Platform door opening and closing control method and system based on RS485 communication

Abstract

The invention provides a platform door opening and closing control method and system based on RS485 communication, and the method comprises the steps: building the communication connection between a central control panel and each door control unit through employing an RS485 communication protocol, and enabling each door control unit to correspond to one platform door; and the central control panel receives a door opening and closing instruction of a control end, constructs the door opening and closing instruction into an RS485 data packet, and sends the RS485 data packet to the corresponding door control unit, so that the door control unit drives the door motor driving device to complete door opening and closing actions of the platform door after analyzing the RS485 data packet. According to the scheme, connection between the central control panel and the door control unit is established in a communication connection mode, in the door opening and closing instruction sending process, the door opening and closing instruction is established into an RS485 data packet, normal control over a platform door is guaranteed, line breakage, wrong connection, missing connection and the like which frequently occur due to the complex site construction condition can be avoided, and the safety of the platform door is guaranteed. And the situation that the instruction cannot be normally issued is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of platform screen door systems, and in particular, to a method and system for controlling the opening and closing of platform screen doors based on RS485 communication. Background Art

[0002] The station platform screen door system is an automated facility installed at the platform edge to isolate the platform area from the track area, integrating safety, energy saving, and comfort functions. The system consists of sliding doors, fixed doors, emergency doors, and a control system, and realizes synchronous opening and closing with the train doors through signal linkage. The sliding doors correspond to the train doors and are equipped with obstacle detection and anti-pinch functions; the emergency doors are for emergency evacuation; the control system integrates sensors and monitoring devices to monitor the door state in real time and link with the signal system.

[0003] In the existing platform screen door systems, the opening and closing process requires the cooperation of the PSC (Central Control Panel), DCU (Door Controller Unit), transmission, and locking mechanisms. During the opening and closing process of the system: the central control panel receives the control instructions sent by the signal system, local control panel, or emergency control panel, drives the relay group to act, and finally transmits the opening and closing signals to the door control unit DCU in a hard-wired manner. The DCU then drives the electromagnetic lock to unlock and the motor to act after relevant processing; during the closing process of the system, the electromagnetic lock locks when the door closes in place to ensure that the door cannot be accidentally opened. However, in actual applications, it is necessary to use control cables (hard wires for transmitting control instructions) to construct the connection between the central control panel and the door control unit. Due to the complex on-site construction conditions, problems such as wire breakage, incorrect connection, and missed connection often occur, resulting in the inability to issue instructions normally. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for controlling the opening and closing of platform screen doors based on RS485 communication to eliminate or improve one or more defects existing in the prior art.

[0005] One aspect of the present invention provides a method for controlling the opening and closing of platform screen doors based on RS485 communication. The steps of the method include:

[0006] Construct a communication connection between the central control panel and each door control unit using the RS485 communication protocol, and each door control unit corresponds to a platform screen door;

[0007] The central control panel receives the opening and closing instructions from the control end, constructs the opening and closing instructions into an RS485 data packet, and sends the RS485 data packet to the corresponding door control unit, so that after the door control unit parses the RS485 data packet, it drives the door machine driving device to complete the opening and closing actions of the platform screen door.

[0008] Adopting the above solution, this solution is firstly different from the traditional way of constructing the connection between the central control panel and the door control unit by using control cables (hard wires for transmitting control instructions), but instead constructs the connection between the central control panel and the door control unit by means of a communication connection. During the process of sending the door opening and closing instructions, the door opening and closing instructions are constructed into RS485 data packets to ensure the normal control of the platform doors and avoid the situation where the instructions cannot be normally issued due to complex on-site construction conditions, such as frequent wire breakage, wrong connection, missed connection, etc.

[0009] In some embodiments of the present invention, in the step of constructing the door opening and closing instructions into RS485 data packets, the RS485 data packet is a data structure including data bits, check bits, and stop bits.

