Multipath thermocouple signal generating circuit and device

Abstract

The utility model relates to the technical field of special equipment, and discloses a multipath thermocouple signal generation circuit and device, and the circuit comprises a digital-to-analog conversion unit which is used for converting a thermocouple simulation digital signal to output a thermocouple simulation analog signal; a plurality of analog output units which are connected with the digital-to-analog conversion unit and are used for amplifying the thermocouple analog signals so as to output thermocouple signals; the self-calibration unit is connected with at least one analog output unit and is used for converting the thermocouple signal output by the corresponding analog output unit so as to output a self-calibration signal; and the main control unit is connected with the digital-to-analog conversion unit and the self-calibration unit, and is used for outputting the thermocouple simulation digital signal and receiving the self-calibration signal. According to the utility model, multipath thermocouple signals can be simulated and output, the efficiency of verification, debugging, burn-in and the like of the nuclear power station temperature inspection instrument can be effectively improved, and the thermocouple signal output is accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of special equipment, in particular to a multi-channel thermocouple signal generating circuit and a device. Background Art

[0002] The temperature inspection instrument is one of the important equipment for monitoring the operating status of important equipment (such as generators, etc.) in nuclear power plants. Therefore, the accuracy of its temperature measurement is of great significance to maintaining the stable operation of nuclear power plants. In the relevant technology, the existing thermocouple signal generator is usually a single-channel or dual-channel output, and the function is relatively simple. However, the temperature inspection instrument of a nuclear power plant is usually equipped with multiple thermocouples to measure the temperature at multiple locations. Therefore, when using the existing thermocouple signal generator to calibrate, debug, copy the temperature inspection instrument of a nuclear power plant, there are defects such as low efficiency and reliability. Utility Model Content

[0003] In order to solve the above problems, the utility model provides a multi-channel thermocouple signal generating circuit and device.

[0004] The technical solution adopted by the utility model to solve the technical problem is: construct a multi-channel thermocouple signal generating circuit, including:

[0005] A digital-to-analog conversion unit, the digital-to-analog conversion unit is used to convert the thermocouple simulation digital signal to output a thermocouple simulation analog signal;

[0006] A plurality of analog output units, each of which is connected to the digital-to-analog conversion unit, and is used to amplify the thermocouple simulation analog signal to output a thermocouple signal;

[0007] A self-calibration unit, the self-calibration unit being connected to at least one of the analog output units, the self-calibration unit being used to convert a thermocouple signal outputted by the analog output unit to output a self-calibration signal; and

[0008] A main control unit, wherein the main control unit is connected to the digital-to-analog conversion unit and the self-calibration unit, and the main control unit is used to output the thermocouple simulation digital signal and receive the self-calibration signal.

[0009] Preferably, each of the analog output units comprises:

[0010] a first operational amplifier for reducing the first voltage-divided signal according to the bias voltage to output the thermocouple signal;

[0011] a bias voltage regulating unit for dividing the first DC voltage according to the operation to output the bias voltage;

[0012] A first voltage dividing unit connected to the non-inverting input terminal of the first operational amplifier and used for dividing the voltage of the thermocouple simulation analog signal and outputting the first voltage dividing signal;

[0013] a first resistive unit connected between the bias voltage adjustment unit and the negative phase input terminal of the first operational amplifier; and

[0014] A first negative feedback unit is connected between the negative phase input terminal and the output terminal of the first operational amplifier.

[0015] Preferably, the bias voltage adjustment unit includes a thirty-first resistor, an adjustable resistor, a ninety-first resistor, a forty-first resistor and a fifty-first resistor; the first end of the thirty-first resistor is connected to a first DC voltage, the second end of the thirty-first resistor is connected to a first ground via the first end, the second end and the ninety-first resistor of the adjustable resistor, the second end of the thirty-first resistor is also connected to the second end of the adjustable resistor via the forty-first resistor and the fifty-first resistor, the adjustable end of the adjustable resistor P2 is connected to a connection node between the forty-first resistor and the fifty-first resistor, and outputs the bias voltage;

[0016] The first resistive unit includes a fifty-second resistor; the fifty-second resistor is connected between the adjustable end of the adjustable resistor and the negative phase input end of the first operational amplifier AR3;

[0017] The first voltage dividing unit includes a fifty-third resistor and an eighty-first resistor; a non-inverting input terminal of the first operational amplifier is connected to the thermocouple simulation signal through the fifty-third resistor in one path, and is connected to the first ground in another path through the eighty-first resistor;

[0018] The first negative feedback unit includes a ninety-second resistor; the ninety-second resistor is connected between the negative phase input terminal and the output terminal of the first operational amplifier.

[0019] Preferably, the digital-to-analog conversion unit includes a reference voltage output unit and two sub-digital-to-analog conversion units; the reference voltage output unit is connected to the two sub-digital-to-analog conversion units, one of the sub-digital-to-analog conversion units is connected to one part of the analog output units, and the other sub-digital-to-analog conversion unit is connected to the other part of the analog output units.

[0020] Preferably, the number of the analog output units is ten.

