Direct current carrier communication device and method

Abstract

The invention provides a direct-current carrier communication device and method.The direct-current carrier communication device comprises a single-core cable, a ground direct-current carrier communication module and a plurality of underground direct-current carrier communication modules, and the underground direct-current carrier communication modules are connected to the single-core cable; the underground direct-current carrier communication modules are connected to the ground direct-current carrier communication module through the single-core cable, the ground direct-current carrier communication module and the underground direct-current carrier communication modules are the same in structure and function, data transmission is conducted through the single-core cable, and data transmission is transparent transmission. And the ground direct current carrier communication module and the plurality of underground direct current carrier communication modules do not carry out any processing on transmission data. The direct-current carrier communication device and method can enhance the long-distance transmission capability of signals. The single-core cable transmits communication signals while transmitting electric energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the fields of communication and petroleum technology, in particular to a kind of direct current carrier communication device and method. BACKGROUND

[0002] When multi-layer oil wells are exploited, due to the differences in pressure between oil layers, physical properties of oil layers, properties of crude oil and the like, mutual interference often occurs, so that some oil layers cannot play their due roles. In order to reduce or eliminate interlayer interference, separate layer exploitation should be carried out. In order to realize separate layer oil production, it is necessary to control the opening and closing and opening degree of valves in each layer from the ground, and to monitor the working conditions such as pressure and temperature in each layer. At present, the technologies for controlling the valves in the downhole from the ground include electric control, hydraulic control, electric-hydraulic composite control and liquid pressure pulse control, etc. Among them, the electric control method has developed rapidly due to its fast communication speed and high communication success rate. However, the current electric control communication technology is limited in the promotion and application of direct current carrier long-distance communication technology in oil fields and other fields due to the non-uniformity of interfaces and communication protocols, the independent design of different downhole tools, and the complexity of structure.

[0003] In the Chinese patent application with the application number CN202010762711.8, a downhole bidirectional communication system based on direct current carrier is disclosed, which includes a data forwarding module, a downlink data analysis and reframe module, a local execution module, a direct current carrier modulation module, an AC-DC conversion unit, a first modulatable DC power output and data processing module, a direct current carrier demodulation module, an uplink data analysis and reframe module, and a terminal unit. The terminal unit includes a second modulatable DC power output and data processing module, a direct current carrier demodulation module, a terminal main control module, and a direct current carrier modulation module. This system is a downhole bidirectional communication system based on direct current carrier proposed to address the unreliability of data caused by the harsh downhole environment. It realizes power supply to the downhole and bidirectional communication of uplink and downlink data. The digital signal used in the data transmission process improves the accuracy of information transmission and enhances the anti-noise performance of the system. This application requires data analysis and processing before data modulation, and adds transmission guide frame headers and check frame tails. After data demodulation, the terminal main control module also processes the data and performs corresponding tasks such as controlling the drilling direction and angle of the drill bit, thus having specific functions and lacking universality.

[0004] In the Chinese patent application No. CN201810018329.9, a DC carrier communication system based on RS485 is involved, which comprises a power module, a first coupler, a second coupler, a signal sending device and a signal receiving device. The first coupler is connected with the power module, the signal sending device and the second coupler respectively, and the second coupler is connected with the power module and the signal receiving device respectively. The first coupler is used for coupling the communication signal sent by the signal sending device to the power module, and the second coupler is used for coupling the communication signal in the power module to the signal receiving device. The signal sending device and the signal receiving device are both integrated with RS485 interface to make the DC carrier communication system transmit signals according to RS485 protocol. When the system communicates based on the bus of RS485, the problem of wrong line caused by too many lines can be avoided, thereby simplifying the line complexity, improving the wiring efficiency and reducing the hardware cost. However, the signal sending device and the signal receiving device of the application are both integrated with RS485 interface, and the DC carrier communication system transmits signals according to RS485 protocol. Limited by the RS485 communication interface signal, the signal transmission distance is less than 1200m, which cannot meet the application requirements of oil wells.