[0010] In some embodiments of the present invention, in the step of sending the RS485 data packet to the corresponding door control unit, calculate the CRC check value and add it to the frame of the data packet, send the data frame through the serial port, and start the timeout timer to wait for the feedback frame; if the feedback frame is received within the timeout period and the CRC check passes, then judge whether the sending is successful according to the response code of the feedback frame.

[0011] In some embodiments of the present invention, the step of sending the RS485 data packet to the corresponding door control unit further includes: if it is determined that the sending fails according to the response code of the feedback frame or the feedback frame is not received within the timeout period, then retransmit, and count each retransmission. When the number of retransmissions reaches the upper limit, stop sending and report an error.

[0012] In some embodiments of the present invention, in the step of stopping sending and reporting an error when the number of retransmissions reaches the upper limit, when the number of retransmissions reaches the upper limit, stop sending, and determine it as a communication failure, record the occurrence time, type, and device information of the communication failure, display the information of the communication failure on the HMI interface, send the information of the communication failure to the staff side, and switch the communication link to the standby link.

[0013] In some embodiments of the present invention, the steps of the method further include, in the initial communication between the central control panel and the door control unit, the central control panel sends a supervision program to the door control unit to make the supervision program run in the door control unit, and the supervision program is used to detect the operation state of the platform doors.

[0014] In some embodiments of the present invention, the operation state of the platform doors includes the door body failure state and the safety loop state. During the process of the supervision program running in the door control unit, construct the operation state of the platform doors into an RS485 data packet and feedback it to the central control panel.

[0015] In some embodiments of the present invention, in the step where the gating unit drives the door driving device to complete the opening and closing actions of the platform door after parsing the RS485 data packet, the gating unit continuously monitors the serial port data. When the start flag is detected, it starts to receive data, calculates the CRC check value and compares it with the received check value; if the CRC check passes, corresponding processing is performed according to the received data frame.

[0016] In some embodiments of the present invention, in the step where the gating unit drives the door driving device to complete the opening and closing actions of the platform door after parsing the RS485 data packet, if the CRC check passes, for the data frame, the data is parsed and business processing is performed, and then a feedback frame is constructed and sent to the sender; if the CRC check fails, the data frame is discarded and a feedback frame containing an error response code is sent to feedback to the central control panel.

[0017] The second aspect of the present invention further provides a platform door opening and closing control system based on RS485 communication. The system includes a computer device, the computer device includes a processor and a memory, computer instructions are stored in the memory, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the system implements the steps implemented by the method described above.

[0018] The third aspect of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps implemented by the foregoing platform door opening and closing control method based on RS485 communication are implemented.

[0019] The additional advantages, objectives, and features of the present invention will be partially described below, and will become partially apparent to those of ordinary skill in the art after studying the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be pointed out and obtained specifically in the description and the drawings.

[0020] Those skilled in the art will understand that the objectives and advantages that can be achieved by the present invention are not limited to the above specifically described, and the above and other objectives that the present invention can achieve will be more clearly understood according to the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not limit the present invention.

[0022] Figure 1 It is a schematic diagram of an embodiment of the platform door opening and closing control method based on RS485 communication of the present invention;

[0023] Figure 2Schematic diagram of the overall framework of the present invention;

[0024] Figure 3 Schematic diagram of the RS485 communication configuration process;

[0025] Figure 4 Schematic diagram of the sending process;

[0026] Figure 5 Schematic diagram of the receiving process;

[0027] Figure 6 Schematic diagram of the operation process for door body failure;

[0028] Figure 7 Schematic diagram of the opening operation process for platform screen doors;

[0029] Figure 8 Schematic diagram of the closing operation process for platform screen doors. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the implementation manners and the attached drawings. Herein, the illustrative implementation manners of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0031] Herein, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0032] In practical applications, the problems with the hard-wired cable (for transmitting control instructions) method include:

[0033] 1. Due to the complex on-site construction conditions, disconnection, wrong connection, missed connection, etc. often occur, resulting in the inability to issue instructions normally;

[0034] 2. The instruction feedback time of the platform unit doors is inconsistent, and the opening and closing states are not synchronized;

[0035] 3. Additional communication cables are required for DCU status monitoring, increasing the cost.

