Electric control system and method for belt elevator of gantry crane

Abstract

The invention discloses an electric control system and method for a belt elevator of a gantry crane, and belongs to the technical field of control over the belt elevator of the gantry crane. The electric control system of the belt elevator of the gantry crane comprises the belt elevator, an operation input unit, a PLC (Programmable Logic Controller) control unit, a safety monitoring unit, an execution indication unit and a variable frequency driving unit. The invention provides an electric control system and method for a belt elevator of a gantry crane, which are high in integration level, intelligent and reliable, can cooperate with the gantry crane to work, can realize full-automatic, continuous and efficient conveying of materials from the gantry crane to a storage yard, fundamentally replaces vehicle transfer, and improves the working efficiency. The system has complete safety protection and intelligent fault diagnosis functions, and aims to improve the operation efficiency, reduce the operation cost and realize green and environment-friendly wharf operation.

Description

An electrical control system and method for a belt hoist of a gantry crane Technical Field

[0001] This invention relates to an electrical control system and method for a belt hoist of a gantry crane, belonging to the field of belt hoist control technology for gantry cranes. Background Technology

[0002] Gantry cranes are the main crane equipment used for loading and unloading bulk cargo and general cargo at bulk cargo terminals. In the traditional bulk cargo terminal loading and unloading process, after the gantry crane grabs the material, it usually relies on dump trucks (tipping trucks) to transfer it to the storage yard. However, this method has the following significant drawbacks: 1. Serious environmental pollution: During transportation, material spillage and vehicle exhaust emissions lead to dust and air pollution in the terminal area. On sunny days, it is dusty, and on rainy days, it is muddy, which seriously does not meet the increasingly stringent environmental protection policy requirements.

[0003] 2. High operating costs: The overall costs of vehicle purchase, fuel consumption, daily maintenance, driver manpower and vehicle dispatch management are extremely high, and the lifespan of vehicles is limited, resulting in poor long-term operating economy.

[0004] 3. Low operational efficiency: The loading and unloading process is not continuous and relies on vehicle turnover. Frequent occurrences of vehicle queues, empty runs, and waiting for loading severely restrict the overall throughput capacity and operational efficiency of the terminal.

[0005] 4. Heavy safety and management burden: Dense traffic flow at the dock increases the risk of traffic accidents. At the same time, road cleaning and maintenance, traffic order management, and vehicle coordination place a heavy management burden on the area.

[0006] To address these issues, existing technologies typically employ belt hoists for continuous conveying. However, integrating a highly efficient and reliable electrical control system for a belt hoist onto a mobile, multi-degree-of-freedom gantry crane presents technical challenges in areas such as control coordination, safety interlocking, precise speed regulation, and intelligent fault diagnosis. Existing technologies lack a mature, complete, and intelligent electrical control solution. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an electrical control system and method for a belt hoist of a gantry crane. The system is highly integrated, intelligent and reliable, and can work in conjunction with the gantry crane. It can realize fully automatic, continuous and efficient material transportation from the gantry crane to the yard, fundamentally replacing vehicle transfer. It has complete safety protection and intelligent fault diagnosis functions, aiming to improve operational efficiency, reduce operating costs and achieve green and environmentally friendly port operations.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: The present invention provides an electrical control system for a belt hoist of a gantry crane, including a belt hoist, an operation input unit, a PLC control unit, a safety monitoring unit, an execution instruction unit, and a frequency converter drive unit; the operation input unit is used to receive operation commands from the operator; the PLC control unit is used to process the operation commands and the switching signals of the belt hoist and output control commands; the execution instruction unit is used to control the start-up, stop, braking, and heat dissipation operations of the belt hoist according to the control commands of the PLC control unit, and to display the status information of the belt hoist; the frequency converter drive unit is used to drive the belt hoist to run according to the control commands of the PLC control unit; the safety monitoring unit is used to monitor the operating status of the belt hoist in real time and perform fault diagnosis.

[0009] Furthermore, the belt elevator includes a belt, a belt motor, a motor brake, and a fan. The belt motor drives the belt to run, the motor brake mechanically brakes the belt motor, and the fan cools the belt motor.

[0010] Furthermore, the execution indication unit includes a contactor group, an intermediate relay group, an audible and visual alarm, and a status indicator panel. The contactor group is used to control the on / off of the main circuit and auxiliary circuit of the belt hoist's electrical control system. The intermediate relay group is used for logic expansion and signal conversion. The audible and visual alarm is used to provide audible and visual alarms when the belt hoist malfunctions. The status indicator panel is used to display the operating status and fault type.

