Self-powered temperature transmitter

Abstract

The invention belongs to the technical field of industrial automation instruments, and particularly relates to a self-powered temperature transmitter, which comprises an explosion-proof cast aluminum shell, a circuit board and a lithium battery, and is characterized in that the circuit board comprises a microcontroller MCU, a signal conditioning circuit, an analog-to-digital converter ADC, a power management circuit and a display driving circuit; the average working current of the whole machine is reduced to a microampere level by adopting multi-stage low-power-consumption design such as an ultra-low-power-consumption MCU, a low-quiescent-current power supply chip, a programmable sampling interval and intelligent backlight control, and the theoretical endurance time can reach several years in cooperation with a high-capacity lithium battery, so that the constraint of an external power supply and a cable is thoroughly eliminated; according to the technical scheme, signal range adaptation is achieved through a programmable gain amplifier on hardware, a full-scale linearization algorithm is built in software, various common industrial temperature sensors such as Pt100, Cu50, K, S, E, J, T and N can be compatible only through panel key selection, and the universality and field applicability of equipment are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of industrial automation instrumentation technology, and particularly relates to a self-powered temperature transmitter. Background Technology

[0002] In industrial settings such as metallurgy, chemical engineering, power generation, and textiles, real-time temperature monitoring is essential. Traditional temperature transmitters typically require an external 24V DC power supply or the laying of power cables, leading to complex system installation, high wiring costs, and safety hazards and maintenance difficulties in harsh environments such as flammable, explosive, corrosive, and humid conditions. While battery-powered instruments exist, they generally suffer from high power consumption, short battery life, lack of support for sensors with full range of graduations, and inconvenient battery replacement, making it difficult to meet the requirements for long-term stable and maintenance-free operation. Summary of the Invention

[0003] The purpose of this invention is to provide a self-powered temperature transmitter to solve the above-mentioned technical problems.

[0004] To achieve the above objectives, the specific technical solution of a self-powered temperature transmitter according to the present invention is as follows: A self-powered temperature transmitter includes an explosion-proof cast aluminum housing, a circuit board, and a lithium battery. The circuit board is disposed inside the explosion-proof cast aluminum housing, and the lithium battery is installed inside the explosion-proof cast aluminum housing. The lithium battery powers the circuit board. An LCD screen and operation buttons are provided on the front panel of the explosion-proof cast aluminum housing. The input terminal of the signal conditioning circuit is connected to an external resistance temperature detector (RTD) or thermocouple via a terminal block, and the output terminal is connected to the ADC. The signal conditioning circuit includes a programmable gain amplifier. The MCU outputs a control signal to the programmable gain amplifier according to the configured sensor index number to adjust its gain and bias. The ADC is connected to the MCU and converts the acquired analog signals into digital signals; The input terminal of the power management circuit is connected to the lithium battery, and the output terminal provides a stable operating voltage for the MCU, signal conditioning circuit and ADC; the power management circuit includes a low quiescent current linear regulator. The MCU is programmed to periodically wake up from a low-power sleep mode, control the ADC to sample the temperature signal, and linearize the sampled value according to the stored graduation number data to obtain the temperature value for display on the LCD screen; the MCU is also connected to the operation buttons for setting parameters.

[0005] Furthermore, the liquid crystal display screen is a backlit LCD, and the MCU controls the backlight's on / off state and brightness level.

[0006] Furthermore, the lithium battery is a 3.6V replaceable industrial lithium-ion battery, and the outer casing has an independent snap-fit ​​battery compartment module. The battery compartment has anti-reverse insertion electrode springs, and the battery compartment is connected to the circuit board via connectors.

[0007] Furthermore, the housing is provided with a threaded interface for connecting an integrated temperature sensor and a transverse electrical interface for connecting a split temperature sensor; the wiring terminals are located inside the housing and are connected to the transverse electrical interface or sensor leads via a sealed gland.

[0008] Furthermore, the MCU is connected to a power monitoring circuit for monitoring the lithium battery voltage.

[0009] Furthermore, the operation buttons include function keys, shift keys, and modification keys. By combining these keys, users can access a multi-level menu to set the sampling interval, sensor type, backlight time, and display unit parameters.

