Zigbee-based locomotive wireless printing device and implementation method

Abstract

A kind of locomotive wireless printing device and implementation method based on Zigbee belong to railway communication technical field;Wireless printing device and MMI wireless transmitting end start, Zigbee terminal and Zigbee wireless coordinator work cooperatively, complete the function of printing dispatching command, query printer version information, upload wireless printing device battery information.The present application realizes the wireless connection of MMI and printer, transmits printing content and interactive data information by the mode of Zigbee wireless communication, meets the printing function of CIR dispatching command of locomotive comprehensive wireless communication device, can reduce wiring in vehicle, facilitates maintenance and installation, prolongs the service life of printer.

Description

Technical Field

[0001] This invention relates to a Zigbee-based locomotive wireless printing device and its implementation method, belonging to the field of railway communication technology. Background Technology

[0002] Currently, in my country, the operator display terminal (MMI) of the integrated wireless communication equipment (CIR) on railway locomotives (CIR) and the equipped printers are generally connected via wired connections, typically using an RS422 bus to send the content to be printed to the printer. Due to differences in locomotive models, the locations where printers can be installed on the locomotive vary. The internal space of a locomotive is complex and compact, with clearly defined functional divisions for each area. Different models and design philosophies result in vastly different internal structures. This situation presents challenges for printer wiring. If the printer is installed far from the MMI, long cables are required, increasing costs and potentially causing voltage instability that could affect printer operation. Simultaneously, interference between the printer cable and other data transmission cables must be avoided to ensure signal stability and accuracy. Furthermore, the strong vibrations and bumps generated during locomotive operation necessitate careful consideration of cable securing and protection to prevent loosening, wear, or even breakage, further complicating the wiring process. Because of the wired connection, the printer remains in standby mode after the equipment is powered on, consuming power and impacting its lifespan. Summary of the Invention

[0003] To address the problems of limited installation, difficult wiring, loose cables, wear and even breakage, and printer lifespan reduction due to prolonged standby, existing wired connection methods, this invention provides a Zigbee-based wireless printing device and implementation method for locomotives. This device enables wireless connection between the MMI and the printer, facilitating maintenance and installation, and extending printer lifespan while avoiding power consumption during standby.

[0004] The technical solution adopted in this invention is: a Zigbee-based wireless printing device for locomotives, comprising a wireless printing device and an MMI wireless transmitter; the wireless printing device and the MMI wireless transmitter respectively receive and transmit wireless signals via antennas; the wireless printing device includes a rechargeable lithium battery, a Zigbee terminal unit, and a printer, wherein the Zigbee terminal unit is unidirectionally connected to the rechargeable lithium battery and bidirectionally connected to the printer; the MMI wireless transmitter includes a Zigbee wireless coordinator unit and an MMI interface, wherein the MMI interface is bidirectionally connected to the Zigbee wireless coordinator unit; the wireless printing device is powered by a rechargeable lithium battery and does not require additional power cables and data cables. The Zigbee terminal unit implements functions such as battery voltage conversion, battery voltage detection, UART serial port and RS422 serial port level conversion, wireless transmission of battery voltage information, printer power supply control, wireless reception of version information query commands, wireless transmission of printer version information, and wireless reception of print data. The printer is used for printing. The MMI wireless transmitter is installed in the MMI through the MMI interface, which is used to provide power and transmit data. The Zigbee wireless coordinator unit implements functions such as voltage conversion, UART serial port and RS422 serial port level conversion, wireless reception of battery voltage information sent by the wireless printer, wireless transmission of version information query commands, wireless reception of printer version information, and wireless transmission of print data.

[0005] A method for implementing a Zigbee-based wireless printing device for locomotives, wherein after the wireless printing device and the MMI wireless transmitter are powered on, the Zigbee terminal and the Zigbee wireless coordinator work together to complete the functions of printing scheduling commands, querying printer version information, and uploading wireless printing device battery information.

[0006] The method for completing the print scheduling command is as follows: the MMI wireless transmitter sends the scheduling command information to be printed to the wireless printing device. The wireless printing device receives the scheduling command information and drives the printer to print the scheduling command. When there is a need for a print scheduling command, the MMI interface sends the scheduling command information to the Zigbee wireless coordinator through RS422 transceiver II. The Zigbee wireless coordinator transmits the scheduling command information to the Zigbee terminal through the antenna. When the Zigbee terminal receives the scheduling command information, the GPIO pin connected to the NMOS of the Zigbee terminal is set high, turning on the NMOS and powering on the printer. The UART serial port of the Zigbee terminal sends the scheduling command information to the printer through RS422 transceiver I, and the printer starts and prints the scheduling command. After printing is completed, the GPIO pin connected to the NMOS of the Zigbee terminal is set low, turning off the NMOS and powering off the printer.

