A power harvesting interface full-transparent transmission and remote parasitic power supply system

Abstract

The application discloses a kind of power collection interface full transparent transmission and remote parasitic power supply systems, belong to electric power electricity information collection technical field, including local end device, remote end device and the single pair of twisted pair line of connecting two, local end device obtains 4V power supply from special variable acquisition terminal and is boosted to 48V, 48V direct current is coupled to twisted pair line with TXD / RXD service data, downlink control signal modulated by 3MHz OOK using bias tee;Remote end device separates electric energy and signal, is boosted to 3.8V for 4G communication module power supply, and compensates peak current through parallel capacitor energy storage unit, simultaneously, module state pin is returned to local end with 5MHz OOK modulated state byte to carry out level mirror image.The application realizes the complete virtualization and zero delay of physical interface between acquisition terminal and communication module Transmission, solve the remote power supply and communication extension problem of weak coverage area such as basement, remote mountainous area and metal distribution cabinet.

Description

Technical Field

[0001] This invention belongs to the field of power consumption information collection technology, and in particular relates to a fully transparent power acquisition interface transmission and remote parasitic power supply system. Background Technology

[0002] In current electricity consumption information collection systems, the dedicated transformer data acquisition terminal (hereinafter referred to as "terminal") and the remote communication module (usually a 4G wireless communication module) generally adopt an onboard plug-in direct connection method. The interface definition follows the State Grid Corporation of China's enterprise standard "Type Specification for Electricity User Information Collection System" (Q / GDW10376.3). This standard interface specifies multiple signal pins, including power supply (4V), serial data (TXD / RXD), hardware reset (RST), power-on enable (ON / OFF), and module status output (STATE0~STATE4). The terminal is responsible for collecting and storing user electricity consumption data and uploading it to the main station via the wireless public network through the communication module.

[0003] However, in actual engineering deployments, dedicated transformer data acquisition terminals and concentrators are often forced to be installed in highly shielded environments such as basements, metal distribution cabinets, cable wells, remote mountainous areas, or deep within buildings. Wireless signal attenuation is extremely severe in these locations, resulting in very low or even no signal strength received by the 4G communication module, making it impossible to register with the network or maintain a stable data connection. This leads to operational malfunctions such as data acquisition failures and data loss.

[0004] To address the aforementioned signal coverage issue, some field attempts have involved extending the communication module to areas with good outdoor signal coverage using extension cables. However, due to limitations imposed by the standard interface definition, simply extending the serial data lines (TXD / RXD) can lead to the following problems:

[0005] 1. Insufficient power supply: The standard interface only provides 4V DC power, while single-pair twisted-pair cables or ordinary extension cables exhibit significant line resistance over long distances (tens or even hundreds of meters). According to Ohm's law, if 4V voltage is transmitted directly, the voltage drop at the remote module end will cause the voltage to be far below its normal operating threshold (3.8V typical value). Especially when the module needs a peak current of 2A during network search or transmission, the sudden voltage drop will trigger an undervoltage reset of the module, causing the module to repeatedly restart and fail to register.

[0006] 2. Control signal failure: The hardware reset signal (RST) is a DC level pulse. Under long-distance transmission, the pulse waveform will be distorted, broadened or attenuated due to the distributed capacitance and resistance of the cable, and cannot be correctly identified by the remote module. The power-on enable signal (ON / OFF) also faces the problem of DC level loss, which causes the module to be unable to be woken up or shut down normally.

[0007] 3. Status signals cannot be transmitted: The STATE0 to STATE4 status pins in the standard interface are used to output the real-time operating status of the module (such as searching for a network, connected to the network, fault, etc.). These signals are parallel DC levels and cannot be directly transmitted over long distances through a single serial medium. If only TXD / RXD is extended while the status signals are discarded, the terminal side will not be able to perceive the true status of the remote module. Its self-test program will determine "no module inserted" or "module abnormal," resulting in the terminal reporting an error, suspending, or even refusing to work.

[0008] 4. Lack of fault safety mechanism: When the extension line is open-circuited, short-circuited, or the remote module crashes, the terminal will continue to wait for the module to respond, which can easily cause the terminal self-test to time out and the program to hang, affecting the stable operation of the entire acquisition system.

[0009] 5. Although there are some wireless extension solutions in the existing technology, they usually only deploy an independent power supply at the remote end, which cannot solve the power supply problem; and they only transmit serial data, ignoring the transmission of underlying control signals such as hardware reset, power-on enable and status feedback, which causes the terminal to lose the ability to physically control the remote module, and the module cannot be remotely recovered after it crashes.

[0010] In summary, there is an urgent need to design a system that can solve the problems of remote extension of communication modules and reliable power supply in areas with weak coverage without changing the existing terminal hardware and software. Summary of the Invention

[0011] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and design a fully transparent transmission and remote parasitic power supply system based on frequency division multiplexing (FDM) for power acquisition interfaces. It includes a local terminal device, a remote terminal device, and a single-pair twisted-pair cable connecting the two. The local terminal device obtains 4V power from the dedicated transformer acquisition terminal and boosts it to 48V. Using a bias tee, it couples the 48V DC power, data (TXD / RXD), and downlink control signals (RST / ON / OFF / PCTRL, 3MHz OOK modulation) onto the single-pair twisted-pair cable. The remote terminal device separates the power and signals, stepping down the voltage to 3.8V to power the 4G module. Simultaneously, it compensates for peak current through a capacitor energy storage unit and transmits the module status pins (STATE0~STATE4, 5MHz OOK modulation) back to the local terminal for level mirroring. This invention achieves complete virtualization and "zero-latency" transparent transmission of the physical interface between the dedicated transformer acquisition terminal and the remote communication module, without requiring modification of the terminal firmware. It solves the problem of remote power supply and communication extension in passive, weakly covered areas such as basements, metal distribution cabinets, and remote mountainous regions.

[0012] This invention provides,

[0013] The solution adopted by this invention to solve its technical problem is as follows:

[0014] A fully transparent power acquisition interface transmission and remote parasitic power supply system, comprising:

[0015] The local terminal device is used to connect to the dedicated transformer data acquisition terminal, monitor all signals of the dedicated transformer data acquisition terminal's communication interface, and boost the low-voltage power supply provided by the dedicated transformer data acquisition terminal to high-voltage DC power.