[0005] In the Chinese patent application No. CN202021344104.1, a DC carrier communication circuit is involved, which comprises a master station circuit and a plurality of substation circuits electrically connected with the master station circuit through a transmission bus. The master station circuit comprises a master station DC circuit and a master station carrier circuit connected in parallel with the master station DC circuit. The master station DC circuit comprises a master station DC power supply module and a bus driving circuit connected in series with the master station DC power supply module. The bus driving circuit comprises a first power field effect transistor Q1. The master station carrier modulation and demodulation circuit comprises a first control module U1. The substation circuit comprises a substation DC circuit and a substation carrier circuit connected in parallel with the substation DC circuit. The substation DC circuit comprises a substation power extraction circuit connected with the transmission bus. The substation carrier circuit comprises a second control module U2. The first control module U1 and the second control module U2 are matched DC carrier control chips, and the highest voltage supported is 48V. The DC carrier communication circuit of the utility model supports higher carrier voltage and has wider application range. The highest voltage supported by the DC carrier control chip used in the patent is 48V, which cannot meet the requirements of long-distance transmission between the ground and the downhole of oil and water wells. When the ground and the downhole are long-distance transmitted, both the electric energy and the signal have line loss, which affects the downhole power supply and communication.

[0006] The above-mentioned comparative patent discloses a bidirectional communication system based on direct current carrier, and the communication part does not form an independent module with specific functions and has no universality, or the independent communication module uses a general RS485 communication protocol, which leads to limited communication distance, and the above technologies cannot be applied to oil wells or other long-distance communication requirements. The above prior art is quite different from the present application and cannot solve the technical problems we want to solve, and therefore we have invented a new direct current carrier communication device and method. SUMMARY

[0007] The purpose of the present application is to provide a direct current carrier communication device and method that can improve the universality of the direct current carrier communication device in other long-distance communication application scenarios and enhance the long-distance transmission capability of signals.

[0008] The purpose of the present application can be achieved by the following technical measures: a direct current carrier communication device comprising a single-core cable, a ground direct current carrier communication module and a plurality of downhole direct current carrier communication modules, the plurality of downhole direct current carrier communication modules being connected to the single-core cable and connected to the ground direct current carrier communication module through the single-core cable, the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules having the same structure and function, transmitting data through the single-core cable, and the data transmission being transparent transmission, and the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules not processing the transmitted data in any way.

[0009] The purpose of the present application can also be achieved by the following technical measures:

[0010] The direct current carrier communication device further comprises an AC / DC conversion module connected to the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules through the single-core cable, which converts a 220V AC power supply into an adjustable DC power supply to power the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules.

[0011] The communication signal on the single-core cable uses pulse signals, and the direct current carrier communication distance is relatively long.

[0012] The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules each comprise a signal filtering and amplifying circuit and a single-chip microcomputer, the signal filtering and amplifying circuit being connected to the single-core cable and the single-chip microcomputer, filtering and amplifying the signal when the signal is obtained from the single-core cable, and transmitting the signal to the single-chip microcomputer, the single-chip microcomputer decoding the received signal and sending it to an upper computer through a standard communication interface.

[0013] The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules further comprise a signal conversion circuit connected to the single-chip microcomputer; when the single-chip microcomputer receives data from the upper computer through the communication interface, the single-chip microcomputer encodes the data and transmits the encoded data to the signal conversion circuit; the signal conversion circuit converts the encoded data into a pulse signal; the pulse signal is coupled to the single-core cable through a capacitor to perform signal transmission.

[0014] The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules further comprise a direct current voltage conversion circuit; the direct current voltage conversion circuit converts the voltage transmitted by the single-core cable into a voltage required by the signal filtering and amplifying circuit, the single-chip microcomputer and the signal conversion circuit, and respectively provides the voltage to the signal filtering and amplifying circuit, the single-chip microcomputer and the signal conversion circuit.

