention comprises the following steps:
the device provided by the invention externally comprises a +24v power supply interface and eight paths of Pt100 sensor data acquisition interfaces. In the use process, the data preprocessing unit converts the Pt100 sensor signal into a 4.097-9.418 v voltage signal, the voltage signal is transmitted to the main control unit 3 through the analog-to-digital conversion unit 2, and the main control unit 3 is responsible for processing, calibrating and converting the sampling value and transmitting the sampling value to the touch screen 5 through the communication unit 4, so that the acquisition and display of the Pt100 sensor data are realized.
Example 2
As shown in fig. 6 and 7, the calibration method of the temperature detection device of the high-precision multichannel Pt100 sensor mainly comprises two parts of data processing and data calibration, wherein the data processing mainly completes the processing of an AD sampling value and calculates to obtain a current temperature value; the data calibration is used for calibrating the detection device, so that the accuracy of temperature measurement is improved;
the method specifically comprises the following steps:
data processing, i.e. temperature conversion
Establishing a Pt100 sensor resistance-temperature comparison array (R-T comparison table for short) within the range of-100 ℃ to 100 ℃ at each interval of 0.01 ℃, namely Buf [ T ] n ]＝{R -100.00 ，R -99.99 ，R -99.98 ...R n ...R 99.98 ，R 99.99 ，R 100.00 }，T n ∈(-100.00℃，100.00℃)，R n Refers to the temperature T n The theoretical output resistance of Pt 100.
From the Pt100 sampling principle, it is known that:
CH＝(2 16 )*R t *I ref *K/V ref
wherein: CH is an AD sampling value; r is R t The current resistance value of Pt 100; i ref Is constant current source current; k is the magnification; v (V) ref Is the reference voltage. Thus, pt100 is currently resistive:
R t ＝CH*V ref /(2 16 )/I ref /K
r is R t Substituting the value into the (R-T) comparison table, and calculating to obtain the temperature value of the current environment.
A specific data processing flow is shown in figure 6,
s1: starting.
S2: an R-T lookup table is created. Namely, establishing R-T control array Buf [ T ] of the Pt100 sensor within the range of minus 100 ℃ to 100 ℃ at each interval of 0.01 DEG C n ]＝{R -100.00 ，R -99.99 ，R -99.98 ...R n ...R 100.00 }，T n ∈(-100.00℃，100.00℃)，R n At a temperature of T n The theoretical resistance value output by Pt 100.
S3: the AD conversion unit initializes, and initializes the ADS8568 analog-to-digital conversion chip.
S4: the AD sample value is read.
S5: whether the AD sample value is correct. If S6 is performed correctly, otherwise S4 is performed.
S6: the Pt100 resistance was calculated according to the hardware sampling principle. The principle of Pt100 sampling is as follows:
CH＝(2 16 )*R t *I ref *K/V ref
wherein CH is an AD sampling value; r is R t The current resistance of Pt 100; i ref Is constant current source current; k is AD822 amplification factor; v (V) ref Is the ADS8568 reference voltage. Thus, pt100 resistance:
R t ＝CH*V ref /(2 16 )/I ref /K
R t ＝CH*20v/(65536*0.001A*68)
s7: root of Chinese characterAccording to the calibration algorithm, the Pt100 resistance value R t And compensating.
S8: and calculating according to the R-T comparison table to obtain the current temperature value.
However, due to systematic errors such as wiring resistance and soldering of the circuit board, different R's exist at different temperatures t The deviation is measured. Therefore, the whole range of the detection device needs to be calibrated to improve the accuracy of temperature detection, and the data calibration step (II) is carried out,
(II) data calibration
Searching and recording theoretical resistance values, namely Buf1[ T ] in an R-T comparison table at intervals of 10 DEG C 1 ]＝{R -100.00 ，R -90.00 ，R -80.00 ，R -70.00 ...Rn1...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 1 ∈(-100.00℃，100.00℃)。
(ii) calibration was performed by means of a FLUKE 754Pt100 process signal calibrator (precision: 0.01 ℃ C.): according to the R-T comparison table, every 10 deg.C, inputting the standard Pt100 signal of the calibrator into the detection device, recording the actual measured resistance value, i.e. Buf2[ T ] at the current temperature 2 ]＝{R -100.00 ，R -90.00 ，R -80.00 ，R -70.00 ...Rt...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 2 ∈(-100.00℃，100.00℃)。
(iii) one-to-one correspondence between the theoretical resistance value in (i) and the measured resistance value in (ii) is made, and error value, i.e. Buf3[ T ] is recorded 3 ]＝{error -100.00 ，error -90.00 ，error -80.00 ，error -70.00 ...error n2 ...erro r70.00 ，error 80.00 ，error 90.00 ，error 100.00 }，T 3 ∈(-100.00℃，100.00℃)。
(iv) Buf2[ T ] 2 ]The elements in (a) are on the abscissa, buf3[ T ] 3 ]The elements in the method are taken as ordinate, a quadratic fitting curve is made, and a fitting equation error=k is obtained 2 *R t 2 +k 1 *R t +k 0 (k 2 、k 1 、k 0 Is a constant coefficient, R t For the measured resistance, error is the bias).
(v) at R t In the calculation of the value, the resistance R is measured t And adding a calibration value error on the basis, and performing temperature conversion to obtain a final detection temperature value.
