Data transmission device with bidirectional signal conversion function and communication equipment

Abstract

The invention discloses a data transmission device with a bidirectional signal conversion function and communication equipment, and the device comprises a power supply module which is used for carrying out the rectification and voltage conversion of a signal provided by a power distribution network, and outputting power supply; the carrier communication circuit is used for electrically isolating the power distribution network from the carrier control module; the carrier control module is used for realizing signal modulation / demodulation processing and bidirectional signal transmission between the carrier communication circuit and the signal conversion circuit; and the signal conversion circuit is provided with a first communication interface and a second communication interface which support different communication protocols, and the signal conversion circuit is used for carrying out bidirectional communication protocol conversion on the data signal provided by the second communication interface and the power carrier signal provided by the first communication interface. By designing the data transmission device with the bidirectional signal conversion function, the problem that the wiring condition and the communication space of communication equipment are limited is solved, and the compatibility and the communication reliability of a communication system in different scenes are improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a data transmission device and communication equipment with a bidirectional signal conversion function. Background Art

[0002] RS-485 is a differential transmission, half-duplex serial communication standard with advantages such as strong anti-interference ability and long transmission distance. It is widely used in industrial automation control systems.

[0003] With the development of industrial automation and remote monitoring technology, industrial automation control systems usually need to be equipped with a variety of devices (such as sensors and smart meters) that use the RS-485 protocol, and the demand for cross-regional communication is gradually increasing. However, existing RS-485 devices are limited by wiring conditions and wiring costs, and cannot meet the monitoring needs of cross-regional projects. They are also unable to perform remote modifications and program upgrades in a timely and convenient manner. As a result, RS-485 devices are inconvenient to use in some industrial control scenarios (such as cross-regional projects or scenarios with restricted wiring) and have low system communication reliability. Summary of the Invention

[0004] The present invention provides a data transmission device and communication equipment with a bidirectional signal conversion function to solve the problems of existing communication methods with limited wiring conditions and communication space, which cannot meet the monitoring needs of cross-regional projects and cannot perform remote modifications and program upgrades in a timely and convenient manner, thereby improving the compatibility and communication reliability of the communication system in different scenarios.

[0005] According to one aspect of the present invention, there is provided a data transmission device with a bidirectional signal conversion function, comprising: a carrier communication circuit, a carrier control module, a signal conversion circuit and a power supply module; the power supply module is used to connect to a power distribution network, perform rectification and voltage conversion processing on the signal provided by the power distribution network, and output power to the carrier control module and the signal conversion circuit; the carrier communication circuit is arranged between the power distribution network and the carrier control module, and is used to electrically isolate the power distribution network from the carrier control module; the carrier control module is arranged between the carrier communication circuit and the signal conversion circuit, and is used to realize signal modulation / demodulation processing and bidirectional signal transmission between the carrier communication circuit and the signal conversion circuit; the signal conversion circuit is provided with a first communication interface and a second communication interface supporting different communication protocols, the first communication interface is used to connect to the carrier control module, and the second communication interface is used to connect to an external device, and the signal conversion circuit is used to perform bidirectional communication protocol conversion between the data signal provided by the second communication interface and the power carrier signal provided by the first communication interface.

[0006] Optionally, the power supply module includes: an AC-DC conversion unit, a power management unit, a transformer, a DC output unit and a feedback unit; the AC side of the AC-DC conversion unit is connected to the power distribution network, and the DC positive terminal of the AC-DC conversion unit is connected to the first end of the primary winding of the transformer; the DC output unit is connected to the first secondary winding of the transformer, outputs a first supply voltage through the first power supply terminal, and outputs a second supply voltage through the second power supply terminal; the feedback unit is used to detect the first supply voltage and output a feedback signal; the input terminal of the power management unit is connected to the DC negative terminal of the AC-DC conversion unit, the output terminal of the power management unit is connected to the second end of the primary winding, the control terminal of the power management unit is connected to the feedback signal output terminal of the feedback unit, and the power management unit is used to adjust the conduction frequency of the primary winding according to the feedback signal to adjust the first supply voltage.

[0007] Optionally, the feedback unit includes: an optoelectronic isolator and a voltage detection circuit; the voltage detection circuit is arranged on the input side of the optoelectronic isolator, and the output end of the optoelectronic isolator is connected to the control end of the power management unit; the detection end of the voltage detection circuit is connected to the first power supply end to detect the first power supply voltage, and when the first power supply voltage reaches a preset voltage, the input side of the optoelectronic isolator is controlled to be turned on, so that the optoelectronic isolator outputs the feedback signal to the power management unit.

[0008] Optionally, the signal conversion circuit includes: a first signal processing sub-circuit, a second signal processing sub-circuit and a protocol conversion unit; the first signal processing sub-circuit is arranged between the first communication interface and the protocol conversion unit, and the first signal processing sub-circuit is used to perform signal processing on the carrier signal transceiver side of the protocol conversion unit; the second signal processing sub-circuit is arranged between the second communication interface and the protocol conversion unit, and the second signal processing sub-circuit is used to perform signal processing on the data signal transceiver side of the protocol conversion unit; the protocol conversion unit is used to adjust the data transmission direction according to the level state of the power carrier signal.