[0011] Furthermore, the contactor group includes: a main contactor for controlling the on / off state of the power supply to the belt hoist; a belt motor main circuit contactor for controlling the on / off state of the power supply to the frequency converter drive unit; a brake contactor for controlling the holding and releasing of the motor brake; and a fan contactor for controlling the opening and closing of the fan. The intermediate relay group includes: a first relay and a second relay for switching between manual and remote control operation of the belt hoist; a third relay, a fourth relay, and a fifth relay, where the third relay is an output relay for frequency converter drive unit faults, the fourth relay is a running relay, and the fifth relay is a relay for opening the motor brake; a sixth relay and a seventh relay, where the sixth relay controls the forward rotation of the belt, and the seventh relay controls the reverse rotation of the belt; and an eighth relay and a ninth relay for controlling the belt speed.

[0012] Another aspect of the present invention provides a control method for the electrical control system of a belt hoist of a gantry crane, comprising the following steps: Step S1: Power on the system, perform safety interlock and enable judgment, and if the system meets the safety conditions, the system enters the ready state; Step S2: Wait for and identify the operator's operation instructions; Step S3: Perform pre-judgment of start conditions, and after all start conditions meet the requirements, run the belt hoist according to the preset timing sequence; Step S4: During the operation of the belt hoist, perform belt speed control and belt hoist fault detection in parallel; Step S5: When a normal stop command is received or a fault stop is triggered, execute the intelligent braking timing control process to safely stop the belt hoist.

[0013] Furthermore, in step S1, a safety interlock and enable judgment are performed. If the system meets the safety conditions, the system enters the ready state. Specifically, this includes the following steps: The PLC control unit cyclically detects all hardware safety signals of the system. When all hardware safety signals meet the safety conditions, the system enable flag is set, and the system enters the ready state. At any time, if any safety condition is not met, the system enable flag is reset, and the system enters the safety prohibition state.

[0014] Furthermore, in step S2, waiting for and recognizing the operator's operation instructions specifically includes the following steps: determining whether the current operation is a local operation or a remote operation based on the switch signal of the operation input unit; if it is a local operation, the operation panel of the local operation box is activated; if it is a remote operation, the remote control is activated; recognizing the working mode selected by the operator, the working mode includes belt mode and loading mode.

[0015] Furthermore, in step S3, a pre-judgment of the start-up conditions is performed. After all the start-up conditions are met, the belt hoist is operated according to a preset timing sequence. Specifically, this includes the following steps: After receiving the start-up operation command, a pre-judgment of the start-up conditions is performed to comprehensively check whether the operating conditions of the belt hoist meet the requirements. After all the operating conditions are met, the belt hoist is controlled to operate according to the following preset timing sequence: First, the main contactor is closed, then the main circuit contactor of the belt motor is closed to energize the frequency converter drive unit. After a delay, a signal is output to open the brake contactor, and finally, the operation and speed command is sent to the frequency converter drive unit.

[0016] Furthermore, in step S4, the fault detection of the belt elevator specifically includes the following steps: classifying the fault level of the belt elevator into a warning level and a fault level; when the fault level is a warning level, triggering an audible and visual alarm, at which time the belt elevator can continue to operate; when the fault level is a fault level, triggering a fault shutdown of the belt elevator and locking the fault status.

[0017] Furthermore, in step S5, the intelligent braking timing control process is executed, which specifically includes the following steps: first, a stop command is sent to the frequency converter drive unit, and the frequency converter drive unit reduces the speed of the belt motor to zero according to the preset deceleration time; when the speed of the belt motor is close to zero, the output signal controls the brake contactor to engage the motor brake, and then the main contactor is disconnected.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects: 1. The present invention organically combines the gantry crane grab bucket and belt conveyor through the electronic control system to form a continuous operation flow, completely replacing vehicle transportation, eliminating dust and exhaust pollution from the source, and realizing continuous transportation and environmental protection innovation.

[0019] 2. This invention uses a crane-specific frequency converter and a PLC control unit for coordinated control to achieve motor vector drive and intelligent braking management, ensuring smooth start-stop, precise speed, extended equipment life, and accurate control and stable operation.