[0016] A remote terminal device is used to connect to a 4G communication module, receive and separate electrical energy and communication signals in a mixed signal, supply power to the 4G communication module and restore control signals and data signals;

[0017] A single twisted pair cable connects the local terminal device and the remote terminal device;

[0018] The local terminal device and the remote terminal device transmit energy domain, data domain and control domain signals simultaneously on the single pair of twisted pairs via frequency division multiplexing.

[0019] The energy domain is a DC power supply, the data domain is transparently transmitted serial service data, and the control domain includes a downlink control channel and an uplink status channel. The downlink control channel transmits hardware control commands from the dedicated transformer acquisition terminal to the 4G communication module, and the uplink status channel transmits physical status feedback signals from the 4G communication module.

[0020] The remote terminal device is equipped with a power buffer unit, which is used to provide compensation power when the 4G communication module generates a transient large current, so as to prevent the 4G communication module from resetting due to long line voltage drop.

[0021] As a preferred embodiment of the present invention

[0022] The local terminal device is provided with a first bias three-way circuit, and the remote terminal device is provided with a second bias three-way circuit. Both the first bias three-way circuit and the second bias three-way circuit are composed of inductors and capacitors. The inductor is used to inject or extract DC power, and the capacitor is used to couple high-frequency communication signals to realize the coexistence transmission of power and signals on the single pair of twisted pairs.

[0023] The local terminal device includes a DC-DC boost circuit for boosting the 4V power supply provided by the dedicated transformer acquisition terminal to 48V DC power; the remote terminal device includes a DC-DC buck circuit for bucking the 48V DC power to the 3.8V operating voltage required by the 4G communication module.

[0024] As a preferred embodiment of the present invention

[0025] The power buffer unit is a large-capacity capacitor array connected in parallel to the output of the DC-DC step-down circuit of the remote terminal device. The capacitor array consists of three 2200μF / 6.3V low ESR capacitors connected in parallel. It is used to slowly charge the 4G communication module when it is idle and to release the charge to provide peak current when the 4G communication module searches for the network or transmits.

[0026] As a preferred embodiment of the present invention

[0027] The data domain adopts a bit-level transparent forwarding method: the local terminal device and the remote terminal device each include an RS485 transceiver, which converts serial service data into RS485 differential signals for transmission on the single pair of twisted-pair lines without buffering, packing or parsing the data, thus achieving zero-latency transparent transmission.

[0028] The RS485 transceiver uses a differential transceiver chip with slew rate limiting characteristics to limit the signal edge transition time of the serial service data to a preset range, thereby filtering out high-frequency harmonics generated by data transitions at the physical layer and preventing frequency domain crosstalk to the high-frequency carrier of the control domain.

[0029] As a preferred embodiment of the present invention

[0030] The bit-level transparent forwarding method of the data field integrates a high-speed automatic flow control mechanism:

[0031] The GPIO pins of the first MCU and the second MCU are respectively connected to the enable pins of the corresponding RS485 transceivers. In the default state, the first MCU and the second MCU control their respective RS485 transceivers to be in the receive listening state. When either MCU detects the start bit transition edge of the service data frame output by the transmitting pin in real time at the hardware level, it quickly pulls the transmit enable pin of the corresponding RS485 transceiver high to seize the bus transmission right, and releases the enable pin to restore the receive state after detecting that the bus is idle. This strips away the intervention of the software protocol stack and realizes pure physical layer adaptive flow control on the half-duplex bus.

[0032] As a preferred embodiment of the present invention

[0033] Both the local terminal device and the remote terminal device are equipped with an AC terminal matching network. The AC terminal matching network is connected across the differential line between the RS485 transceiver and the bias tee circuit. The AC terminal matching network is composed of an impedance matching resistor and a DC blocking capacitor connected in series, which is used to absorb the high-frequency reflection oscillation of the serial service data and block DC leakage current.

[0034] As a preferred embodiment of the present invention

[0035] The downlink control channel uses a 3MHz carrier, and the uplink status channel uses a 5MHz carrier.

[0036] The local terminal device is equipped with a 3MHz OOK modulator and a 5MHz OOK demodulator. The 3MHz OOK modulator is used to modulate the downlink control command into a 3MHz carrier signal, and the 5MHz OOK demodulator is used to demodulate the 5MHz carrier signal of the uplink status channel.

[0037] The remote terminal device is equipped with a 3MHz OOK demodulator and a 5MHz OOK modulator. The 3MHz OOK demodulator is used to demodulate the 3MHz carrier signal of the downlink control channel, and the 5MHz OOK modulator is used to modulate the uplink status signal into a 5MHz carrier signal.

[0038] Both the downlink control channel and the uplink status channel adopt an on / off keying modulation method, that is, after the parallel control signal or parallel status signal is encoded into serial bytes, the presence or absence of the carrier represents logic "1" and logic "0" for transmission on the single pair of twisted-pair lines.

[0039] As a preferred embodiment of the present invention

[0040] The downlink control channel operates in the following modes:

[0041] a. The local terminal device is equipped with a first MCU. The first MCU periodically scans the RST, ON / OFF and PCTRL pin levels of the dedicated transformer acquisition terminal interface and combines the three parallel signals into an 8-bit control byte through its internal shift register, where bit0 is RST, bit1 is ON / OFF, bit2 is PCTRL, and bits3 to 7 are reserved bits or check bits.

[0042] b. The first MCU controls its internal timer to output a 3MHz square wave. When the current bit of the control byte is "1", a 3MHz carrier wave is sent; when it is "0", it is silent. The modulated signal is coupled to the single pair of twisted wires through the capacitor of the first bias three-way circuit.

[0043] c. The capacitor of the second bias three-way circuit of the remote terminal device extracts a 3MHz signal. After demodulation by the second 3MHz OOK demodulator, the second MCU parses the control byte: if bit0 is "1", the second MCU pulls the RST pin of the connected 4G communication module low for 1000ms and then releases it to a high impedance state; if bit1 is "1", the ON / OFF pin is pulled high to power on the module; if bit1 is "0", the pin is pulled low to power off the module.