[0009] Optionally, the first signal processing subcircuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first switching tube; the first end of the first resistor is connected to the second power supply end of the power supply module, the second end of the first resistor is connected to the carrier output end of the protocol conversion unit via the second resistor, a first node is provided between the first resistor and the second resistor, and the first node is connected to the signal output end of the first communication interface; the first end of the third resistor is connected to the carrier input end of the protocol conversion unit, and the second end of the third resistor is connected to the signal input end of the first communication interface; the first end of the fourth resistor is connected to the signal input end of the first communication interface, the second end of the fourth resistor is connected to the control end of the first switching tube, the input end of the first switching tube is connected to the second power supply end via the fifth resistor, the output end of the first switching tube is grounded, a second node is provided between the input end of the first switching tube and the fifth resistor, and the second node is respectively connected to the receive enable end and the transmit enable end of the protocol conversion unit.

[0010] Optionally, the second signal processing sub-circuit includes: a first bidirectional trigger diode, a second bidirectional trigger diode and a third bidirectional trigger diode; the first bidirectional trigger diode is arranged between the first end and the second end of the second communication interface; the first end of the second bidirectional trigger diode is connected to the first end of the second communication interface, and the second end of the second bidirectional trigger diode is grounded; the first end of the third bidirectional trigger diode is connected to the second end of the second communication interface, and the second end of the third bidirectional trigger diode is grounded.

[0011] Optionally, the data transmission device with bidirectional signal conversion function also includes: a lightning protection circuit and a filtering circuit; the first side of the lightning protection circuit is connected to the power distribution network, and the second side of the lightning protection circuit is connected to the carrier communication circuit and the power supply module respectively, and the lightning protection circuit is used to perform surge protection processing on the signal provided by the power distribution network; the filtering circuit is arranged between the second side of the lightning protection circuit and the power supply module, and is used to filter the AC side power supply of the power supply module.

[0012] Optionally, the filtering circuit includes: a first inductor and a second inductor, the first inductor is arranged between the lightning protection circuit and the AC power supply end of the power supply module, and the second inductor is arranged between the lightning protection circuit and the AC grounding end of the power supply module; the lightning protection circuit includes: a current limiting protection element, a first varistor, a second varistor, a third varistor, a thermistor, a first discharge tube, a second discharge tube and a third discharge tube; the first end of the current limiting protection element is connected to the live wire of the power distribution network, and the second end of the current limiting protection element is connected to the AC power supply end of the power supply module via the first inductor, and a fifth node is provided between the current limiting protection element and the first inductor; the first end of the first varistor The first terminal of the first varistor is connected to the fifth node, the second end of the first varistor is connected to the neutral line of the power distribution network; the first end of the thermistor is connected to the neutral line of the power distribution network, the second end of the thermistor is connected to the AC grounding terminal of the power supply module via the second inductor, and a sixth node is provided between the thermistor and the second inductor; the first end of the second varistor is connected to the fifth node, the second end of the second varistor is connected to the grounding wire via the first discharge tube; the first end of the third varistor is connected to the sixth node, the second end of the third varistor is connected to the grounding wire via the first discharge tube; the second discharge tube is connected in parallel to the first inductor; and the third discharge tube is connected in parallel to the second inductor.

[0013] Optionally, the carrier communication circuit includes: an isolation transformer, a fourth bidirectional trigger diode and a fifth bidirectional trigger diode; the first side of the isolation transformer is connected to the connection node between the lightning protection circuit and the filter circuit, and the second side of the isolation transformer is connected to the carrier control module; the fourth bidirectional trigger diode is arranged on the first side of the isolation transformer; the fifth bidirectional trigger diode is arranged on the second side of the isolation transformer.

[0014] According to another aspect of the present invention, there is provided a communication device comprising: the above-mentioned data transmission device with a bidirectional signal conversion function.

[0015] The technical solution of the embodiment of the present invention is to set up a carrier communication circuit, a carrier control module, a signal conversion circuit and a power supply module, which is connected to the power distribution network through the power supply module, rectifies and voltage-converts the signal provided by the power distribution network, and outputs power to the carrier control module and the signal conversion circuit; the carrier communication circuit is arranged between the power distribution network and the carrier control module, and is used to electrically isolate the power distribution network and the carrier control module; the carrier control module is arranged between the carrier communication circuit and the signal conversion circuit, and is used to realize signal modulation / demodulation processing and bidirectional signal transmission between the carrier communication circuit and the signal conversion circuit; the signal conversion circuit is provided with a first communication interface and a second communication interface supporting different communication protocols, the first communication interface is used to connect to the carrier control module, the second communication interface is used to connect to an external device, and the signal conversion circuit is used to convert the data signal provided by the second communication interface into the power carrier signal provided by the first communication interface The system performs two-way communication protocol conversion, which solves the problems of limited wiring conditions and communication space of existing communication methods, which cannot meet the monitoring needs of cross-regional projects and cannot perform remote modifications and program upgrades in a timely and convenient manner. The data transmission device uses power lines as transmission media, and there is no need to lay special communication lines, which reduces wiring costs and construction difficulty; the modulation and demodulation technology used in carrier communication can suppress stray signals and interference signals, improve the system's anti-interference ability, and can adapt to different power line conditions (such as line impedance, voltage fluctuations, etc.) to maintain stable communication in harsh environments; by adding signal conversion circuits, it can connect to a variety of external devices (such as RS-485 interface devices) without the need for additional communication cables, reducing the cost of purchasing, laying and maintaining cables, facilitating unified management of equipment, improving interoperability between devices in the communication system, and improving the compatibility and communication reliability of the communication system in different scenarios.