[0020] 3. This invention integrates multiple protections such as hardware emergency stop, mechanical detection and software interlock, to build a deep security system, significantly improve system reliability, and provide comprehensive and reliable security protection.

[0021] 4. This invention centrally implements control and diagnostic logic through a PLC control unit, enabling online monitoring and rapid fault location in case of failure, significantly reducing maintenance difficulty and time costs, and making diagnosis intelligent and maintenance convenient.

[0022] 5. This invention supports local and remote operation, has multi-speed adjustment function, adapts to different working conditions, and the frequency conversion drive has significant energy-saving effect, making it flexible, energy-efficient and efficient in operation.

[0023] 6. The electrical control system of the present invention adopts a modular design, with a programmable logic controller (PLC) as the control core and a crane-specific frequency converter as the drive unit. Combined with comprehensive signal monitoring and a perfect human-machine interface, it forms a complete closed-loop control system. Attached Figure Description

[0024] Figure 1 is a schematic block diagram of the belt hoist electrical control system of the gantry crane of the present invention; Figure 2 is a schematic diagram of the main circuit electrical principle of the belt hoist electrical control system of the gantry crane of the present invention; Figure 3 is a wiring diagram of the control circuit of the frequency converter drive unit of the present invention; Figure 4 is a schematic diagram of the switching principle of manual / remote belt start of the present invention; Figure 5 is a schematic diagram of the belt speed control principle of the present invention; Figure 6 is a schematic diagram of the belt speed selection principle of the present invention; Figure 7 is a flowchart of the control method of the belt hoist electrical control system of the gantry crane of the present invention. Detailed Implementation

[0025] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] As shown in Figure 1, this embodiment provides an electrical control system for a belt hoist of a gantry crane, including a belt hoist, an operation input unit, a PLC control unit, a safety monitoring unit, an execution instruction unit, and a frequency converter drive unit.

[0027] The operation input unit is the human-machine interface of the system, used to receive operation instructions from the operator.

[0028] The PLC control unit is the logic and decision-making core of the system, used to process operation commands and switch signals of the belt hoist and output control commands.

[0029] The execution instruction unit is the system's actuator and status display. It is used to control the start-up, stop, braking, and heat dissipation operations of the belt hoist according to the control instructions of the PLC control unit, and to display the status information of the belt hoist.

[0030] The variable frequency drive unit is the core of the system's power, used to drive the belt hoist according to the control instructions of the PLC control unit.

[0031] The safety monitoring unit is the system's sensory network, used to monitor the operating status of the belt hoist in real time and perform fault diagnosis.

[0032] The belt elevator of this embodiment includes a belt, a belt motor, a motor brake, and a fan. The belt motor is used to drive the belt to run, the motor brake is used to mechanically brake the belt motor, and the fan is used to cool the belt motor.

[0033] The working principle of the main circuit of the system in this embodiment is as follows: As shown in Figure 2, the power supply of the belt hoist is first supplied to the main contactor 7KM1 by switch 1Q1, and then introduced by switch 2Q1. After passing through the belt motor main circuit contactor 8KM2, fuse 2F1, and incoming line reactor 2L1, it is finally supplied to the frequency conversion drive unit. The frequency conversion drive unit then controls the rotation direction and speed of the belt motor.

[0034] The variable frequency drive unit in this embodiment, as shown in Figure 3, uses the Huichuan CS710 series crane-specific frequency converter, specifically model CS710-4T75GB. This unit receives start / stop, direction, and multi-speed digital commands from the PLC. Internally, it employs a vector control algorithm to drive a 55kW asynchronous motor, achieving stepless smooth speed regulation and forward / reverse operation of the belt conveyor. The unit incorporates professional crane braking timing control logic, which, in conjunction with an external 25kW braking resistor, ensures that the belt motor can quickly consume regenerative energy during deceleration and stopping, maintaining stable DC bus voltage, achieving smooth start / stop, and preventing load impact and slippage during shutdown. Its operating status and fault signals are fed back to the PLC control unit via relay output contacts.

[0035] The operation input unit in this embodiment includes a local operation box (containing an emergency stop button, mode selection switch, speed gear knob, etc.), a wireless remote control receiver, and its interface relay. The working principle is as follows: the operator issues commands such as "start," "stop," "mode selection," and "speed selection" via buttons and switches on the local operation box, or sends commands via the wireless remote control. These command signals, in DC 24V level form, are directly connected to the input module of the PLC control unit via cable, serving as the basis for PLC program judgment, as shown in Figure 4, realizing the switching between local / remote control mode and belt / loading mode.