[0015] When the ground upper computer and the downhole upper computers communicate through the direct current carrier communication device, the ground upper computer actively sends information to the downhole upper computers; after receiving the information, the downhole upper computers immediately send information required by the ground upper computer to the downhole direct current carrier communication modules through the standard communication interface; the downhole direct current carrier communication modules transmit the information to the ground direct current carrier module through the single-core cable, and then transmit the information to the ground upper computer through the standard communication interface.

[0016] When the ground upper computer and the plurality of downhole upper computers communicate through the direct current carrier communication device, the ground upper computer actively sends information to the plurality of downhole upper computers; after receiving the information, the plurality of downhole upper computers identify the upper computer inquiring about which layer in the downhole through the received address information; the inquired downhole upper computer immediately sends information required by the ground upper computer to the corresponding downhole direct current carrier communication module through the standard communication interface; the downhole direct current carrier communication module transmits the information to the ground direct current carrier module through the single-core cable, and then transmits the information to the ground upper computer through the standard communication interface; the returned information also comprises address information, and the ground upper computer identifies whether the inquiry is replied through the returned address information.

[0017] The purpose of the application can also be achieved by the following technical measures: a direct current carrier communication method using a direct current carrier communication device, comprising:

[0018] Step 1: the single-chip microcomputer judges whether the upper computer data is received; if the upper computer data is received, the data is received, and the flow enters step 2; if the upper computer data is not received, the flow enters step 3;

[0019] Step 2: the single-chip microcomputer encodes the data, starts the signal conversion circuit, and performs signal transmission; the flow returns to step 1;

[0020] Step 3, the single-chip microcomputer judges whether the signal transmitted by the single-core cable is received, if not, the flow returns to step 1, if yes, the flow enters step 4;

[0021] Step 4, the single-chip microcomputer decodes the signal and sends the extracted data to the upper computer.

[0022] The object of the application can also be achieved by the following technical measures:

[0023] In step 2, the single-chip microcomputer encodes the data, starts the signal conversion circuit, the signal conversion circuit converts the encoded data into a pulse signal, and the pulse signal is coupled to the single-core cable through the capacitor for signal transmission.

[0024] In step 4, when the single-chip microcomputer obtains the signal from the single-core cable, the signal filtering and amplifying circuit filters and amplifies the signal and transmits the signal to the single-chip microcomputer, and the single-chip microcomputer decodes the received signal and sends it to the upper computer through the standard communication interface.

[0025] In step 2, the single-chip microcomputer encodes the data, starts the signal conversion circuit, the signal conversion circuit converts the encoded data into a pulse signal, and the pulse signal is coupled to the single-core cable through the capacitor for signal transmission.

[0026] In step 4, when the single-chip microcomputer obtains the signal from the single-core cable, the signal filtering and amplifying circuit filters and amplifies the signal and transmits the signal to the single-chip microcomputer, and the single-chip microcomputer decodes the received signal and sends it to the upper computer through the standard communication interface.

[0027] The DC carrier communication device and method in the application can improve the universality of the DC carrier communication module by using modular design for the problem of long-distance communication between the ground and the well; the DC carrier communication module transmits data in a transparent transmission mode through the single-core cable without any processing of the transmitted data; the DC carrier communication device composed of the DC carrier communication module, the single-core cable and the AC / DC conversion module has a standard RS485 communication interface, and when transmitting data with the outside, it is not affected by the communication protocol, so that the universality of the DC carrier communication device in other long-distance communication application scenarios can be improved; the encoding circuit converts the TTL level signal into a pulse signal and couples the signal to the single-core cable for transmission, which can enhance the long-distance transmission capability of the signal, the communication distance is greater than 5000m, and the single-core cable transmits the communication signal while transmitting the electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The DC carrier communication device principle diagram in a specific embodiment of the application;