[0021] Preferably, the self-calibration unit comprises two sub-self-calibration units for amplifying the thermocouple signal, and an analog-to-digital conversion unit for converting the amplified thermocouple signal into a digital signal to output the self-calibration signal; one of the sub-self-calibration units is connected to one of the analog output units, the other sub-self-calibration unit is connected to the other analog output unit, and the analog-to-digital conversion unit is connected to the two sub-self-calibration units;

[0022] Wherein, each of the sub-self-calibration units includes a second operational amplifier, a thirtieth resistor, a twenty-ninth resistor and a twenty-eighth resistor;

[0023] The non-inverting input terminal of the second operational amplifier is connected to the analog output unit via the 30th resistor, the two gain setting terminals of the second operational amplifier are connected in parallel with the 29th resistor, the output terminal of the second operational amplifier is connected to the analog-to-digital conversion unit, and the negative input terminal of the second operational amplifier is connected to the first ground via the 28th resistor.

[0024] Preferably, the main control unit comprises:

[0025] A human-computer interaction unit, the human-computer interaction unit is used to display the working status and set the thermocouple signal; and

[0026] A processor unit is connected to the human-computer interaction unit, the digital-to-analog conversion unit and the self-calibration unit.

[0027] Preferably, the human-computer interaction unit comprises:

[0028] a display unit connected to the processor unit; and

[0029] A key unit is connected to the processor unit.

[0030] Preferably, the multi-channel thermocouple signal generating circuit further includes:

[0031] Cooling unit;

[0032] A multi-supply unit; and

[0033] A communication unit, the communication unit is connected to the processor unit, and the communication unit is used to communicate with a host computer;

[0034] Wherein, the multi-channel power supply unit comprises:

[0035] A first power supply unit, wherein the first power supply unit is connected to the processor unit and the button unit;

[0036] A second power supply unit, the second power supply unit is connected to the digital-to-analog conversion unit;

[0037] a third power supply unit, the third power supply unit being connected to the self-calibration unit and each of the analog output units;

[0038] a fourth power supply unit, the fourth power supply unit being connected to the display screen unit and being capable of supplying power to the temperature inspection instrument; and

[0039] A fifth power supply unit is connected to the heat dissipation unit.

[0040] The utility model also constructs a multi-channel thermocouple signal generating device, which comprises the multi-channel thermocouple signal generating circuit mentioned above.

[0041] The implementation of the utility model has the following beneficial effects: providing a multi-channel thermocouple signal generating circuit; converting the thermocouple simulation digital signal through the digital-to-analog conversion unit to output the thermocouple simulation analog signal, then amplifying the thermocouple simulation analog signal through multiple analog output units to output the thermocouple signal, then converting the thermocouple signal output by the corresponding analog output unit through the self-calibration unit to output the self-calibration signal, and finally outputting the thermocouple simulation digital signal and receiving the self-calibration signal through the main control unit; the utility model can simulate and output multi-channel thermocouple signals, which can effectively improve the efficiency of nuclear power plant temperature inspection instruments in calibration, debugging, copying and other operations, and also has the advantage of accurate thermocouple signal output. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0043] Figure 1 It is a circuit structure block diagram of a multi-channel thermocouple signal generating circuit in some embodiments of the utility model;

[0044] Figure 2 is a circuit schematic diagram of an analog output unit and a sub-digital-to-analog conversion unit in some embodiments of the utility model;

[0045] Figure 3 is a circuit schematic diagram of a reference voltage output unit in some embodiments of the utility model;

[0046] Figure 4 is a circuit schematic diagram of a sub-self-calibration unit in some embodiments of the utility model;

[0047] Figure 5 is a circuit schematic diagram of an analog-to-digital conversion unit in some embodiments of the utility model;

[0048] Figure 6 is a circuit schematic diagram of a main control unit in some embodiments of the utility model;

[0049] Figure 7 is a circuit schematic diagram of a display unit in some embodiments of the utility model;

[0050] Figure 8 is a circuit schematic diagram of a key unit in some embodiments of the utility model;

[0051] Fig. 9 is a circuit schematic diagram of a heat dissipation unit in some embodiments of the utility model;

[0052] Fig.10 is a circuit schematic diagram of a communication unit in some embodiments of the utility model;

[0053] Fig.11 is a circuit schematic diagram of the first power supply unit in some embodiments of the utility model;

[0054] Fig.12 is a circuit schematic diagram of the second power supply unit in some embodiments of the utility model;

[0055] Fig.13a and Fig.13b is a circuit schematic diagram of the third power supply unit in some embodiments of the utility model;

[0056] Fig.14 is a circuit schematic diagram of a fourth power supply unit in some embodiments of the utility model;

[0057] Fig.15 It is a circuit schematic diagram of the fifth power supply unit in some embodiments of the utility model. DETAILED DESCRIPTION

[0058] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0059] In the following description, it is necessary to understand that the directions or positional relationships indicated by “front”, “back”, “up”, “down”, “left”, “right”, “longitudinal”, “horizontal”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “head”, and “tail”, etc., are based on the directions or positional relationships shown in the accompanying drawings, and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution, and do not indicate that the device or element referred to must have a specific direction. Therefore, they should not be understood as a limitation on the present utility model.

[0060] like Figure 1 As shown in FIG. 1 , it is a circuit structure block diagram of a multi-channel thermocouple signal generating circuit in some embodiments of the utility model. The circuit can simulate and output multi-channel thermocouple signals to perform calibration, debugging, copying, etc. of nuclear power plant temperature inspection instruments, and has the advantage of high simulation accuracy. Figure 1As shown, the multi-channel thermocouple signal generating circuit includes a digital-to-analog conversion unit 1 , a self-calibration unit 3 , a main control unit 4 , and a plurality of analog output units 2 .