[0007] The method for querying printer version information is as follows: the MMI interface sends the printer version query command to the Zigbee wireless coordinator via RS422 transceiver II. The Zigbee wireless coordinator transmits the printer version query command to the Zigbee terminal via its antenna. The GPIO pin of the Zigbee terminal connected to the NMOS is set high, turning on the NMOS and powering on the printer. The UART serial port of the Zigbee terminal sends the printer version query command to the printer via RS422 transceiver I. The printer sends the version information to the Zigbee terminal via RS422 transceiver I. The Zigbee terminal sends the printer version information to the Zigbee wireless coordinator via its antenna. The Zigbee wireless coordinator then sends the information to the MMI interface via RS422 transceiver II.

[0008] The method for uploading battery information of the wireless printing device is as follows: The Zigbee terminal periodically queries the power monitor through the GPIO pin to simulate the IIC interface. The power monitor transmits the collected voltage value to the Zigbee terminal. When the battery voltage is lower than 11.4V and 10.8V, the Zigbee terminal sends the battery information to the Zigbee wireless coordinator through the antenna. The UART serial port of the Zigbee wireless coordinator sends the battery information to the MMI interface through the RS422 transceiver II. When the MMI receives a battery voltage lower than 11.4V, the MMI screen displays the text "Printer battery low" and provides a voice prompt. The prompt can be closed by pressing the MMI "OK" button. When the MMI receives a battery voltage lower than 10.8V, the MMI screen displays the text "Printer battery low, please charge" and provides a voice prompt three times. The prompt can be closed by pressing and holding the MMI "OK" button.

[0009] The beneficial effects of this invention are: it enables wireless connection between the MMI and the printer, transmitting printed content and interactive data information via Zigbee wireless communication, thus improving the stability and accuracy of signal transmission.

[0010] This invention can fulfill the printing function of locomotive dispatching commands, reducing the workload of cab wiring and maintenance, facilitating maintenance and installation, and lowering costs. Simultaneously, when there is no printing demand, the printer is completely powered off, avoiding standby power consumption, extending printer lifespan, saving battery power, extending battery usage time, increasing the flexibility of printer installation location, and making it more convenient to use. Attached Figure Description

[0011] Figure 1 The circuit connection block diagram for implementing the present invention;

[0012] Figure 2 The circuit connection block diagram for implementing the Zigbee terminal unit of this invention;

[0013] Figure 3 The circuit connection block diagram for implementing the Zigbee wireless coordinator unit of this invention is shown below.

[0014] Figure 4 The circuit connection block diagram is shown in the embodiment of the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments; for example Figure 1 As shown, a Zigbee-based wireless printing device for locomotives includes a wireless printing device and an MMI wireless transmitter. The wireless printing device includes a rechargeable lithium battery, a Zigbee terminal unit, and a printer. The rechargeable lithium battery is connected to the Zigbee terminal unit to provide power, and the Zigbee terminal unit is bidirectionally connected to the printer to control printer power supply and data transmission. The printer is used for printing. The MMI wireless transmitter includes a Zigbee wireless coordinator unit and an MMI interface. The MMI interface is bidirectionally connected to the Zigbee wireless coordinator unit to provide power and transmit data, and the Zigbee wireless coordinator unit is used for data reception and transmission. The wireless printing device and the MMI wireless transmitter receive and transmit wireless signals respectively via antennas.