[0029] Figure 2A DC carrier communication module schematic diagram in a specific embodiment of the present application;

[0030] Figure 3 A single-chip microcomputer control flow chart in a specific embodiment of the present application;

[0031] Figure 4 A multi-slave mode DC carrier communication schematic diagram in a specific embodiment of the present application. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0033] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0034] The DC carrier communication device and method of the present application, the ground DC carrier communication module is connected with the downhole DC carrier communication module through a single-core cable; the downhole can have multiple layers, and the DC carrier communication modules of each layer are connected on the single-core cable in turn; the DC carrier communication module adopts an RS485 communication interface, and can also adopt an RS422, RS232 or other standard communication interface, and is not limited to the above interface types; the AC / DC conversion module converts a 220V AC power supply into a 50-110V adjustable DC power supply, such as a 58V DC power supply, to supply power to the DC carrier communication module. The DC carrier communication device is composed of at least two DC carrier communication modules, a single-core cable and an AC / DC conversion module.

[0035] The DC carrier communication module installed on the ground and the DC carrier communication module installed in the well are the same type of module, and their structures and functions are completely the same. The DC carrier communication module installed on the ground and the DC carrier communication module installed in the well transmit data through a single-core cable. The data transmission is transparent transmission, and the DC carrier communication module does not process the transmitted data. The communication signal on the cable adopts a pulse signal, and the DC carrier communication distance is greater than 5000m.

[0036] The DC carrier communication device adopts a standard communication interface, and is not affected by communication protocols when transmitting data with the outside. The DC carrier communication device is universal, and can also be applied to other remote communication scenarios based on DC carrier. The working process of the DC carrier communication module is as follows: signals are obtained from a single-core cable, filtered and amplified, the signal receiving and sending control circuit receives the signals, sends them to the upper computer through a standard communication interface, obtains the return signals from the upper computer through a standard communication interface, then controls the coding circuit to work, the coding circuit converts the TTL level signal into a pulse signal, and the pulse signal is coupled to the single-core cable through a capacitor to enhance the long-distance transmission capability of the signal.

[0037] The hardware communication interface of the input signal and the output signal of the DC carrier communication device adopts a standard communication interface, and the software communication protocol adopts a MODBUS RTU standard communication protocol.

[0038] When the upper computers communicate through the DC carrier communication device, the communication between the DC carrier communication modules adopts a half-duplex communication mode, which is controlled and realized by the upper computer using a master-slave communication method.

[0039] The communication process between the ground and the downhole upper computer is as follows: the ground upper computer actively sends information to the downhole upper computer through the DC carrier communication device, and the downhole upper computer returns the information required by the ground upper computer to the ground upper computer through the DC carrier communication device. The returned information also includes address information of multiple layers downhole, and the ground upper computer identifies whether the inquiry is replied through the returned address information.

[0040] The DC carrier communication device adopts a standard communication interface and a communication protocol, which can enhance the universality of the device. When other remote communication technologies are researched, the DC carrier communication device can be directly used, and secondary development can be carried out on this basis, which can shorten the development process and save development time.

[0041] The AC-DC conversion module converts a 220V AC power supply into a 50-110V adjustable DC power supply, and can also design an output voltage value according to specific needs. The converted DC power supplies the upper computer and the DC carrier communication module, and transmits the DC power to the downhole through a single-core cable to provide DC power for the circuit downhole.

[0042] The single-core cable transmits signals while transmitting DC power.

[0043] The DC carrier communication module installed on the ground and the DC carrier communication module installed downhole are the same kind of module, and their structures and functions are completely the same.

[0044] The DC carrier communication module includes a DC voltage conversion circuit, a signal filtering and amplifying circuit, a single-chip microcomputer, and a signal conversion circuit.

[0045] The direct current voltage conversion circuit converts the voltage on the cable into +5V, +3.3V and the like to provide the signal filter amplification circuit, the single-chip microcomputer and the signal conversion circuit.