[0036] The safety monitoring unit in this embodiment includes pull-rope emergency stop switches, belt misalignment detection sensors (light / heavy), overload signal contacts for each motor thermal relay, auxiliary normally open / normally closed contacts for all power contactors (such as main contactor 7KM1, belt contactor 8KM2, etc.), status contacts for the belt hoist power supply and branch circuit breakers, and sensors for the trolley anchoring limit and the material drop pipe mechanical locking. The working principle is as follows: This unit constitutes the system's hardware safety network. The status signals (on or off) of all safety monitoring devices are input to the PLC control unit's input module in the form of switch signals. The PLC program scans these signals in real time. Any abnormality (such as emergency stop activation, excessive misalignment, motor overload, contactor failure) will immediately trigger the corresponding interlocking protection logic, prohibiting equipment startup or causing an emergency stop during operation, and triggering an alarm through the indicator unit.

[0037] The execution indication unit of this embodiment includes a contactor group, an intermediate relay group, an audible and visual alarm, and a status indicator panel. The contactor group is used to control the on / off of the main circuit and auxiliary circuit of the belt hoist's electrical control system. The intermediate relay group is used for logic expansion and signal conversion. The audible and visual alarm is used to provide audible and visual alarms when the belt hoist malfunctions. The status indicator panel is used to display the operating status and fault type.

[0038] As shown in Figure 2, the contactor group in this embodiment includes a main contactor 7KM1, which is used to control the on / off state of the power supply for the belt hoist.

[0039] The 8KM2 main circuit contactor for the belt motor is used to control the power supply to the frequency converter drive unit.

[0040] Brake contactor 8KM3 is used to control the holding and releasing of the motor brake.

[0041] The 8KM4 fan contactor is used to control the opening and closing of the fan.

[0042] As shown in Figures 3, 4, and 5, the intermediate relay group in this embodiment includes a first relay 11KA8 and a second relay 11KA9. The first relay 11KA8 and the second relay 11KA9 are used to switch between manual and remote control operation of the belt hoist. The switching between manual and remote control operation is controlled by the normally open contacts of relays 11KA8 and 11KA9, and the operation of these two relays is controlled by a two-position selector switch 11SA1.

[0043] The third relay 2KA1, the fourth relay 2KA2, and the fifth relay 2KA3 are used as relays. The third relay 2KA1 is the output relay for the frequency converter drive unit failure, the fourth relay 2KA2 is the running relay, and the fifth relay 2KA3 is the motor brake opening relay. The running relay refers to the intermediate relay when the equipment is running. It is activated under the control of the PLC and is used to send electrical signals to the external circuit.

[0044] The sixth relay 12KA3 and the seventh relay 12KA4 are used to control the forward rotation of the belt and the seventh relay 12KA4 is used to control the reverse rotation of the belt.

[0045] The eighth relay 12KA6 and the ninth relay 12KA7 are used to control the belt speed.

[0046] Example 2, as shown in Figure 7, provides a control method for the electrical control system of a belt hoist of a gantry crane as described in Example 1, including the following steps: Step S1: Power on the system and perform safety interlock and enable judgment. If the system meets the safety conditions, the system enters the ready state. Specifically, after the system is powered on, the PLC control unit cyclically detects all hardware safety signals of the system. When all hardware safety signals meet the safety conditions, such as the belt hoist power supply being switched on, no emergency stop, no mechanical locking, no anchoring, etc., the system enable flag is set, and the system enters the ready state. At any time, if any safety condition is not met, the flag is immediately reset, and the system enters the safety prohibition state.

[0047] Step S2: Wait for and identify the operator's operation instructions. Specifically, based on the switch signal of the operation input unit, determine whether the current operation is a local operation or a remote control operation. The specific process is as follows: The operator turns the selector switch to change the on / off state of the PLC input point, then the PLC program reads the input point state, sets the "local / remote" flag bit internally, and the PLC selects to execute the subsequent control instructions corresponding to the "local operation box" or "remote control" according to the flag bit.

[0048] If it is a local operation, the control panel of the local control box will be active; if it is a remote control operation, the remote control will be active.