[0010] The advantages of this invention are: 1. By adopting a multi-level low-power design, including an ultra-low-power MCU, a low quiescent current power chip, a programmable sampling interval, and intelligent backlight control, the average operating current of the whole machine is reduced to the microampere level. Combined with a large-capacity lithium battery, the theoretical battery life can reach several years, completely freeing the user from the constraints of external power supply and cables.

[0011] 2. On the hardware side, the signal range is adapted through a programmable gain amplifier, and on the software side, a full-gradient linearization algorithm is built-in. It can be compatible with a variety of commonly used industrial temperature sensors such as Pt100, Cu50, K, S, E, J, T, and N simply by selecting via the panel buttons, which greatly improves the equipment's versatility and field applicability.

[0012] 3. Featuring a unique snap-on battery compartment design, users can safely replace batteries by hand without tools after opening the cover. The cast aluminum casing, sealed gland, and grounding design ensure stable and reliable operation of the product in harsh environments with high explosion-proof (such as Ex d IIC T6 Gb) and high protection (IP65 / IP67) requirements.

[0013] 4. Supports flexible on-site configuration of key parameters, and the backlit display facilitates reading at night or in low-light environments, meeting the actual usage needs of complex industrial sites. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the overall structure of the present invention. Figure 3 ; Figure 4 for Figure 3 A sectional view along section AA; Figure 5 This is a schematic diagram of the circuit system of the present invention; Explanation of markings in the diagram: 1. Cast aluminum housing; 2. Front panel; 3. LCD screen; 4. Function keys; 5. Shift keys; 6. Modify keys; 7. Down-threaded interface; 8. Horizontal electrical interface; 9. Sealed gland; 10. Terminal block; 11. Circuit board; 14. Lithium battery; 15. Snap-on battery compartment. Detailed Implementation

[0015] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] Example 1 like Figure 1-5 As shown, a self-powered temperature transmitter includes an explosion-proof cast aluminum housing 1, a circuit board 11, and a lithium battery 14. The circuit board 11 is disposed inside the explosion-proof cast aluminum housing 1, and the lithium battery 14 is installed inside the explosion-proof cast aluminum housing 1. The lithium battery 14 supplies power to the circuit board 11. The front panel 2 of the explosion-proof cast aluminum housing is provided with an LCD display screen 3 and operation buttons. like Figure 5 As shown, the circuit board 11 includes a microcontroller (MCU), a signal conditioning circuit, an analog-to-digital converter (ADC), a power management circuit, and a display driver circuit. The input terminal of the signal conditioning circuit is connected to an external resistance temperature detector (RTD) or thermocouple via a terminal block, and the output terminal is connected to the ADC. The signal conditioning circuit includes a programmable gain amplifier. The MCU outputs a control signal to the programmable gain amplifier according to the configured sensor index number to adjust its gain and bias. The ADC is connected to the MCU and converts the acquired analog signals into digital signals; The input terminal of the power management circuit is connected to the lithium battery 14, and the output terminal provides a stable operating voltage for the MCU, signal conditioning circuit and ADC; the power management circuit includes a low quiescent current linear regulator. The MCU is programmed to periodically wake from a low-power sleep mode, control the ADC to sample temperature signals, and linearize the sampled values ​​according to stored index data to obtain the temperature value for display on the LCD screen 3. The MCU is also connected to operation buttons for setting parameters. With this configuration, the circuit board 11 is fixed inside the cavity of the cast aluminum housing 1, and the 3.6V high-capacity lithium-ion battery 14 is installed in a separate snap-fit ​​battery compartment 15, connected to the circuit board 11 via connectors. The leads of the external temperature sensor (RTD or thermocouple) can be directly screwed into the threaded interface 7, or passed through the sealed gland 9 of the transverse electrical interface 8 into the housing and secured to the terminal block 10. The signal is sent from the terminal block 10 to the signal conditioning circuit. The core of this circuit is a programmable gain amplifier, the configuration of which is controlled by the microcontroller MCU. The MCU automatically calculates and outputs a control word based on the sensor type (e.g., Pt100) set by the user via buttons (function key 4, shift key 5, modification key 6), ensuring the amplifier gain matches the sensor's full-scale output and achieving "full range coverage." The conditioned standard voltage signal is sampled and digitized by a high-precision ADC. The MCU calls the corresponding calibration table or polynomial in its internal memory to linearize the digital quantity, obtaining an accurate temperature value. The result is displayed on the LCD screen 3 via the display driver circuit. The backlight of the display screen 3 can be triggered by a button and automatically turns off after a set time to save energy. The power management circuit uses an ultra-low quiescent current LDO chip to convert the battery voltage into the multi-channel stable voltage required by the system. The MCU continuously monitors the battery voltage through a voltage divider circuit and displays an alarm on the screen when the battery is low. After power-on initialization, the MCU enters a low-power-consumption-centric main loop. The MCU is in deep sleep mode most of the time, only periodically woken up by an internal low-power timer (RTC). Upon wake-up, it first checks for interruptions from button presses; if none are found, it determines whether the preset sampling time (e.g., 30 seconds) has been reached. If the temperature reaches the target value, the relevant analog circuitry is instantly powered on to perform a complete temperature measurement and display update. The analog circuitry is then immediately powered off, returning to sleep mode. This "instantaneous operation, long-term sleep" mode is key to achieving ultra-low power consumption.

