Power line carrier communication method and device for cableway safety monitoring system

Abstract

The invention provides a power line carrier communication method and device for a cableway safety monitoring system, the cableway safety system comprises a plurality of monitoring sites, and each monitoring site comprises a programmable logic controller corresponding to the monitoring site and a carrier corresponding to the monitoring site; the method comprises the following steps: distributing corresponding fixed communication time slots for all monitoring sites based on a unified time reference; and for any monitoring site, the monitoring data corresponding to the monitoring site is sent on the power line channel by using the carrier corresponding to the monitoring site in the fixed communication time slot allocated by the monitoring site. According to the invention, data transmission channel conflicts in a cableway safety system are solved through a time division multiplexing mechanism, reliable transmission of key signals is guaranteed, and the communication reliability of a PLC carrier network is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial control communication, and in particular to a power line carrier communication method and device for a cableway safety monitoring system. BACKGROUND

[0002] In the existing cableway monitoring communication technology, multi-node carrier communication mainly adopts the following schemes: a traditional scheme is to directly connect multiple carriers in parallel on the power system along the cableway, each of which independently transmits data; a more advanced scheme adopts a carrier sense multiple access / collision avoidance (CSMA / CA) carrier sense multiple access protocol for collision detection; some systems use time division multiple access (TDMA) technology for time slot allocation; and there is also a master-slave communication mode that controls the communication timing by polling each monitoring station through a master control station. These technologies have mature applications in other industrial fields, but still have adaptability problems in the special environment of cableways.

[0003] In the practical engineering application of a cableway safety monitoring system, especially in small and medium-sized cableway systems using transparent mode carriers, the existing technology has the following core problem of channel conflict during data transmission. In the transparent mode, when multiple monitoring stations transmit safety monitoring data at a similar time, the carrier channel is prone to serious data conflict. Due to the lack of an effective anti-collision mechanism, critical safety signals such as emergency stop instructions, steel wire rope tension abnormal alarm, etc. may be delayed or lost in transmission, directly threatening the safety of cableway operation, especially when multiple stations report abnormal monitoring data at the same time in an emergency, the channel conflict problem is particularly prominent, making the system communication unstable. SUMMARY

[0004] The present application provides a power line carrier communication method and device for a cableway safety monitoring system to solve the defect of unstable system communication in the prior art, solves the data transmission channel conflict in the cableway safety system through a time division multiplexing mechanism, guarantees the reliable transmission of critical signals, and improves the communication reliability of the PLC carrier network.

[0005] In a first aspect, the present application provides a power line carrier communication method for a cableway safety monitoring system, the cableway safety system comprising a plurality of monitoring stations, each of the monitoring stations comprising a programmable logic controller (PLC) corresponding to the monitoring station and a carrier corresponding to the monitoring station; the method comprising the following steps: allocating a corresponding fixed communication time slot for each of the monitoring stations based on a unified time reference; For any of the monitoring stations, the monitoring station transmits the monitoring data corresponding to the monitoring station on the power line channel using the carrier corresponding to the monitoring station in the fixed communication time slot assigned to the monitoring station.

[0006] According to the power line carrier communication method for the ropeway safety monitoring system, the monitoring station transmits the monitoring data corresponding to the monitoring station on the power line channel using the carrier corresponding to the monitoring station in the fixed communication time slot assigned to the monitoring station. The power-on delay timer is used as the main cycle time base. The monitoring station determines whether the cumulative value of the TON is in the fixed communication time slot corresponding to the monitoring station based on a comparison instruction. If the cumulative value of the TON is in the fixed communication time slot, the monitoring station executes a message instruction MSG data transmission instruction to transmit the monitoring data corresponding to the monitoring station.

[0007] According to the power line carrier communication method for the ropeway safety monitoring system, the method further comprises: If the error flag of the MSG data transmission instruction is detected to be set, the monitoring station retransmits data in the fixed communication time slot. If the retransmission number reaches a preset upper limit or the cumulative communication failure number exceeds a threshold, a system alarm is triggered.

[0008] According to the power line carrier communication method for the ropeway safety monitoring system, the ropeway safety system further comprises a master control station. Before the fixed communication time slots corresponding to the monitoring stations are assigned based on the unified time base, the method further comprises: After the ropeway safety system is powered on and the carrier network is initially established, the master control station sends a unified reset instruction to all monitoring stations through wireless communication. After receiving the unified reset instruction, the monitoring stations synchronously execute a local hardware reset operation to trigger the internal parameter zero clearing of the PLC controller corresponding to the monitoring station. The local hardware reset operation is executed based on a local hardware reset button arranged on the monitoring station, and the local hardware reset button is directly connected to the PLC controller parameter zero clearing input port corresponding to the monitoring station. The monitoring stations start the time division multiplexing timer simultaneously from the zero clearing state through all PLC controllers to establish the unified time base.

[0009] The application provides a power line carrier communication method for a ropeway safety monitoring system. When the ropeway safety system is started, the physical communication links between the carrier of each monitoring station and the PLC controller of each monitoring station are in a disconnected state. After the carrier of the master station completes network initialization, the physical communication links of the monitoring stations are sequentially closed at preset time intervals, so that the carriers of the monitoring stations sequentially access the power line carrier network.

[0010] The application provides a power line carrier communication method for a ropeway safety monitoring system. The network switches of the monitoring stations are in a disconnected state, so that the physical links are in a disconnected state.

