A multi-channel temperature measuring device supporting LoRa wireless remote transmission

Abstract

The utility model provides a kind of multi-channel temperature measuring device supporting LoRa wireless remote transmission, including main control module, the LCD display module, current energy storage module, analog output module, LoRa wireless module being connected with main control module, multiple analog signal conditioning module, and multiple temperature sensors being connected with multiple analog signal conditioning module respectively;The utility model increases the LoRa function that can be wirelessly remotely transmitted on the basis of being compatible with original 4-20mA process by unique current loop energy storage technology, it is convenient for multiple measurement point data synchronous upload to host computer, realizes centralized management, and better improves process control ability.

Description

Technical Field

[0001] This utility model relates to the field of temperature measurement technology, specifically to a multi-channel temperature measurement device that supports LoRa wireless long-distance transmission. Background Technology

[0002] In industrial production, it is necessary to monitor the temperature of the medium in real time to ensure production quality. With the development of modern production technology, higher requirements have been put forward for production big data. The traditional 4-20mA transmission method of transmitters is based on the transmission of a single variable, which is not conducive to the collection and transmission of big data.

[0003] Furthermore, the existing technology uses a 4-20mA analog output method, which requires the PLC's analog acquisition module to collect data and then convert it into a digital signal for transmission. Multiple conversions will cause a decrease in accuracy, and multiple temperature measurement points require multiple PLC modules, resulting in high system costs and making it difficult to apply and promote.

[0004] In view of this, the present invention proposes a multi-channel temperature measurement device that supports LoRa wireless long-distance transmission. Utility Model Content

[0005] The purpose of this invention is to propose a multi-channel temperature measurement device that supports LoRa wireless remote transmission. It employs multi-channel automatic inspection technology, allowing a single unit to support multiple temperature measurement points, effectively reducing equipment costs. Through a unique current loop energy storage technology, it adds LoRa wireless remote transmission functionality while remaining compatible with existing 4-20mA processes. This facilitates the simultaneous uploading of data from multiple measurement points to a host computer, enabling centralized management and significantly improving process control capabilities.

[0006] To achieve the above objectives, the technical solution of this utility model is: a multi-channel temperature measurement device supporting LoRa wireless long-distance transmission, including a main control module, an LCD display module, a current energy storage module, an analog output module, a LoRa wireless module, multiple analog signal conditioning modules, and multiple temperature sensors connected to the multiple analog signal conditioning modules respectively.

[0007] The analog signal conditioning module includes an RC filter circuit and an operational amplifier, used to process the temperature signal output by the temperature sensor;

[0008] The main control module acquires the temperature signal processed by the analog signal conditioning module through the temperature sensor interface and obtains the temperature value.

[0009] The main control module outputs the temperature value to the LCD display module for temperature display via the LED display interface;

[0010] The main control module acquires the voltage level of the energy storage capacitor in the current energy storage module through the current energy storage interface and replenishes the energy storage capacitor for use by the LoRa wireless module.

[0011] The main control module outputs a square wave with adjustable pulse width according to the temperature value through a 4-20mA output interface, and the analog output module outputs a 4-20mA signal.

[0012] The main control module uses the LoRa communication interface to enable the LoRa wireless module to read temperature values.

[0013] Preferably, the main control module uses an M2L31SIDAE microcontroller.

[0014] Preferably, the analog signal conditioning module and the temperature sensor are each provided in three sets.

[0015] Preferably, the LoRa wireless module uses the E22-400T22S chip.

[0016] Preferably, the LCD display module uses a 128x128 dot matrix liquid crystal display screen.

