Redundant PLC system for controlling special crane and control method

Abstract

The invention discloses a redundant PLC system for controlling a special crane and a control method, and belongs to the technical field of industrial automation control, the redundant PLC system comprises a redundant power supply module, a PLC control module, a redundant communication module, an input and output module, a safety monitoring module and an execution mechanism, the PLC control module comprises a master PLC control unit and a slave PLC control unit, through the arrangement of the slave PLC control unit, the risk of single-point failure in the use process of the crane is reduced, when the master PLC control unit breaks down, the control right is taken over in time, so that the continuous and stable operation of the crane is ensured, the PLC system is used as a standby system, the system architecture, the control strategy, the operation complexity and the application field are the same, and the control cost is reduced. The reaction time can be effectively shortened, so that the downtime of the crane is reduced, after the standby system is started, the operation logic is not changed, and an operator can control the crane to work and monitor the working state of the crane easily.

Description

Technical Field

[0001] This invention belongs to the field of industrial automation control technology, specifically relating to a redundant PLC system and control method for controlling a special crane. Background Technology

[0002] Programmable Logic Controllers (PLCs) are the core of industrial automation control systems, and their reliability and stability are crucial for the control and safety early warning of bridge crane equipment. To achieve uninterrupted and risk-free operation, the control system (especially the core PLC) must possess redundancy capabilities. Currently, mainstream solutions for achieving redundant control in the industry have the following significant drawbacks: 1. Replace PLC with DCS system: Although distributed control system (DCS) is mature in process industry, its architecture, control logic, programming method and operation concept are fundamentally different from PLC system which is oriented towards discrete control. Specifically, there are significant differences in system architecture, control strategy, operation complexity and application fields.

[0003] 2. A dual-CPU hot standby architecture is adopted, where the primary CPU and the backup CPU run simultaneously. The primary CPU is responsible for control tasks, while the backup CPU monitors the primary CPU's status in real time. When the primary CPU fails, the backup CPU takes over control. However, this architecture has disadvantages such as long switchover time, resource waste (the backup CPU is idle under normal circumstances), high cost, and poor autonomy and controllability. Summary of the Invention

[0004] To address some or all of the technical problems existing in the prior art, the present invention provides a redundant PLC system for controlling a special crane, comprising: Redundant power supply modules provide redundant power inputs to the PLC system, ensuring the continuity of power supply to the PLC system; The PLC control module is used to generate control commands. The PLC control module includes a master PLC control unit and a slave PLC control unit. The master PLC control unit and the slave PLC control unit are configured identically and use a common switch and open communication protocol. The PLC control module implements redundancy functions based on running control programs. A redundant communication module is provided, which adopts a ring topology network based on industrial Ethernet. The redundant communication module is communicatively connected to the main PLC control unit, the slave PLC control unit, and the network switch. The network switch is communicatively connected to the host computer. An input / output module, which is connected to the redundant communication module and the PLC control module, is used to transmit control commands generated by the PLC control module. The safety monitoring module is used to detect the crane's operating environment and mechanical status in real time. When an abnormality occurs, it triggers a safety protection mechanism, which includes emergency braking and audible and visual alarms. An actuator is used to control the operation of a mechanical structure based on control commands.

[0005] Furthermore, the operation control program includes: The PLC monitoring program is used to monitor the operating status and communication link status of the main PLC control unit and the slave PLC control unit. The master-slave switching procedure transfers control when a fault is detected in the operating status or communication link status of either the master PLC control unit or the slave PLC control unit.

[0006] Furthermore, the PLC monitoring program includes: The health monitoring program is used to monitor the operating status of the main PLC control unit and the slave PLC control unit. The heartbeat monitoring program is used to detect the communication link status between the PLC control module and the redundant communication module. The fault detection program is used to identify, classify, and locate the fault type, severity level, and root cause of the fault in the PLC control module.

[0007] Furthermore, the redundant power supply module includes: The UPS device is connected to an external power source and is equipped with a battery output terminal and a power output terminal. The power status judgment unit is used to determine the working device of the external power supply. When the external power supply is working normally, the power output terminal is used as the power source of the PLC system. When the external power supply is working abnormally, the battery output terminal is used as the power source of the PLC system.