[0011] In a second aspect, the application further provides a power line carrier communication device for a ropeway safety monitoring system. The time slot allocation module is configured to allocate a fixed communication time slot to each monitoring station based on a unified time reference. The communication module is configured to, for any monitoring station, use the carrier of the monitoring station to send monitoring data corresponding to the monitoring station on a power line channel in the fixed communication time slot allocated to the monitoring station.

[0012] In a third aspect, the application further provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the power line carrier communication method for a ropeway safety monitoring system as described above.

[0013] In a fourth aspect, the application further provides a non-transitory computer readable storage medium having a computer program stored thereon, and the computer program is executable on a processor to implement the power line carrier communication method for a ropeway safety monitoring system as described above.

[0014] In a fifth aspect, the application further provides a computer program product including a computer program, and the computer program is executable on a processor to implement the power line carrier communication method for a ropeway safety monitoring system as described above.

[0015] The application provides a power line carrier communication method and device for a cableway safety monitoring system. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0017] Figure 1 Fig. 1 is one of flow diagrams of the power line carrier communication method for the cableway safety monitoring system provided by the application.

[0018] Figure 2 Fig. 2 is one of principle diagrams of the power line carrier communication method for the cableway safety monitoring system provided by the application.

[0019] Figure 3 Fig. 3 is another flow diagram of the power line carrier communication method for the cableway safety monitoring system provided by the application.

[0020] Figure 4 Fig. 4 is another principle diagram of the power line carrier communication method for the cableway safety monitoring system provided by the application.

[0021] Figure 5 Fig. 5 is a structural diagram of the power line carrier communication device for the cableway safety monitoring system provided by the application.

[0022] Figure 6 Fig. 6 is a structural diagram of the electronic device provided by the application. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, not limited in number; for example, a first node can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] To more clearly understand the various embodiments provided by the present invention, the technical content involved in the present invention will first be described as follows: In the practical engineering application of cableway safety monitoring systems, especially in small and medium-sized cableway systems using transparent transmission mode carriers, existing technologies face three interrelated core problems: First, there is the problem of inconsistent startup timing of Programmable Logic Controllers (PLCs). Due to differences in hardware performance, load, and power supply distance, the startup time of PLCs at various monitoring stations along the cableway varies by 2 to 8 seconds. This timing inconsistency prevents each station from starting work from a unified time base, seriously affecting the synchronization of the time-sharing communication mechanism and making it difficult to coordinate subsequent time slot allocation and data scheduling.

[0026] Secondly, there is the issue of carrier network initialization conflicts. When the cableway system is powered on, the carriers at multiple monitoring stations start up and execute network discovery and parameter configuration programs simultaneously, resulting in severe initialization conflicts on the power line channel. This causes the carriers to be unable to establish communication links normally, leading to unstable network topology discovery. As a result, some stations often cannot join the network. In actual projects, maintenance personnel often need to manually plug and unplug network cables at each station or restart the equipment in sequence to establish a normal connection.

[0027] Third, the channel conflict problem in data transmission. In the transparent mode, when multiple monitoring sites send safety monitoring data at similar times, the carrier channel is prone to serious data conflict. Due to the lack of effective anti-collision mechanism, the transmission of critical safety signals such as emergency stop instructions, steel wire tension abnormal alarm, etc. may be delayed or lost, directly threatening the safety of the cableway operation, especially when multiple sites report abnormal data at the same time in an emergency, the channel conflict problem is particularly prominent.

[0028] These three technical problems are superimposed on each other, not only making the system communication extremely unstable, but also leading to difficult operation and maintenance. Cableway sites are usually located in mountainous or remote areas, and each communication failure needs to be checked and manually intervened by technical personnel in the field, which seriously restricts the automation level of small and medium-sized cableway systems.

[0029] In view of the defects existing in the prior art, the purpose of the present application is to provide a power line carrier time division multiplexing communication method for a cableway safety monitoring system, focusing on solving the three core technical problems: First, the synchronization reset device is used to solve the inconsistent PLC start timing problem, and a unified time reference is achieved. Second, the network switch access control is used to solve the carrier concurrent initialization conflict and ensure the stable establishment of the network. Third, the time division multiplexing mechanism is used to solve the data transmission channel conflict and ensure the reliable transmission of critical signals.

[0030] The present application aims to improve the communication reliability of the PLC carrier network and is particularly suitable for engineering applications in multi-site monitoring systems such as cableways.

[0031] The following will be described in conjunction with Figures 1-6 The power line carrier communication method and device for a cableway safety monitoring system of the present application.

[0032] Figure 1 is one of the flowcharts of the power line carrier communication method for a cableway safety monitoring system provided by the present application. The cableway safety system includes multiple monitoring sites, each monitoring site including a programmable logic controller (PLC) corresponding to the monitoring site and a carrier corresponding to the monitoring site; as Figure 1 shown, the method comprises the following steps: Step 101, based on a unified time reference, allocate a corresponding fixed communication time slot for each monitoring site.

[0033] Specifically, the present application is applied to a cableway safety monitoring system, which includes multiple monitoring sites, each monitoring site including a programmable logic controller (PLC) corresponding to the monitoring site and a carrier, and real-time data exchange is required between each monitoring site and the main site.

[0034] In the embodiment of the present application, before data transmission, a unified time reference is used to allocate fixed communication time slots to each monitoring site. That is, a communication scheduling strategy based on time division multiple access is used to allocate fixed time slots to each monitoring site for data transmission.

[0035] The unified time reference can be understood as the same time reference of each site and the master station, and the timing starts at the same time, thereby solving the problem of inconsistent PLC start timing and achieving a unified time reference.