[0046] The direct current carrier communication modules transmit signals through the single-core cable. The direct current carrier communication modules have the functions of receiving signals and sending signals. The data transmission between the direct current carrier communication modules is transparent transmission, and the direct current carrier communication modules do not process the transmitted data.

[0047] When one direct current carrier communication module receives the signal sent by another direct current carrier module, the processing process is as follows: the signal filter amplification circuit removes the direct current signal on the cable through band-pass filtering to extract the alternating current signal, amplifies the signal and provides the amplified signal to the single-chip microcomputer. The single-chip microcomputer adjusts the amplification multiple of the signal filter amplification circuit according to the signal receiving condition, realizes communication adaptive adjustment and improves the communication success rate. The single-chip microcomputer decodes the received signal to form data in the format conforming to the MODBUS RTU communication protocol and sends the data to the upper computer through the standard communication interface.

[0048] When one direct current carrier communication module sends a signal to another direct current carrier module, the processing process is as follows: the single-chip microcomputer receives data in the format conforming to the MODBUS RTU communication protocol through the standard communication interface, encodes the data, starts the signal conversion circuit to work, converts the encoded TTL level signal into a pulse signal, couples the pulse signal to the single-core cable through a capacitor and transmits the pulse signal to another direct current carrier communication module.

[0049] The single-chip microcomputer judges whether the upper computer data is received. If the upper computer data is received, the data is received, encoded, the signal conversion circuit is started and then it is judged whether the upper computer data is received.

[0050] If the upper computer data is not received, it is judged whether the cable signal is received. If the cable signal is not received, it is judged whether the upper computer data is received. If the cable signal is received, the signal is received, decoded and the data in the format conforming to the MODBUS RTU protocol is extracted and sent to the upper computer.

[0051] The communication signal on the cable adopts an encoded and phase-modulated pulse signal, which can enhance the long-distance transmission capability of the signal. The direct current carrier communication distance is greater than 5000m.

[0052] The following are several specific embodiments of the application

[0053] Embodiment 1

[0054] In the application of a specific embodiment 1 of the application, the direct current carrier communication module is as shown in Figure 2 ​

[0055] The direct current carrier communication module obtains signals from the single-core cable for filtering and amplification. The signal receiving and sending control circuit receives the signals and sends them to the upper computer through the RS458 interface. The signal receiving and sending control circuit obtains the return signals from the upper computer through the RS485 interface, and then controls the encoding circuit to work. The encoding circuit converts the TTL level signals into pulse signals, which are coupled to the single-core cable through a capacitor to enhance the long-distance transmission capability of the signals.

[0056] The direct current voltage conversion circuit converts the direct current voltage obtained from the single-core cable into the direct current power supply voltage required by the signal filtering and amplification circuit, the signal receiving and sending control circuit, and the encoding circuit.

[0057] The working process of the single-chip microcomputer of the direct current carrier communication module is as shown in Figure 3

[0058] Step 1: The single-chip microcomputer determines whether the data from the upper computer is received. If the data from the upper computer is received, the data is received, and the flow enters step 2. If the data from the upper computer is not received, the flow enters step 3.

[0059] Step 2: The single-chip microcomputer encodes the data, starts the signal conversion circuit, and converts the encoded data into pulse signals through the signal conversion circuit. The pulse signals are coupled to the single-core cable through a capacitor for signal transmission. The flow returns to step 1.

[0060] Step 3: The single-chip microcomputer determines whether the signals transmitted from the single-core cable are received. If the signals transmitted from the single-core cable are not received, the flow returns to step 1. If the signals transmitted from the single-core cable are received, the flow enters step 4.

[0061] Step 4: When the single-chip microcomputer obtains the signals from the single-core cable, the signal filtering and amplification circuit filters and amplifies the signals and transmits the signals to the single-chip microcomputer. The single-chip microcomputer decodes the received signals and sends them to the upper computer through the RS485 communication interface.