[0044] The uplink status channel operates as follows:

[0045] d. The remote terminal device is equipped with a second MCU. The second MCU periodically reads the STATE0 to STATE4 pin levels of the 4G communication module to obtain a 5-bit parallel value, which is then filled into the lower 5 bits of an 8-bit status byte, and the higher 3 bits are filled into the signal quality code.

[0046] e. The second MCU controls its internal timer to output a 5MHz square wave, performs OOK modulation bit by bit, and the modulated signal is injected into the single pair of twisted wires through the capacitor of the second bias three-way circuit;

[0047] f. The capacitor of the first bias three-way circuit of the local terminal device extracts a 5MHz signal. After demodulation by the first 5MHz OOK demodulator, the first MCU extracts the lower 5 bits of the status byte and drives the GPIO of the STATE0~STATE4 pins of the local terminal device to output the corresponding level combination, thereby realizing status mirroring.

[0048] As a preferred embodiment of the present invention

[0049] A heartbeat monitoring mechanism is provided between the local terminal device and the remote terminal device: both parties send each other an idle heartbeat packet every 100ms on the 3MHz and 5MHz channels; when either party fails to receive the other party's heartbeat for 3 consecutive times, the communication link is determined to be faulty.

[0050] After the local terminal device detects a fault, it sets all GPIOs connected to the dedicated transformer data acquisition terminal STATE0 to STATE4 to a high level and cuts off the 48V power supply to enter fault lockout.

[0051] After the remote terminal device detects a fault, it shuts down the power of the 4G communication module and enters low-power standby mode; after the link is restored, it automatically re-initializes and establishes communication.

[0052] As a preferred embodiment of the present invention

[0053] The remote terminal device also includes an intelligent power management unit: the second MCU reads the STATE0 to STATE4 state combinations of the 4G communication module in real time. When it detects that the state combination changes from "standby" to "preparing to search for the network", it temporarily shuts down the power supply of unnecessary peripherals and detects the voltage of the capacitor energy storage unit. If it is lower than 3.5V, it delays for 200ms and allows the module to start searching for the network and registering only after it is charged to above 3.5V.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. Overcoming the technical bottlenecks in long-distance power supply and peak current compensation:

[0056] Existing solutions such as RS485 extenders require independent power supplies at both ends or additional power lines, making it impossible to simultaneously achieve power supply and communication using a single twisted pair cable. This invention employs bias-Tee technology. At the local end, a DC-DC boost circuit raises the 4V power supply from the acquisition terminal to 48V, which is then injected into the twisted pair cable via an inductor. At the remote end, a DC-DC step-down circuit restores the voltage to 3.8V, and a large-capacity capacitor is connected in parallel at the output. When the 4G communication module is idle, the capacitor charges slowly; when the module searches for a network or transmits, the capacitor releases energy locally, maintaining the module voltage at least 3.5V, completely avoiding undervoltage reset caused by long-distance line resistance. This mechanism reduces line loss and enables the coexistence of power, control signals, and data signals on a single twisted pair cable, solving the fundamental problem of "no power source" for remote modules in weak coverage areas such as basements and metal distribution cabinets.

[0057] 2. Achieve complete virtualization and transparency of the physical interface without modifying the terminal firmware:

[0058] Existing technologies can only extend the TXD / RXD data lines, but cannot transmit control signals such as reset (RST) and power on / off (ON / OFF), nor can they acquire information from the module's status pins (STATE0~STATE4), causing the acquisition terminal to be unable to complete module self-tests or fault diagnosis. This invention utilizes the collaborative work of a local first MCU and a remote second MCU to package the acquisition terminal's parallel RST, ON / OFF, and PCTRL signals into control bytes, transmitting them using 3MHz carrier OOK modulation; and to package the module's parallel STATE0~STATE4 states into status bytes, transmitting them back using 5MHz carrier OOK modulation. The remote end accurately simulates a 1000ms reset pulse, and the local end accurately mirrors the module's status level combinations. The acquisition terminal perceives the existence of the virtual module at the physical layer, "tricking" the self-test program into believing the module is inserted in the local slot, achieving non-intrusive modification without requiring any changes to the terminal's firmware or software.

[0059] 3. Establish a fault-oriented, safety-based, dual-end collaborative protection mechanism:

[0060] To address potential anomalies such as open circuits, short circuits, poor contact, or remote module crashes that may occur in long-distance single-pair twisted-pair cables, this invention designs a heartbeat monitoring mechanism: the local and remote ends exchange idle heartbeat packets every 100ms on 3MHz and 5MHz channels. If no heartbeat is received for three consecutive times, a link failure is determined. The local end immediately forces the STATE0-STATE4 pins to all high levels, triggering an error report from the acquisition terminal to prevent program hang; simultaneously, it cuts off the 48V power supply and enters fault lockout. The remote end shuts down the module power and enters low-power standby. After the link is restored, the system automatically reinitializes and establishes communication. This mechanism avoids the crashes or data acquisition failures caused by indefinite timeouts at the terminal in traditional solutions, significantly improving system reliability.

[0061] 4. Intelligent power management improves the stability of power supply over long distances:

[0062] This invention addresses the high-current surge during the 4G module's transition from standby to network search by incorporating a pre-charging mechanism. The remote second MCU continuously reads the STATE0-STATE4 state combinations. When a transition from "standby" to "preparing to search for a network" is detected, it proactively shuts off power to unnecessary peripherals and checks the capacitor energy storage unit voltage. If the voltage is below 3.5V, a 200ms delay is made to allow charging to reach above the threshold before the module can begin network search and registration. This mechanism ensures that the capacitor energy storage unit stores sufficient energy before the high-current operation, further reducing the risk of module restart due to insufficient capacitor power and improving operational reliability under long-distance power supply conditions.

[0063] The system of this invention achieves fully transparent remote extension and parasitic power supply of the power acquisition interface through a series of technical means such as biased three-way single-line multiplexing power supply, dual MCU collaborative state machine mapping, frequency division multiplexing OOK modulation, heartbeat fault safety and intelligent power management. It fills the gap in the existing technology in terms of low-level control signal transmission and remote reset capability, and has significant industrial practical value. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the structure of a fully transparent power acquisition interface and remote parasitic power supply system proposed in this invention;

[0065] Figure 2 This is a schematic diagram illustrating the principle of a heartbeat monitoring mechanism for a fully transparent power acquisition interface and a remote parasitic power supply system proposed in this invention.