[0036] Exemplarily, Figure 2 is one of the principle diagrams of the power line carrier communication method for the ropeway safety monitoring system provided by the present application, which represents a multi-node time division multiplexing communication mechanism, such as Figure 2 As shown in the figure, the communication time slot allocation formula includes: (system) total cycle T=Nx1.5 seconds (N is the number of monitoring sites), for example, N=3~10, that is, the ropeway safety monitoring system supports 3-10 site configurations (corresponding to a period of 4.5-15 seconds), which meets the real-time requirements of the ropeway safety monitoring. Among them, a single time slot is configured as 1.2 seconds of sending (window) and 0.3 seconds of protection interval, that is, the communication time slot allocation formula also includes: single time slot=1.2 seconds of sending+0.3 seconds of protection interval, in order to prevent data conflict of adjacent time slots.

[0037] In the time slot allocation, the time slot of each site is 1.5 seconds, including 1.2 seconds of sending (window) and 0.3 seconds of protection interval (such as the time slot of the master station, the time slot of PLC 1, and the time slot of PLC 2), and correspondingly, under the same time reference, the time slot allocated for the master station is 0s-1.5s, the time slot allocated for PLC 1 is 1.5s-3s, and the time slot allocated for PLC 2 is 3s-4.5s.

[0038] Step 102, for any monitoring site, the monitoring site uses the carrier corresponding to the monitoring site to send the monitoring data corresponding to the monitoring site on the power line channel in the fixed communication time slot allocated to the monitoring site.

[0039] Specifically, after obtaining the allocated time slot corresponding to each monitoring site, further, in the process of data transmission, each monitoring site performs data transmission in the allocated time slot.

[0040] For example, the carrier corresponding to the monitoring site is used to send the monitoring data corresponding to the monitoring site on the power line channel, and the specific implementation steps are as follows: Step 1: Data preparation and triggering (PLC side) Data collection: PLC reads the signals from various sensors (such as wire tension, running speed, emergency stop button status, etc.) through its local input modules. These signals are processed and stored in specific data registers (e.g., D100, D101,...) of the PLC.

[0041] Time slot determination: The time division multiplexing program inside the PLC runs continuously, using the TON timer and GRT / LES comparison instructions to determine in real time whether the current time belongs to its own fixed communication time slot.

[0042] Triggered transmission: Once it enters its own time slot, the program logic becomes "true", triggering the execution of the message instruction or communication instruction (Message Instruction, MSG).

[0043] Step 2: Data encapsulation and network transmission (between PLC and carrier) MSG instruction configuration: This MSG instruction has been pre-configured, and the MSG instruction is introduced as follows: Target: Which data registers (such as 10 words starting from D100) to send out.

[0044] Target address: The target address is the IP address of the master station PLC or the network node number.

[0045] Communication path: The communication path points to the PLC's local Ethernet port.

[0046] Data packet formation: The CPU of the PLC executes the MSG instruction, packaging the specified data into a standard Ethernet data frame (e.g., based on TCP / IP or Modbus TCP protocol).

[0047] Physical transmission: This Ethernet data frame is output through the RJ45 Ethernet port of the PLC, and sent to the Ethernet interface of the carrier through the network cable.

[0048] Step 3: Signal modulation and coupling (inside the carrier) After the carrier receives the data packet, it processes as follows: Protocol processing and modulation: The processor inside the carrier receives the Ethernet data frame from the PLC. Instead of simply forwarding, it will modulate the digital data onto a specific high-frequency carrier signal (e.g., a certain center frequency within the range of 2MHz to 30MHz) according to the communication parameters set in its firmware (such as mentioned in the disclosure: modulation rate, network ID, relay settings, etc.).

[0049] The essence of modulation: is to use digital signals representing "0" and "1" to change some characteristics (such as amplitude, frequency or phase) of the high-frequency carrier, so that the wave carries information.

[0050] Signal Amplification and Coupling: The modulated high-frequency signal is very weak and needs to be amplified. Then, the amplified high-frequency signal is injected into the power line through a coupling circuit (usually containing an isolation transformer and capacitors). The key role of "coupling": This circuit allows high-frequency communication signals to pass through smoothly, but at the same time blocks the 50 / 60 Hz power frequency on the power line, thus protecting the fragile communication circuitry inside the carrier from being burned out.

[0051] Step 4: Transmission on power line channels The modulated and coupled high-frequency signal shares the same power line with the 50 / 60Hz power frequency current, and propagates from the monitoring station along the cableway's power supply line toward the main control station.

[0052] Because power lines are not ideal communication media, signals are subject to attenuation, distortion, and interference during transmission. Repeater stages allow intermediate carriers to receive, regenerate, and forward signals, thereby extending communication distances.

[0053] This invention, through a time-division multiplexing mechanism, ensures that when multiple monitoring stations execute the aforementioned complex process, their signals will not appear on the power line channel at the same time, thereby fundamentally avoiding conflicts.

[0054] Optionally, the number of nodes (monitoring sites) in this invention can be adjusted according to actual needs. For 3-5 nodes, the time slot can be increased to 3 seconds to improve reliability, and for 6-10 nodes, it can be shortened to 1 second to improve real-time performance. It can expand the priority mechanism to allocate double time slots and emergency data insertion function to critical equipment. It supports intelligent optimization, dynamically adjusts time slots according to historical success rate and automatically allocates idle time slots to active nodes. It has fault tolerance capability, can automatically detect node disconnection and reallocate time slots, and supports backup communication channel switching. It can integrate host computer functions to add a human machine interface (HMI) monitoring interface and remote parameter configuration.