[0036] This solution can make the debugging of the platform screen door system more convenient and fast, and the new data transmission protocol has the characteristics of high concurrency and fast feedback, while ensuring the correctness of the instruction output.

[0037] As Figure 1 and 2 shown, the present invention proposes a method for controlling the opening and closing of platform screen doors based on RS485 communication. The steps of this method include:

[0038] Step S100, establish a communication connection between the central control panel and each gating unit using the RS485 communication protocol, with each gating unit corresponding to a platform door;

[0039] In the specific implementation process, the central control panel can use an industrial-grade high-performance controller (PLC), such as the Siemens S7-1500 series PLC. It has powerful computing capabilities and rich communication interfaces, supports 485 and new data transmission protocols, and can stably process a large number of door opening and closing control instructions and device status information. Install the PLC in a dedicated control cabinet in the station control room to ensure a good heat dissipation and electromagnetic shielding environment.

[0040] Use appropriate processors, 458 transceiver chips, terminal blocks, and twisted pairs at the DCU and PLC transceiver ends to establish a communication network, and have a redundant design to ensure the reliability of communication. Terminal resistors are configured at both ends of the bus to form a stable ring network topology to improve the fault tolerance of the network.

[0041] The central control panel uses the corresponding software platform of the PLC to develop the PSC program. In the program, as Figure 3 shown, first perform the initialization configuration of the RS485 communication module to enable it to establish a stable communication connection with the DCU. Then, write the door opening and closing control logic program. When the PSC receives an opening / closing instruction from the train control system or station staff, the program encodes the instruction into a corresponding data frame according to the new data transmission protocol and sends it to the corresponding DCU through the communication network. At the same time, the program continuously monitors the status information of the platform door feedback by the DCU, such as the position of the door, whether there is a fault, etc., and displays this information on the station monitoring interface.

[0042] The gating unit programs the DCU based on the STM32 processor. In the software, as Figure 3 shown, initialize the S485 communication slave function and set the communication parameters corresponding to the PLC. When the DCU receives the door opening and closing instruction data frame sent by the PLC, it checks and decodes the data frame. If the check is correct, it drives the door machine drive device to perform the corresponding door opening and closing actions according to the instruction. During the operation of the door machine, it continuously collects the position sensor signal and fault signal of the door machine, and packs these status information into a data frame according to the new data protocol and feeds it back to the PLC. In addition, the DCU also has a local manual control function. When communication fails or on-site debugging is required, the staff can operate the platform door to open and close through the operation buttons on the DCU.

[0043] Step S200, the central control panel receives the door opening / closing instruction from the control terminal, constructs the door opening / closing instruction into an RS485 data packet, and sends the RS485 data packet to the corresponding door control unit, so that after the door control unit parses the RS485 data packet, it drives the door machine drive device to complete the door opening / closing action of the platform screen door.

[0044] In the specific implementation process, in the step where the central control panel receives the door opening / closing instruction from the control terminal, the control terminal can be the signal system (SIG), the local control panel (PSL) or the emergency control panel (PEC) of the station.

[0045] In the specific implementation process, the door control unit adopts a door controller (DCU). Each door control unit is equipped with a DCU, which has a compact design and high reliability and can work stably in the harsh environment on the platform site. The DCU is installed in the control box near the door machine of the platform screen door, which is convenient for direct connection with the door machine drive device.

[0046] Furthermore, the door machine drive device selects a DC brushless motor drive system, which can accurately control the speed and position of the door machine and realize a smooth door opening / closing action. The drive device is firmly connected to the mechanical structure of the platform screen door, and it is ensured that the electrical connection between the motor and the driver is correct.