[0016] like Figure 2 As shown, the Zigbee termination unit consists of a power monitor, a switching power supply I, an RS422 transceiver I, an NMOS transistor, and a Zigbee termination unit. A rechargeable lithium battery (DC12V) is connected to the power monitor, the input of the switching power supply I, and the drain of the NMOS transistor. The source of the NMOS transistor is connected to the DC12V power input of the printer. The output of the switching power supply I provides DC3.3V power to the Zigbee termination unit, the power monitor, and the RS422 transceiver I. The Zigbee termination unit uses two GPIO pins to simulate the bidirectional IIC bus interface of the power monitor and the IIC bus. The Zigbee termination unit uses one GPIO pin connected to the gate of the NMOS transistor through a 10K current-limiting resistor. The UART string of the Zigbee termination unit... The interface connects to the printer's RS422 serial port via RS422 transceiver I, and the RF interface of the Zigbee terminal connects to the antenna. A rechargeable lithium battery provides DC 12V power. A power monitor acquires the rechargeable lithium battery's voltage. A switching power supply I steps down the DC 12V voltage to 3.3V. The RS422 transceiver I is used for UART and RS422 level conversion. An NMOS transistor is positioned between the rechargeable lithium battery and the printer's DC 12V power path to turn the printer's DC 12V power supply on and off. The Zigbee terminal uses a GPIO pin connected to the NMOS gate via a 10K current-limiting resistor to control the NMOS's on / off state. The Zigbee terminal is also used for control and data transmission / reception.

[0017] The Zigbee terminal is model CC2530, the switching power supply I is model LM22670-ADJ, the power monitor is model INA226, the RS422 transceiver I is model THVD9491-SEP, and the MOSFET is model NTR4501NT1G.

[0018] like Figure 3 As shown, the Zigbee wireless coordinator unit consists of a switching power supply II, an RS422 transceiver II, and a Zigbee wireless coordinator. The 13.8V power supply of the MMI interface provides 3.3V power to the RS422 transceiver II and the Zigbee wireless coordinator through the switching power supply II. The UART serial port pin of the Zigbee wireless coordinator is connected to the RS422 serial port of the MMI interface through the RS422 transceiver II. The RF interface of the Zigbee wireless coordinator is connected to the antenna. The switching power supply II is used to step down the DC 13.8V voltage to 3.3V. The RS422 transceiver II is used for UART and RS422 level conversion. The Zigbee wireless coordinator is used for control and data transmission and reception.

[0019] The Zigbee wireless coordinator is model CC2530, the switching power supply II is model LM22670-ADJ, and the RS422 transceiver II is model THVD9491-SEP.

[0020] Example 1 Figure 4 As shown, a method for implementing a Zigbee-based locomotive wireless printing device involves connecting an MMI wireless transmitter to an MMI in the locomotive via an MMI interface, connecting the MMI to a CIR via an MMI connection cable, and wirelessly connecting the CIR to station equipment. The wireless printing device and the MMI wireless transmitter transmit and receive wireless signals via antennas, respectively.

[0021] Install the MMI wireless transmitter in the MMI and install the wireless printing device (printer) inside the locomotive;

[0022] The specific steps are as follows:

[0023] After the wireless printing device and MMI wireless transmitter are powered on, the Zigbee terminal and Zigbee wireless coordinator work together. The Zigbee terminal in the wireless printing device is automatically set as an end device according to the program, and the Zigbee wireless coordinator in the MMI wireless transmitter is automatically set as a coordinator according to the program. The Zigbee terminal initializes and sends a network access request to the Zigbee wireless coordinator through the antenna to join the network. It then completes the functions of printing scheduling commands, querying printer version information, and uploading wireless printing device battery information.

[0024] Dispatch command information is transmitted using the GSM-R digital mobile communication network or the 450MHz train wireless dispatch communication system. The dispatcher sends dispatch commands through station equipment. The CIR has the function of receiving dispatch command information sent to this train and has the function of recording and storing dispatch command information.

[0025] Complete the print scheduling command:

[0026] After the CIR receives and stores the scheduling command information, it accesses the scheduling command interface through the MMI to view the detailed content of the scheduling command. Only signed scheduling commands can be printed. Pressing the "Print" button, the MMI transmits the scheduling command information to the MMI interface, which then sends it to the Zigbee wireless coordinator via RS422 transceiver II. The Zigbee wireless coordinator transmits the scheduling command information to the Zigbee terminal via its antenna. Upon receiving the scheduling command information, the Zigbee terminal sets its GPIO pin connected to the NMOS high, turning on the NMOS and powering on the printer. The Zigbee terminal's UART serial port then sends the scheduling command information to the printer via RS422 transceiver I, starting the printer and printing the scheduling command. After printing is complete, the GPIO pin connected to the NMOS low, turning off the NMOS and powering off the printer. The printer is powered on during printing and powered off during non-printing periods, preventing the printer from remaining in standby mode for extended periods, extending printer life, and saving battery power.