[0017] Preferably, the current energy storage module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a MOSFET, a diode, and an energy storage supercapacitor;

[0018] The first resistor's first terminal is connected to the microcontroller's AD interface; the second resistor's second terminal is connected to the first terminal of the second resistor and the first terminal of the third resistor; the first capacitor's first terminal is connected to the first resistor's first terminal; the first capacitor's second terminal is connected to the second resistor's second terminal and connected to analog ground AVSS; the second resistor's second terminal is connected to the diode's cathode; the diode's anode is connected to the energy storage supercapacitor's positive terminal, the second terminal of the fourth resistor, and the MOSFET's source, and a positive voltage power supply VCC is led out for use by the LoRa wireless module; the MOSFET's drain is connected to the positive voltage power supply VDD; the MOSFET's gate is connected to the first terminal of the fourth resistor and the microcontroller's IO port BAT; the energy storage supercapacitor's negative terminal is grounded.

[0019] Preferably, the MOS transistor is an SI2301 chip.

[0020] Preferably, the analog output module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor, a fourth capacitor, an NPN transistor, and an operational amplifier;

[0021] The first terminal of the fifth resistor is connected to the microcontroller's PWM interface; the second terminal of the fifth resistor is connected to the first terminal of the second capacitor and the inverting input terminal of the operational amplifier; the non-inverting input terminal of the operational amplifier is connected to the first terminals of the sixth and eighth resistors; the second terminal of the sixth resistor is connected to the first terminal of the third capacitor, the positive power supply terminal of the operational amplifier, and connected to the positive voltage power supply VDD; the output terminal of the operational amplifier is connected to the first terminal of the seventh resistor; the second terminal of the seventh resistor is connected to the base of the NPN transistor; the collector of the NPN transistor is connected to the second terminal of the fourth capacitor; the emitter of the NPN transistor is connected to the second terminal of the eighth resistor and the first terminal of the ninth resistor; the second terminal of the ninth resistor is grounded; the second terminals of the third and second capacitors and the negative power supply of the operational amplifier are connected to analog ground AVSS; the first terminal of the fourth capacitor is connected to the positive voltage power supply VDD, and the module output terminal is led out from the two terminals of the fourth capacitor.

[0022] Preferably, the operational amplifier uses the OPA2333 chip.

[0023] Preferably, each of the analog signal conditioning modules includes a dual operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fifth capacitor;

[0024] The positive power supply terminal of the dual operational amplifier is connected to the positive voltage power supply VDD, and the negative power supply terminal is connected to analog ground AVSS. In the dual operational amplifier, the non-inverting input terminal of op-amp UA is connected to the first terminal of the fourteenth resistor and the second terminal of the fifth capacitor; the inverting input terminal of op-amp UA is connected to the second terminal of the eleventh resistor and the first terminal of the twelfth resistor; the output terminal of op-amp UA is connected to the second terminal of the twelfth resistor and then to the microcontroller's AD interface. Similarly, the non-inverting input terminal of op-amp UB is connected to the first terminal of the thirteenth resistor and the first terminal of the fifth capacitor; the inverting input terminal of op-amp UB is connected to the second terminal of the tenth resistor and the first terminal of the eleventh resistor; the output terminal of op-amp UB is connected to the first terminal of the tenth resistor and then to the microcontroller's AD interface. The second terminals of the thirteenth and fourteenth resistors are connected to a temperature sensor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention employs a multi-channel automatic inspection mode, allowing one transmitter to connect to multiple temperature points. It is compatible with the existing 4-20mA mode and can also directly transmit digital signals without a PLC module. Utilizing LoRa wireless transmission, one main unit can connect to multiple nodes, offering high cost-effectiveness and ease of use. Current storage and conditioning technology ensures that wireless communication does not affect the stability of the 4-20mA current output. Attached Figure Description

[0027] Figure 1 This is a structural diagram of the device of this utility model. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1 The technical solution of this utility model will be described in detail below.

[0029] This utility model proposes a multi-channel temperature measurement device that supports LoRa wireless long-distance transmission, including a main control module, an LCD display module, a current energy storage module, an analog output module, a LoRa wireless module, multiple analog signal conditioning modules, and multiple temperature sensors connected to the multiple analog signal conditioning modules respectively.