[0055] The method provided in this invention relates to a cableway safety system comprising multiple monitoring stations, each monitoring station including a corresponding PLC controller and a corresponding carrier transceiver. The method includes: first, allocating fixed communication time slots to each monitoring station based on a unified time reference; then, for any given monitoring station, transmitting monitoring data on a power line channel using its corresponding carrier transceiver within its allocated fixed communication time slot. This invention resolves data transmission channel conflicts in the cableway safety system through a time-division multiplexing mechanism, ensuring reliable transmission of critical signals and improving the communication reliability of the PLC carrier network.

[0056] It should be noted that each embodiment of the present application can be freely combined, exchanged order or executed alone, and does not need to rely on or depend on the fixed execution order.

[0057] The application provides a power line carrier communication method for a ropeway safety monitoring system, wherein a monitoring station sends monitoring data corresponding to the monitoring station on a power line channel by using a carrier corresponding to the monitoring station in a fixed communication time slot allocated to the monitoring station, and the method comprises the following steps: using a power-on delay timer TON as a main cycle time base; judging whether the cumulative value of the TON is in the fixed communication time slot corresponding to the monitoring station based on a comparison instruction by the monitoring station; in the case that the cumulative value of the TON timer is in the fixed communication time slot, executing a message instruction MSG data sending instruction to send the monitoring data corresponding to the monitoring station by the monitoring station.

[0058] Specifically, in some embodiments, step 102 comprises the following specific implementation steps: using the TON timer T4:0 as the main cycle time base, and the preset value PRE of the timer is N*1500 milliseconds ms, wherein N is the total number of the monitoring stations. The main cycle time base is essentially the origin of the whole system synchronization heartbeat, and the ACC value of the TON timer T4:0 is cyclically counted from 0 to N*1500 milliseconds, thereby providing a unique time base for each station to judge whether it is the speaking time.

[0059] each monitoring station judges whether the cumulative value of the TON timer is in the fixed communication time slot corresponding to the monitoring station based on a comparison instruction.

[0060] wherein GRT and LES are comparison instructions commonly used in programmable logic controller (PLC) programming, GRT represents "Greater Than" (greater than). Function: used for comparing two values, if the first value is greater than the second value, then the logic condition where the instruction is located is "true" (True). LES represents "Less Than" (less than). Function: used for comparing two values, if the first value is less than the second value, then the logic condition where the instruction is located is "true" (True).

[0061] the cumulative value of the TON timer, such as T4:0.ACC, is constantly increasing, serving as a unified time base, and each monitoring station has a pre-allocated fixed time window (time slot), i.e., a fixed communication time slot. In order to judge whether the current time belongs to its own time slot, the PLC program will simultaneously use GRT and LES instructions to create an "interval comparison" logic.

[0062] For example, for the No. 1 monitoring site, its time slot is 0 to 1500 milliseconds. The program will check: Whether T4:0.ACC>0? (use GRT instruction) Whether T4:0.ACC<1500? (use LES instruction) In the embodiment of the application, the GRT and the LES are used in combination and cooperate with each other to accurately determine the exclusive communication time period of each PLC node on the unified time axis, so that time division multiplexing is realized at the software level and data transmission conflicts are avoided.

[0063] Only when the two conditions are met at the same time, it means that the current time is exactly in the transmission window of the No. 1 monitoring site (node), and the message instruction or the communication instruction is triggered to send data. The MSG instruction is responsible for packaging the local safety monitoring data (such as tension, speed, alarm signal) of the node and sending it to the master station through the carrier network, and it is a specific execution means to realize data exchange between PLCs.

[0064] The carrier communication parameters are configured as follows: the master station carrier is configured in a broadcast mode to realize one-to-many control instruction issuing, and each monitoring site carrier is configured in a unicast mode to realize point-to-point data return. The system uniformly configures the parameters as follows: the modulation rate setting value is 10 (corresponding to a transmission rate of 20 kbps), the relay level is 4 (covering the transmission distance of the whole cableway), the number of response confirmations is 3 (ensuring data transmission reliability), and the data packet survival time is 40 (matching the system monitoring period). The carrier communication parameter configuration provides the underlying network path and protocol support for the smooth execution of the MSG instruction.

[0065] That is, in the case that the cumulative value T4:0.ACC of the TON timer is in the fixed communication time slot corresponding to the node, the MSG data sending instruction is executed through the node to send the monitoring data corresponding to the monitoring site.

[0066] The method provided by the embodiment of the application uses a TON timer as a main period time base, judges whether the cumulative value of the TON timer is in the fixed communication time slot corresponding to the monitoring site based on a comparison instruction through the monitoring site; and in the case that the cumulative value of the TON timer is in the fixed communication time slot, executes a MSG data sending instruction through the monitoring site to send the monitoring data corresponding to the monitoring site. The application solves the channel conflict in data transmission through the time division multiplexing mechanism, guarantees the reliable transmission of key signals, and improves the communication stability.

[0067] According to the power line carrier communication method for the cableway safety monitoring system provided by the application, the method further comprises: In the case of detecting that the error flag of the MSG data sending instruction is set, data retransmission is performed by the monitoring station in the fixed communication time slot; If the retransmission number reaches the preset upper limit or the cumulative communication failure number exceeds the threshold, the system alarm is triggered.

[0068] Specifically, in some embodiments, the method further comprises the introduction of a data retransmission mechanism, and the specific implementation steps are as follows: The MSG data sending instruction is executed by the node (monitoring station) to send the monitoring data corresponding to the monitoring station, and if the error flag MSG.ER of the MSG data sending instruction is detected to be set, data retransmission is triggered, that is, data retransmission is performed by the monitoring station in the fixed communication time slot.