[0008] In another aspect of the present invention, a redundant PLC system control method for controlling a special crane is provided, comprising the following steps: Initialization and configuration: When starting work, the main PLC control unit first performs self-test and initialization, and then establishes a connection with the slave PLC control unit through the redundant communication module to complete data synchronization and configuration; Redundant monitoring: During system operation, the main PLC control unit and the slave PLC control unit continuously monitor each other's operating status and communication link status. When any of the operating status or communication link status fails, the transfer of control is immediately triggered. Fault switching: When a fault is detected in the main PLC control unit, the slave PLC control unit automatically takes over control. When a fault is detected in the slave PLC control unit, the main PLC control unit automatically takes over control to ensure that the lifting operation is not interrupted, and at the same time, the fault information is recorded. Operation control: Based on the preset control logic and operation requirements, the PLC control module sends control commands to the actuator through the input / output module to complete the lifting operation; Safety monitoring: The safety monitoring module monitors the crane's operating environment and mechanical status in real time, and immediately triggers the safety protection mechanism when an abnormality occurs.

[0009] Furthermore, the security monitoring steps include: Fault identification: After the safety monitoring module detects an abnormality in the crane's operating environment or mechanical condition, it identifies the fault type, classifies the severity level of the fault, locates the root cause of the fault, and generates a fault log record. Once the alarm type is determined, the type of safety protection mechanism is determined based on the severity level of the fault. If the severity level of the fault is emergency, the external power supply is cut off for emergency braking; if the severity level of the fault is warning, an audible and visual alarm is triggered.

[0010] The redundant PLC system and control method for controlling special cranes of the present invention have the following advantages and beneficial effects: By configuring the PLC control unit, the risk of single-point failure during crane operation is reduced. When the main PLC control unit fails, it can promptly take over control, thereby ensuring the continuous and stable operation of the crane. Furthermore, using the PLC system as a backup system ensures that the system architecture, control strategy, operational complexity, and application areas are identical. On the one hand, it can effectively shorten the response time, thereby reducing the crane's downtime. On the other hand, after the backup system is started, the operating logic remains unchanged, making it easy for operators to control the crane's operation and monitor its working status. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the redundant PLC system for controlling a special crane according to the present invention; Figure 2 This is a schematic diagram of the hardware architecture of the redundant PLC system for controlling a special crane according to the present invention. Figure 3 This is a schematic diagram of the working logic of the redundant power supply module of the redundant PLC system for controlling a special crane according to the present invention. Figure 4 This is a schematic diagram of the safety monitoring steps of the redundant PLC system control method for controlling a special crane according to the present invention. Detailed Implementation

[0012] 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 in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. 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.

[0013] like Figure 1-4 As shown, the redundant PLC system for controlling a special crane provided by the present invention includes: Redundant power supply modules provide redundant power inputs to the PLC system, ensuring the continuity of power supply to the PLC system; The PLC control module is used to generate control commands. The PLC control module includes a master PLC control unit and a slave PLC control unit. The master PLC control unit and the slave PLC control unit are configured identically and use a common switch and open communication protocol. The PLC control module implements redundancy functions based on running control programs. A redundant communication module is provided, which adopts a ring topology network based on industrial Ethernet. The redundant communication module is communicatively connected to the main PLC control unit, the slave PLC control unit, and the network switch. The network switch is communicatively connected to the host computer. By adopting a ring topology network structure and connecting both the master PLC control unit and the slave PLC control unit to the ring topology network, data can be transmitted in the other direction if communication is interrupted at a certain point in the ring topology network, thus ensuring uninterrupted communication and improving the reliability of the communication network.

[0014] An input / output module, which is connected to the redundant communication module and the PLC control module, is used to transmit control commands generated by the PLC control module. The safety monitoring module is used to detect the crane's operating environment and mechanical status in real time. When an abnormality occurs, it triggers a safety protection mechanism, which includes emergency braking and audible and visual alarms. An actuator is used to control the operation of a mechanical structure based on control commands.