[0030] The analog signal conditioning module includes an RC filter circuit and an operational amplifier, used to process the temperature signal output by the temperature sensor;

[0031] The main control module acquires the temperature signal processed by the analog signal conditioning module through the temperature sensor interface and obtains the temperature value.

[0032] The main control module outputs the temperature value to the LCD display module for temperature display via the LED display interface;

[0033] The main control module acquires the voltage level of the energy storage capacitor in the current energy storage module through the current energy storage interface and replenishes the energy storage capacitor for use by the LoRa wireless module.

[0034] The main control module outputs a square wave with adjustable pulse width according to the temperature value through a 4-20mA output interface, and the analog output module outputs a 4-20mA signal.

[0035] The main control module uses the LoRa communication interface to enable the LoRa wireless module to read temperature values.

[0036] In this embodiment, the main control module uses the M2L31SIDAE microcontroller. The M2L31SIDAE is a new generation 32-bit low-power microcontroller based on the Arm® Cortex®-M23 core, supporting the Armv8-M instruction set architecture, with an operating speed of up to 72 MHz. It features 512 KB of ReRAM, a built-in dual-bank architecture, supports OTA (Over-The-Air) firmware upgrades, and 40 to 168 KB of SRAM. It provides an operating voltage of 1.71V to 3.6V, an operating temperature of -40℃ to 105℃, and excellent high noise immunity characteristics with 4 kV ESD HBM and 4.4kV EFT.

[0037] In this embodiment, the analog signal conditioning module and the temperature sensor are each provided in three groups. After the microcontroller is powered on and initialized, the multi-channel SAR ADC (AD0-AD5) built into the MCU is used to simultaneously sample multiple temperature signals that have been amplified and conditioned by the operational amplifier. After the sampled values ​​are corrected by internal calibration parameters, the correct temperature value is obtained, the LCD display value is refreshed, and the temperature value is written to the communication-related registers for subsequent wireless communication reading.

[0038] In this embodiment, the LoRa wireless module uses the E22-400T22S chip; it adopts the new LoRa spread spectrum modulation technology, which has a longer communication distance, stronger anti-interference ability, multiple transmission modes, operates in the (410.125-493.125MHz) frequency band, TTL level output, and is compatible with 3.3V and 5V IO voltage.

[0039] In this embodiment, the LCD display module adopts a 128x128 dot matrix liquid crystal display screen; viewing angle: 6H; backlight type: white light; interface method: MCU / SPI; operating temperature: -20~70℃; power supply voltage: 3.3V.

[0040] In this embodiment, the current energy storage module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a MOSFET, a diode, and an energy storage supercapacitor;

[0041] The first resistor's first terminal is connected to the microcontroller's AD interface; the second resistor's second terminal is connected to the first terminal of the second resistor and the first terminal of the third resistor; the first capacitor's first terminal is connected to the first resistor's first terminal; the first capacitor's second terminal is connected to the second resistor's second terminal and connected to analog ground AVSS; the second resistor's second terminal is connected to the diode's cathode; the diode's anode is connected to the energy storage supercapacitor's positive terminal, the second terminal of the fourth resistor, and the MOSFET's source, and a positive voltage power supply VCC is led out for use by the LoRa wireless module; the MOSFET's drain is connected to the positive voltage power supply VDD; the MOSFET's gate is connected to the first terminal of the fourth resistor and the microcontroller's IO port BAT; the energy storage supercapacitor's negative terminal is grounded.

[0042] In this embodiment, the MOS transistor is an SI2301 chip.

[0043] The current energy storage module uses the ADC8 of the main control MCU to collect the level of the energy storage capacitor and uses the IO port BAT to precisely control the switching of the MOSFET. It utilizes the residual energy of the loop current to replenish the supercapacitor during idle time for use during wireless transmission, ensuring that wireless communication does not affect the stability of the 4~20mA current output.