[0069] Further, the upper limit of the retransmission number and the threshold of the failure number can be preset, and if the retransmission number reaches the preset upper limit (such as 3 times) or the cumulative communication failure number exceeds the threshold (10 times), the system alarm is triggered.

[0070] Exemplarily, Figure 3 is a flowchart of the power line carrier communication method for the ropeway safety monitoring system provided by the present application, as shown in Figure 3 The method comprises the following steps: System startup: main cycle timer TON T4:0, preset value PRE=N×1500 milliseconds ms; Each node (monitoring station) judges: Time window judgment module (comparison instruction judgment), comprising: GRT: T4:0.ACC>(node number-1)×1500; LES: T4:0.ACC<node number×1500); Data transmission: if the window matches, execute the MSG data sending module to trigger the data transmission instruction; After successful data transmission, the retransmission counter is cleared by the RST instruction, and the next cycle transmission is prepared, that is, the RST retransmission counter is successfully reset; If there is an error detection MSG.ER flag, it indicates that the sending fails, the retransmission control mechanism is executed, the CTU counter is counted, and the maximum retransmission is 3 times; cumulative failure statistics are executed, and if the failure number>10, the system alarm output is triggered, triggering the safety alarm (failure handling link). That is, if the MSG.ER error flag is detected, automatic retransmission is executed, the upper limit of the retransmission number is set to 3 times, and the cumulative communication failure exceeds 10 times to trigger the system alarm.

[0071] The retransmission counter here uses the counter of the CTU instruction. Each time a transmission fails (MSG.ER is set), the CTU counter is incremented. If the data transmission is successful, it means that no retransmission is needed in this communication cycle. At this time, the current value of the retransmission counter must be cleared using the RST instruction, so that it returns to the initial state and is ready for counting in the next communication cycle.

[0072] If there is no RST instruction, the counter will always keep the current value, resulting in incorrect counting in the next cycle and failure of the retransmission logic.

[0073] A simple logic flow comparison is as follows: Error case: transmission failure -> MSG.ER set -> CTU counter + 1 -> (not cleared) -> next transmission failure -> CTU counter + 1 (becomes 2)... soon reaches the upper limit of 3, triggering an alarm.

[0074] Correct case: transmission failure -> MSG.ER set -> CTU counter + 1 -> (still in the time slot, try retransmission) -> transmission success -> execute RST instruction -> CTU counter is cleared -> wait for the next communication cycle that belongs to itself.

[0075] In the method provided by the embodiment, in the case where the error flag of the MSG data transmission instruction is detected to be set, data retransmission is performed by the monitoring station in the fixed communication time slot, and if the retransmission number reaches a preset upper limit or the cumulative communication failure number exceeds a threshold value, a system alarm is triggered, so as to avoid data loss and ensure the stability of communication.

[0076] According to the power line carrier communication method for the ropeway safety monitoring system provided by the application, the ropeway safety system further comprises a master control station; Before the corresponding fixed communication time slots are allocated to the monitoring stations based on the unified time reference, the method further comprises the following steps of: After the ropeway safety system is powered on and the carrier network is initially established, the master control station sends a unified reset instruction to all monitoring stations through wireless communication; After receiving the unified reset instruction, the monitoring stations synchronously perform local hardware reset operations, triggering the corresponding PLC controller internal parameter zero clear of the monitoring stations; the local hardware reset operation is performed based on a local hardware reset button arranged on each monitoring station, and each local hardware reset button is directly connected with a PLC controller parameter zero clear input port corresponding to the monitoring station; The monitoring stations start the time division multiplexing timer simultaneously from the zero clear state through all PLC controllers, so as to establish a unified time reference.

[0077] Specifically, the cableway safety system further comprises a master station, and in some embodiments, the step 102 further comprises introduction of a synchronous reset mechanism, the process of which is described as follows: In the synchronous reset mechanism, each monitoring station is configured with an independent local hardware reset button, which is directly connected to a parameter clear input port of a PLC corresponding to the monitoring station, and the local hardware reset operation is performed based on an operation of the local hardware reset button arranged at each monitoring station.

[0078] The specific implementation steps of the synchronous reset are as follows: After the cableway safety system is powered on and the power line carrier network is initially established (30 seconds are waited to ensure that the power line carrier network is initially established), the master station sends a unified reset instruction to all monitoring stations through wireless communication. Specifically, the master station comprises a reset button, and the master station sends a synchronous instruction (i.e., the unified reset instruction) to all monitoring stations through the master device. Further, each monitoring station synchronously performs a local hardware reset operation after receiving the unified reset instruction, for example, triggers the PLC controller corresponding to the monitoring station to clear internal parameters, and simultaneously starts a time division multiplexing timer to establish a unified time reference.

[0079] The method provided by the embodiment of the application uses the wireless communication device that is standard equipped in the cableway system to achieve remote synchronous control, avoids the problem of additional laying of a synchronous signal line, and solves the problem of inconsistent PLC start timing by starting timing from zero time after each PLC is reset, thereby achieving a unified time reference and ensuring that the time division multiplexing mechanism is started from the unified time reference.

[0080] According to the power line carrier communication method for the cableway safety monitoring system provided by the application, before each monitoring station is allocated a corresponding fixed communication time slot based on the unified time reference, the method further comprises the following steps: When the cableway safety system is started, the physical communication link between the carrier corresponding to each monitoring station and the PLC controller corresponding to each monitoring station is in a disconnected state; After the carrier of the master station completes network initialization, the physical communication link of each monitoring station is sequentially closed at a preset time interval, so that the carrier corresponding to each monitoring station is sequentially accessed to the power line carrier network.

