NMEA to TCP / IP protocol converter for ships

Abstract

The utility model discloses a ship is with NMEA turns TCPIP protocol converter, including control module, first communication module, second communication module, power module, first communication module, second communication module, power module all are connected with control module, wherein control module adopts microcontroller, and the control module is integrated with memory, voltage conversion is carried out in power module to the wide voltage power supply chip, first communication module adopts the isolated RS485 chip, and supports duplex communication, and the second communication module is TCPIP communication module, and the second communication module adopts the ethernet controller, and its ethernet interface adopts RJ45 connector. Ship is with NMEA turns TCPIP protocol converter compatible RS422 physical layer's NMEA data and TCPIP protocol bidirectional conversion, when relying on ethernet, lengthens transmission distance to 1km above. In addition ship is with NMEA turns TCPIP protocol converter still has reduced operation and maintenance cost, has guaranteed navigation data reliability etc.

Description

Technical Field

[0001] This utility model relates to the field of marine electronic communication technology, specifically to a marine NMEA to TCP / IP protocol converter adapted to the harsh environment of ships and suitable for data interconnection of multiple devices in ship navigation, positioning and monitoring systems. Background Technology

[0002] In ship navigation systems, the NMEA protocol (such as NMEA0183) is the mainstream data exchange standard for navigation equipment. Its physical layer typically uses an RS422 bus, which features differential transmission characteristics and can resist some electromagnetic interference over short distances (≤1200m). However, with the development of ship intelligence, the following technical challenges have emerged: Limited transmission distance: The RS422 bus cannot meet the data transmission requirements of large ships (such as container ships and oil tankers) across compartments (distances exceeding 2000m), requiring the additional deployment of repeaters, which increases costs and potential points of failure; Insufficient networking capabilities: Traditional RS422 only supports point-to-point or bus topology and cannot be connected to ship Ethernet (such as TCP / IP architecture), which means that data from devices such as GPS, radar, and depth sounder cannot be shared with the remote monitoring center or multiple terminals. Poor compatibility: Some third-party devices do not support the NEMA protocol and only support the MODBUS command protocol, making them difficult to match in actual projects. Utility Model Content

[0003] The purpose of this invention is to provide a marine NMEA to TCP / IP protocol converter to solve one or more of the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model discloses a marine NMEA-to-TCP / IP protocol converter, comprising a control module, a first communication module, a second communication module, and a power supply module. The first communication module, the second communication module, and the power supply module are all connected to the control module. The control module uses a microcontroller and integrates a memory. The power module uses a wide-voltage power chip for voltage conversion; The first communication module uses an isolated RS485 chip and supports half-duplex communication; The second communication module is a TCP / IP communication module. The second communication module uses an Ethernet controller, and its Ethernet interface uses an RJ45 connector.

[0005] In some implementations... The microcontroller supports a 64MHz main frequency and is equipped with hardware CRC check and a multi-serial port control system to meet the high-speed parsing requirements of NMEA data. The memory consists of 1MB Flash and 128k EEPROM, which can be used to store configuration parameters (such as TCP / IP and RS422 baud rate) and temporary data so that data can be saved after power failure.

[0006] In some implementations... The first communication module has a 5kVrms isolation voltage and ±15kVVESD protection, making it suitable for the strong electromagnetic interference environment on ships. Half-duplex communication conforms to the NMEA0183 bus topology; The first communication module uses a TVS diode to achieve bus overvoltage protection, preventing damage to the chip from lightning strikes or power fluctuations. The first communication module is configured with a switchable terminating resistor to adapt to different transmission distances.

[0007] In some implementations, the switching of the switchable terminating resistor is selected via a hardware DIP switch.

[0008] In some implementations, a terminating resistor is not connected for short transmission distances of 500m or less, and a terminating resistor is connected for long transmission distances of 1000m or more.

[0009] In some implementations, the Ethernet controller supports 10 / 100Mbps adaptive Ethernet and integrates a TCP / IP protocol stack, reducing MCU computing power consumption.

[0010] In some implementations, the housing of the RJ45 connector is grounded to reduce the impact of electromagnetic interference within the ship's cabin on data transmission.

[0011] In some implementations, the second communication module adopts dual-mode communication, which supports TCP client / server dual mode and can connect to two TCP terminals at the same time. The two TCP terminals can be a navigation display and a remote control center, respectively.

[0012] In some implementations, the power module has an input voltage of 9-36V DC, which is converted to a 5V / 1.2A output by a wide-voltage power chip.

[0013] In some implementations, the power module integrates protection circuits, including overvoltage protection circuits, overcurrent protection circuits, and overtemperature protection circuits, and adds an LC filter circuit at the output to reduce power ripple.