[0062] The communication signals on the cable are pulse signals that are encoded and phase-modulated, which can enhance the long-distance transmission capability of the signals. The communication distance of the direct current carrier communication is greater than 5000m.

[0063] Example 2

[0064] As shown in Figure 1 , the ground direct current carrier communication module in the direct current carrier communication device is connected with the upper computer through the RS485 interface, and the downhole direct current carrier communication module in the direct current carrier communication device is connected with the downhole upper computer through the RS485 interface.

[0065] ​The field staff operates the ground host computer, which sends signals to the ground DC carrier communication module through RS485, the ground DC carrier communication module transmits the signals to the downhole through the single-core cable, and the downhole DC carrier module transmits the received signals to the downhole host computer through RS485.

[0066] The AC-DC conversion module converts 220V AC into 50-110V DC, which provides DC power for the ground host computer and the ground DC carrier communication module. The 50-110V DC is also transmitted to the downhole through the single-core cable, providing DC power for the downhole host computer and the downhole DC carrier communication module.

[0067] The communication between the ground host computer and the downhole host computer adopts the master-slave half-duplex communication mode. The ground host computer actively sends information to the downhole host computer. After receiving the information, the downhole host computer immediately sends the information required by the ground host computer to the downhole DC carrier communication module through the RS485 interface. The downhole DC carrier communication module transmits the information to the ground DC carrier module through the single-core cable, and then transmits the information to the ground host computer through the RS485 interface.

[0068] Example 3

[0069] As shown in Figure 4 The ground DC carrier communication module in the DC carrier communication device is connected with the host computer through the RS485 interface, and each layer of the downhole DC carrier communication module is connected with the host computer 1, the host computer 2, …, and the host computer n through the RS485 interface.

[0070] The field staff operates the host computer, which sends signals to the ground DC carrier communication module through RS485, the ground DC carrier communication module transmits the signals to the downhole through the single-core cable, and the downhole DC carrier module transmits the received signals to the host computer 1, the host computer 2, …, and the host computer n through RS485.

[0071] The communication between the ground host computer and the downhole host computer n adopts the master-slave half-duplex communication mode. The host computer 1, the host computer 2, …, and the host computer n identify the communication between the host computer and the downhole through the received address information. After receiving the information, the host computer 1, the host computer 2, …, and the host computer n immediately send the information required by the host computer to the downhole DC carrier communication module through the RS485 interface. The downhole DC carrier communication module returns the information to the ground DC carrier module through the single-core cable, and then transmits the information to the host computer through the RS485 interface. The returned information also includes address information, and the ground host computer identifies whether the inquiry is replied through the returned address information.

[0072] The AC-DC conversion module converts 220V AC into 50-110V DC, which not only provides DC power for the ground host computer and the DC carrier communication module, but also provides DC power for the downhole host computer 1, host computer 2,..., host computer n and the DC carrier communication module.

[0073] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the purpose of limiting the present application, although the foregoing detailed description of the present application is made with reference to the foregoing examples, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included within the scope of the present application.

[0074] In addition to the technical features described in the specification, they are known to those skilled in the art.

Claims

1. A device for carrier-current communication, characterized in that The direct current carrier communication device comprises a single-core cable, a ground direct current carrier communication module and a plurality of downhole direct current carrier communication modules, the plurality of downhole direct current carrier communication modules are connected to the single-core cable and the ground direct current carrier communication module through the single-core cable, the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules are the same in structure and function, data transmission is carried out through the single-core cable, the data transmission is transparent transmission, and the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules do not process the transmission data.

2. The device for carrier current communication according to claim 1, characterized in that The direct current carrier communication device further comprises an AC / DC conversion module, the AC / DC conversion module is connected to the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules through the single-core cable, 220V AC power is converted into adjustable DC power to supply power to the ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules.