[0066] Figure 3 This invention provides an implementation method for a downlink control channel of a fully transparent power acquisition interface and a remote parasitic power supply system.

[0067] Figure 4This invention provides an implementation method for a fully transparent power acquisition interface transmission and a remote parasitic power supply system uplink control channel. Detailed Implementation

[0068] The specific embodiments of the present invention are described below with reference to the accompanying drawings and examples:

[0069] It should be noted that the structures, colors, proportions, sizes, etc. shown in the accompanying drawings are only used to complement the content disclosed in the specification, so that those skilled in the art can understand and read them, and are not intended to limit the conditions under which the present invention can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0070] At the same time, in the description of the present invention, it should be understood that the terms "one end", "the other end", "middle", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and 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, and therefore should not be construed as a limitation of the present invention.

[0071] Furthermore, the terms “first,” “second,” “third,” and “fourth” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as “first,” “second,” “third,” or “fourth” may explicitly or implicitly include at least one of those features.

[0072] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0073] like Figure 1As shown, this invention provides a fully transparent power acquisition interface transmission and remote parasitic power supply system, including a local end device, a remote end device, and a single-pair twisted-pair cable connecting the two. The local end device physically connects to a dedicated transformer acquisition terminal to complete all signal acquisition, low-voltage to high-voltage conversion, signal and energy coupling, and status mirroring output. The remote end device physically connects to a 4G communication module to complete signal and energy separation, step-down energy storage, command decoding and timing reconstruction, and status acquisition encoding. The single-pair twisted-pair cable serves as the transmission medium, carrying three-dimensional orthogonal signals in the energy domain, data domain, and control domain, realizing transmission and parasitic power supply.

[0074] The local terminal device is equipped with a male connector that matches the Q / GDW 10376.3 standard interface of the dedicated transformer acquisition terminal. It integrates a first MCU, a first RS485 transceiver, a first 3MHz OOK modulator, a first 5MHz OOK demodulator, a first bias tee circuit, and a DC-DC boost circuit.

[0075] In this embodiment, the first MCU is an STM32F103C8T6; the first RS485 transceiver is a MAX483; the first 3MHz OOK modulator is implemented by the internal timer of the first MCU in conjunction with the GPIO port; the first 5MHz OOK demodulator is composed of an envelope detector circuit and a comparator; the first bias tee circuit is composed of an inductor and a capacitor, wherein the inductor (i.e., the bias-Tee inductor) is dedicated to the DC channel and is used to inject 48V DC power into a single pair of twisted wires, and the capacitor is used for high-frequency signal coupling, with an inductance value of 100μH and a capacitance value of 10nF; the DC-DC boost circuit has an input voltage of 4V, an output voltage of 48V, and a power of 15W.

[0076] The remote terminal device has a female connector that matches the Q / GDW 10376.3 standard interface of the 4G communication module. Internally, it includes a second MCU, a second RS485 transceiver, a second 3MHz OOK demodulator, a second 5MHz OOK modulator, a second bias tee circuit, a DC-DC step-down circuit, and a capacitor energy storage unit.

[0077] In this embodiment, the model of the second MCU is the same as that of the first MCU; the model of the second RS485 transceiver is the same as that of the first RS485 transceiver; the second 3MHz OOK demodulator consists of a diode envelope detector and a Schmitt trigger; the second bias three-way circuit also consists of an inductor and a capacitor, and its parameters are the same as those of the first bias three-way circuit; the DC-DC step-down circuit is used to convert the 48V voltage to 3.8V, and the output current is 2A; the capacitor energy storage unit consists of three 2200μF / 6.3V low ESR capacitors connected in parallel.

[0078] The local terminal device is inserted into the communication interface slot of the dedicated transformer data acquisition terminal via its male connector; the remote terminal device is inserted into the interface pin of the 4G communication module via its female connector; the local and remote terminals are connected via a single-pair twisted-pair cable, with the two ends of the cable soldered to the output terminals of the first and second bias tee circuits, respectively. The single-pair twisted-pair cable is a CAT5e type, and its length can be adjusted from 10 meters to 1200 meters according to the actual site conditions.

[0079] Three non-interfering physical transmission domains are constructed on a single twisted pair cable, and parallel transmission is achieved using frequency division multiplexing and offset tee technology, including:

[0080] Energy domain: Used to inject / extract DC48V power using Bias-Tee to solve the problem of remote power supply.

[0081] In practical operation, 4G communication modules generate sudden peak currents of up to 2A during network search or signal transmission. Due to the significant resistance of a single twisted pair over long distances, direct power supply can cause the voltage of the remote device to drop sharply to the shutdown threshold of the 4G communication module, triggering an abnormal restart. To address this, the system of this invention uses a DC-DC boost circuit to raise the voltage to 48V on the local device to reduce operating current and line voltage loss, and injects 48V DC into the single twisted pair through the inductor of the first bias tee circuit. A capacitor energy storage unit is connected in parallel at the output of the DC-DC buck circuit on the remote device. When the 4G communication module is idle, the single twisted pair slowly charges the capacitor energy storage unit through the DC-DC buck circuit; when the 4G communication module enters network search or transmission mode, the capacitor energy storage unit provides instantaneous high-current compensation from the nearest available source, overcoming the physical bottleneck of power transmission in a single twisted pair.

[0082] Specifically, the local device obtains 4V power from the dedicated transformer acquisition terminal, boosts it to 48V DC through a DC-DC boost circuit, and then safely injects the 48V DC into the single twisted pair using the inductor of the first bias tee circuit. Simultaneously, high-frequency communication signals are allowed to be injected in parallel through the capacitor branch, achieving "power supply and communication on the same line." The remote device receives the mixed signal from the single twisted pair, extracts 48V DC through the inductor of the second bias tee circuit, sends it to the DC-DC step-down circuit, and outputs 3.8V to power the 4G communication module and other circuits on the remote end.