[0016] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic structural diagram of a data transmission device with a bidirectional signal conversion function provided by an embodiment of the present invention;

[0019] Figure 2A circuit schematic diagram of a data transmission device with a bidirectional signal conversion function provided by an embodiment of the present invention;

[0020] Figure 3 A circuit schematic diagram of a signal conversion circuit provided by an embodiment of the present invention;

[0021] Figure 4 A circuit schematic diagram of another data transmission device with bidirectional signal conversion function provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] Figure 1 This is a schematic diagram of the structure of a data transmission device with bidirectional signal conversion capabilities, provided in an embodiment of the present invention. This embodiment is suitable for applications such as cross-regional project monitoring, wiring-constrained environments, and communication between smart meters and PLCs. In this embodiment, the data transmission device with bidirectional signal conversion capabilities can be used to perform bidirectional signal conversion between power carrier communication signals and RS485 communication signals. This data transmission device can be integrated into a wireless terminal device (Data Transfer Unit, DTU).

[0025] like Figure 1 As shown, the data transmission device with bidirectional signal conversion function of the present application includes: a carrier communication circuit 100, a carrier control module 200, a signal conversion circuit 300 and a power supply module 400.

[0026] Among them, the power supply module 400 is used to connect to the power distribution network 1, rectify and voltage convert the signal provided by the power distribution network 1 (such as 220VAC mains electricity), and output power to the carrier control module 200 and the signal conversion circuit 300; the carrier communication circuit 100 is arranged between the power line pins of the power distribution network 1 and the carrier control module 200, and is used to electrically isolate the power distribution network 1 from the carrier control module 200; the carrier control module 200 is arranged between the carrier communication circuit 100 and the signal conversion circuit 300, and is used to realize signal modulation / demodulation processing and bidirectional signal transmission between the carrier communication circuit 100 and the signal conversion circuit 300; the signal conversion circuit 300 is provided with a first communication interface and a second communication interface supporting different communication protocols, the first communication interface is used to connect to the carrier control module 200, and the second communication interface is used to connect to the external device 2, and the signal conversion circuit 300 is used to perform bidirectional communication protocol conversion on the data signal provided by the second communication interface and the power carrier signal provided by the first communication interface.

[0027] In this embodiment, the power supply module 400 can integrate functions such as AC-DC conversion, DC-DC voltage conversion, and filtering protection, and output a power supply voltage of at least one voltage level. Typically, the power supply voltage of the carrier control module 200 and the signal conversion circuit 300 can be DC +3.3V.

[0028] The first communication interface is a Power Line Carrier (PLC) interface, which supports bidirectional data transmission and reception.

[0029] The second communication interface is an RS485 interface that supports bidirectional data transmission and reception. The external device 2 connected to the second communication interface can be understood as a sensor or intelligent meter with an RS485 interface.

[0030] Signal conversion circuit 300 can be understood as a circuit that performs bidirectional protocol conversion between signals using different communication protocols. In this embodiment, external device 2 and power carrier communication use different communication protocols. Signal conversion circuit 300 can receive data signals from external device 2, convert them into power carrier signals, and transmit them to the power lines of power distribution network 1. It can also receive power carrier signals and convert them into data signals that support the RS485 interface protocol and output them to external device 2.

[0031] Specifically, the distribution network 1 is connected to the power carrier control platform, and the power carrier signal emitted by the power carrier control platform is transmitted to the carrier communication circuit 100 through the power line of the distribution network 1. After the carrier communication circuit 100 receives the power carrier signal provided by the power line, it is transmitted to the carrier control module 200. The carrier control module 200 modulates and demodulates the power carrier signal to obtain corresponding control instructions (such as modifying operating parameters or upgrading programs), and then performs signal protocol conversion through the signal conversion circuit 300 to convert the control instructions corresponding to the power carrier signal into data signals (for example, RS485 signals), thereby realizing control of external devices (for example, RS485 interface devices). At the industrial control site, a variety of external devices (such as RS485 interface devices) can be connected to the signal conversion circuit 300 via the second communication interface (such as the RS485 interface). The signal conversion circuit 300 receives the data signal (such as the RS485 signal) provided by the external device (such as the RS485 interface device) and converts the data signal (such as the RS485 signal) into a power carrier signal. The carrier control module 200 loads the data collected by the external device into the power waveform and transmits it to the power carrier control platform via the carrier communication circuit 100 and the power line of the distribution network 1. During the data transmission process, the software architecture of the carrier control module 200 uses data synchronization technology (such as timing control) to ensure data synchronization, and uses error detection and correction mechanisms (such as link layer protection and protocol layer protection) to ensure data integrity, thereby improving the reliability of data transmission.