3. The device for carrier current communication according to claim 1, wherein The communication signal on the single-core cable adopts a pulse signal, and the direct current carrier communication distance is relatively long.

4. The device for carrier current communication according to claim 1, wherein The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules each comprise a signal filtering and amplifying circuit and a single-chip microcomputer, the signal filtering and amplifying circuit is connected to the single-core cable and the single-chip microcomputer, when a signal is obtained from the single-core cable, the signal is filtered and amplified, and the signal is transmitted to the single-chip microcomputer, and the single-chip microcomputer decodes the received signal and sends the signal to an upper computer through a standard communication interface.

5. The device for carrier current communication according to claim 4, characterized in that The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules further comprise a signal conversion circuit, the signal conversion circuit is connected to the single-chip microcomputer, when the single-chip microcomputer receives data from the upper computer through a communication interface, the data is encoded, and the encoded data is transmitted to the signal conversion circuit, the signal conversion circuit converts the encoded data into a pulse signal, and the pulse signal is coupled to the single-core cable through a capacitor to carry out signal transmission.

6. The device for carrier current communication according to claim 5, characterized in that The ground direct current carrier communication module and the plurality of downhole direct current carrier communication modules further comprise a direct current voltage conversion circuit, the direct current voltage conversion circuit converts the voltage transmitted by the single-core cable into the voltage required by the signal filtering and amplifying circuit, the single-chip microcomputer and the signal conversion circuit, and respectively provides the voltage to the signal filtering and amplifying circuit, the single-chip microcomputer and the signal conversion circuit.

7. The device of claim 5, wherein, When the upper computer on the ground and the upper computer in the well communicate through the direct current carrier communication device, the upper computer on the ground actively sends information to the upper computer in the well, the upper computer in the well immediately sends the information required by the upper computer on the ground to the downhole direct current carrier communication module through a standard communication interface, the downhole direct current carrier communication module sends the information to the ground direct current carrier module through the single-core cable, and the information is transmitted to the upper computer on the ground through the standard communication interface.

8. The device of claim 5, wherein, When the ground host computer and the plurality of downhole host computers communicate through the direct current carrier communication device, the ground host computer actively sends information to the plurality of downhole host computers, and the plurality of downhole host computers identify the layer inquired by the ground host computer through the received address information after receiving the information, and the inquired downhole host computer immediately sends the information required by the ground host computer to the corresponding downhole direct current carrier communication module through the standard communication interface, the downhole direct current carrier communication module sends the information to the ground direct current carrier module through the single-core cable, and then the information is transmitted to the ground host computer through the standard communication interface, the returned information also includes address information, and the ground host computer identifies whether the inquiry is replied through the returned address information.

9. A method of carrier-current communication, characterized by The direct current carrier communication method adopts the direct current carrier communication device of claim 1, and comprises the following steps: Step 1: the single-chip microcomputer judges whether the host computer data is received, if the host computer data is received, the data is received, and the flow enters step 2, if the host computer data is not received, the flow enters step 3; Step 2: the single-chip microcomputer encodes the data, starts the signal conversion circuit, and performs signal transmission, and the flow returns to step 1; Step 3: the single-chip microcomputer judges whether the signal transmitted by the single-core cable is received, if the signal is not received, the flow returns to step 1, if the signal is received, the flow enters step 4; Step 4: the single-chip microcomputer decodes the signal and sends the extracted data to the host computer.

10. The method of claim 9, wherein, In step 2, the single-chip microcomputer encodes the data, starts the signal conversion circuit, and the signal conversion circuit converts the encoded data into a pulse signal, and the pulse signal is coupled to the single-core cable through a capacitor for signal transmission.

11. The method of claim 9, wherein, In step 4, when the single-chip microcomputer obtains the signal from the single-core cable, the signal filter amplification circuit filters and amplifies the signal, and transmits the signal to the single-chip microcomputer, and the single-chip microcomputer decodes the received signal and sends it to the host computer through the standard communication interface.

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