[0047] Adopting the above solution, this solution is first different from the traditional way of constructing the connection between the central control panel and the door control unit by using a control cable (a hard wire for transmitting control instructions), but uses a communication connection to construct the connection between the central control panel and the door control unit. During the sending process of the door opening / closing instruction, the door opening / closing instruction is constructed into an RS485 data packet to ensure the normal control of the platform screen door, and it can avoid the situation that the instruction cannot be normally issued due to complex on-site construction conditions, such as frequent wire breakage, wrong connection, missed connection, etc.

[0048] In some embodiments of the present invention, in the step of constructing the door opening / closing instruction into an RS485 data packet, the RS485 data packet is a data structure including data bits, parity bits and stop bits.

[0049] In some embodiments of the present invention, in the step of sending the RS485 data packet to the corresponding door control unit, calculate the CRC check value and add it to the frame of the data packet, send the data frame through the serial port, and start the timeout timer to wait for the feedback frame; if the feedback frame is received within the timeout period and the CRC check passes, judge whether the sending is successful according to the response code of the feedback frame.

[0050] In some embodiments of the present invention, the step of sending the RS485 data packet to the corresponding gating unit further includes: if it is determined that the transmission fails or no feedback frame is received within the timeout period according to the response code of the feedback frame, retransmission is performed, and the retransmission count is carried out for each retransmission. When the retransmission count reaches the upper limit, the transmission is stopped and an error is reported.

[0051] Adopting the above solution, as Figure 4 and 5 shown, in order to achieve high concurrency, this solution adopts a frame structure with a fixed length, which is convenient for quick parsing and processing. At the same time, cyclic redundancy check (CRC) is used to ensure the integrity of the data and reduce the number of error retransmissions. The fast feedback mechanism is realized by setting a feedback frame and a timeout retransmission mechanism. When the sender sends data, if no feedback is received within the specified time, retransmission is performed.

[0052] As Figure 6 shown, in some embodiments of the present invention, in the step of stopping the transmission and reporting an error when the retransmission count reaches the upper limit, when the retransmission count reaches the upper limit, the transmission is stopped, and it is determined as a communication failure. The occurrence time, type and device information of the communication failure are recorded, the information of the communication failure is displayed on the HMI interface, the information of the communication failure is sent to the staff side, and the communication link is switched to the backup link.

[0053] In the specific implementation process, the HMI interface is the interface of the HMI software in the station monitoring room. The HMI software in the station monitoring room can adopt configuration software such as ForceControl. On the HMI interface, the real-time status of the platform screen doors is intuitively displayed, including the opening and closing status of each door, fault information, etc. The staff can manually send opening and closing door instructions through the HMI interface, and can also perform operations such as system parameter setting and historical data query. The HMI software realizes the centralized monitoring and management of the platform screen door system through the communication connection with the DCU.

[0054] Further, the DCU will upload the normal operation status including door opening and closing actions, safety loop closing, etc. and fault status including motor faults, electromagnetic lock faults, communication faults, door opening and closing timeouts, etc. to the monitoring system through the RS485 communication line and display them on the HMI interface for operation, inspection, maintenance and record.

[0055] Specifically, when the PLC detects a communication timeout or data verification error with a certain DCU, it immediately attempts to resend the instruction data frame. If the continuous resending fails three times, it is determined as a communication failure. At this time, on the one hand, the PLC sends this failure information to the HMI interface for display to notify the staff; on the other hand, it automatically switches to the backup communication link (if any) and attempts to re - establish a communication connection with the DCU. Meanwhile, the PLC records the time, type, and relevant device information when the failure occurs for subsequent troubleshooting.

[0056] In some embodiments of the present invention, the steps of the method further include that in the initial communication between the central control panel and the door control unit, the central control panel sends a supervision program to the door control unit to make the supervision program run on the door control unit, and the supervision program is used to detect the operating state of the platform door.

[0057] In the specific implementation process, adding a JLINK conversion 485 interface circuit to each door control unit can realize the unified distribution of the execution programs of each door control unit from the central control panel through the RS485 line, reducing the on - site debugging workload.