[0032] Therefore, the data transmission device of the present application uses power lines as the transmission medium, and there is no need to lay special communication lines, which reduces wiring costs and construction difficulty; the modulation and demodulation technology used in carrier communication can suppress stray signals and interference signals, improve the system's anti-interference ability, and can adapt to different power line conditions (such as line impedance, voltage fluctuations, etc.), and maintain stable communication in harsh environments; by adding signal conversion circuits, it can connect to a variety of external devices (such as RS-485 interface devices) without the need for additional communication cables, reducing the cost of purchasing, laying and maintaining cables, facilitating unified management of equipment, and improving interoperability between devices in the communication system. It solves the problem that the wiring conditions and communication space of existing communication methods are limited, and the monitoring needs of cross-regional projects cannot be met, and remote modifications and program upgrades cannot be performed in a timely and convenient manner, thereby improving the compatibility and communication reliability of the communication system in different scenarios.

[0033] Figure 2 A circuit schematic diagram of a data transmission device with bidirectional signal conversion function provided by an embodiment of the present invention.

[0034] See also Figure 2As shown, the carrier control module 200 is provided with power line pins PLC+, PLC-, a first input and output pin I / O1, a second input and output pin I / O2, a data receiving pin RX and a data sending pin TX. The power line pins PLC+ and PLC- are connected to the power line of the distribution network 1 via the carrier communication circuit 100, providing a power carrier communication channel; the first input and output pin I / O1 and the second input and output pin I / O2 and the signal conversion circuit 300 can perform bidirectional data exchange with the external device 2; the data receiving pin RX and the data sending pin TX can be connected to other communication devices to realize the expansion of the communication system.

[0035] See also Figure 2 As shown, the power supply module 400 includes: an AC-DC conversion unit 410, a power management unit 420, a transformer T400, a DC output unit 430 and a feedback unit 440; the AC side of the AC-DC conversion unit 410 is connected to the power distribution network 1, and the DC positive terminal DC+ of the AC-DC conversion unit 410 is connected to the first end of the primary winding of the transformer T400; the DC output unit 430 is connected to the first secondary winding of the transformer T400, outputs a first supply voltage (for example, +12V) through the first power supply terminal J, and outputs a second supply voltage (for example, +3.3V) through the second power supply terminal VCC. The output unit 430 is also provided with a low-voltage side ground terminal OUT-, and the ground terminal GND of the carrier control module 200 is connected to the low-voltage side ground terminal OUT-; the feedback unit 440 is used to detect the first supply voltage and output a feedback signal; the input end of the power management unit 420 is connected to the DC negative terminal DC- of the AC-DC conversion unit 410, the output end of the power management unit 420 is connected to the second end of the primary winding, and the control end of the power management unit 420 is connected to the feedback signal output end FB of the feedback unit 440. The power management unit 420 is used to adjust the conduction frequency of the primary winding according to the feedback signal to adjust the first supply voltage.

[0036] See also Figure 2 As shown, the first power supply terminal J is connected to the step-down chip IC2 via the first magnetic bead FB1. The step-down chip IC2 steps down the first power supply voltage (e.g., +12V) and connects it to the 3.3V power supply terminal of the carrier control module 200 via the intermediate power supply terminal S. The intermediate power supply terminal S is connected to the second power supply terminal VCC via the second magnetic bead FB2 and outputs the second power supply voltage (e.g., +3.3V). The magnetic beads absorb transient high-frequency pulses and filter out high-frequency noise and spike interference on the power line.

[0037] See also Figure 2As shown, the power management unit 420 includes a power management chip IC1, with an inductor C10 disposed between the input and output terminals of the power management chip IC1. The feedback unit 440 includes an optoelectronic isolator IC3 and a voltage detection circuit. The voltage detection circuit is disposed on the input side of the optoelectronic isolator IC3, and the output terminal of the optoelectronic isolator IC3 serves as a feedback signal output terminal FB, which is connected to the control terminal of the power management unit 420. The detection terminal of the voltage detection circuit is connected to the first power supply terminal J to detect the first power supply voltage. When the first power supply voltage reaches a preset voltage (e.g., +12V), the input side of the optoelectronic isolator IC3 is turned on, causing the feedback signal output terminal FB to output a feedback signal to the power management unit 420.

[0038] Specifically, the PLC-RS485 data transmission device is connected to the power distribution network 1 (such as a 220VAC mains), the AC-DC conversion unit 410 converts AC alternating current into strong DC power, and the power management unit 420 drives the loop where the primary winding of the transformer T400 is located to be turned on or off, so that the first secondary winding induces and outputs AC power. After rectification by the DC output unit 430, the first power supply voltage (for example, +12V) is output through the first power supply terminal J. The first power supply voltage (for example, +12V) is processed by the step-down chip to power the signal conversion circuit 300 and the carrier control module 200. The power management unit 420 uses secondary side feedback to control the operation of the transformer T400, so that the power supply module can provide a stable power supply voltage to the back-end circuit in a strong magnetic field environment.