[0061] The digital-to-analog conversion unit 1 is used to convert the thermocouple simulation digital signal to output the thermocouple simulation analog signal. Specifically, the digital-to-analog conversion unit 1 can convert the thermocouple simulation digital signal into an analog signal (i.e., the thermocouple simulation analog signal). In addition, the voltage value of the thermocouple simulation analog signal can be greater than the target voltage value of the thermocouple signal to be simulated, and has a correlation with the size of the target voltage value, that is, the thermocouple simulation analog signal can characterize the size of the target voltage value. In this way, information is transmitted through a large voltage signal, which can not only reduce the impact of clutter and improve anti-interference ability, but also make the subsequent circuit easier to identify, which helps to improve the signal output accuracy.

[0062] Each analog output unit 2 is connected to the digital-to-analog conversion unit 1, and each analog output unit 2 is used to amplify the thermocouple simulation signal to output the thermocouple signal. Specifically, the analog output unit 2 can restore the thermocouple simulation signal according to the correlation between the thermocouple simulation signal and the target voltage value (that is, the amplification factor of the analog output unit 2 can be less than 1), so that the voltage value of the thermocouple signal output by the analog output unit 2 is equal to or nearly equal to the target voltage value of the thermocouple signal to be simulated.

[0063] The self-calibration unit 3 is connected to at least one of the analog output units 2, and is used to convert the thermocouple signal output by the corresponding analog output unit 2 to output a self-calibration signal. Specifically, the self-calibration unit 3 amplifies the thermocouple signal and converts it into a digital signal, that is, obtains a self-calibration signal, and the self-calibration signal is correlated with the thermocouple signal, that is, the self-calibration signal can characterize the voltage magnitude of the thermocouple signal.

[0064] The main control unit 4 is connected to the digital-to-analog conversion unit 1 and the self-calibration unit 3, and the main control unit 4 is used to output a thermocouple simulation digital signal and receive a self-calibration signal. Specifically, the main control unit 4 can amplify the target voltage value of the thermocouple signal to be simulated according to a preset linear function, so as to obtain a thermocouple simulation analog signal corresponding to the target voltage value of the thermocouple signal. For example, the preset linear function can be Y=X*130+0.5V (or other existing linear functions), where X represents the target voltage value, and Y represents the voltage value of the thermocouple simulation analog signal. When the measured temperature of a simulated K-type thermocouple is 720°C, it can be seen from the graduation table of the K-type thermocouple that the voltage value output by the thermocouple is 29.965mV. Based on the preset linear function, it can be calculated that the voltage value of the thermocouple simulation analog signal is 4.395V (equal to 29.965mV*130+0.5V), that is, in this case, the thermocouple simulation digital signal can control the digital-to-analog conversion unit 1 to output a 4.395V analog signal; in addition, it is easy to understand that the main control unit 4 can also compare the error between the thermocouple signal and the target voltage value through the self-calibration signal to see whether it meets the requirements. If it does not meet the requirements, the thermocouple simulation digital signal can be adjusted to make the thermocouple signal close to the target voltage value, thereby effectively ensuring the accuracy of the thermocouple signal.

[0065] In some embodiments, Figure 2 and Figure 3 As shown, the digital-to-analog conversion unit 1 includes a reference voltage output unit 11 and two sub-digital-to-analog conversion units 12. The reference voltage output unit 11 is connected to the two sub-digital-to-analog conversion units 12, one of which is connected to a part of the analog output unit 2, and the other sub-digital-to-analog conversion unit 12 is connected to another part of the analog output unit 2.

[0066] In some embodiments, Figure 3 As shown, the reference voltage output unit 11 may include a first voltage reference chip U19, an eighty-fourth capacitor C84, an eighty-fifth capacitor C85 and an eighty-ninth capacitor C89. Among them, the first voltage reference chip U19 may be a voltage reference chip of model ADR441BRZ. The input end of the first voltage reference chip U19 is connected to the second DC voltage (+3.3V) and connected to the digital ground (digital ground corresponds to DGND) through the eighty-fourth capacitor C84, the eighty-fifth capacitor C85 is connected in parallel with the eighty-fourth capacitor C84, and the output end of the first voltage reference chip U19 outputs the reference voltage and is connected to the digital ground through the eighty-ninth capacitor C89. It should be noted that the reference voltage output by the reference voltage output unit 11 can be supplied to multiple sub-digital-to-analog conversion units 12 at the same time.

[0067] In some embodiments, Figure 2As shown, each sub-digital-to-analog conversion unit 12 includes a digital-to-analog conversion chip U18, a first crystal oscillator X4, a seventy-ninth capacitor C79 and an eightieth capacitor C80. Among them, the signal of the digital-to-analog conversion chip U18 can be DAC1220. The reference voltage input terminal of the digital-to-analog conversion chip U18 is connected to the reference voltage output unit 11, the two crystal oscillator signal input terminals of the digital-to-analog conversion chip U18 are connected in parallel with the first crystal oscillator X4, one end of the first crystal oscillator X4 is also connected to the digital ground via the seventy-ninth capacitor C79, and one end of the first crystal oscillator X4 is also connected to the digital ground via the eightieth capacitor C80, the digital signal input terminal of the digital-to-analog conversion chip U18 is connected to the main control unit 4, and the analog signal output terminal of the digital-to-analog conversion chip U18 is connected to at least one analog output unit 2. In this embodiment, the digital-to-analog conversion unit 1 can convert the thermocouple simulation digital signal output by the main control unit 4 into a thermocouple simulation analog signal, and the voltage value of the thermocouple simulation analog signal is greater than the target voltage value of the thermocouple signal, and there is a correlation between the two, in preparation for subsequent signal restoration.