[0058] In some embodiments of the present invention, the operating state of the platform door includes the door body failure state and the safety loop state. During the running of the supervision program on the door control unit, the operating state of the platform door is constructed as an RS485 data packet and fed back to the central control panel.

[0059] In some embodiments of the present invention, in the step where the door control unit drives the door machine driving device to complete the opening and closing actions of the platform door after parsing the RS485 data packet, the door control unit continuously listens to the serial port data. When the start flag is detected, it starts to receive data, calculates the CRC check value and compares it with the received check value; if the CRC check passes, corresponding processing is performed according to the received data frame.

[0060] Specifically, when the start flag 0xAA is detected, a frame of data starts to be received.

[0061] In some embodiments of the present invention, in the step where the door control unit drives the door machine driving device to complete the opening and closing actions of the platform door after parsing the RS485 data packet, if the CRC check passes, for the data frame, the data is parsed and business processing is performed, and then a feedback frame is constructed and sent to the sender; if the CRC check fails, the data frame is discarded and a feedback frame containing an error response code is sent to feedback to the central control panel.

[0062] With the above solution, the DCU monitors the fault signals fed back by the door machine drive device in real time. If a door machine fault is detected, such as motor overload, position sensor fault, etc., the DCU immediately stops the operation of the door machine and feeds back the fault information to the PLC according to the new data protocol. After receiving the fault information, the PLC displays the specific fault type and location on the HMI interface, and at the same time activates the audible and visual alarm device to remind the staff to handle it. After troubleshooting, the staff can perform a reset operation on the fault through the reset button on the HMI interface or the DCU, so that the platform door system resumes normal operation.

[0063] Furthermore, to improve the reliability of the system, this solution adopts a redundant design. For example, the PLC and key communication devices adopt the dual-machine hot standby method. When the main device fails, the standby device can automatically switch and take over the work to ensure the uninterrupted operation of the system. At the same time, the software programs and configuration parameters of the system are regularly backed up and stored in an external storage device to enable quick recovery in case of a serious system failure.

[0064] Specifically, the door opening and closing control process of this solution includes

[0065] As Figure 7 shown, the door opening control process: When the central control unit receives the door opening instruction, it encodes the door opening command into a corresponding data frame according to the new data communication protocol and sends it to the corresponding local control unit through the communication network. After receiving the data frame, the local control unit performs verification and decoding. After confirming that it is correct, it drives the platform door to perform the door opening action and feeds back the door opening status information to the central control unit through the new data communication protocol.

[0066] As Figure 8 shown, the door closing control process: Similarly, elaborate on the specific process of door closing control, from the central control unit sending the door closing instruction to the local control unit receiving, processing the instruction and controlling the platform door to close, and the whole process of feeding back the door closing status.

[0067] In the specific implementation process, this solution can be quickly transformed on the basis of the existing hard-wired connection, reducing the installation difficulty;

[0068] For the convenience of system debugging and operation, the specific transformation steps include:

[0069] Remove the control hard wires and related interfaces in the original platform door system;

[0070] Add an RS 485 communication interface circuit to the DCU control board circuit design;

[0071] Configure parameters such as the baud rate, data bits, parity bits, and stop bits of the communication link on the basis of the RS 485 communication protocol;

[0072] Data exchange and control between PLC and DCU using a new transmission protocol, featuring high concurrency and fast feedback;

[0073] The transmission communication content includes the master station sending unit door opening and closing instructions to the slave station, and the master station collecting unit door faults and safety loop conditions from the slave station.

[0074] In summary, by optimizing the communication protocol, control strategy, and system architecture, the reliability, real-time performance, and scalability of the platform door system have been significantly improved, with broad application prospects and remarkable economic benefits.

[0075] The embodiment of the present invention also provides a platform door opening and closing control system based on RS485 communication. The system includes a computer device, the computer device includes a processor and a memory, the memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the system implements the steps implemented by the method described above.