[0039] Figure 3 A circuit schematic diagram of a signal conversion circuit provided by an embodiment of the present invention.

[0040] See also Figure 3 As shown, the signal conversion circuit 300 of the present application includes: a first signal processing sub-circuit 310, a second signal processing sub-circuit 320 and a protocol conversion unit 330; the first signal processing sub-circuit 310 is arranged between the first communication interface and the protocol conversion unit 330, and the first signal processing sub-circuit 310 is used to perform signal processing on the carrier signal transceiver side of the protocol conversion unit; the second signal processing sub-circuit 320 is arranged between the second communication interface and the protocol conversion unit 330, and the second signal processing sub-circuit 320 is used to perform signal processing on the data signal transceiver side of the protocol conversion unit; the protocol conversion unit 330 is used to adjust the data transmission direction according to the level state of the power carrier signal. When operating in the first data transmission direction, the power carrier signal is converted into the format of the data signal, and data transmission is realized through the second signal processing sub-circuit 320; when operating in the second data transmission direction, the data signal received by the second communication interface is converted into the format of the power carrier signal, and transmitted to the carrier control module 200 through the first signal processing sub-circuit 310.

[0041] The protocol conversion unit 330 may be an RS-485 transceiver. The protocol conversion unit 330 includes a carrier output pin RO, a receiver output enable (e.g., active low) pin RE, a transmitter output enable (e.g., active high) pin DE, a carrier input pin DI, a ground pin GND, a first data transceiver pin A', a second data transceiver pin B', and a power supply pin VCC'.

[0042] Specifically, the RS-485 transceiver adopts differential transmission, and the first input and output pin I / O1 of the carrier control module 200 is connected to the RO pin of the protocol conversion unit 330 via the signal output terminal M7 of the first communication interface, and the second input and output pin I / O2 is connected to the DI pin of the protocol conversion unit 330 via the signal input terminal M8 of the first communication interface.

[0043] If it is necessary to send instruction data to the external device 2 (such as modifying operating parameters or upgrading the program), the carrier control module 200 controls the protocol conversion unit 330 to operate in the sending mode, and the carrier control module 200 sends data to the carrier input pin DI of the signal conversion circuit 300. The protocol conversion unit 330 converts the power carrier signal (asynchronous serial data format) received by the first communication interface into a data signal (differential signal format). After the data leaves the signal conversion circuit 300, the carrier control module 200 immediately switches the mode of the protocol conversion unit 330 to the receiving mode.

[0044] If data (such as sensor data) needs to be received from the external device 2, the carrier control module 200 controls the protocol conversion unit 330 to operate in the receiving mode, and the protocol conversion unit 330 converts the data signal (differential signal format) received by the second communication interface into a power carrier signal (asynchronous serial data format), and transmits it to the carrier control module 200 through the first signal processing sub-circuit 310.

[0045] Optionally, the first signal processing subcircuit 310 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a first switch tube Q1; a first end of the first resistor R1 is connected to the second power supply terminal VCC of the power supply module 400, a second end of the first resistor R1 is connected to the carrier output pin RO of the protocol conversion unit 330 via the second resistor R2, a first node P1 is provided between the first resistor R1 and the second resistor R2, and the first node P1 is connected to the signal output terminal M7 of the first communication interface; a first end of the third resistor R3 is connected to the carrier output pin RO of the protocol conversion unit 330 The input pin DI is connected, the second end of the third resistor R3 is connected to the signal input terminal M8 of the first communication interface; the first end of the fourth resistor R4 is connected to the signal input terminal M8 of the first communication interface, the second end of the fourth resistor R4 is connected to the control end of the first switch tube Q1, the input end of the first switch tube Q1 is connected to the second power supply end VCC via the fifth resistor R5, the output end of the first switch tube Q1 is grounded, and a second node P2 is provided between the input end of the first switch tube Q1 and the fifth resistor R5. The second node P2 is respectively connected to the receive enable pin DE and the transmit enable pin RE of the protocol conversion unit 330.

[0046] Specifically, when the signal input terminal M8 of the first communication interface receives a high-level signal, the first switch tube Q1 is turned on, and the levels of the receive enable pin DE and the transmit enable pin RE are pulled low, and the protocol conversion unit 330 operates in the receive mode; when the signal input terminal M8 of the first communication interface receives a low-level signal, the first switch tube Q1 is turned off, and the levels of the receive enable pin DE and the transmit enable pin RE are pulled high by the second power supply terminal VCC, and the protocol conversion unit 330 operates in the transmit mode.