[0081] Specifically, in some embodiments, the method further comprises a mechanism of network cable switch access control, which comprises: a network cable switch (electronic relay S1-S n ) is arranged at an Ethernet interface between the PLC and the carrier of each monitoring station, and preset time sequence control is performed by the master station PLC or an independent timing controller. Figure 4This is the second schematic diagram of the power line carrier communication method for a cableway safety monitoring system provided by the present invention, illustrating the synchronous reset mechanism and the step-by-step access control of the carrier, as shown below. Figure 4 As shown, for monitoring station (middle station) 1, an electronic relay S1 is installed between middle station PLC 1 and carrier device 1; for monitoring station (middle station) 2, an electronic relay S2 is installed between middle station PLC 2 and carrier device 2, and an electronic relay S2 is installed between middle station PLC n and carrier device 2; for monitoring station (middle station) n, an electronic relay S2 is installed between middle station PLC n and carrier device n, and an electronic relay S2 is installed between middle station PLC n and carrier device 2. The master control station includes a reset button and sends synchronization commands (i.e., unified reset commands) to all monitoring stations through the master control device.

[0082] As shown in the carrier startup sequence, when the cableway safety system starts, the physical communication link between the carriers corresponding to all monitoring stations and the PLC controllers corresponding to all monitoring stations is disconnected. This physical communication link is an Ethernet interface, and its on / off state is controlled by a network cable switch installed on the Ethernet interface. The network cable switch is controlled by the main control station PLC or an independent timer controller according to a preset sequence. That is, all network cable switches are initially open to prevent multiple carriers from simultaneously executing the network initialization program. The main control station carriers are powered on and run for 30 seconds to complete network parameter configuration and link establishment.

[0083] After the carrier at the main control station completes network initialization, the physical communication links of each monitoring station are closed sequentially at preset time intervals, so that the carriers corresponding to each monitoring station can be connected to the power line carrier network in sequence.

[0084] For example, such as Figure 4 As shown, the step-by-step access control of the carriers includes: after confirming that the network status of the main carrier is normal (continuous operation, stable network acceptance of new sites), after a first preset time period (e.g., starting from the 30th second), the network cable switches of each monitoring site are closed sequentially at 5-second intervals, so that the carriers of each monitoring site (carrier 1, carrier 2, ..., carrier n) are connected to the power line carrier network in sequence. That is, the carrier startup sequence (to avoid network conflicts, one carrier is connected every 5 seconds).

[0085] The method provided in this invention employs a step-by-step access strategy that adapts to the topology of distributed stations along the cableway, avoiding network conflicts caused by concurrent initialization of multiple carriers and improving the success rate of communication network establishment. Furthermore, the entire access process is executed automatically according to a preset program, reducing the need for manual on-site debugging.

[0086] The application provides a power line carrier communication method for a cableway safety monitoring system. The network switch corresponding to all monitoring sites is in a disconnected state, so that the physical links are in a disconnected state.

[0087] Specifically, the process of controlling the physical communication links between the carrier corresponding to all monitoring sites and the PLC controller corresponding to all monitoring sites in a disconnected state is realized by the network switch corresponding to the monitoring site, for example, the network switch corresponding to all monitoring sites is in a disconnected state, so that the physical links are in a disconnected state.

[0088] The method provided by the application controls the state of the physical link through the network switch, is simple and feasible, solves the initialization conflict caused by the concurrency of multiple carriers through network switch access control, and can ensure the stable establishment of the network.

[0089] In summary, the technical effects of the application include the following: 1. The local reset button scheme based on wireless communication coordination is used to realize the parameter synchronization and zero clearing of the PLCs of the monitoring sites of the cableway. The device uses the wireless communication equipment that is standard for the cableway system, and avoids the engineering difficulty of additional synchronous signal line arrangement. After the PLCs of the sites are reset, the timing starts from zero, ensures that the time division multiplexing mechanism starts from a unified time reference, solves the problem of inconsistent starting time of the sites, and guarantees the synchronous collection of the safety monitoring data of the cableway.

[0090] 2. The step-by-step access mode is used, the carrier of the master control station is separately operated for 30 seconds to complete network parameter configuration and link establishment, and then the other monitoring sites are sequentially accessed to the network every 5 seconds. This ordered access strategy adapts to the topological structure of the distributed sites along the cableway, avoids the network conflict caused by the concurrent initialization of multiple carriers, and improves the success rate of the establishment of the communication network.

[0091] 3. The communication scheduling strategy based on the time division multiple access principle is used to allocate a fixed time slot (1.2 seconds of a sending window + 0.3 seconds of a protection interval) of 1.5 seconds to each monitoring site. In combination with the retransmission control logic based on the CTU counter and the cumulative fault alarm mechanism, the conflict problem in the safety data transmission process of the cableway is effectively solved. The mechanism enables the reliable transmission of key safety data such as tension monitoring, speed monitoring and emergency parking in the respective time slots, the total cycle of the system flexibly adapts to the quantitative site configuration, and meets the real-time requirements of the safety monitoring of the small and medium-sized cableway.

[0092] In summary, the application realizes collision-free data transmission of the carrier channel by allocating 1.5 seconds of dedicated time slot (1.2 seconds of transmission window + 0.3 seconds of protection interval) for each PLC node, combining TON timer accurate control and MSG instruction scheduling. With two auxiliary innovative technologies, synchronous reset control (unified time reference) and network switch step-by-step access (avoiding initialization conflict), the three technologies cooperatively build a complete anti-collision communication architecture. The method is particularly suitable for multi-node PLC network of the transparent mode carrier, can flexibly configure 3-10 nodes, and provides a reliable engineering solution for industrial monitoring systems such as cableways.