[0027] Query printer version information:

[0028] The MMI queries the version information of each CIR unit. The MMI transmits the printer version query command to the MMI interface, which then sends it to the Zigbee wireless coordinator via RS422 transceiver II. The Zigbee wireless coordinator transmits the printer version query command to the Zigbee terminal via its antenna. The GPIO pin of the Zigbee terminal, connected to the NMOS, is set high, turning on the NMOS and powering on the printer. The UART serial port of the Zigbee terminal sends the printer version query command to the printer via RS422 transceiver I. The printer sends the version information to the Zigbee terminal via RS422 transceiver I. The Zigbee terminal sends the printer version information to the Zigbee wireless coordinator via its antenna. The Zigbee wireless coordinator then sends it to the MMI interface via RS422 transceiver II. After receiving the printer version information through the MMI interface, the MMI displays it. The printer is powered on when querying the version and powered off when not printing or querying the version, avoiding prolonged standby mode, extending printer life, and saving battery power.

[0029] Upload wireless printer battery information:

[0030] The Zigbee terminal simulates an IIC interface via GPIO pins. During printer power outages, it periodically queries the power monitor. The power monitor transmits the collected voltage values ​​to the Zigbee terminal. When the rechargeable lithium battery voltage drops below 11.4V and 10.8V, the Zigbee terminal sends battery information to the Zigbee wireless coordinator via its antenna. The Zigbee wireless coordinator's UART serial port then transmits the battery information to the MMI interface via an RS422 transceiver II. When the MMI receives a battery voltage below 11.4V, it displays "Printer battery low" in the center of the screen and provides a voice prompt. Pressing the "OK" button on the MMI will close the prompt. When the MMI receives a battery voltage below 10.8V, it displays "Printer battery low, please recharge" in the center of the screen and provides a voice prompt three times. Pressing and holding the "OK" button on the MMI will close the prompt, reminding staff to replace and recharge the battery promptly.

[0031] When the rechargeable lithium battery is low on power, it can be removed and charged using a DC 12V power adapter.

Claims

1. A Zigbee-based wireless printing device for locomotives, characterized in that: It includes a wireless printing device and an MMI wireless transmitter; the wireless printing device and the MMI wireless transmitter respectively receive and transmit wireless signals via antennas. The wireless printing device includes a rechargeable lithium battery, a Zigbee terminal unit, and a printer. The Zigbee terminal unit is unidirectionally connected to the rechargeable lithium battery and bidirectionally connected to the printer. The MMI wireless transmitter includes a Zigbee wireless coordinator unit and an MMI interface, wherein the MMI interface is bidirectionally connected to the Zigbee wireless coordinator unit. The wireless printing device is powered by a rechargeable lithium battery, eliminating the need for additional power and data cables. The Zigbee terminal unit performs functions such as battery voltage conversion, battery voltage detection, UART and RS422 serial port level conversion, wireless transmission of battery voltage information, printer power supply control, wireless reception of version information query commands, wireless transmission of printer version information, and wireless reception of print data information. The printer is used for printing. The MMI wireless transmitter is installed in the MMI through the MMI interface, which is used to provide power and transmit data. The Zigbee wireless coordinator unit realizes the functions of voltage conversion, UART serial port and RS422 serial port level conversion, wireless reception of battery voltage information sent by wireless printing devices, wireless transmission of version information query commands, wireless reception of printer version information and wireless transmission of print data information. The Zigbee termination unit consists of a power monitor, a switching power supply I, an RS422 transceiver I, an NMOS transistor, and a Zigbee termination unit. The rechargeable lithium battery DC12V is connected to the power monitor, the input terminal of the switching power supply I, and the drain of the NMOS. The source of the NMOS is connected to the DC12V power input terminal of the printer. The output terminal of the switching power supply I provides DC3.3V power to the Zigbee terminal, the power monitor, and the RS422 transceiver I. The Zigbee terminal uses two GPIO pins to simulate the bidirectional connection of the IIC bus interface with the power monitor. The Zigbee terminal uses one GPIO pin to connect to the gate of the NMOS through a 10K current-limiting resistor. The UART serial port of the Zigbee terminal is connected to the RS422 serial port of the printer through the RS422 transceiver I. The RF interface of the Zigbee terminal is connected to the antenna. The rechargeable lithium battery provides DC 12V power; the power monitor acquires the voltage value of the rechargeable lithium battery; the switching power supply I steps down the DC 12V voltage to 3.3V; the RS422 transceiver I converts UART and RS422 levels; the NMOS is located between the rechargeable lithium battery and the printer's DC 12V power path, used to turn the printer's DC 12V power supply on and off; the Zigbee terminal uses a GPIO pin connected to the gate of the NMOS through a 10K current-limiting resistor to control the NMOS's on and off state; the Zigbee terminal is also used for control and data transmission / reception. The Zigbee terminal is model CC2530, the switching power supply I is model LM22670-ADJ, the power monitor is model INA226, the RS422 transceiver I is model THVD9491-SEP, and the MOSFET is model NTR4501NT1G.