[0083] The capacitor energy storage unit is connected in parallel to the output of the DC-DC step-down circuit. When the 4G communication module is idle (operating current ≤100mA), the capacitor energy storage unit slowly charges to 3.8V; when the 4G communication module enters network search or transmission mode (transient current reaches 2A), the capacitor energy storage unit immediately releases its charge to provide the peak current required by the 4G communication module, maintaining the 4G communication module voltage at no less than 3.5V and preventing the 4G communication module from resetting due to undervoltage.

[0084] Data Domain: Data sent by the dedicated transformer acquisition terminal via its TXD pin enters the first MCU of the local terminal device. The first MCU does not package or buffer the data; it simply sends it directly to the first RS485 transceiver. The first RS485 transceiver converts the TTL level to an RS485 differential signal. Both the first and second RS485 transceivers use the MAX483 differential transceiver chip with slew-rate limited characteristics. This chip integrates a slew-rate limiting circuit, which can limit the edge transition time of the RS485 differential signal to more than 250ns. This directly filters out high-frequency harmonic components (especially spectral components near 3MHz and 5MHz) generated by data transitions at the physical layer, preventing high-speed transitions in the data domain from causing frequency domain crosstalk to the 3MHz downlink channel and 5MHz uplink channel in the control domain, and ensuring the orthogonality of the three transmission domains under frequency division multiplexing. Through this slew rate limiting design, the RS485 signal transmitted in the data domain can coexist harmoniously with the high-frequency carrier in the control domain on the same twisted pair, without the need for additional notch filters or shielding measures. It is then transmitted via capacitive coupling through the first bias tee circuit to the single twisted pair. Correspondingly, the second RS485 transceiver of the remote device receives the differential signal from the single twisted pair, restores it to TTL level, and then sends it directly to the RXD pin of the 4G communication module via the second MCU; the reverse transmission path (TXD of the 4G communication module to RXD of the dedicated transformer acquisition terminal) is similar. This process achieves "zero-delay" transparent transmission and is compatible with all power communication protocols such as DL / T645 and IEC62056.

[0085] To achieve half-duplex differential data transmission over a single-pair twisted-pair cable, both the first and second RS485 transceivers in the local and remote devices integrate a high-speed automatic data flow control mechanism. Specifically, the GPIO pin of the first MCU is connected to the transmit enable pin (RE / DE) of the first RS485 transceiver, and the GPIO pin of the second MCU is connected to the transmit enable pin of the second RS485 transceiver. In the default idle state, the first and second MCUs control their respective RS485 transceivers to be in receive listening mode (enable pin is low). When any MCU detects the start bit of the service data frame output from the transmitting end (TX) pin of the peer end (i.e., the falling edge of the UART start bit "0") in real time through its serial port receive pin (RX), the MCU quickly pulls high the transmit enable pin of the corresponding RS485 transceiver within 1μs, switching the transceiver from receive mode to transmit mode and preempting the bus transmission right; after the data frame is transmitted and the bus is detected to be idle (i.e., the TX pin remains high for more than one byte), the MCU releases the enable pin and resumes the receive state. The entire flow switching process does not require the intervention or judgment of the software protocol stack, but only relies on the hardware-level edge-triggered interrupt, thus eliminating the intervention of the software protocol stack, eliminating the delay and uncertainty caused by protocol parsing, realizing pure physical layer adaptive flow control on the half-duplex bus, and ensuring zero-delay transparent transmission of service data.

[0086] To eliminate signal reflection oscillations caused by impedance mismatch in long-distance single-pair twisted-pair transmission, both the local and remote end devices are equipped with an AC terminating matching network. This AC terminating matching network is connected across the differential line (i.e., between line A and line B) between the RS485 transceiver (including the first and second RS485 transceivers) and the corresponding bias tee circuit, and consists of an impedance matching resistor and a DC blocking capacitor connected in series. The impedance matching resistor is preferably 120Ω (consistent with the characteristic impedance of the twisted pair), and the DC blocking capacitor is preferably 0.1μF. This series structure provides the necessary terminating impedance matching for the AC signal, absorbs the reflection oscillations generated at the end of the transmission line, thereby improving the signal eye diagram quality and reducing the bit error rate; it also blocks the DC bias current on the RS485 bus through the DC blocking capacitor, preventing DC components from being injected into the inductor branch of the bias tee circuit and avoiding any impact on the transmission efficiency of the DC power supply in the energy domain. The AC terminal matching network and the bias tee circuit work together to achieve optimal impedance matching for both DC power supply and high-frequency signal transmission on a single pair of twisted pairs.

[0087] Control Domain: Employing two carrier channels, 3MHz and 5MHz, and combining ASK / OOK modulation (binary amplitude shift keying, i.e., on / off keying) with frequency division multiplexing (FDM) technology, full-duplex real-time control between local and remote devices is achieved. Specifically:

[0088] The 3MHz channel is used for downlink control direction, transmitting control signals such as ON / OFF and RST from the local device to the 4G communication module;

[0089] The 5MHz channel is used for the uplink state direction to transmit status feedback signals such as STATE0 to STATE4 of the 4G communication module.

[0090] Specifically, the first MCU of the local device packages the RST, ON / OFF, and PCTRL signals from the acquisition terminal interface into control bytes, generates a 3MHz OOK modulated signal through an internal timer and GPIO, and couples it to a single pair of twisted-pair cables via the capacitor of the first bias three-way circuit. The capacitor of the second bias three-way circuit of the remote device extracts the 3MHz signal, sends it to the second 3MHz OOK demodulator for demodulation, and then the second MCU recovers and executes the corresponding control commands.

[0091] Conversely, the second MCU of the remote device reads the STATE0-STATE4 pin levels of the 4G communication module, packages them into status bytes, modulates them with 5MHz OOK, and injects them into a single pair of twisted-pair wires via the capacitor of the second bias tee circuit. The capacitor of the first bias tee circuit of the local device extracts the 5MHz signal, demodulates it through the first 5MHz OOK demodulator, and then the first MCU recovers and drives the corresponding status pins of the acquisition terminal, realizing status mirroring and full-duplex real-time control.

[0092] It should be noted that the downlink control channel (3MHz) and the uplink status channel (5MHz) do not transmit meter reading data, but rather serial messages of physical status.