[0015] By configuring the PLC control unit, the risk of single-point failure during crane operation is reduced. When the main PLC control unit fails, it can promptly take over control, thereby ensuring the continuous and stable operation of the crane. Furthermore, using the PLC system as a backup system ensures that the system architecture, control strategy, operational complexity, and application areas are identical. On the one hand, it can effectively shorten the response time, thereby reducing the crane's downtime. On the other hand, after the backup system is started, the operating logic remains unchanged, making it easy for operators to control the crane's operation and monitor its working status.

[0016] The modular design facilitates subsequent maintenance and component replacement.

[0017] Furthermore, the operation control program includes: The PLC monitoring program is used to monitor the operating status and communication link status of the main PLC control unit and the slave PLC control unit. The master-slave switching procedure transfers control when a fault is detected in the operating status or communication link status of either the master PLC control unit or the slave PLC control unit.

[0018] Furthermore, the PLC monitoring program includes: The health monitoring program is used to monitor the operating status of the main PLC control unit and the slave PLC control unit. The heartbeat monitoring program is used to detect the communication link status between the PLC control module and the redundant communication module. The fault detection program is used to identify, classify, and locate the fault type, severity level, and root cause of the fault in the PLC control module.

[0019] The diversified monitoring configuration, including health checks, heart rate monitoring, and fault detection, meets the safety configuration requirements of the crane and ensures the safe use of the crane.

[0020] Furthermore, the redundant power supply module includes: The UPS device is connected to an external power source and is equipped with a battery output terminal and a power output terminal. The power status judgment unit is used to determine the working device of the external power supply. When the external power supply is working normally, the power output terminal is used as the power source of the PLC system. When the external power supply is working abnormally, the battery output terminal is used as the power source of the PLC system.

[0021] The present invention provides a redundant PLC system control method for controlling a special crane, comprising the following steps: Initialization and configuration: When starting work, the main PLC control unit first performs self-test and initialization, and then establishes a connection with the slave PLC control unit through the redundant communication module to complete data synchronization and configuration; Redundant monitoring: During system operation, the main PLC control unit and the slave PLC control unit continuously monitor each other's operating status and communication link status. When any of the operating status or communication link status fails, the transfer of control is immediately triggered. Fault switching: When a fault is detected in the main PLC control unit, the slave PLC control unit automatically takes over control. When a fault is detected in the slave PLC control unit, the main PLC control unit automatically takes over control to ensure that the lifting operation is not interrupted, and at the same time, the fault information is recorded. Operation control: Based on the preset control logic and operation requirements, the PLC control module sends control commands to the actuator through the input / output module to complete the lifting operation; Safety monitoring: The safety monitoring module monitors the crane's operating environment and mechanical status in real time, and immediately triggers the safety protection mechanism when an abnormality occurs.

[0022] Furthermore, the security monitoring steps include: Fault identification: After the safety monitoring module detects an abnormality in the crane's operating environment or mechanical condition, it identifies the fault type, classifies the severity level of the fault, locates the root cause of the fault, and generates a fault log record. Once the alarm type is determined, the type of safety protection mechanism is determined based on the severity level of the fault. If the severity level of the fault is emergency, the external power supply is cut off for emergency braking; if the severity level of the fault is warning, an audible and visual alarm is triggered.

[0023] By continuously checking the status of the main PLC control unit and the slave PLC control unit during operation, if one of them fails, the line-of-sight control can be quickly and automatically transferred, ensuring that the lifting operation process is uninterrupted and unpaused, which greatly improves the continuous operation time and overall availability of the system.

[0024] By constructing a severity level for faults and then triggering differentiated safety protection mechanisms based on the severity level, the system can provide both rapid and decisive rigid protection (emergency braking) for major hazards and warning-friendly flexible alerts (audible and visual alarms) for general anomalies. This avoids the excessive downtime or insufficient warnings that may result from the inability to timely assess the severity of faults in a single response mode, significantly improving the safety level and operational efficiency of lifting operations. By recording fault logs, it is convenient to conduct predictive maintenance on potential fault areas during maintenance, thereby reducing long-term maintenance costs and system risks.