[0068] In some examples, the number of analog output units 2 may be ten.

[0069] In some embodiments, Figure 2 As shown, each analog output unit 2 includes a first operational amplifier AR3 , a bias voltage adjustment unit 21 , a first voltage dividing unit 22 , a first resistive unit 23 and a first negative feedback unit 24 .

[0070] The first operational amplifier AR3 is used to reduce the first voltage-divided signal according to the bias voltage to output a thermocouple signal. The first operational amplifier AR3 may be an amplifier of model ADA4638-1.

[0071] The bias voltage adjustment unit 21 is used to divide the first DC voltage (5Vref) according to the operation to output the bias voltage. Further, in some embodiments, Figure 2 As shown, the bias voltage adjustment unit 21 may include a thirty-first resistor R31, an adjustable resistor P2, a ninety-first resistor R91, a forty-first resistor R41, and a fifty-first resistor R51. The first end of the thirty-first resistor R31 is connected to the first DC voltage (5Vref), the second end of the thirty-first resistor R31 is connected to the first ground (the first ground corresponds to GND) via the first end and the second end of the adjustable resistor P2 and the ninety-first resistor R91, the second end of the thirty-first resistor R31 is also connected to the second end of the adjustable resistor P2 via the forty-first resistor R41 and the fifty-first resistor R51, the adjustable end of the adjustable resistor P2 is connected to the connection node of the forty-first resistor R41 and the fifty-first resistor R51, and the bias voltage is output. It can be understood that the magnitude of the bias voltage is adjusted by adjusting the position of the adjustable end of the adjustable resistor P2.

[0072] The first voltage dividing unit 22 is connected to the non-inverting input terminal of the first operational amplifier AR3, and is used to divide the voltage of the thermocouple simulation analog signal and output a first voltage dividing signal. Figure 2 As shown, the first voltage-dividing unit 22 includes a fifty-third resistor R53 and an eighty-first resistor R81; the non-inverting input terminal of the first operational amplifier AR3 is connected to the thermocouple simulation analog signal through the fifty-third resistor R53, and is connected to the first ground through the eighty-first resistor R81. It can be understood that the magnitude of the first voltage-dividing signal can be adjusted by adjusting the resistance ratio of the fifty-third resistor R53 and the eighty-first resistor R81, so as to adjust the amplification factor of the analog output unit 2.

[0073] The first resistive unit 23 is connected between the bias voltage adjustment unit 21 and the negative phase input terminal of the first operational amplifier AR3. Figure 2 As shown, the first resistive unit 23 may include a fifty-second resistor R52. The fifty-second resistor R52 is connected between the adjustable end of the adjustable resistor P2 and the negative phase input end of the first operational amplifier AR3 to transmit the bias voltage to the negative phase input end of the first operational amplifier AR3.

[0074] The first negative feedback unit 24 is connected between the negative phase input terminal and the output terminal of the first operational amplifier AR3. Figure 2 As shown, the first negative feedback unit 24 may include a ninety-second resistor R92. The ninety-second resistor R92 is connected between the negative phase input terminal and the output terminal of the first operational amplifier AR3.

[0075] It is understandable that the first operational amplifier AR3, the bias voltage adjustment unit 21, the first voltage divider unit 22, the first resistive unit 23 and the first negative feedback unit 24 constitute an amplifier circuit, which can reduce the thermocouple simulation analog signal so that the thermocouple simulation analog signal is restored to a thermocouple signal. It is easy to understand that this method of first amplifying a small signal helps to improve the recognition accuracy of the subsequent circuit, and then performs an inverse operation for output, which can effectively ensure the output accuracy and improve the anti-interference ability.

[0076] In some embodiments, Figure 4 and Figure 5As shown, the self-calibration unit 3 may include two sub-self-calibration units 31 for amplifying the thermocouple signal, and an analog-to-digital conversion unit 32 for converting the amplified thermocouple signal into a digital signal to output the self-calibration signal. One of the sub-self-calibration units 31 is connected to one of the analog output units 2 to obtain the thermocouple signal output by the one of the analog output units 2, and the other sub-self-calibration unit 31 is connected to the other analog output unit 2 to obtain the thermocouple signal output by the other analog output unit 2, and the analog-to-digital conversion unit 32 is connected to the two sub-self-calibration units 31.

[0077] Furthermore, if Figure 4 As shown, each sub-self-calibration unit 31 may include a second operational amplifier U16, a 30th resistor R30, a 29th resistor R29 and a 28th resistor R28. The model of the second operational amplifier U16 may be AD8221. The positive phase input terminal of the second operational amplifier U16 is connected to an analog output unit 2 via the 30th resistor R30, the two gain setting terminals of the second operational amplifier U16 are connected in parallel with the 29th resistor R29, the output terminal of the second operational amplifier U16 is connected to the analog-to-digital conversion unit 32, and the negative phase input terminal of the second operational amplifier U16 is connected to the first ground via the 28th resistor R28.