[0047] Optionally, the second signal processing sub-circuit 320 includes: a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9, a first bidirectional trigger diode D1, a second bidirectional trigger diode D2 and a third bidirectional trigger diode D3; a first end of the sixth resistor R6 is connected to the second power supply terminal VCC of the power supply module 400, a second end of the sixth resistor R6 is connected to the first end A of the second communication interface via the seventh resistor R7, a third node P3 is provided between the sixth resistor R6 and the seventh resistor R7, and the third node P3 is connected to the first data transceiver pin A' of the protocol conversion unit 330; a first end of the eighth resistor R8 is connected to the second communication interface VCC; a second end of the sixth resistor R6 is connected to the first end A of the second communication interface via the seventh resistor R7; a third node P3 is provided between the sixth resistor R6 and the seventh resistor R7, and the third node P3 is connected to the first data transceiver pin A' of the protocol conversion unit 330; a first end of the eighth resistor R8 is connected to the second communication interface VCC; a second end of the sixth resistor R6 is connected to the first end A of the second communication interface via the seventh resistor R7; a third node P3 is provided between the sixth resistor R6 and the seventh resistor R7, and the third node P3 is connected to the first data transceiver pin A' of the protocol conversion unit 330; a first end of the eighth resistor R8 is connected to the second communication interface VCC; a second end of the sixth resistor R6 is connected to the second ... The first end of the eighth resistor R8 is connected to the second end B of the second communication interface, the second end of the eighth resistor R8 is grounded via the ninth resistor R9, a fourth node P4 is provided between the eighth resistor R8 and the ninth resistor R9, and the fourth node P4 is connected to the second data transceiver pin B' of the protocol conversion unit 330; the first bidirectional trigger diode D1 is provided between the first end A and the second end B of the second communication interface; the first end of the second bidirectional trigger diode D2 is connected to the first end A of the second communication interface, and the second end of the second bidirectional trigger diode D2 is grounded; the first end of the third bidirectional trigger diode D3 is connected to the second end B of the second communication interface, and the second end of the third bidirectional trigger diode D3 is grounded.

[0048] Specifically, the sixth resistor R6 is a pull-up resistor, and the ninth resistor R9 is a pull-down resistor. In the default state, the voltage level of the first data transceiver pin A' is pulled high, and the voltage level of the second data transceiver pin B' is pulled low. This ensures the stability of the signal transmission and reception of the second signal processing sub-circuit 320 and prevents signal drift from interfering with the pins of the protocol conversion unit 330 and the carrier control module 200. The first bidirectional trigger diode D1, the second bidirectional trigger diode D2, and the third bidirectional trigger diode D3 stabilize the voltage between the first terminal A and the second terminal B of the second communication interface, protecting the chip pins in harsh industrial control environments and improving the reliability and stability of the data transmission device.

[0049] Figure 4 A circuit schematic diagram of another data transmission device with bidirectional signal conversion function provided by an embodiment of the present invention.

[0050] See also Figure 4As shown, the data transmission device with bidirectional signal conversion function of the present application also includes: a lightning protection circuit 500 and a filter circuit 600; the first side of the lightning protection circuit 500 is connected to the power distribution network 1, and the second side of the lightning protection circuit 500 is connected to the carrier communication circuit 100 and the power supply module 400 respectively. The lightning protection circuit 500 is used to perform surge protection processing on the signal provided by the power distribution network 1; the filter circuit 600 is provided between the second side of the lightning protection circuit 500 and the power supply module 400, and is used to filter the AC side power supply of the power supply module 400. In this embodiment, the filter circuit 600 can be an electromagnetic interference (EMI) filter circuit.

[0051] See also Figure 4 As shown, the filter circuit 600 includes: a first inductor L1 and a second inductor L2, the first inductor L1 is arranged between the lightning protection circuit 500 and the AC power supply terminal AC+ of the power supply module 400, and the second inductor L2 is arranged between the lightning protection circuit 500 and the AC ground terminal AC- of the power supply module 400; the lightning protection circuit includes: a current limiting protection element, a first varistor RV1, a second varistor RV2, a third varistor RV3, a thermistor RT1, a first discharge tube GD1, a second discharge tube GD2 and a third discharge tube GD3; a first end of the current limiting protection element is connected to the live wire L of the power distribution network 1, and a second end of the current limiting protection element is connected to the AC power supply terminal of the power supply module 400 via the first inductor L1, and a fifth node P5 is provided between the current limiting protection element and the first inductor L1; the first varistor A first end of RV1 is connected to a fifth node P5, and a second end of the first varistor RV1 is connected to a neutral line N of the power distribution network 1; a first end of the thermistor RT1 is connected to the neutral line N of the power distribution network 1, and a second end of the thermistor RT1 is connected to the AC ground terminal of the power supply module 400 via a second inductor L2, and a sixth node P6 is provided between the thermistor RT1 and the second inductor L2; a first end of the second varistor RV2 is connected to a fifth node P5, and a second end of the second varistor RV2 is connected to the ground line via a first discharge tube GD1; a first end of the third varistor RV3 is connected to a sixth node P6, and a second end of the third varistor RV3 is connected to the ground line GE via the first discharge tube GD1; the second discharge tube GD2 is connected in parallel with the first inductor L1; and the third discharge tube GD3 is connected in parallel with the second inductor L2.

[0052] In this embodiment, the current limiting protection element includes but is not limited to: a fuse, a current limiting resistor, and a current limiting diode. Preferably, the current limiting protection element is a fuse F1.