2. The Zigbee-based wireless printing device for locomotives according to claim 1, characterized in that, The Zigbee wireless coordinator unit consists of a switching power supply II, an RS422 transceiver II, and a Zigbee wireless coordinator. The 13.8V power supply of the MMI interface provides 3.3V power to the RS422 transceiver II and the Zigbee wireless coordinator through the switching power supply II. The UART serial port pin of the Zigbee wireless coordinator is connected to the RS422 serial port of the MMI interface through the RS422 transceiver II. The switching power supply II is used to step down the DC 13.8V voltage to 3.3V, the RS422 transceiver II is used for UART and RS422 level conversion, and the Zigbee wireless coordinator is used for control and data transmission and reception. The Zigbee wireless coordinator is model CC2530, the switching power supply II is model LM22670-ADJ, and the RS422 transceiver II is model THVD9491-SEP.

3. A method for implementing the Zigbee-based locomotive wireless printing device as described in claim 2, characterized in that, After the wireless printing device and MMI wireless transmitter are powered on, the Zigbee terminal and Zigbee wireless coordinator work together to complete functions such as printing scheduling commands, querying printer version information, and uploading wireless printing device battery information.

4. The implementation method of a Zigbee-based locomotive wireless printing device according to claim 3, characterized in that, The method for completing the print scheduling command is as follows: the MMI wireless transmitter sends the scheduling command information to be printed to the wireless printing device. The wireless printing device receives the scheduling command information and drives the printer to print the scheduling command. When there is a need to print the scheduling command, the MMI interface sends the scheduling command information to the Zigbee wireless coordinator through RS422 transceiver II. The Zigbee wireless coordinator transmits the scheduling command information to the Zigbee terminal through the antenna. When the Zigbee terminal receives the scheduling command information, the GPIO pin connected to the NMOS of the Zigbee terminal is set high, so that the NMOS is turned on and the printer is powered on. The UART serial port of the Zigbee terminal sends the scheduling command information to the printer through RS422 transceiver I. The printer starts and prints the scheduling command. After printing is complete, the GPIO pins connected to the Zigbee terminal and the NMOS are set low, causing the NMOS to disconnect and the printer to power off.

5. The implementation method of a Zigbee-based locomotive wireless printing device according to claim 3, characterized in that, The method for querying printer version information is as follows: the MMI interface sends the printer version query command to the Zigbee wireless coordinator via RS422 transceiver II. The Zigbee wireless coordinator transmits the printer version query command to the Zigbee terminal via its antenna. The GPIO pin of the Zigbee terminal connected to the NMOS is set high, turning on the NMOS and powering on the printer. The UART serial port of the Zigbee terminal sends the printer version query command to the printer via RS422 transceiver I. The printer sends the version information to the Zigbee terminal via RS422 transceiver I. The Zigbee terminal sends the printer version information to the Zigbee wireless coordinator via its antenna. The Zigbee wireless coordinator then sends the information to the MMI interface via RS422 transceiver II.

6. The implementation method of a Zigbee-based locomotive wireless printing device according to claim 3, characterized in that, The method for uploading battery information of the wireless printing device is as follows: The Zigbee terminal periodically queries the power monitor through the GPIO pin to simulate the IIC interface. The power monitor transmits the collected voltage value to the Zigbee terminal. When the battery voltage is lower than 11.4V and 10.8V, the Zigbee terminal sends the battery information to the Zigbee wireless coordinator through the antenna. The UART serial port of the Zigbee wireless coordinator sends the battery information to the MMI interface through the RS422 transceiver II. When the MMI receives a battery voltage lower than 11.4V, the MMI screen displays the text "Printer battery low" and provides a voice prompt. The prompt can be closed by pressing the MMI "OK" button. When the MMI receives a battery voltage lower than 10.8V, the MMI screen displays the text "Printer battery low, please charge" and provides a voice prompt three times. The prompt can be closed by pressing and holding the MMI "OK" button.

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