Wireless monitoring circuit and wireless monitoring device

Abstract

The utility model discloses a wireless monitoring circuit comprising a power supply module, an MCU module, a signal acquisition and processing module, and a communication module. Wherein the power supply module comprises a DC-DC module and an LOD module, and the input end and the output end of the power supply module are connected with capacitors; the MCU module comprises an MCU, a peripheral circuit of the MCU, a crystal oscillator and an RTC, and each pin is pre-configured according to functions; the signal acquisition and processing module comprises a high-pass filter, a low-pass filter, an anti-aliasing filter, an in-phase amplifier, an AD converter and a constant current source which share the same independent LDO power supply; the communication module comprises an NB-IoT module, an SIM card and a level switch. The NB-IoT module controls the on-off of a power supply through a switch. According to the technical scheme starting from a hardware circuit and a shell structure, the power consumption of the sensor is greatly reduced in an omnibearing manner, and the battery life is prolonged, so that the product loophole of incomplete power consumption control is avoided.

Description

Technical Field

[0001] The utility model belongs to the field of wireless monitoring of equipment, and specifically relates to a wireless monitoring circuit and a wireless monitoring device. Background Art

[0002] With the development of wireless communication technology, its application in industrial equipment is becoming more and more extensive. In order to reduce the construction and maintenance costs of industrial sites, the number of wireless monitoring equipment (including wireless sensors) is increasing. At the current stage, the field of online monitoring technology of equipment mostly adopts wireless communication technologies such as NB-IoT, Cat.1, ZigBee, etc. While the transmission power consumption is large, sensor standby, signal acquisition and processing also generally become the main part of power consumption. As a result, in complex industrial environments, the sensor battery power consumption is fast, the battery life does not meet expectations, and frequent after-sales operation and maintenance services of battery replacement are required, which makes users and manufacturers overwhelmed.

[0003] Therefore, there is an urgent need for a low-power wireless sensor to adapt to complex industrial field application environments and the trend of increasingly streamlined after-sales maintenance. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide a wireless monitoring circuit and a wireless monitoring device, which solve the problems of high power consumption and short standby time of wireless transmission in the prior art.

[0005] The utility model adopts the following technical solutions to solve the above technical problems:

[0006] A wireless monitoring circuit includes a power module, an MCU module, a signal acquisition and processing module, and a communication module; wherein:

[0007] The power module includes a DC-DC and LOD module, and capacitors are connected to the input and output ends of the power module;

[0008] The MCU module includes the MCU and its peripheral circuits, crystal oscillator, and RTC, and each pin is pre-configured according to the function;

[0009] The signal acquisition and processing module includes a high-pass filter, a low-pass filter, an anti-aliasing filter, a common-mode amplifier, an AD converter, and a constant current source, and shares the same independent LDO power supply;

[0010] The communication module includes an NB-IoT module, a SIM card, and a level converter. The NB-IoT module controls the on and off of the power supply through a switch.

[0011] The output end of the power module includes DC3.6V, DC3.3V, and DC1.8V.

[0012] The filter, operational amplifier and constant current source are made of TI low-power chips, and the AD converter is made of ADI chips.

[0013] The power module, MCU module, signal acquisition and processing module are arranged on the main board circuit board, the communication module is arranged on the communication board circuit board, and the main board and the communication board are connected via a signal line.

[0014] The MCU enters sleep mode after completing the task, and the sleep current is as low as 0.5 μA.

[0015] The capacitors connected to the input and output ends of the power module have respective matching capacities.

[0016] A wireless monitoring device comprises a shell, a circuit board and a battery pack arranged in the shell; the circuit board and the battery pack are spaced apart and electrically connected to each other; the battery pack is fixed in the shell and has a gap with the shell; the wireless monitoring circuit is arranged on the circuit board.

[0017] The shell comprises a metal base and a plastic upper shell matched with the metal base; the battery pack and the circuit board are arranged in the plastic shell, and there is a certain gap between the plastic shell and the metal base.

[0018] A heat insulating device is provided between the battery pack and the metal base.

[0019] The standby current of the device is less than 4 μA, and the average operating current is less than 300 μA.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] 1. A technical solution based on hardware circuit and shell structure can significantly reduce sensor power consumption and improve battery life, thus avoiding product vulnerabilities caused by incomplete power consumption control.

[0022] 2. The hardware framework includes power module, MCU module, signal acquisition and processing module, and communication module. Each functional module has its corresponding measures to reduce power consumption. The MCU module achieves maximum energy saving through deep sleep, while the acquisition module and communication module achieve maximum energy saving by reducing the total working time and cutting off power at the right time.

[0023] 3. The shell structure adopts the combination of metal base and plastic upper shell, in which the main circuit board and battery pack are assembled in a plastic shell that blocks heat conduction. By lowering the ambient temperature of the circuit board and the battery body, the working current is reduced and the effective capacity of the battery pack is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a circuit block diagram of the wireless monitoring circuit of the utility model.

[0025] Figure 2 This is a working flow chart of the wireless monitoring circuit of the utility model. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, rather than all of the embodiments.