[0093] The power line carrier communication device for the cableway safety monitoring system provided by the application is described below, and the power line carrier communication device for the cableway safety monitoring system described below can be correspondingly referred to the power line carrier communication method for the cableway safety monitoring system described above.

[0094] Figure 5 It is a structural schematic diagram of the power line carrier communication device for the cableway safety monitoring system provided by the application, and the cableway safety system includes a plurality of monitoring sites, each of which includes a programmable logic controller (PLC) corresponding to the monitoring site and a carrier corresponding to the monitoring site. Figure 5 As shown in the figure, the power line carrier communication device 500 for the cableway safety monitoring system includes the following modules: The time slot allocation module 510 is used to allocate a corresponding fixed communication time slot for each monitoring site based on a unified time reference. The communication module 520 is used to transmit the monitoring data corresponding to any monitoring site on the power line channel by using the carrier corresponding to the monitoring site within the fixed communication time slot allocated to the monitoring site.

[0095] The power line carrier communication device for the cableway safety monitoring system provided by the application includes a time slot allocation module 510 for allocating a corresponding fixed communication time slot for each monitoring site based on a unified time reference, and a communication module 520 for transmitting the monitoring data corresponding to any monitoring site on the power line channel by using the carrier corresponding to the monitoring site within the fixed communication time slot allocated to the monitoring site. The application solves the data transmission channel conflict in the cableway safety system through time division multiplexing mechanism, guarantees the reliable transmission of key signals, and improves the communication reliability of the PLC carrier network.

[0096] According to the application, the power line carrier communication device 500 for the ropeway safety monitoring system comprises a communication module 520, and the communication module 520 is specifically used for: The energization time delay timer TON is used as the main cycle time base; The monitoring station judges whether the cumulative value of the TON is in the fixed communication time slot corresponding to the monitoring station based on the comparison instruction; In the case that the cumulative value of the TON is in the fixed communication time slot, the monitoring station executes the message instruction MSG data sending instruction to send the monitoring data corresponding to the monitoring station.

[0097] According to the application, the power line carrier communication device 500 for the ropeway safety monitoring system comprises a communication module 520, and the communication module 520 is specifically used for: In the case that the error flag of the message instruction MSG data sending instruction is detected to be set, the data retransmission is performed by the monitoring station in the fixed communication time slot; If the retransmission number reaches a preset upper limit or the cumulative communication failure number exceeds a threshold value, the system alarm is triggered.

[0098] According to the application, the power line carrier communication device 500 for the ropeway safety monitoring system comprises a communication module 520, and the communication module 520 is specifically used for: The device further comprises a synchronization reset module; The synchronization reset module is used for: After the ropeway safety system is powered on and the carrier network is initially established, the main control station sends a unified reset instruction to all monitoring stations through wireless communication; After the unified reset instruction is received, the local hardware reset operation is synchronously performed by each monitoring station, and the internal parameter zero clearing of the PLC controller corresponding to each monitoring station is triggered; the local hardware reset operation is performed based on the local hardware reset button arranged in each monitoring station, and each local hardware reset button is directly connected with the PLC controller parameter zero clearing input port corresponding to each monitoring station; The time division multiplexing timer is started at the same time by all PLC controllers from the zero clearing state through each monitoring station, so as to establish the unified time base.

[0099] According to the application, the power line carrier communication device 500 for the ropeway safety monitoring system comprises a communication module 520, and the communication module 520 is specifically used for: The carrier distribution access control module is used for: When the ropeway safety system is started, the physical communication link between the carrier corresponding to each monitoring station and the PLC controller corresponding to each monitoring station is controlled to be in a disconnected state. After the carrier at the master control station completes network initialization, the physical communication links of each monitoring station are closed sequentially at preset time intervals, so that the carriers corresponding to each monitoring station can be connected to the power line carrier network in sequence.

[0100] According to the present invention, a power line carrier communication device 500 for a cableway safety monitoring system is provided, wherein the carrier is distributed and accessed by a control module, specifically used for: Turn off the network cable switches corresponding to all monitoring sites to disconnect all physical links.

[0101] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other through the communication bus 640. The processor 610 can call logic instructions in the memory 630 to execute a power line carrier communication method for a cableway safety monitoring system. The cableway safety system includes multiple monitoring stations, each monitoring station including a programmable logic controller (PLC) corresponding to the monitoring station and a carrier wave device corresponding to the monitoring station. The method includes: Based on a unified time base, a corresponding fixed communication time slot is allocated to each of the monitoring stations. For any of the monitoring stations, the monitoring station transmits its corresponding monitoring data on the power line channel using the carrier corresponding to the monitoring station within its allocated fixed communication time slot.

[0102] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0103] In another aspect, the present application also provides a computer program product comprising a computer program, which can be stored on a non-transitory computer readable storage medium, and the computer program can be executed by a processor to enable a computer to perform the power line carrier communication method for a ropeway safety monitoring system provided by the above-mentioned methods, the ropeway safety system comprising a plurality of monitoring sites, each of the monitoring sites comprising a programmable logic controller (PLC) corresponding to the monitoring site and a carrier corresponding to the monitoring site; the method comprising: allocating a fixed communication time slot corresponding to each of the monitoring sites based on a unified time reference; for any of the monitoring sites, transmitting monitoring data corresponding to the monitoring site on a power line channel using the carrier corresponding to the monitoring site within the fixed communication time slot allocated to the monitoring site.