[0049] The system identifies the operator's selected operating mode, which includes belt conveyor mode and loading mode. In belt conveyor mode, materials are stacked, meaning they are fed to the stockyard, and the belt operates at a relatively high speed. In loading mode, materials are unloaded or loaded onto trucks, and the belt operates at a slower speed, requiring control of the material drop pipe's positioning.

[0050] Step S3: Perform a pre-judgment of the start-up conditions. After all start-up conditions are met, the belt hoist will run according to the preset timing sequence. Specifically, after receiving the start-up operation command, the program does not output immediately, but first performs a pre-judgment of the start-up conditions. It comprehensively checks dozens of signals such as the rope emergency stop switch, belt misalignment, motor brake status, frequency converter drive unit status, and belt motor thermal protection. After all operating conditions are met (e.g., the rope emergency stop switch is not triggered, the belt is not misaligned, and the motor brake is working normally), the program will act in sequence according to strict timing control: first, close the main contactor 7KM1, then close the belt motor main circuit contactor 8KM2 to energize the frequency converter drive unit. After a delay (e.g., 500ms) to ensure that the frequency converter drive unit is ready, the program will output a signal to open the brake contactor 8KM3, and finally issue the running and speed command to the frequency converter drive unit.

[0051] This timing ensures that the motor releases the mechanical brake only after it has built up sufficient torque, achieving true "zero-speed braking and start-up," completely avoiding starting jitter and shock.

[0052] Step S4: During the operation of the belt elevator, belt speed control and belt elevator fault detection are performed in parallel. Specifically: Belt speed control: As shown in Figure 6, the gear code of the speed selection knob 13SA1 is read, and through decoding logic, the corresponding multi-speed control signal is output to the frequency converter drive unit (for example, the seventh relay 12KA6 and the eighth relay 12KA7 are controlled by the multi-speed control signal to perform precise selection of high, medium and low speeds.

[0053] Belt elevator fault detection: The fault levels of the belt elevator are divided into warning level and fault level. When the fault level is warning level (e.g., slight belt misalignment), the program sets the internal alarm flag and triggers the audible and visual alarm. At this time, the belt elevator can continue to run, prompting maintenance personnel to pay attention. When the fault level is fault level (e.g., heavy belt misalignment, abnormal status of the pull rope emergency stop switch, frequency converter drive unit failure, contactor feedback abnormality, etc.), the program immediately sets the fault flag, triggers fault shutdown, and locks the fault status.

[0054] Fault Indication and Location: Each fault signal corresponds to a specific indicator light. For example, the first indicator light corresponds to the belt misalignment indicator, the second indicator light corresponds to the pull rope fault indicator, and the third indicator light corresponds to the strain gauge fault indicator. When a fault occurs, the corresponding indicator light illuminates, allowing operators to quickly locate the fault type. Maintenance personnel can also connect to a programming computer to monitor the PLC program online and directly view which input point is abnormal, achieving rapid location from fault symptoms to specific fault points, greatly shortening troubleshooting time. After maintenance personnel have investigated and eliminated the fault, the system resets and returns to step S1.

[0055] Step S5: Upon receiving a normal shutdown command or triggering a fault shutdown, execute the intelligent braking timing control process to safely stop the belt hoist. Specifically, regardless of whether it is a normal shutdown or a fault shutdown, the program executes intelligent braking timing control: First, a shutdown command is sent to the frequency converter drive unit, which smoothly reduces the belt motor speed to zero according to the preset deceleration time; when the belt motor speed is close to zero, the program outputs a signal to control the brake contactor 8KM3 to engage the motor brake; after a short delay to ensure that the mechanical braking is effective, the main contactor 7KM1 is then disconnected. This process prevents inertial slippage caused by sudden power failure.

[0056] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrical control system for a belt hoist of a gantry crane, characterized in that: The system includes a belt hoist, an operation input unit, a PLC control unit, a safety monitoring unit, an execution instruction unit, and a frequency converter drive unit. The operation input unit receives operator commands. The PLC control unit processes these commands and the belt hoist's switching signals, outputting control commands. The execution instruction unit controls the belt hoist's start, stop, braking, and cooling operations according to the PLC control unit's commands, and displays the belt hoist's status information. The frequency converter drive unit drives the belt hoist according to the PLC control unit's commands. The safety monitoring unit monitors the belt hoist's operating status in real time and performs fault diagnosis. Fault diagnosis; the belt hoist includes a belt, a belt motor, a motor brake, and a fan. The belt motor drives the belt, the motor brake mechanically brakes the belt motor, and the fan cools the belt motor. The execution indication unit includes a contactor group, an intermediate relay group, an audible and visual alarm, and a status indicator panel. The contactor group controls the on / off of the main and auxiliary circuits of the belt hoist's electrical control system. The intermediate relay group performs logic expansion and signal conversion. The audible and visual alarm provides audible and visual alarms when a fault occurs in the belt hoist. The status indicator panel displays the operating status and fault type.