[0027] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of protection of this application.

[0028] A wireless monitoring circuit includes a power module, an MCU module, a signal acquisition and processing module, and a communication module; wherein:

[0029] The power module includes a DC-DC and LOD module, and capacitors are connected to the input and output ends of the power module;

[0030] The MCU module includes the MCU and its peripheral circuits, crystal oscillator, and RTC, and each pin is pre-configured according to the function;

[0031] The signal acquisition and processing module includes a high-pass filter, a low-pass filter, an anti-aliasing filter, a common-mode amplifier, an AD converter, and a constant current source, and shares the same independent LDO power supply;

[0032] The communication module includes an NB-IoT module, a SIM card, and a level converter. The NB-IoT module controls the on and off of the power supply through a switch.

[0033] A wireless monitoring device comprises a shell, a circuit board and a battery pack arranged in the shell; the circuit board and the battery pack are spaced apart and electrically connected to each other; the battery pack is fixed in the shell and has a gap with the shell; the wireless monitoring circuit is arranged on the circuit board.

[0034] Specific embodiments, such as Figure 1 , Figure 2 As shown,

[0035] A low-power wireless acquisition and transmission device includes a hardware circuit, embedded software and a shell. This embodiment starts from the three dimensions of hardware circuit, embedded software and shell structure to reduce its power consumption to a standby current of less than 4μA and an average working current of less than 300μA. The following are detailed descriptions.

[0036] 1. Hardware Circuit

[0037] The hardware circuit includes power module, MCU module, signal acquisition and processing module, communication module, and sensor. The functions of each module and the measures to reduce power consumption are described as follows:

[0038] Power module: The battery output is converted into more stable voltages required for circuit operation through high-efficiency DC-DC and LDO modules, such as DC3.6V, DC3.3V, DC1.8V, etc. In order to prevent the battery from losing power too quickly due to continuous high current output, when the battery pack is equipped with lithium-ion capacitors, high-quality capacitors of appropriate capacity are added to the input and output ends of each power supply to ensure that the battery can power the sensor with a stable low current.

[0039] MCU module: This module includes MCU and its peripheral circuits, crystal oscillator, RTC, etc. Each pin is pre-configured according to the required function, eliminating the pull-up and pull-down resistors that are not required for the function, reducing the pin current sinking and sourcing, and reducing static power consumption. After completing its task, the MCU enters sleep mode, with a sleep current as low as about 0.5μA, and can be awakened regularly to process instruction tasks.

[0040] Signal acquisition and processing module: includes high-pass filter, low-pass filter, anti-aliasing filter, in-phase amplifier, AD converter, constant current source, etc., to achieve signal filtering, proportional amplification, analog-to-digital conversion, and constant current source provides excitation source for vibration sensor probe. Among them, each component uses low-power devices, such as TI chips for filters, operational amplifiers, and constant current sources, and ADI chips for AD converters. In addition, the power supply of various devices in this module uses the same independent LDO. When the signal acquisition is completed, the power supply of the module is quickly turned off to minimize useless power consumption.

[0041] Communication module: including NB-IoT module, SIM card, level conversion, etc., to realize the wireless communication function of the sensor and perform data upload and acquisition operations. Since the NB-IoT module has a large transmission power, this functional module consumes the most power. By optimizing the network injection logic, enhancing the antenna gain, reducing the number of module startups, and reducing the transmission time, the module will no longer enter the PSM low-power mode after the work is completed, but will directly cut off its power supply through the switch, saving its standby current of about 3.5μA.

[0042] 2. Embedded Software

[0043] The embedded software includes RTC and timing tasks, MQTT connection and timing tasks, signal acquisition and data calculation tasks, main tasks, OTA tasks, etc.

[0044] After power-on, the MCU, AT components, and NB-IoT module are initialized, and the scheduled tasks are started;

[0045] After connecting to the MQTT server, upload the configuration information, obtain the signal strength and current battery power, synchronize with the base station to update the local RTC, and query whether the server has new configuration information or instructions issued. If not, in order to reduce unnecessary operations, enter the sleep mode, that is, the MCU sleeps and the NB-IoT module is powered off;

[0046] According to the received new configuration information, the module is woken up at a fixed time, the power of the signal acquisition and processing module is turned on, the device status signal is collected, and the power of the signal acquisition and processing module is immediately turned off after the collection is completed;

[0047] Extract the characteristic value of the collected data and compare it with the set alarm threshold. If it is less than the alarm threshold, only upload the characteristic value. If it is greater than the alarm threshold, upload the characteristic value and waveform data. Among them, when the device status alarms continuously, only the first three alarms are uploaded to reduce the number of waveforms sent to effectively reduce power consumption. When the upload fails, retry three times and restart the module once. If it still fails, enter the sleep mode (that is, MCU sleeps, NB-IoT module is powered off), and cache the data, and continue to upload historical data when the signal is restored;

[0048] When receiving the upgrade command sent by the server, the current battery power and signal strength are first determined. To avoid increased power consumption caused by repeated downloading of firmware packages, both the battery power and signal strength must be greater than the set threshold.