[0104] In yet another aspect, the present application also provides a non-transitory computer readable storage medium having a computer program stored thereon, which can be executed by a processor to implement the power line carrier communication method for a ropeway safety monitoring system provided by the above-mentioned methods, the ropeway safety system comprising a plurality of monitoring sites, each of the monitoring sites comprising a programmable logic controller (PLC) corresponding to the monitoring site and a carrier corresponding to the monitoring site; the method comprising: allocating a fixed communication time slot corresponding to each of the monitoring sites based on a unified time reference; for any of the monitoring sites, transmitting monitoring data corresponding to the monitoring site on a power line channel using the carrier corresponding to the monitoring site within the fixed communication time slot allocated to the monitoring site.

[0105] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., they can be located in one place, or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the present embodiment scheme according to actual needs. Those skilled in the art can understand and implement it without creative labor.

[0106] Those skilled in the art can clearly understand the technical solutions of the various embodiments from the above description of the embodiments, and the various embodiments can be implemented by means of software with the necessary general hardware platforms, and of course, can also be implemented by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part of the prior art that makes a contribution, can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, and the like, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0107] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A power line carrier communication method for a ropeway safety monitoring system, characterized in that, The cableway safety system comprises a plurality of monitoring stations, each of which comprises a programmable logic controller (PLC) corresponding to the monitoring station and a carrier corresponding to the monitoring station; the method comprises: allocating a fixed communication time slot corresponding to each of the monitoring stations based on a unified time reference; for any of the monitoring stations, transmitting monitoring data corresponding to the monitoring station on a power line channel using the carrier corresponding to the monitoring station within the fixed communication time slot allocated to the monitoring station.

2. The power line carrier communication method for a ropeway safety monitoring system according to claim 1, characterized in that, The transmitting of the monitoring data corresponding to the monitoring station on the power line channel using the carrier corresponding to the monitoring station within the fixed communication time slot allocated to the monitoring station by the monitoring station comprises: using a power-on time-out timer (TON) as a master cycle time base; determining, by the monitoring station, whether an accumulated value of the TON is within the fixed communication time slot corresponding to the monitoring station based on a comparison instruction; in the case that the accumulated value of the TON is within the fixed communication time slot, executing, by the monitoring station, a message instruction (MSG) data transmission instruction to transmit the monitoring data corresponding to the monitoring station.

3. The power line carrier communication method for a ropeway safety monitoring system according to claim 2, characterized in that, The method further comprises: in the case that an error flag of the MSG data transmission instruction is detected to be set, retransmitting data by the monitoring station within the fixed communication time slot; if the number of retransmissions reaches a preset upper limit or the number of accumulated communication failures exceeds a threshold, triggering a system alarm.

4. The power line carrier communication method for a ropeway safety monitoring system according to any one of claims 1 to 3, characterized in that, The cableway safety system further comprises a master control station; Before the allocating of the fixed communication time slot corresponding to each of the monitoring stations based on the unified time reference, the method further comprises: after the cableway safety system is powered on and a carrier network is initially established, sending, by the master control station, a unified reset instruction to all the monitoring stations through wireless communication; after receiving the unified reset instruction, synchronously executing, by each of the monitoring stations, a local hardware reset operation to trigger the PLC controller corresponding to each of the monitoring stations to clear internal parameters; the local hardware reset operation is executed based on a local hardware reset button arranged on each of the monitoring stations, and each of the local hardware reset buttons is directly connected to a parameter clearing input port of the PLC controller corresponding to each of the monitoring stations; starting, by each of the monitoring stations, a time-division multiplexing timer simultaneously from a clearing state through all the PLC controllers to establish the unified time reference.

5. The power line carrier communication method for a ropeway safety monitoring system according to any one of claims 1 to 3, characterized in that, Before the allocating of the fixed communication time slot corresponding to each of the monitoring stations based on the unified time reference, the method further comprises: controlling, when the cableway safety system is started, a physical communication link between the carrier corresponding to each of the monitoring stations and the PLC controller corresponding to each of the monitoring stations to be in a disconnected state; after the carrier of the master control station completes network initialization, sequentially closing the physical communication link of each of the monitoring stations at a preset time interval to enable the carrier corresponding to each of the monitoring stations to sequentially access a power line carrier network.

6. The power line carrier communication method for a ropeway safety monitoring system according to claim 5, characterized in that, The controlling of the physical communication link between the carrier corresponding to each of the monitoring stations and the PLC controller corresponding to each of the monitoring stations to be in the disconnected state comprises: All the network switches corresponding to the monitoring sites are in the off state, so that the physical links are in the off state.

7. A power line carrier communication device for a ropeway safety monitoring system, characterized in that The cableway safety system comprises a plurality of monitoring sites, each of which comprises a programmable logic controller (PLC) corresponding to the monitoring site and a carrier corresponding to the monitoring site; the device comprises: a time slot allocation module configured to allocate a fixed communication time slot to each of the monitoring sites based on a unified time reference; a communication module configured to, for any of the monitoring sites, use the carrier corresponding to the monitoring site to transmit monitoring data corresponding to the monitoring site on a power line channel in the fixed communication time slot allocated to the monitoring site.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the power line carrier communication method for the cableway safety monitoring system according to any one of claims 1 to 6. 9.A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the power line carrier communication method for the cableway safety monitoring system according to any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the power line carrier communication method for the cableway safety monitoring system according to any one of claims 1 to 6.

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