2. The electrical control system for the belt hoist of the gantry crane according to claim 1, characterized in that: The contactor group includes: a main contactor for controlling the on / off state of the power supply to the belt hoist; a belt motor main circuit contactor for controlling the on / off state of the power supply to the frequency converter drive unit; a brake contactor for controlling the holding and releasing of the motor brake; and a fan contactor for controlling the opening and closing of the fan. The intermediate relay group includes: a first relay and a second relay for switching between manual and remote control operation of the belt hoist; a third relay, a fourth relay, and a fifth relay, where the third relay is an output relay for frequency converter drive unit faults, the fourth relay is a running relay, and the fifth relay is a relay for opening the motor brake; a sixth relay and a seventh relay, where the sixth relay controls the forward rotation of the belt, and the seventh relay controls the reverse rotation of the belt; and an eighth relay and a ninth relay for controlling the belt speed.

3. A control method for the electrical control system of the belt hoist of a gantry crane as described in any one of claims 1 to 2, characterized in that, The process includes the following steps: Step S1: Power on the system and perform safety interlock and enable judgment. If the system meets the safety conditions, the system enters the ready state; Step S2: Wait for and identify the operator's operation instructions; Step S3: Perform pre-judgment of start-up conditions. After all start-up conditions are met, the belt elevator runs according to the preset timing sequence; Step S4: During the operation of the belt elevator, belt speed control and belt elevator fault detection are performed in parallel; Step S5: When a normal stop command is received or a fault stop is triggered, the intelligent braking timing control process is executed to safely stop the belt elevator.

4. The control method according to claim 3, characterized in that, In step S1, a safety interlock and enable judgment are performed. If the system meets the safety conditions, the system enters the ready state. Specifically, the following steps are included: The PLC control unit cyclically detects all hardware safety signals of the system. When all hardware safety signals meet the safety conditions, the system enable flag is set and the system enters the ready state. If any safety condition is not met at any time, the system enable flag is reset, and the system enters a safety-prohibited state.

5. The control method according to claim 3, characterized in that, In step S2, waiting for and recognizing the operator's operation instructions specifically includes the following steps: based on the switch signal of the operation input unit, determining whether the current operation is a local operation or a remote operation; if it is a local operation, the operation panel of the local operation box is activated; if it is a remote operation, the remote control is activated. The operator selects a working mode, which includes belt conveyor mode and loading mode.

6. The control method according to claim 3, characterized in that, In step S3, a pre-judgment of the start-up conditions is performed. After all the start-up conditions are met, the belt hoist is operated according to a preset timing sequence. Specifically, the steps are as follows: After receiving the start-up operation command, a pre-judgment of the start-up conditions is performed to comprehensively check whether the operating conditions of the belt hoist meet the requirements. After all the operating conditions are met, the belt hoist is controlled to operate according to the following preset timing sequence: First, the main contactor is closed, then the main circuit contactor of the belt motor is closed to energize the frequency converter drive unit. After a delay, a signal is output to open the brake contactor, and finally, the running and speed command is sent to the frequency converter drive unit.

7. The control method according to claim 3, characterized in that, In step S4, the belt elevator fault detection specifically includes the following steps: classifying the fault level of the belt elevator into a warning level and a fault level; when the fault level is a warning level, triggering an audible and visual alarm, at which time the belt elevator can continue to operate; when the fault level is a fault level, triggering a fault shutdown of the belt elevator and locking the fault status.

8. The control method according to claim 3, characterized in that, In step S5, the intelligent braking timing control process is executed, which specifically includes the following steps: first, a stop command is sent to the frequency converter drive unit, and the frequency converter drive unit reduces the speed of the belt motor to zero according to the preset deceleration time; when the speed of the belt motor is close to zero, the output signal controls the brake contactor to engage the motor brake, and then the main contactor is disconnected.

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