[0053] Specifically, the PLC-RS485 data transmission device is connected to the power distribution network 1 and is connected to the filter circuit 600 and the carrier communication circuit 100 respectively through the lightning protection circuit 500. The fuse F1, varistors (RV1, RV2 and RV3), thermistor (RT1), discharge tubes (GD1, GD2, GD3) and differential mode inductors (L1 and L2) together form an anti-surge protection circuit (for example, a 4KV / 6KV anti-surge protection circuit) to filter out interference signals in the power line signal provided by the power distribution network 1. The anti-surge circuit can achieve a surge protection level of 4KV / 6KV to prevent damage to the equipment caused by lightning and other internal overvoltages. By setting up a 4KV / 6KV surge protection circuit, the stability of the PLC carrier communication and the high reliability of the subsequent circuit are guaranteed.

[0054] See also Figure 4 As shown, the carrier communication circuit 100 of the present application includes: an isolation transformer T100, a fourth bidirectional trigger diode D4, and a fifth bidirectional trigger diode D5; the first side of the isolation transformer T100 is connected to the connection node between the lightning protection circuit 500 and the filter circuit 600, and the second side of the isolation transformer T100 is connected to the carrier control module 200; the fourth bidirectional trigger diode D4 is arranged on the first side of the isolation transformer T100; and the fifth bidirectional trigger diode D5 is arranged on the second side of the isolation transformer T100. In this embodiment, the reverse breakdown voltage of the fourth bidirectional trigger diode D4 and the fifth bidirectional trigger diode D5 is any voltage value greater than or equal to 220V and less than or equal to 250V. The carrier communication circuit 100 is connected to the rear end of the lightning protection circuit 500 and the front end of the filter circuit 600, which can effectively suppress the impact of high-voltage shocks on the circuit, electrically isolate the power line signal provided by the distribution network 1 from the carrier signal provided by the carrier control module 200, and improve communication reliability.

[0055] Based on the above embodiments, an embodiment of the present invention further provides a communication device, including: a data transmission device with a bidirectional signal conversion function provided in the above embodiments, having corresponding functional modules and beneficial effects of the data transmission device, and the same parts will not be repeated.

[0056] In this embodiment, the communication device may be a wireless terminal device (Data Transfer Unit, DTU for short).

[0057] The communication equipment of the present application is provided with a data transmission device with a bidirectional signal conversion function. The data transmission device uses power lines as transmission media, and there is no need to lay special communication lines, which reduces wiring costs and construction difficulty; the modulation and demodulation technology used in carrier communication can suppress stray signals and interference signals, improve the anti-interference ability of communication equipment, and can adapt to different power line conditions (such as line impedance, voltage fluctuations, etc.) to maintain stable communication in harsh environments; by adding a signal conversion circuit, it can connect to a variety of external devices (such as RS-485 interface devices) without the need for additional communication cables, reducing the cost of purchasing, laying and maintaining cables, facilitating unified management of communication equipment, improving interoperability between devices, and improving the compatibility and communication reliability of communication equipment in different scenarios.

[0058] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0059] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A data transmission device with a bidirectional signal conversion function, characterized in that: include: Carrier communication circuit, carrier control module, signal conversion circuit and power supply module; The power supply module is used to connect to the power distribution network, perform rectification and voltage conversion processing on the signal provided by the power distribution network, and output power to the carrier control module and the signal conversion circuit; The carrier communication circuit is provided between the power distribution network and the carrier control module, and is used to electrically isolate the power distribution network from the carrier control module; The carrier control module is provided between the carrier communication circuit and the signal conversion circuit, and is used to implement signal modulation / demodulation processing and bidirectional signal transmission between the carrier communication circuit and the signal conversion circuit; The signal conversion circuit is provided with a first communication interface and a second communication interface supporting different communication protocols, the first communication interface is used to connect to the carrier control module, and the second communication interface is used to connect to an external device, and the signal conversion circuit is used to perform bidirectional communication protocol conversion on the data signal provided by the second communication interface and the power carrier signal provided by the first communication interface.

2. The data transmission device with bidirectional signal conversion function according to claim 1, characterized in that: The power supply module includes: an AC-DC conversion unit, a power management unit, a transformer, a DC output unit and a feedback unit; The AC side of the AC-DC conversion unit is connected to the power distribution network, and the DC positive terminal of the AC-DC conversion unit is connected to the first end of the primary winding of the transformer; The DC output unit is connected to the first secondary winding of the transformer, outputs a first supply voltage via the first power supply terminal, and outputs a second supply voltage via the second power supply terminal; The feedback unit is used to detect the first supply voltage and output a feedback signal; The input end of the power management unit is connected to the negative DC end of the AC-DC conversion unit, the output end of the power management unit is connected to the second end of the primary winding, and the control end of the power management unit is connected to the feedback signal output end of the feedback unit. The power management unit is used to adjust the conduction frequency of the primary winding according to the feedback signal to adjust the first supply voltage.