[0049] What the present application aims to protect is the wireless transmission device and its circuit connection relationship. The host computer control software, embedded software, etc. involved are all prior art and can be fully implemented by those skilled in the art. Needless to say, the content protected by the present application does not involve improvements to the software and methods.

[0050] 3. Shell structure

[0051] The shell structure adopts the combination of a metal base and a plastic upper shell, in which the main circuit board and battery pack are installed in the plastic shell.

[0052] The maximum power and service life of a lithium thionyl chloride battery are closely related to its working environment temperature. In order to increase the battery life, the battery body environment temperature needs to be lowered. This embodiment uses a lithium thionyl chloride battery pack as a power supply.

[0053] The gap between the battery pack and the metal base is increased in structure, and heat insulation measures are adopted to ensure that the high temperature on the surface of the device is dissipated by more than 30°C when it is transmitted to the battery pack, ensuring that it is within its friendly operating temperature range. In addition, the operating current of the main circuit is small when it is in a lower temperature environment.

[0054] As can be seen from the figure, the device structure of this embodiment includes a battery compartment and a circuit board part, the circuit board includes a mainboard and a communication board, wherein the power module, MCU module, signal acquisition and processing module are arranged on the mainboard circuit board, and the communication module is arranged on the communication board circuit board, and the mainboard and the communication board are connected by a signal line; the top layer (top layer) of the communication board is provided with an NB-IoT module and various communication interfaces, and the bottom layer (bottom layer) is provided with a power terminal, a signal connection terminal, and a card holder; the top layer (top layer) of the mainboard is provided with an MCU, a DCDC, an indicator light, a wiring terminal, etc., and the bottom layer (bottom layer) is provided with an LDO module, an ADC module, etc.; a lithium-ion battery, a lithium-ion capacitor connected to the lithium-ion battery, a control switch, etc. are arranged in the battery compartment.

[0055] The settings here are only used as an example for a detailed description of the present device. The specific circuit board layout can be adaptively adjusted according to specific circumstances. No limiting description is given here. Those skilled in the art are aware of how to make adjustments and settings.

[0056] The technical solution from three dimensions, namely hardware circuit, embedded software and shell structure, can significantly reduce the power consumption of sensors and improve battery life, thus avoiding product vulnerabilities due to incomplete power consumption control.

[0057] While reducing power consumption, the sensitivity and timeliness of wireless communication functions are enhanced.

[0058] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0059] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0060] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0061] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0062] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0063] The circuits, electronic components and modules involved are all prior art and can be fully implemented by those skilled in the art. Needless to say, the content protected by this application does not involve improvements to software and methods.

[0064] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wireless monitoring circuit, characterized in that: It includes power module, MCU module, signal acquisition and processing module, and communication module; among them, The power module includes a DC-DC and LOD module, and capacitors are connected to the input and output ends of the power module; The MCU module includes the MCU and its peripheral circuits, crystal oscillator, and RTC, and each pin is pre-configured according to the function; The signal acquisition and processing module includes a high-pass filter, a low-pass filter, an anti-aliasing filter, a common-mode amplifier, an AD converter, and a constant current source, and shares the same independent LDO power supply; The communication module includes an NB-IoT module, a SIM card, and a level converter. The NB-IoT module controls the on and off of the power supply through a switch.

2. The wireless monitoring circuit according to claim 1, characterized in that: The output end of the power module includes DC3.6V, DC3.3V, and DC1.8V.

3. The wireless monitoring circuit according to claim 1, characterized in that: The filter, operational amplifier and constant current source are made of TI low-power chips, and the AD converter is made of ADI chips.

4. The wireless monitoring circuit according to claim 1, characterized in that: The power module, MCU module, signal acquisition and processing module are arranged on the main board circuit board, the communication module is arranged on the communication board circuit board, and the main board and the communication board are connected via a signal line.

5. The wireless monitoring circuit according to claim 1, characterized in that: The MCU enters sleep mode after completing the task, and the sleep current is as low as 0.5 μA.

6. The wireless monitoring circuit according to claim 1, characterized in that: The capacitors connected to the input and output ends of the power module have respective matching capacities.

7. A wireless monitoring device, characterized in that: It comprises a shell, a circuit board and a battery pack arranged in the shell; the circuit board and the battery pack are spaced apart from each other and are electrically connected; the battery pack is fixed in the shell and there is a gap between the battery pack and the shell; the wireless monitoring circuit described in any one of claims 1 to 6 is arranged on the circuit board.

8. The wireless monitoring device according to claim 7, characterized in that: The shell comprises a metal base and a plastic upper shell matched with the metal base; the battery pack and the circuit board are arranged in the plastic shell, and there is a gap between the plastic shell and the metal base.

9. The wireless monitoring device according to claim 8, characterized in that: A heat insulating device is provided between the battery pack and the metal base.

10. The wireless monitoring device according to claim 7, characterized in that: The standby current of the device is less than 4 μA, and the average operating current is less than 300 μA.

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