[0078] In some embodiments, Figure 5 As shown, the analog-to-digital conversion unit 32 may include a second voltage reference chip U11, a 42nd capacitor C42, a 44th capacitor C44, a 49th capacitor C49 and a 50th capacitor C50, an analog-to-digital conversion chip U13, a 56th capacitor C56 and a 58th capacitor C58. Among them, the model of the second voltage reference chip U11 may be REF194, and the model of the analog-to-digital conversion chip U13 may be AD7787. The enable end and the power supply end of the second voltage reference chip U11 are connected to the second DC voltage (+3.3V), and are connected to the first ground via the 42nd capacitor C42, the 44th capacitor C44 is connected in parallel with the 42nd capacitor C42, the output end of the second voltage reference chip U11 is connected to the reference end of the analog-to-digital conversion chip U13, and are connected to the first ground via the 49th capacitor C49, the 50th capacitor C50 and the 49th capacitor C49 are connected in parallel, the first analog input end (AIN1 pin) and the second analog input end (AIN2 pin) of the analog-to-digital conversion chip U13 are connected in parallel. The power supply end of the analog-to-digital conversion chip U13 is connected to the third DC voltage (+5VDVDD) and is connected to the first ground via the fifty-sixth capacitor C56. The fifty-eighth capacitor C58 and the fifty-sixth capacitor C56 are connected in parallel. The enable end (CS pin), the clock signal end (SCLK pin), the digital signal output end (DOUT) and the digital signal input and output end (DIN) of the analog-to-digital conversion chip U13 are respectively connected to the main control unit 4 to realize information interaction.

[0079] In some embodiments, the main control unit 4 may include a human-machine interaction unit for displaying the working status and setting the thermocouple signal, and a processor unit 42 connected to the human-machine interaction unit, the digital-to-analog conversion unit 1 and the self-calibration unit 3 .

[0080] Furthermore, if Figure 6 As shown, the main control unit 4 may include a processor U15 of model STM32L071071C8, and peripheral electronic devices related to the processor U15 (specifically including a first button U12, a fifth resistor R5, etc.). The specific circuit connection structure can be referred to Figure 6 .

[0081] Furthermore, if Figure 7 and Figure 8 As shown, the human-computer interaction unit includes a display unit and a key unit connected to the processor unit 42.

[0082] In some embodiments, Figure 7 As shown, the display unit may include a display J9, a RS232 communication chip of model MAX232, and peripheral electronic devices related to the RS232 communication chip (specifically including the 134th capacitor C134, the 135th capacitor C135, etc.). The specific circuit connection structure can be referred to Figure 7 In this embodiment, the function of the RS232 communication chip is to establish a communication channel between the display and the processor U15, so that the processor U15 can control the display content of the display J9, such as the setting value of the thermocouple signal.

[0083] In some embodiments, Figure 8 As shown, the key unit may include two sub-key units 421. Each sub-key unit 421 may include a second key J14, a 111th resistor R121 and a 132nd capacitor C132. The first end of the second key J14 is connected to the main control unit 4 and is connected to the second DC voltage (+3.3V) via the 111th resistor R121. The first end of the second key J14 is also connected to the digital ground and the second end of the second key J14 via the 132nd capacitor C132. In this embodiment, the user can set the working mode of the multi-channel thermocouple signal generating circuit by pressing the second key J14. For example, when the second key J14 included in one of the sub-key units is pressed, the main control unit 4 can control each analog output unit to output a thermocouple signal whose voltage value gradually increases based on a preset time interval, and when the second key J14 included in another sub-key unit is pressed, the main control unit 4 controls each analog output unit to output a thermocouple signal whose voltage value gradually decreases based on a preset time interval.

[0084] In some embodiments, Figure 1 As shown, the multi-channel thermocouple signal generating circuit may further include a heat dissipation unit 5, a multi-channel power supply unit 6, and a communication unit 7 connected to the processor unit 42 for communicating with a host computer.

[0085] Furthermore, if Fig. 9 As shown, the heat dissipation unit 5 may include a first fan J16, a second fan J17, a PCT thermistor, and a first switch connected to each fan for controlling the fan to be turned on or off. Among them, the first fan J16 and the second fan J17 can be existing electric fans, and the first switch can be an existing knob switch or a key switch. Specifically, the moving contact of the first switch is connected to the fourth DC voltage (5V-FY) through the PCT thermistor, the fixed contact of the first switch is simultaneously connected to the positive end of the first fan J16 and the positive end of the second fan J17, and the negative end of the first fan J16 and the negative end of the second fan J17 are connected to the fourth DC voltage ground end (5V-GND). In this embodiment, the function of the heat dissipation unit 5 is to dissipate heat for the multi-channel thermocouple signal generating circuit, which can effectively prevent electronic devices from being damaged due to overheating.