[0018] When users need to modify parameters, they can press function key 4 to wake up the system and enter menu mode. By using shift key 5 and modify key 6, they can set the sampling interval, sensor type, backlight duration, temperature unit, etc., item by item. All parameters are stored in non-volatile memory.

[0019] The housing is made of "Type 010" explosion-proof cast aluminum, and all interfaces have a sealed structure and are equipped with a dedicated grounding screw 17 to ensure that the product meets strict explosion-proof and protection standards and can adapt to various harsh industrial environments.

[0020] Example 2 like Figure 5 As shown, the liquid crystal display screen 3 is a backlit LCD, and the MCU controls the backlight's on / off state and brightness level.

[0021] The lithium battery 14 is a 3.6V replaceable industrial lithium-ion battery. The outer casing has an independent snap-fit ​​battery compartment module. The battery compartment has anti-reverse insertion electrode springs. The battery compartment is connected to the circuit board 11 through a connector.

[0022] The MCU is connected to a power monitoring circuit for monitoring the voltage of the lithium battery 14.

[0023] The operation buttons include function key 4, shift key 5 and modification key 6. By combining operations, you can enter a multi-level menu and set the sampling interval, sensor type, backlight time and display unit parameters.

[0024] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A self-powered temperature transmitter, comprising an explosion-proof cast aluminum housing, a circuit board, and a lithium battery, wherein the circuit board is disposed inside the explosion-proof cast aluminum housing, the lithium battery is installed inside the explosion-proof cast aluminum housing, the lithium battery supplies power to the circuit board, and an LCD display and operation buttons are provided on the front panel of the explosion-proof cast aluminum housing. The circuit board includes a microcontroller (MCU), a signal conditioning circuit, an analog-to-digital converter (ADC), a power management circuit, and a display driver circuit. The input terminal of the signal conditioning circuit is connected to an external resistance temperature detector (RTD) or thermocouple via a terminal block, and the output terminal is connected to the ADC. The signal conditioning circuit includes a programmable gain amplifier. The MCU outputs a control signal to the programmable gain amplifier according to the configured sensor index number to adjust its gain and bias. The ADC is connected to the MCU and converts the acquired analog signals into digital signals; The input terminal of the power management circuit is connected to the lithium battery, and the output terminal provides a stable operating voltage for the MCU, signal conditioning circuit and ADC; the power management circuit includes a low quiescent current linear regulator. The MCU is programmed to periodically wake up from a low-power sleep mode, control the ADC to sample the temperature signal, and linearize the sampled value according to the stored graduation number data to obtain the temperature value for display on the LCD screen; the MCU is also connected to the operation buttons for setting parameters.

2. The self-powered temperature transmitter according to claim 1, characterized in that, The liquid crystal display screen is a backlit LCD, and the MCU controls the backlight's on / off state and brightness level.

3. A self-powered temperature transmitter according to claim 1, characterized in that, The lithium battery is a 3.6V replaceable industrial lithium-ion battery. The outer casing has an independent snap-fit ​​battery compartment module. The battery compartment has anti-reverse insertion electrode springs. The battery compartment is connected to the circuit board via connectors.

4. A self-powered temperature transmitter according to claim 1, characterized in that, The MCU is connected to a power monitoring circuit for monitoring the lithium battery voltage.

5. A self-powered temperature transmitter according to claim 1, characterized in that, The operation buttons include function keys, shift keys, and modification keys. By combining operations, users can access multi-level menus to set the sampling interval, sensor type, backlight time, and display unit parameters.

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