[0025] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A redundant PLC system for controlling a special crane, characterized in that, include: Redundant power supply modules provide redundant power inputs to the PLC system, ensuring the continuity of power supply to the PLC system; The PLC control module is used to generate control commands. The PLC control module includes a master PLC control unit and a slave PLC control unit. The master PLC control unit and the slave PLC control unit are configured identically and use a common switch and open communication protocol. The PLC control module implements redundancy functions based on running control programs. A redundant communication module is provided, which adopts a ring topology network based on industrial Ethernet. The redundant communication module is communicatively connected to the main PLC control unit, the slave PLC control unit, and the network switch. The network switch is communicatively connected to the host computer. An input / output module, which is connected to the redundant communication module and the PLC control module, is used to transmit control commands generated by the PLC control module. The safety monitoring module is used to detect the crane's operating environment and mechanical status in real time. When an abnormality occurs, it triggers a safety protection mechanism, which includes emergency braking and audible and visual alarms. An actuator is used to control the operation of a mechanical structure based on control commands.

2. The redundant PLC system for controlling a special crane according to claim 1, characterized in that, The operation control program includes: The PLC monitoring program is used to monitor the operating status and communication link status of the main PLC control unit and the slave PLC control unit. The master-slave switching procedure transfers control when a fault is detected in the operating status or communication link status of either the master PLC control unit or the slave PLC control unit.

3. The redundant PLC system for controlling a special crane according to claim 2, characterized in that, The PLC monitoring program includes: The health monitoring program is used to monitor the operating status of the main PLC control unit and the slave PLC control unit. The heartbeat monitoring program is used to detect the communication link status between the PLC control module and the redundant communication module. The fault detection program is used to identify, classify, and locate the fault type, severity level, and root cause of the fault in the PLC control module.

4. The redundant PLC system for controlling a special crane according to claim 1, characterized in that, The redundant power supply module includes: The UPS device is connected to an external power source and is equipped with a battery output terminal and a power output terminal. The power status judgment unit is used to determine the working device of the external power supply. When the external power supply is working normally, the power output terminal is used as the power source of the PLC system. When the external power supply is working abnormally, the battery output terminal is used as the power source of the PLC system.

5. A method for controlling a redundant PLC system for a special crane, implemented using any one of claims 1 to 4, characterized in that, Includes the following steps: Initialization and configuration: When starting work, the main PLC control unit first performs self-test and initialization, and then establishes a connection with the slave PLC control unit through the redundant communication module to complete data synchronization and configuration; Redundant monitoring: During system operation, the main PLC control unit and the slave PLC control unit continuously monitor each other's operating status and communication link status. When any of the operating status or communication link status fails, the transfer of control is immediately triggered. Fault switching: When a fault is detected in the main PLC control unit, the slave PLC control unit automatically takes over control. When a fault is detected in the slave PLC control unit, the main PLC control unit automatically takes over control to ensure that the lifting operation is not interrupted, and at the same time, the fault information is recorded. Operation control: Based on the preset control logic and operation requirements, the PLC control module sends control commands to the actuator through the input / output module to complete the lifting operation; Safety monitoring: The safety monitoring module monitors the crane's operating environment and mechanical status in real time, and immediately triggers the safety protection mechanism when an abnormality occurs.

6. The control method for a redundant PLC system for controlling a special crane according to claim 5, characterized in that, Security monitoring steps include: Fault identification: After the safety monitoring module detects an abnormality in the crane's operating environment or mechanical condition, it identifies the fault type, classifies the severity level of the fault, locates the root cause of the fault, and generates a fault log record. Once the alarm type is determined, the type of safety protection mechanism is determined based on the severity level of the fault. If the severity level of the fault is emergency, the external power supply is cut off for emergency braking; if the severity level of the fault is warning, an audible and visual alarm is triggered.

Images