[0086] Furthermore, if Fig.10As shown, the communication unit 7 may include a USB to serial port chip U2, a second crystal oscillator X1, a second capacitor C2, a third capacitor C3, a first capacitor C1, a digital isolator U3 and a 151 capacitor C151. Among them, the model of the USB to serial port chip U2 may be CH340, and the model of the digital isolator U3 may be ADUM1201. The USB positive input terminal, the USB negative input terminal, the USB power supply terminal and the USB ground terminal of the USB to serial port chip U2 are used to connect the upper computer, the two crystal oscillator signal input terminals of the USB to serial port chip U2 are connected in parallel with the second crystal oscillator X1, one end of the second crystal oscillator X1 is connected to the first end of the first capacitor C1 via the second capacitor C2, the other end of the second crystal oscillator X1 is connected to the first end of the first capacitor C1 via the third capacitor C3, the second end of the first capacitor C1 is connected to the USB ground terminal of the USB to serial port chip U2, and the RXD pin of the USB to serial port chip U2 is connected to the digital isolator U 3, the TXD pin of the USB to serial port chip U2 is connected to the VIB pin of the digital isolator U3, the VIA pin and the VOB pin of the digital isolator U3 are respectively connected to the processor U15 in the main control unit 4, the VDD1 pin of the digital isolator U3 is connected to the USB power supply end of the USB to serial port chip U2, the GND1 pin of the digital isolator U3 is connected to the USB grounding end of the USB to serial port chip U2, the VDD2 pin of the digital isolator U3 is connected to the second DC voltage (+3.3V), and the GND2 pin of the digital isolator U3 is connected to the digital ground. In this embodiment, the main control unit 4 can send the operating process setting parameters, status information, fault alarm information, etc. of the multi-channel thermocouple signal generating circuit to the host computer through the communication unit 7, and the host computer includes but is not limited to mobile phones, computers and other devices.

[0087] In some embodiments, Figures 11 to 15 As shown, the multi-way power supply unit 6 includes a first power supply unit 61 , a second power supply unit 62 , a third power supply unit 63 , a fourth power supply unit 64 and a fifth power supply unit 65 .

[0088] like Figure 6 , Figure 8 and Fig.11 As shown, the first power supply unit 61 is connected to the processor unit 42 and the button unit 412 to supply power to the processor unit 42 and the button unit 412. Specifically, the first power supply unit 61 is used to output a second DC voltage (+3.3V). Fig.11As shown, the first power supply unit 61 may include a first linear voltage regulator chip U10, a 30th capacitor C30, a 43rd capacitor C43, a 45th capacitor C45 and a 47th capacitor C47. The model of the first linear voltage regulator chip U10 may be ADP7142. The input end of the first linear voltage regulator chip U10 is connected to the third DC voltage (+5VDVDD) and connected to the digital ground via the 30th capacitor C30. The output end of the first linear voltage regulator chip U10 outputs a second DC voltage (+3.3V) and is connected to the digital ground via the 43rd capacitor C43. The 45th capacitor C45 and the 47th capacitor C47 are respectively connected in parallel with the 43rd capacitor C43.

[0089] like Fig.12 As shown, the second power supply unit 62 is connected to the digital-to-analog conversion unit 1, and the second power supply unit 62 is used to output a third DC voltage (+5VDVDD) and a sixth DC voltage (+5VAVDD). Fig.11As shown, the second power supply unit 62 may include a first power module U4, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a fourteenth capacitor C14, a second resistor R2, a fifteenth capacitor C15, a seventeenth capacitor C17, a fourth resistor R4, a second power module U9, a seventh resistor R7, a third voltage regulator D3, a ninth resistor R9, a twenty-sixth capacitor C26, a twenty-first capacitor C21, a fifteenth resistor R15, a seventeenth resistor R17, a thirty-second capacitor C32, a thirty-sixth capacitor C36, a fortieth capacitor C40, a forty-first capacitor C41, a second inductor L2, a forty-sixth capacitor C46 and a forty-eighth capacitor C48. The model of the first power module U4 may be TMAP2409S, and the model of the second power module U9 may be LMZ14201. The fifth DC voltage (+24V) is included in the input end of the first power module U4, the input ground end of the first power module U4 is connected to the analog ground (the analog ground corresponds to GNDY), the input end and the input ground end of the first power module U4 are also connected in parallel with the tenth capacitor C10, the eleventh capacitor C11, the twelfth capacitor C12 and the fourteenth capacitor C14, respectively, the output end of the first power module U4 outputs the seventh DC voltage (+9V) and is connected to the input end of the second power module U9, the output end of the first power module U4 is also connected to the digital ground via the second resistor R2, the fifteenth capacitor C15 and the seventeenth capacitor C17 are respectively connected in parallel with the second resistor R2, the output end of the first power module U4 is also connected to the enable end of the second power module U9 via the fourth resistor R4, the enable end of the second power module U9 is connected to the digital ground via the seventh resistor R7, and is also connected to the digital ground via the cathode and anode of the third voltage regulator tube D3, the input end of the second power module U9 is connected to the ground of the second power module U9 via the ninth resistor R9. The time setting end, the input end of the second power module U9 is also connected to the digital ground via the twenty-sixth capacitor C26, the twenty-first capacitor C21 is connected in parallel with the twenty-sixth capacitor C26, the output end of the second power module U9 outputs the third DC voltage (+5VDVDD), the fifteenth resistor R15 is connected in parallel with the output end and the feedback end of the second power module U9, the feedback end of the second power module U9 is connected to the digital ground via the seventeenth resistor R17, the thirty-second capacitor C32 is connected in parallel with the fifteenth resistor R15, the output end of the second power module U9 is also connected to the digital ground via the thirty-sixth capacitor C36, the fortieth capacitor C40 and the forty-first capacitor C41 are respectively connected in parallel with the thirty-sixth capacitor C36, the output end of the second power module U9 is also connected to the first end of the second inductor L2, the second end of the second inductor L2 outputs the sixth DC voltage (+5VAVDD), the second end of the second inductor L2 is also connected to the first ground via the forty-sixth capacitor C46, ​​and the forty-eighth capacitor C48 is connected in parallel with the forty-sixth capacitor C46.