[0044] In this embodiment, the analog output module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor, a fourth capacitor, an NPN transistor, and an operational amplifier;

[0045] The first terminal of the fifth resistor is connected to the microcontroller's PWM interface; the second terminal of the fifth resistor is connected to the first terminal of the second capacitor and the inverting input terminal of the operational amplifier; the non-inverting input terminal of the operational amplifier is connected to the first terminals of the sixth and eighth resistors; the second terminal of the sixth resistor is connected to the first terminal of the third capacitor, the positive power supply terminal of the operational amplifier, and connected to the positive voltage power supply VDD; the output terminal of the operational amplifier is connected to the first terminal of the seventh resistor; the second terminal of the seventh resistor is connected to the base of the NPN transistor; the collector of the NPN transistor is connected to the second terminal of the fourth capacitor; the emitter of the NPN transistor is connected to the second terminal of the eighth resistor and the first terminal of the ninth resistor; the second terminal of the ninth resistor is grounded; the second terminals of the third and second capacitors and the negative power supply of the operational amplifier are connected to analog ground AVSS; the first terminal of the fourth capacitor is connected to the positive voltage power supply VDD, and the module output terminal is led out from the two terminals of the fourth capacitor.

[0046] In this embodiment, the operational amplifier uses the OPA2333 chip.

[0047] The analog output module outputs a square wave with adjustable pulse width through a dedicated PWM interface from the main control chip. After RC filtering, it is converted into a DC mV signal. A current loop conditioning circuit is constructed using a low-power zero-drift operational amplifier OPA2333 to control the output of a 4-20mA signal from the current loop.

[0048] In this embodiment, each of the analog signal conditioning modules includes a dual operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fifth capacitor;

[0049] The positive power supply terminal of the dual operational amplifier is connected to the positive voltage power supply VDD, and the negative power supply terminal is connected to analog ground AVSS. In the dual operational amplifier, the non-inverting input terminal of op-amp UA is connected to the first terminal of the fourteenth resistor and the second terminal of the fifth capacitor; the inverting input terminal of op-amp UA is connected to the second terminal of the eleventh resistor and the first terminal of the twelfth resistor; the output terminal of op-amp UA is connected to the second terminal of the twelfth resistor and then to the microcontroller's AD interface. Similarly, the non-inverting input terminal of op-amp UB is connected to the first terminal of the thirteenth resistor and the first terminal of the fifth capacitor; the inverting input terminal of op-amp UB is connected to the second terminal of the tenth resistor and the first terminal of the eleventh resistor; the output terminal of op-amp UB is connected to the first terminal of the tenth resistor and then to the microcontroller's AD interface. The second terminals of the thirteenth and fourteenth resistors are connected to a temperature sensor.

[0050] The above are preferred embodiments of this utility model. Any changes made to the technical solution of this utility model that do not exceed the scope of the technical solution of this utility model shall be protected within the scope of this utility model.

Claims

1. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission, characterized in that, It includes a main control module, an LCD display module, a current energy storage module, an analog output module, a LoRa wireless module, multiple analog signal conditioning modules, and multiple temperature sensors connected to the multiple analog signal conditioning modules respectively; The analog signal conditioning module includes an RC filter circuit and an operational amplifier, used to process the temperature signal output by the temperature sensor; The main control module acquires the temperature signal processed by the analog signal conditioning module through the temperature sensor interface and obtains the temperature value. The main control module outputs the temperature value to the LCD display module for temperature display via the LED display interface; The main control module acquires the voltage level of the energy storage capacitor in the current energy storage module through the current energy storage interface and replenishes the energy storage capacitor for use by the LoRa wireless module. The main control module outputs a square wave with adjustable pulse width according to the temperature value through a 4-20mA output interface, and the analog output module outputs a 4-20mA signal. The main control module uses the LoRa communication interface to enable the LoRa wireless module to read temperature values.