[0093] Taking the 4G communication module connected to the remote device as an example, this module has five status pins STATE0 to STATE4, which simultaneously output high and low levels (i.e., parallel signals). Since the local device and the remote device are connected only through a single pair of twisted-pair cables (a single serial medium), it is impossible to transmit five level signals simultaneously. Therefore, the second MCU of the remote device combines the levels of the five pins STATE0 to STATE4 (e.g., 01011) into an 8-bit status byte (the lower 5 bits are valid) through its internal shift register. Then, it controls its internal timer to generate a 5MHz carrier wave and uses OOK on / off keying modulation (carrier wave represents logic "1", no carrier wave represents logic "0") to convert the status byte into a high-frequency radio frequency pulse. This pulse is then coupled to the single pair of twisted-pair cables through the capacitor of the second bias tee circuit and sent to the local device. The capacitor of the first bias three-way circuit of the local device extracts a 5MHz signal, which is then demodulated by the first 5MHz OOK demodulator to restore the status byte. The first MCU extracts the lower 5 bits and drives the corresponding GPIO to output TTL level, thereby restoring the real-time status of the 4G communication module in the local device and realizing the "local virtualization" of the status signal.

[0094] Similarly, for control signals such as hardware reset (RST), power-on / off, and power control (PCTRL) of the dedicated transformer acquisition terminal, the first MCU of the local device combines these parallel signals into an 8-bit control byte, uses a 3MHz carrier for OOK modulation, and injects it into a single pair of twisted wires through the capacitor of the first bias three-way circuit. The capacitor of the second bias three-way circuit of the remote device extracts the 3MHz signal, demodulates it through the second 3MHz OOK demodulator, and then the second MCU parses the control byte and drives the corresponding GPIO to output TTL level (such as simulating a 1000ms reset low-level pulse, power-on / power-off high / low level), realizing the "local reconstruction" of control commands on the remote device. Both the uplink status channel and the downlink control channel use the same packetization and OOK modulation mechanism, realizing single-channel multiplexing transmission of multiple parallel signals on a single serial medium.

[0095] like Figure 3 As shown, in this embodiment, the downlink control channel uses a 3MHz carrier wave to realize directional transmission from the local device to the remote device. The transmitted content includes control signals such as hardware reset (RST), power-on / off, and power control (PCTRL) of the dedicated transformer data acquisition terminal. Its implementation includes:

[0096] a. The first MCU of the local terminal device scans the RST (pin 14), ON / OFF (pin 12), and PCTRL (pin 15) pin levels of the dedicated transformer data acquisition terminal interface at a 100ms cycle. The shift register within the first MCU combines these three parallel signals into an 8-bit control byte, where:

[0097] bit0: RST (active high);

[0098] bit1: ON / OFF (high level means power on);

[0099] bit2: PCTRL (high level for high power mode);

[0100] Bits 3 through 7: Reserved bits or parity bits. Parity bits enable error detection and verification, ensuring the accuracy of transmitted data, and also assist the receiver in determining whether the data is valid.

[0101] b. The first MCU controls its internal timer to output a 3MHz square wave. When the current bit of the control byte is "1", the output is enabled, and a 3MHz carrier wave is sent to the high-pass path of the first bias tee circuit; when the current bit of the control byte is "0", the output is disabled. Each bit lasts for 50μs, and the transmission time for one byte is 400μs. The modulated signal is coupled to a single pair of twisted-pair cables via the capacitor of the first bias tee circuit, realizing single-channel multiplexing of multiple parallel signals.

[0102] c. The capacitor in the second bias tee circuit of the remote device extracts the 3MHz signal and sends it to the second 3MHz OOK demodulator. The demodulated serial bytes are stored in the receive buffer of the second MCU.

[0103] Second MCU parsing control bytes:

[0104] If bit0 (RST) is "1", a reset simulation is performed: the second MCU pulls the GPIO of the RST pin of the connected 4G communication module low to 0V, and simultaneously starts an internal timer. After 1000ms, the GPIO is released to a high-impedance state. This 1000ms pulse width conforms to the requirements of the Q / GDW10376.3 standard for reset signals.

[0105] If bit1 (ON / OFF) is "1", the second MCU will pull the GPIO of the ON / OFF pin of the connected 4G communication module high and keep it there, so that the 4G communication module is powered on; if bit1 (ON / OFF) is "0", the GPIO of the ON / OFF pin of the connected 4G communication module will be pulled low, so that the 4G communication module is powered off.

[0106] like Figure 4 As shown, in this embodiment, the uplink status channel uses a 5MHz carrier to realize directional transmission from the remote device to the local device. The transmitted content is a 5-bit parallel status signal from STATE0 to STATE4 of the 4G communication module. Its implementation includes:

[0107] d. During data transmission, the second MCU of the remote terminal device reads the pin levels of STATE0 to STATE4 (pins 17, 18, 19, 20, 21) of the 4G communication module at a 100ms cycle to obtain a 5-bit parallel value (e.g., 01011).

[0108] e. The second MCU fills these 5 bits into the lower 5 bits of an 8-bit status byte, and fills the higher 3 bits into the signal quality code (level 0-7) obtained by quantizing the RSRP value read by the AT command of the 4G communication module. The second MCU controls its internal timer to output a 5MHz square wave, and performs OOK modulation bit by bit ("1" with carrier, "0" without carrier). The modulated signal is injected into a single pair of twisted wires through the capacitor of the second bias tee circuit.

[0109] f. The capacitor in the first bias three-way circuit of the local terminal device extracts a 5MHz signal and sends it to the first 5MHz OOK demodulator. The demodulated status byte is transmitted to the first MCU. The first MCU extracts the lower 5 bits and drives the corresponding level combination of the GPIO outputs of the STATE0~STATE4 pins connected to the dedicated transformer data acquisition terminal on the local terminal device. For example, if the lower 5 bits of the received status byte are 01011, the first MCU sets GPIO0 to 0, GPIO1 to 1, GPIO2 to 0, GPIO3 to 1, and GPIO4 to 1. After reading these pins, the dedicated transformer data acquisition terminal senses that the 4G communication module is in a "searching for a network" or "connected to the network" state.