3. The data transmission device with bidirectional signal conversion function according to claim 2, characterized in that: The feedback unit includes: a photoelectric isolator and a voltage detection circuit; The voltage detection circuit is provided at the input side of the photoelectric isolator, and the output end of the photoelectric isolator is connected to the control end of the power management unit; The detection end of the voltage detection circuit is connected to the first power supply end to detect the first power supply voltage, and controls the input side of the optoelectronic isolator to be turned on when the first power supply voltage reaches a preset voltage, so that the optoelectronic isolator outputs the feedback signal to the power management unit.

4. The data transmission device with bidirectional signal conversion function according to claim 1, characterized in that: The signal conversion circuit includes: a first signal processing sub-circuit, a second signal processing sub-circuit and a protocol conversion unit; The first signal processing sub-circuit is provided between the first communication interface and the protocol conversion unit, and the first signal processing sub-circuit is used to perform signal processing on the carrier signal transceiver side of the protocol conversion unit; The second signal processing sub-circuit is provided between the second communication interface and the protocol conversion unit, and the second signal processing sub-circuit is used to perform signal processing on the data signal transceiver side of the protocol conversion unit; The protocol conversion unit is used to adjust the data transmission direction according to the level state of the power carrier signal.

5. The data transmission device with bidirectional signal conversion function according to claim 4, characterized in that: The first signal processing sub-circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first switch tube; A first end of the first resistor is connected to the second power supply end of the power supply module, a second end of the first resistor is connected to the carrier output end of the protocol conversion unit via the second resistor, a first node is provided between the first resistor and the second resistor, and the first node is connected to the signal output end of the first communication interface; A first end of the third resistor is connected to the carrier input end of the protocol conversion unit, and a second end of the third resistor is connected to the signal input end of the first communication interface; A first end of the fourth resistor is connected to the signal input end of the first communication interface, a second end of the fourth resistor is connected to the control end of the first switching tube, the input end of the first switching tube is connected to the second power supply end via the fifth resistor, the output end of the first switching tube is grounded, a second node is provided between the input end of the first switching tube and the fifth resistor, and the second node is respectively connected to the receive enable end and the transmit enable end of the protocol conversion unit.

6. The data transmission device with bidirectional signal conversion function according to claim 4, characterized in that: The second signal processing sub-circuit includes: a first bidirectional trigger diode, a second bidirectional trigger diode and a third bidirectional trigger diode; The first bidirectional trigger diode is arranged between the first end and the second end of the second communication interface; A first end of the second bidirectional trigger diode is connected to the first end of the second communication interface, and a second end of the second bidirectional trigger diode is grounded; A first end of the third bidirectional trigger diode is connected to the second end of the second communication interface, and a second end of the third bidirectional trigger diode is grounded.

7. The data transmission device with bidirectional signal conversion function according to any one of claims 1 to 6, characterized in that: Also includes: Lightning protection circuit and filter circuit; The first side of the lightning protection circuit is connected to the power distribution network, and the second side of the lightning protection circuit is connected to the carrier communication circuit and the power supply module respectively, and the lightning protection circuit is used to perform surge protection on the signal provided by the power distribution network; The filter circuit is arranged between the second side of the lightning protection circuit and the power supply module, and is used for filtering the AC side power supply of the power supply module.

8. The data transmission device with bidirectional signal conversion function according to claim 7, characterized in that: The filter circuit includes: a first inductor and a second inductor, the first inductor is arranged between the lightning protection circuit and the AC power supply terminal of the power supply module, and the second inductor is arranged between the lightning protection circuit and the AC grounding terminal of the power supply module; The lightning protection circuit includes: a current limiting protection element, a first varistor, a second varistor, a third varistor, a thermistor, a first discharge tube, a second discharge tube and a third discharge tube; A first end of the current limiting protection element is connected to the live wire of the power distribution network, a second end of the current limiting protection element is connected to the AC power supply end of the power supply module via the first inductor, and a fifth node is provided between the current limiting protection element and the first inductor; A first end of the first varistor is connected to the fifth node, and a second end of the first varistor is connected to the neutral line of the power distribution network; A first end of the thermistor is connected to a neutral line of the power distribution network, a second end of the thermistor is connected to an AC ground terminal of the power supply module via the second inductor, and a sixth node is provided between the thermistor and the second inductor; A first end of the second varistor is connected to the fifth node, and a second end of the second varistor is connected to the ground line via the first discharge tube; A first end of the third varistor is connected to the sixth node, and a second end of the third varistor is connected to the ground wire via the first discharge tube; The second discharge tube is connected in parallel with the first inductor; The third discharge tube is connected in parallel with the second inductor.

9. The data transmission device with bidirectional signal conversion function according to claim 7, characterized in that: The carrier communication circuit includes: an isolation transformer, a fourth bidirectional trigger diode and a fifth bidirectional trigger diode; The first side of the isolation transformer is connected to the connection node between the lightning protection circuit and the filter circuit, and the second side of the isolation transformer is connected to the carrier control module; The fourth bidirectional trigger diode is arranged on the first side of the isolation transformer; The fifth bidirectional trigger diode is arranged on the second side of the isolation transformer.

10. A communication device, characterized in that: include: The data transmission device with bidirectional signal conversion function according to any one of claims 1 to 9.

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