[0090] like Fig.13a and Fig.13bAs shown, the third power supply unit 63 is connected to the self-calibration unit 3 and each analog output unit 2, and the third power supply unit 63 is used to output the eighth DC voltage (+14V), the ninth DC voltage (-14V) and the first DC voltage (5Vref).

[0091] like Fig.13a As shown, the third power supply unit 63 may include a third power supply module U5 of model TMR3-2423, a second linear voltage regulator chip U6 of model ADP7142, a third linear voltage regulator chip U7 of model LT1964, and related peripheral electronic devices (specifically including a first inductor L1, a sixteenth capacitor C6, a third inductor L3, a fourth inductor L4, etc.). The specific circuit connection structure can be referred to Fig.13a . Among them, the third power supply module U5 can output the eleventh DC voltage (+15V) and the twelfth DC voltage (-15V) based on the fifth DC voltage (+24V); then the second linear voltage regulator chip U6 outputs the fourteenth DC voltage (+14VDVDD) based on the eleventh DC voltage (+15V), and the fourteenth DC voltage (+14VDVDD) is processed by the filter composed of the third inductor L3, the one hundred and forty-fourth capacitor C144 and the one hundred and forty-fifth capacitor C145 to obtain the eighth DC voltage (+14V); the third linear voltage regulator chip U7 outputs the thirteenth DC voltage (-14VDVDD) based on the twelfth DC voltage (-15V), and the thirteenth DC voltage (-14VDVDD) is processed by the filter composed of the fourth inductor L4, the one hundred and forty-eighth capacitor C148 and the one hundred and forty-ninth capacitor C149 to obtain the ninth DC voltage (-14V).

[0092] like Fig.13b As shown, the third power supply unit 63 may also include a fourth power module U8 of model LMZ14201, a voltage reference chip U14 of model ADR4550BRZ, a fourth operational amplifier AR1, a fifth operational amplifier AR2, and related peripheral electronic components (specifically including a fourteenth resistor R14, a sixteenth resistor R16, a twenty-fourth resistor R24, a fourth inductor L4, etc.). The specific circuit connection structure can be referred to Fig.13b . Among them, the fourth power supply module U8 can output the tenth DC voltage (+5.6V) based on the seventh DC voltage (+9V), the voltage reference chip U14 outputs a 5V DC voltage based on the tenth DC voltage (+5.6V), and the fourth operational amplifier AR1 and the fifth operational amplifier AR2 respectively form a follower circuit with related peripheral devices, wherein the fourth operational amplifier AR1 outputs a first group of first DC voltages (5Vref) (5Vref-1) based on the 5V DC voltage, and the fourth operational amplifier AR1 outputs a second group of first DC voltages (5Vref) (5Vref-2) based on the 5V DC voltage.

[0093] The fourth power supply unit 64 is connected to the display unit (not shown) and can supply power to the temperature inspection instrument. The fourth power supply unit 64 is used to output a fifth DC voltage (+24V). Fig.14 As shown, the fourth power supply unit 64 may include a first fuse F0, a second fuse F1, an ACDC power supply module U1 of model TMP30124, and related peripheral electronic components (specifically including a seventh capacitor C7, an eighth capacitor C8, etc.). The specific circuit connection structure can be referred to Fig.14 Among them, the ACDC power module U1 can output the fifth DC voltage (+24V) based on the AC power.

[0094] like Fig.15 As shown, the fifth power supply unit 65 is connected to the heat dissipation unit 5, and the fifth power supply unit 65 is used to output a fourth DC voltage (5V-FY). The fifth power supply unit 65 may include a sixth power supply module U22 of model TMR1-2411, and related peripheral electronic components (specifically including the 153rd capacitor C153, the 152nd capacitor C152, etc.). The specific circuit connection structure can be referred to Fig.15 The sixth power supply module U22 can output a fourth DC voltage (5V-FY) based on the fifth DC voltage (+24V).

[0095] The utility model also provides a multi-channel thermocouple signal generating device, comprising the multi-channel thermocouple signal generating circuit provided in the embodiment of the utility model.

[0096] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should belong to the scope covered by the claims of the utility model.

Claims

1. A multi-channel thermocouple signal generating circuit, characterized in that: include: A digital-to-analog conversion unit (1), the digital-to-analog conversion unit (1) being used to convert a thermocouple simulation digital signal to output a thermocouple simulation analog signal; A plurality of analog output units (2), each of the analog output units (2) is connected to the digital-to-analog conversion unit (1), and the analog output unit (2) is used to amplify the thermocouple simulation analog signal to output a thermocouple signal; A self-calibration unit (3), the self-calibration unit (3) being connected to at least one of the analog output units (2), the self-calibration unit (3) being used for converting a thermocouple signal outputted by the analog output unit (2) to output a self-calibration signal; as well as A main control unit (4), the main control unit (4) is connected to the digital-to-analog conversion unit (1) and the self-calibration unit (3), and the main control unit (4) is used to output the thermocouple simulation digital signal and receive the self-calibration signal.