[0110] Because the local and remote devices are connected via long-distance single-pair twisted-pair cables, communication may be interrupted due to cable malfunctions such as open circuits, short circuits, poor contact, or remote device crashes. If such faults are not detected and addressed promptly, the transformer data acquisition terminal will continuously wait for a response from the 4G communication module, potentially leading to self-test timeouts, program suspension, or data acquisition failures.

[0111] like Figure 2 As shown, to address this issue, the present invention employs a heartbeat monitoring mechanism: the local and remote devices exchange idle heartbeat packets (coded 0xAA) every 100ms on 3MHz and 5MHz channels respectively. If one end fails to receive a heartbeat from the other for three consecutive times (i.e., 300ms), a communication link failure is determined. This mechanism can quickly identify link anomalies, providing triggering conditions for subsequent fault-tolerant operations, thereby preventing terminal crashes and ensuring overall system reliability.

[0112] Similarly, when the sampling device reads the status bit level at both the local and remote ends, and the status bit level result is consistent with the previous cycle, an idle heartbeat packet can be sent. When the other side receives the heartbeat packet normally, the status bit remains unchanged.

[0113] When the first MCU of the local device determines that the communication link is faulty, it immediately performs the following operations:

[0114] 1) Set all GPIOs of STATE0 to STATE4 of the local terminal device connected to the dedicated transformer data acquisition terminal to high level (corresponding to the "no module insertion" state) to make the terminal report an error and prevent the terminal from crashing and hanging.

[0115] 2) Turn off the output of the DC-DC boost circuit and disconnect the 48V power supply.

[0116] 3) The first MCU of the local device enters a fault-locked state and only periodically attempts to restore power for short periods of time to detect whether the link has been restored.

[0117] When the second MCU of the remote terminal device determines a communication failure, it immediately performs the following operations:

[0118] 4) Pull the power enable pin of the connected module low to turn off the module power.

[0119] 5) The remote second MCU enters a low-power standby state, waiting for the local end to re-power it.

[0120] 6) When the link is restored, the local end first restores 48V power supply, the remote end is powered on and reset, and both parties re-initialize and establish communication.

[0121] When the 4G communication module switches from standby mode to network search and registration mode, it generates a transient peak current of up to 2A, requiring the capacitor energy storage unit to provide instantaneous energy compensation. If the capacitor energy storage unit has insufficient power (e.g., the capacitor energy storage unit voltage is below 3.5V), it cannot maintain the 4G communication module voltage above the undervoltage reset threshold, which may cause the 4G communication module to restart or fail to register.

[0122] Therefore, before the 4G communication module initiates high-current operation, the system of this invention pre-disables unnecessary peripherals on the remote device to reduce background power consumption, and detects the voltage of the capacitor energy storage unit. Only after the voltage has been charged to a sufficient level is the 4G communication module allowed to begin network searching, thereby ensuring that the capacitor energy storage unit has sufficient discharge capacity and preventing the 4G communication module from resetting due to undervoltage. The specific implementation method is as follows:

[0123] The second MCU of the remote terminal device reads the STATE0~STATE4 status pin combinations of the 4G communication module in real time. When it detects that the status combination changes from "standby" (e.g., 00001) to "ready to search for network" (e.g., 00101), the second MCU executes:

[0124] Temporarily shut down the power supply to non-essential peripherals (such as LED indicators) on the remote device to reduce the overall power consumption of the system and prioritize the charging of the capacitor energy storage unit.

[0125] The voltage of the capacitor energy storage unit is detected. If the voltage is lower than 3.5V, a delay of 200ms is made to wait for the capacitor energy storage unit to charge to above 3.5V before the 4G communication module is allowed to start searching for and registering the network.

[0126] Once the 4G communication module completes network search and enters normal working state, the second MCU restores power supply to non-essential peripherals.

[0127] The above mechanism ensures that the capacitor energy storage unit has sufficient energy reserves when the 4G communication module operates under high current, effectively preventing the 4G communication module from resetting due to undervoltage and improving the reliability of the system under long-distance power supply conditions.

[0128] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

[0129] Many other changes and modifications can be made without departing from the concept and scope of this invention. It should be understood that this invention is not limited to the specific embodiments, and the scope of this invention is defined by the appended claims.

Claims

1. A fully transparent power acquisition interface and remote parasitic power supply system. Its features are, include: The local terminal device is used to connect to the dedicated transformer data acquisition terminal, monitor all signals of the dedicated transformer data acquisition terminal's communication interface, and boost the low-voltage power supply provided by the dedicated transformer data acquisition terminal to high-voltage DC power. A remote terminal device is used to connect to a 4G communication module, receive and separate electrical energy and communication signals in a mixed signal, supply power to the 4G communication module and restore control signals and data signals; A single twisted pair cable connects the local terminal device and the remote terminal device; The local terminal device and the remote terminal device transmit energy domain, data domain and control domain signals simultaneously on the single pair of twisted pairs via frequency division multiplexing. The energy domain is a DC power supply, the data domain is transparently transmitted serial service data, and the control domain includes a downlink control channel and an uplink status channel. The downlink control channel transmits hardware control commands from the dedicated transformer acquisition terminal to the 4G communication module, and the uplink status channel transmits physical status feedback signals from the 4G communication module. The remote terminal device is equipped with a power buffer unit, which is used to provide compensation power when the 4G communication module generates a transient large current, so as to prevent the 4G communication module from resetting due to long line voltage drop.

2. The fully transparent power acquisition interface and remote parasitic power supply system as described in claim 1, Its features are, The local terminal device is provided with a first bias three-way circuit, and the remote terminal device is provided with a second bias three-way circuit. Both the first bias three-way circuit and the second bias three-way circuit are composed of inductors and capacitors. The inductor is used to inject or extract DC power, and the capacitor is used to couple high-frequency communication signals to realize the coexistence transmission of power and signals on the single pair of twisted pairs. The local terminal device includes a DC-DC boost circuit for boosting the 4V power supply provided by the dedicated transformer acquisition terminal to 48V DC power; the remote terminal device includes a DC-DC buck circuit for bucking the 48V DC power to the 3.8V operating voltage required by the 4G communication module.

3. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 1. Its features are, The power buffer unit is a large-capacity capacitor array connected in parallel to the output of the DC-DC step-down circuit of the remote terminal device. The capacitor array consists of three 2200μF / 6.3V low ESR capacitors connected in parallel. It is used to slowly charge the 4G communication module when it is idle and to release the charge to provide peak current when the 4G communication module searches for the network or transmits.

4. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 1. Its features are, The data domain adopts a bit-level transparent forwarding method: the local terminal device and the remote terminal device each include an RS485 transceiver, which converts serial service data into RS485 differential signals for transmission on the single pair of twisted-pair lines without buffering, packing or parsing the data, thus achieving zero-latency transparent transmission. The RS485 transceiver uses a differential transceiver chip with slew rate limiting characteristics to limit the signal edge transition time of the serial service data to a preset range, thereby filtering out high-frequency harmonics generated by data transitions at the physical layer and preventing frequency domain crosstalk to the high-frequency carrier of the control domain.

5. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 4. Its features are, The bit-level transparent forwarding method of the data field integrates a high-speed automatic flow control mechanism: The GPIO pins of the first MCU and the second MCU are respectively connected to the enable pins of the corresponding RS485 transceivers. In the default state, the first MCU and the second MCU control their respective RS485 transceivers to be in the receive listening state. When either MCU detects the start bit transition edge of the service data frame output by the transmitting pin in real time at the hardware level, it quickly pulls the transmit enable pin of the corresponding RS485 transceiver high to seize the bus transmission right, and releases the enable pin to restore the receive state after detecting that the bus is idle. This strips away the intervention of the software protocol stack and realizes pure physical layer adaptive flow control on the half-duplex bus.

6. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 2. Its features are, Both the local terminal device and the remote terminal device are equipped with an AC terminal matching network. The AC terminal matching network is connected across the differential line between the RS485 transceiver and the bias tee circuit. The AC terminal matching network is composed of an impedance matching resistor and a DC blocking capacitor connected in series, which is used to absorb the high-frequency reflection oscillation of the serial service data and block DC leakage current.

7. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 6. Its features are, The downlink control channel uses a 3MHz carrier, and the uplink status channel uses a 5MHz carrier. The local terminal device is equipped with a 3MHz OOK modulator and a 5MHz OOK demodulator. The 3MHz OOK modulator is used to modulate the downlink control command into a 3MHz carrier signal, and the 5MHz OOK demodulator is used to demodulate the 5MHz carrier signal of the uplink status channel. The remote terminal device is equipped with a 3MHz OOK demodulator and a 5MHz OOK modulator. The 3MHz OOK demodulator is used to demodulate the 3MHz carrier signal of the downlink control channel, and the 5MHz OOK modulator is used to modulate the uplink status signal into a 5MHz carrier signal. Both the downlink control channel and the uplink status channel adopt an on / off keying modulation method, that is, after the parallel control signal or parallel status signal is encoded into serial bytes, the presence or absence of the carrier represents logic "1" and logic "0" and is transmitted on the single pair of twisted pairs.

8. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 7. Its features are, The downlink control channel operates in the following modes: a. The local terminal device is equipped with a first MCU. The first MCU periodically scans the RST, ON / OFF and PCTRL pin levels of the dedicated transformer acquisition terminal interface and combines the three parallel signals into an 8-bit control byte through its internal shift register, where bit0 is RST, bit1 is ON / OFF, bit2 is PCTRL, and bits3 to 7 are reserved bits or check bits. b. The first MCU controls its internal timer to output a 3MHz square wave. When the current bit of the control byte is "1", a 3MHz carrier wave is sent; when it is "0", it is silent. The modulated signal is coupled to the single pair of twisted wires through the capacitor of the first bias three-way circuit. c. The capacitor of the second bias three-way circuit of the remote terminal device extracts a 3MHz signal. After demodulation by the second 3MHz OOK demodulator, the second MCU parses the control byte: if bit0 is "1", the second MCU pulls the RST pin of the connected 4G communication module low for 1000ms and then releases it to a high impedance state; if bit1 is "1", the ON / OFF pin is pulled high to power on the module; if bit1 is "0", the pin is pulled low to power off the module. The uplink status channel operates as follows: d. The remote terminal device is equipped with a second MCU. The second MCU periodically reads the STATE0 to STATE4 pin levels of the 4G communication module to obtain a 5-bit parallel value, which is then filled into the lower 5 bits of an 8-bit status byte, and the higher 3 bits are filled into the signal quality code. e. The second MCU controls its internal timer to output a 5MHz square wave, performs OOK modulation bit by bit, and the modulated signal is injected into the single pair of twisted wires through the capacitor of the second bias three-way circuit; f. The capacitor of the first bias three-way circuit of the local terminal device extracts a 5MHz signal. After demodulation by the first 5MHz OOK demodulator, the first MCU extracts the lower 5 bits of the status byte and drives the GPIO of the STATE0~STATE4 pins of the local terminal device to output the corresponding level combination, thereby realizing status mirroring.

9. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 1. Its features are, A heartbeat monitoring mechanism is provided between the local terminal device and the remote terminal device: both parties send each other an idle heartbeat packet every 100ms on the 3MHz and 5MHz channels; when either party fails to receive the other party's heartbeat for 3 consecutive times, the communication link is determined to be faulty. After the local terminal device detects a fault, it sets all GPIOs connected to the dedicated transformer data acquisition terminal STATE0 to STATE4 to a high level and cuts off the 48V power supply to enter fault lockout. After the remote terminal device detects a fault, it shuts down the power of the 4G communication module and enters low-power standby mode; after the link is restored, it automatically re-initializes and establishes communication.

10. A fully transparent power acquisition interface and remote parasitic power supply system as described in claim 8. Its features are, The remote terminal device also includes an intelligent power management unit: the second MCU reads the STATE0 to STATE4 state combinations of the 4G communication module in real time. When it detects that the state combination changes from "standby" to "preparing to search for the network", it temporarily shuts down the power supply of unnecessary peripherals and detects the voltage of the capacitor energy storage unit. If it is lower than 3.5V, it delays for 200ms and allows the module to start searching for the network and registering only after it is charged to above 3.5V.

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