[0014] Compared with the prior art, the beneficial effects of this utility model are: The marine NMEA to TCP / IP protocol converter is compatible with RS422 physical layer NMEA data and TCP / IP protocol bidirectional conversion, and extends the transmission distance to more than 1 km when relying on Ethernet; The NMEA to TCP / IP protocol converter for ships supports remote configuration and status monitoring, reducing operation and maintenance costs; When using a shipboard NMEA to TCP / IP converter for bidirectional conversion between NMEA data and TCP / IP protocol, the data packet loss rate can be less than or equal to 0.1%, ensuring the reliability of navigation data. The NMEA to TCP / IP protocol converter for marine applications has good compatibility and is basically compatible with all PLC products on the market. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of a marine NMEA to TCP / IP protocol converter in some embodiments of this utility model; Figure 2 This is a schematic diagram of the structure of the NMEA to TCP / IP protocol converter for ships in some embodiments of this utility model; Figure 3 This is a circuit diagram of the control module in some embodiments of this utility model; Figure 4 This is a circuit diagram of the first communication module in some embodiments of this utility model; Figure 5 This is a circuit diagram of the second communication module in some embodiments of this utility model; Figure 6 This is a circuit diagram of the power module in some embodiments of this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] See Figures 1 to 6 The figure shows a preferred embodiment of the present invention, which discloses a marine NMEA to TCP / IP protocol converter, including a control module 1, a first communication module 2, a second communication module 3, and a power supply module 4. The first communication module 2, the second communication module 3, and the power supply module 4 are all connected to the control module 1.

[0018] Control module 1 employs a microcontroller (MCU, such as an STM32F10RCT6), supporting a 64MHz main frequency, and featuring hardware CRC verification and a multi-serial port control system to meet the high-speed data parsing requirements of NMEA. Control module 1 integrates a memory, with specific parameters including 1MB Flash and 128kEEPROM. The memory can be configured to store configuration parameters (such as TCP / IP and RS422 baud rate) and temporary data, enabling data retention even after power failure. The circuit schematic of control module 1 is shown below. Figure 3 As shown, the control module can be a microcontroller minimum system, mainly responsible for data interaction with the first communication module 2 and the second communication module 3. The microcontroller pins PC10 and PC11 are connected to the second communication module 3, and PB10 and PB11 are connected to the first communication module 2. All of these pins can be serial communication pins, used for core data processing and interaction. The power supply module 4 provides a 3.3V DC power supply, which is filtered by a filter capacitor before powering the microcontroller.

[0019] The first communication module 2 is an RS422 communication module, which can use an isolated RS485 chip (specifically, the TDA51S485HC), featuring a 5kVrms isolation voltage and ±15kV ESD protection, suitable for the strong electromagnetic interference environment of ships. The first communication module 2 supports half-duplex communication (compliant with the NMEA0183 bus topology), and uses a TVS diode (specifically, the SM712) for bus overvoltage protection to prevent damage to the chip from lightning strikes or power fluctuations. The first communication module 2 is equipped with a switchable terminating resistor (120Ω), which can be selected via a hardware DIP switch to adapt to different transmission distances (no terminating resistor for short transmission distances less than or equal to 500m, and a terminating resistor for long transmission distances greater than or equal to 1000m). The circuit schematic of the first communication module 2 is shown below. Figure 4 As shown, this module can be used to convert the serial port data output by the microcontroller into a 485 differential signal through the 485 chip of U7. After conversion, the signal is protected by the surge protection module of U12 to prevent damage to the device module caused by external high voltage static electricity.

[0020] The second communication module 3 is a TCP / IP communication module. It uses an Ethernet controller (specifically, the CH9121T model), supports 10 / 100Mbps adaptive Ethernet, and integrates a TCP / IP protocol stack (including TCP, UDP, IP, ARP, etc.) to reduce MCU computing power consumption. The Ethernet interface on the second communication module 3 uses an RJ45 connector (specifically, the HR911105A model). The RJ45 connector shell is grounded to reduce the impact of electromagnetic interference inside the ship's cabin on data transmission. The second communication module 3 adopts dual-mode communication, supporting both TCP client and server modes, and can simultaneously connect two TCP terminals. These two TCP terminals can be a navigation display and a remote control center, respectively. The circuit schematic of the second communication module 3 is shown below. Figure 5 As shown, it can convert TTL to Ethernet. The TXD4 and RXD4 pins are connected to the CH9121T chip. The CH9121T converts the serial port into Ethernet data signals. After ESD protection of the Ethernet bus through D1, the signals are sent out through the Ethernet transformer.

[0021] Power module 4 employs a wide-voltage power supply chip for voltage conversion. Its input voltage is 9-36V DC (covering the 12V / 24V power supply system of ships), which is converted to a 5V / 1.2A output by the wide-voltage power supply chip (specifically model K7803-1000). Power module 4 integrates protection circuitry, including overvoltage protection (≥40V), overcurrent protection (≥3A), and overtemperature protection (≥125℃). An LC filter circuit (10μH inductor + 1000μF capacitor) is added to the output to reduce power ripple to ≤50mV. The circuit schematic of power module 4 is shown below. Figure 6 As shown, it can take the input 24V power supply, after overcurrent protection by the F2 fuse and ESD protection by the subsequent TVS, and then filter it through the capacitor before supplying it to the U13 power module, converting the 24V voltage to 3.3V to power the load.