2. The multi-channel thermocouple signal generating circuit according to claim 1, characterized in that: Each of the analog output units (2) comprises: A first operational amplifier, the first operational amplifier is used to reduce the first voltage-divided signal according to the bias voltage to output the thermocouple signal; A bias voltage regulating unit (21), the bias voltage regulating unit (21) being used for dividing the first DC voltage according to an operation to output the bias voltage; A first voltage dividing unit (22), the first voltage dividing unit (22) being connected to the non-phase input terminal of the first operational amplifier and being used for dividing the voltage of the thermocouple simulation analog signal and outputting the first voltage dividing signal; A first resistive unit (23), the first resistive unit (23) being connected between the bias voltage adjustment unit (21) and the negative phase input terminal of the first operational amplifier; and A first negative feedback unit (24), wherein the first negative feedback unit (24) is connected between the negative phase input terminal and the output terminal of the first operational amplifier.

3. The multi-channel thermocouple signal generating circuit according to claim 2, characterized in that: The bias voltage adjustment unit (21) comprises a thirty-first resistor, an adjustable resistor, a ninety-first resistor, a forty-first resistor and a fifty-first resistor; the first end of the thirty-first resistor is connected to a first DC voltage, the second end of the thirty-first resistor is connected to a first ground via the first end, the second end and the ninety-first resistor of the adjustable resistor, the second end of the thirty-first resistor is also connected to the second end of the adjustable resistor via the forty-first resistor and the fifty-first resistor, the adjustable end of the adjustable resistor is connected to a connection node between the forty-first resistor and the fifty-first resistor, and the bias voltage is output; The first resistive unit (23) comprises a fifty-second resistor; the fifty-second resistor is connected between the adjustable end of the adjustable resistor and the negative phase input end of the first operational amplifier; The first voltage dividing unit (22) comprises a fifty-third resistor and an eighty-first resistor; a non-inverting input terminal of the first operational amplifier is connected to the thermocouple simulation signal through the fifty-third resistor in one path, and is connected to the first ground in another path through the eighty-first resistor; The first negative feedback unit (24) comprises a ninety-second resistor; the ninety-second resistor is connected between the negative phase input terminal and the output terminal of the first operational amplifier.

4. The multi-channel thermocouple signal generating circuit according to claim 2, characterized in that: The digital-to-analog conversion unit (1) comprises a reference voltage output unit (11) and two sub-digital-to-analog conversion units (12); the reference voltage output unit (11) is connected to the two sub-digital-to-analog conversion units (12), one of the sub-digital-to-analog conversion units (12) is connected to a portion of the analog output units (2), and the other sub-digital-to-analog conversion unit (12) is connected to another portion of the analog output units (2).

5. The multi-channel thermocouple signal generating circuit according to claim 4, characterized in that: The number of the analog output units (2) is ten.

6. The multi-channel thermocouple signal generating circuit according to claim 2, characterized in that: The self-calibration unit (3) comprises two sub-self-calibration units (31) for amplifying the thermocouple signal, and an analog-to-digital conversion unit (32) for converting the amplified thermocouple signal into a digital signal to output the self-calibration signal; one of the sub-self-calibration units (31) is connected to one of the analog output units (2), the other sub-self-calibration unit (31) is connected to the other analog output unit (2), and the analog-to-digital conversion unit (32) is connected to the two sub-self-calibration units (31); Each of the sub-self-calibration units (31) comprises a second operational amplifier, a thirtieth resistor, a twenty-ninth resistor and a twenty-eighth resistor; The non-inverting input terminal of the second operational amplifier is connected to the analog output unit (2) via the 30th resistor, the two gain setting terminals of the second operational amplifier are connected in parallel with the 29th resistor, the output terminal of the second operational amplifier is connected to the analog-to-digital conversion unit (32), and the negative input terminal of the second operational amplifier is connected to the first ground via the 28th resistor.

7. The multi-channel thermocouple signal generating circuit according to any one of claims 1 to 6, characterized in that: The main control unit (4) comprises: A human-computer interaction unit, the human-computer interaction unit is used to display the working status and set the thermocouple signal; and A processor unit (42), the processor unit (42) being connected to the human-machine interaction unit, the digital-to-analog conversion unit (1) and the self-calibration unit (3).

8. The multi-channel thermocouple signal generating circuit according to claim 7, characterized in that: The human-computer interaction unit comprises: a display unit connected to the processor unit (42); and A key unit is connected to the processor unit (42).

9. The multi-channel thermocouple signal generating circuit according to claim 8, characterized in that: Also includes: Heat dissipation unit (5); A multi-way power supply unit (6); as well as A communication unit (7), the communication unit (7) being connected to the processor unit (42), and the communication unit (7) being used for communicating with a host computer; Wherein, the multi-channel power supply unit (6) comprises: A first power supply unit (61), the first power supply unit (61) being connected to the processor unit (42) and the key unit (412); A second power supply unit (62), the second power supply unit (62) being connected to the digital-to-analog conversion unit (1); A third power supply unit (63), the third power supply unit (63) being connected to the self-calibration unit (3) and each of the analog output units (2); a fourth power supply unit (64), the fourth power supply unit (64) being connected to the display screen unit, and the fourth power supply unit (64) being capable of supplying power to the temperature inspection instrument; and A fifth power supply unit (65), wherein the fifth power supply unit (65) is connected to the heat dissipation unit (5).

10. A multi-channel thermocouple signal generating device, characterized in that: It comprises a multi-channel thermocouple signal generating circuit as described in any one of claims 1 to 9.

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