[0076] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps implemented by the foregoing platform door opening and closing control method based on RS485 communication. The computer-readable storage medium can be a tangible storage medium, such as a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, floppy disk, hard disk, removable storage disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0077] Those of ordinary skill in the art should understand that the various exemplary components, systems, and methods described in connection with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Specifically, whether to implement in hardware or software depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted through a data signal carried in a carrier wave on a transmission medium or a communication link.

[0078] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0079] In the present invention, features described and / or illustrated for one embodiment can be used in the same or a similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0080] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for controlling the opening and closing of platform screen doors based on RS485 communication, characterized in that The steps of the method include: Establish a communication connection between the central control panel and each door control unit using the RS485 communication protocol, with each door control unit corresponding to a platform door; The central control panel receives the door opening and closing instructions from the control end, constructs the door opening and closing instructions into an RS485 data packet, and sends the RS485 data packet to the corresponding door control unit, so that after parsing the RS485 data packet, the door control unit drives the door machine driving device to complete the door opening and closing actions of the platform door.

2. The door opening and closing control method of the platform screen door based on RS485 communication according to claim 1, characterized in that In the step of constructing the door opening and closing instructions into an RS485 data packet, the RS485 data packet is a data structure including data bits, parity bits, and stop bits.

3. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to claim 1, characterized in that In the step of sending the RS485 data packet to the corresponding door control unit, calculate the CRC check value and add it to the frame of the data packet, send the data frame through the serial port, and start a timeout timer to wait for the feedback frame; if the feedback frame is received within the timeout period and the CRC check passes, determine whether the sending is successful according to the response code of the feedback frame.

4. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to claim 3, characterized in that, The step of sending the RS485 data packet to the corresponding door control unit further includes: if it is determined that the sending fails according to the response code of the feedback frame or the feedback frame is not received within the timeout period, retransmit, and count each retransmission. When the number of retransmissions reaches the upper limit, stop sending and report an error.

5. The door opening and closing control method of platform screen doors based on RS485 communication according to claim 4, characterized in that In the step of stopping sending and reporting an error when the number of retransmissions reaches the upper limit, stop sending when the number of retransmissions reaches the upper limit, determine it as a communication failure, record the occurrence time, type, and device information of the communication failure, display the information of the communication failure on the HMI interface, send the information of the communication failure to the staff terminal, and switch the communication link to the backup link.

6. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to any one of claims 1 to 5, characterized in that, The steps of the method further include that in the initial communication between the central control panel and the door control unit, the central control panel sends a supervision program to the door control unit to make the supervision program run on the door control unit, and the supervision program is used to detect the operation status of the platform door.

7. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to claim 6, wherein The operation status of the platform door includes the door body failure status and the safety loop status. During the operation of the supervision program on the door control unit, construct the operation status of the platform door into an RS485 data packet and feedback it to the central control panel.

8. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to claim 1, wherein, In the step of the door control unit driving the door machine driving device to complete the door opening and closing actions of the platform door after parsing the RS485 data packet, the door control unit continuously monitors the serial port data. When the start flag is detected, start receiving data, calculate the CRC check value and compare it with the received check value; If the CRC check passes, perform corresponding processing according to the received data frame.

9. The method for controlling the opening and closing of platform screen doors based on RS485 communication according to claim 8, wherein, In the step of the door control unit driving the door machine driving device to complete the door opening and closing actions of the platform door after parsing the RS485 data packet, if the CRC check passes, for the data frame, parse the data and perform business processing, and then construct a feedback frame and send it to the sender; if the CRC check fails, discard the data frame and send a feedback frame containing an error response code to feedback to the central control panel.

10. A platform door opening and closing control system based on RS485 communication, characterized in that, The system includes a computer device, the computer device includes a processor and a memory, computer instructions are stored in the memory, the processor is configured to execute the computer instructions stored in the memory, and when the computer instructions are executed by the processor, the system implements the steps implemented by the method according to any one of claims 1 to 9.

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