[0022] The microcontroller within the shipboard NMEA-to-TCP / IP converter receives data and performs data processing. If the data does not meet the frame format requirements, the system discards the data. The specific process is as follows: After the application program for the NMEA to TCP / IP protocol converter for ships starts, it initializes the communication module: configures the baud rate (e.g., 4800 / 9600bps, depending on the NMEA device requirements), data bits (8 bits), stop bits (1 bit), and no parity (a feature of the NMEA0183 protocol), and opens the data receive buffer. It creates a TCP socket, configures network parameters (e.g., IP address, port), and establishes a connection between the first communication module 2 and the target terminal (or enters listening mode to wait for a connection).

[0023] During initialization, the system continuously reads a byte stream from the interface on the first communication module 2 and stores it in the receive buffer. Complete NMEA frames are identified by detecting the end-of-frame marker (\r\n, i.e., ASCII code 0x0D+0x0A), or a timeout mechanism is set to prevent buffer overflow.

[0024] When extracting data frames from the receive buffer, check if they begin with a $ and end with \r\n. If not (incorrect format, not starting with $), discard the error frame. If the data meets the requirements, extract the segment between $ and * in the NMEA frame, perform an XOR operation on each character to calculate the checksum. If the checksum is correct, assemble the TCP packet according to the specified format and send the TCP packet out.

[0025] When receiving TCP packets from the Ethernet end, the start and validity of the data are determined by examining the frame header. The specific process is as follows: The application program for the NMEA-to-TCP / IP converter for ships completes the communication module initialization after startup: creating a TCP server socket, configuring network parameters (such as IP address and port), establishing a connection between the second communication module 3 and the target terminal (or entering listening mode to wait for a connection). It configures the baud rate (e.g., 4800 / 9600bps, depending on the NMEA device requirements), data bits (8 bits), stop bits (1 bit), and no parity (a feature of the NMEA0183 protocol), and enables the data receive buffer.

[0026] The program continuously listens for established TCP connections, receives data packets from remote terminals, and stores them in the receive buffer. It performs packet integrity checks by detecting preset frame header identifiers (e.g., 0xAA) and frame trailer identifiers (e.g., 0x55). If a data packet does not contain a valid frame identifier, it performs a "discard invalid packet" operation.

[0027] When a valid data frame is detected, the data area content (the original NMEA command string) is parsed and extracted. The valid NMEA command is forwarded to the bus device through the first communication module 2, completing the issuance of the remote control command. The program also records the reception log, including key information such as the source terminal IP address and command transmission time, to achieve operation traceability and communication monitoring.

[0028] Combination Figure 2 As shown, in some specific implementations, the above-mentioned shipboard NMEA to TCP / IP protocol converter also includes a housing 6 and a motherboard 5. The motherboard 5 is located inside the housing 6, and the control module 1, the first communication module 2, the second communication module 3, and the power supply module 4 are integrated on the motherboard 5.

[0029] All of the above-mentioned undisclosed matters can be implemented using existing technologies, so they will not be elaborated here.

[0030] Finally, it should be noted that in the description of this utility model, the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0031] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set", "install", "connect", and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0032] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present utility model. It should not be construed that the specific implementation of the present utility model is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present utility model, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted by the present utility model.

Claims

1. A marine NMEA to TCP / IP protocol converter, characterized in that, It includes a control module, a first communication module, a second communication module, and a power supply module. The first communication module, the second communication module, and the power supply module are all connected to the control module. The control module uses a microcontroller and integrates a memory. The power module uses a wide-voltage power chip for voltage conversion; The first communication module uses an isolated RS485 chip and supports half-duplex communication; The second communication module is a TCP / IP communication module. The second communication module uses an Ethernet controller, and its Ethernet interface uses an RJ45 connector.

2. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The microcontroller supports a 64MHz main frequency and has hardware CRC check and a multi-serial port control system. The memory consists of 1MB Flash and 128k EEPROM.

3. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The first communication module has a 5kVrms isolation voltage and ±15kVVESD protection, making it suitable for the strong electromagnetic interference environment on ships. Half-duplex communication conforms to the NMEA0183 bus topology; The first communication module implements bus overvoltage protection through a TVS diode; The first communication module is configured with a switchable terminating resistor to adapt to different transmission distances.

4. The NMEA to TCP / IP protocol converter for ships according to claim 3, characterized in that, The switchable terminating resistor can be switched via a hardware DIP switch.

5. The NMEA to TCP / IP protocol converter for ships according to claim 4, characterized in that, For short transmission distances of 500m or less, no terminating resistor is required; for long transmission distances of 1000m or more, a terminating resistor is required.

6. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The Ethernet controller supports 10 / 100Mbps adaptive Ethernet and integrates a TCP / IP protocol stack.

7. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The housing of the RJ45 connector is grounded.

8. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The second communication module adopts dual-mode communication.

9. The NMEA to TCP / IP protocol converter for ships according to claim 1, characterized in that, The power module has an input voltage of 9-36V DC, which is converted to 5V / 1.2A output by a wide-voltage power chip.

10. The marine NMEA to TCP / IP protocol converter according to claim 1 or 9, characterized in that, The power module integrates protection circuits, including overvoltage protection, overcurrent protection, and overtemperature protection, and an LC filter circuit is added to the output terminal.

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