2. The multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 1, characterized in that, The main control module uses an M2L31SIDAE microcontroller.

3. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 1, characterized in that, The analog signal conditioning module and temperature sensor are each provided in three sets.

4. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 1, characterized in that, The LoRa wireless module uses the E22-400T22S chip.

5. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 1, characterized in that, The LCD display module uses a 128x128 dot matrix liquid crystal display screen.

6. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 2, characterized in that, The current energy storage module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a MOSFET, a diode, and an energy storage supercapacitor; The first resistor's first terminal is connected to the microcontroller's AD interface; the second resistor's second terminal is connected to the first terminal of the second resistor and the first terminal of the third resistor; the first capacitor's first terminal is connected to the first resistor's first terminal; the first capacitor's second terminal is connected to the second resistor's second terminal and connected to analog ground AVSS; the second resistor's second terminal is connected to the diode's cathode; the diode's anode is connected to the energy storage supercapacitor's positive terminal, the second terminal of the fourth resistor, and the MOSFET's source, and a positive voltage power supply VCC is led out for use by the LoRa wireless module; the MOSFET's drain is connected to the positive voltage power supply VDD; the MOSFET's gate is connected to the first terminal of the fourth resistor and the microcontroller's IO port BAT; the energy storage supercapacitor's negative terminal is grounded.

7. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 6, characterized in that, The MOSFET used is an SI2301 chip.

8. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 2, characterized in that, The analog output module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a third capacitor, a fourth capacitor, an NPN transistor, and an operational amplifier; The first terminal of the fifth resistor is connected to the microcontroller's PWM interface; the second terminal of the fifth resistor is connected to the first terminal of the second capacitor and the inverting input terminal of the operational amplifier; the non-inverting input terminal of the operational amplifier is connected to the first terminals of the sixth and eighth resistors; the second terminal of the sixth resistor is connected to the first terminal of the third capacitor, the positive power supply terminal of the operational amplifier, and connected to the positive voltage power supply VDD; the output terminal of the operational amplifier is connected to the first terminal of the seventh resistor; the second terminal of the seventh resistor is connected to the base of the NPN transistor; the collector of the NPN transistor is connected to the second terminal of the fourth capacitor; the emitter of the NPN transistor is connected to the second terminal of the eighth resistor and the first terminal of the ninth resistor; the second terminal of the ninth resistor is grounded; the second terminals of the third and second capacitors and the negative power supply of the operational amplifier are connected to analog ground AVSS; the first terminal of the fourth capacitor is connected to the positive voltage power supply VDD, and the module output terminal is led out from the two terminals of the fourth capacitor.

9. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 8, characterized in that, The operational amplifier uses the OPA2333 chip.

10. A multi-channel temperature measurement device supporting LoRa wireless long-distance transmission according to claim 2, characterized in that, Each of the aforementioned analog signal conditioning modules includes a dual operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fifth capacitor; The positive power supply terminal of the dual operational amplifier is connected to the positive voltage power supply VDD, and the negative power supply terminal is connected to analog ground AVSS. In the dual operational amplifier, the non-inverting input terminal of op-amp UA is connected to the first terminal of the fourteenth resistor and the second terminal of the fifth capacitor; the inverting input terminal of op-amp UA is connected to the second terminal of the eleventh resistor and the first terminal of the twelfth resistor; the output terminal of op-amp UA is connected to the second terminal of the twelfth resistor and then to the microcontroller's AD interface. Similarly, the non-inverting input terminal of op-amp UB is connected to the first terminal of the thirteenth resistor and the first terminal of the fifth capacitor; the inverting input terminal of op-amp UB is connected to the second terminal of the tenth resistor and the first terminal of the eleventh resistor; the output terminal of op-amp UB is connected to the first terminal of the tenth resistor and then to the microcontroller's AD interface. The second terminals of the thirteenth and fourteenth resistors are connected to a temperature sensor.

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