The specific data calibration algorithm flow is shown in fig. 7:
s9: creating a theoretical R-T comparison array BUF1[ T ] 1 ]＝{R n1 }. The temperature and Pt100 theoretical output resistance value comparison array Buf1[ T ] is recorded at intervals of 10 ℃ between minus 100 ℃ and 100 DEG C 1 ]＝{R -100.00 ，R -90.00 ，R -80.00 ，R - 70.00 ...R n1 ...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 1 ∈(-100.00℃，100.00℃)。
S10: creating a measured R-T control array BUF2[ T2 ]]＝{R t }. Calibrating through a FLUKE 754 process signal calibrator: inputting the standard signal of the check meter into the detecting device at intervals of 10 ℃ between-100 ℃ and recording the temperature and resistance value comparison array Buf2[ T ] 2 ]＝{R -100.00 ，R -90.00 ，R -80.00 ，R -70.00 ...R t ...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 2 ∈(-100.00℃，100.00℃)。
S11：BUF1[T 1 ]、BUF2[T 2 ]The elements in the array are subjected to one-to-one correspondence difference to obtain an array BUF 3T 3 ]＝{error n2 }，T 3 ∈(-100.00℃，100.00℃)。
S12: by BUF2[ T ] 2 ]、BUF3[T 3 ]And establishing a fitting curve to obtain a fitting equation. I.e. with Buf2[ T ] 2 ]The elements in (a) are on the abscissa, buf3[ T ] 3 ]The elements in the method are taken as ordinate, a quadratic fitting curve is made, and a fitting equation error=k is obtained 2 *R t 2 +k 1 *R t +k 0 (k 2 、k 1 、k 0 Is a constant coefficient, R t For the measured resistance, error is the bias).
S13: substituting the fitting equation into the data processing flow S7 to compensate the resistance Rt.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.
Claims (10)
1.A high-precision multichannel Pt100 sensor temperature detection device is characterized in that: the device comprises a data preprocessing unit group (1), an analog-to-digital conversion unit (2), a main control unit (3), a communication unit (4), a touch screen (5) and a power management unit (6) for supplying power to the device, which are connected in sequence;
the data preprocessing unit group (1) consists of a plurality of data preprocessing units, wherein the data preprocessing units are connected with the Pt100 sensor (7), convert the resistance change of the Pt100 sensor (7) into a voltage signal and input the voltage signal to the analog-to-digital conversion unit (2);
the analog-to-digital conversion unit (2) converts the voltage signal input by the data preprocessing unit into a digital signal and transmits the digital signal to the main control unit (3);
the main control unit (3) reads the data input by the analog-to-digital conversion unit (2), completes the processing, calibration and conversion of sampling values, and completes data interaction with the touch screen (5) through the communication unit (4).
2. The high-precision, multi-channel Pt100 sensor temperature detecting apparatus of claim 1, wherein: the data preprocessing unit converts the Pt100 resistance change into a voltage signal of 0-10 v.
3. The high-precision, multi-channel Pt100 sensor temperature detecting apparatus of claim 1, wherein: the analog-to-digital conversion unit (2) supports eight-channel analog signal acquisition and is connected with the main control unit (3) through a parallel data interface.
4. The high-precision, multi-channel Pt100 sensor temperature detecting apparatus of claim 1, wherein: the communication unit (4) adopts an RS-485 communication mode.
5. The high-precision, multi-channel Pt100 sensor temperature detecting apparatus of claim 1, wherein: the touch screen (5) is an industrial serial screen.
6. The high-precision, multi-channel Pt100 sensor temperature detecting apparatus of claim 1, wherein: the power management unit (6) includes five voltages of +24v, +12v, +5v, +3.3v, and +1.9v.
7. A calibration method of a high-precision multichannel Pt100 sensor temperature detection device is characterized by comprising the following steps of: the method comprises the following steps:
temperature conversion
Establishing a Pt100 sensor resistance temperature comparison array;
(II) data calibration
Creating a theoretical resistance temperature comparison array;
(ii) creating a measured resistance temperature control array;
(iii) making differences in one-to-one correspondence between elements in the theoretical resistance temperature and the actually measured resistance temperature comparison array, and obtaining an error value array;
(iv) establishing a fitting curve by using the actually measured resistance temperature control array and the error value array to obtain a fitting equation;
(v) at R t In the calculation of the value, the resistance R is measured t And adding a calibration value error on the basis, and performing temperature conversion to obtain a final detection temperature value.
8. The method for calibrating a high-precision multichannel Pt100 sensor temperature detecting device of claim 7, wherein: the specific resistance temperature control array is as follows: establishing a Pt100 sensor resistance temperature control array at intervals of 0.01 ℃ within the range of-100 ℃ to 100 ℃,
Buf[T n ]={R -100.00 ，R -99.99 ，R -99.98 ...R n ...R 99.98 ，R 99.99 ，R 100.00 }，
T n ∈（-100.00℃，100.00℃），
wherein R is n Refers to the temperature T n The theoretical output resistance of Pt 100.
9. The method for calibrating a high-precision multichannel Pt100 sensor temperature detecting device of claim 7, wherein: the measured resistance temperature control array is calibrated by a FLUKE 754 process signal calibrator, standard signals of the calibrator are input into a detection device at intervals of 10 ℃ between-100 ℃ and 100 ℃, and the temperature and resistance control array Buf2[ T ] is recorded 2 ]={R -100.00 ，R -90.00 ，R -80.00 ，R -70.00 ...R t ...R 70.00 ，R 80.00 ，R 90.00 ，R 100.00 }，T 2 ∈（-100.00℃，100.00℃）。
10. The method for calibrating a high-precision multichannel Pt100 sensor temperature detecting device of claim 7, wherein: the fitting equation takes elements in the measured resistance temperature comparison array as abscissa and elements in the error value array as ordinate, a secondary fitting curve is made, and a fitting equation error=k is obtained 2 *R t 2 +k 1 *R t +k 0 Wherein k is 2 、k 1 、k 0 Is a constant coefficient, R t The measured resistance value, error, is the deviation value.
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