Electromagnetic steel plate hoisting flow control system and method of operating the same

Abstract

The present application relates to the crane technical field, disclose a kind of electromagnetic hoist steel plate flow control system and its operating method, the absolute value encoder (1) of rotation of control system, hoisting absolute value encoder (3), weight sensor (5) are connected with controller (4) by interface module (2), DP fieldbus (6), and communication protocol uses MODBUS RTU protocol;Controller (4) carries out calculation and data transmission is carried out to man-machine interface (7) and is shown and stored, while controlling the operation of rotation absolute value encoder (1), hoisting absolute value encoder (3);Man-machine interface (7) and controller (4) are communicated by Ethernet, the present application system effectively improves the accuracy of weight data acquisition, and only one person is operated, improve work efficiency, reduce the cost caused by inaccurate reading when weight is changed from time to time.

Description

Technical Field

[0001] This invention relates to the field of crane technology, specifically to an electromagnetic steel plate flow control system and its operation method. Background Technology

[0002] With the development of China's shipbuilding industry, the transportation of raw material steel plates plays an indispensable role. Electromagnetic cranes have become an essential means of transporting steel plates in shipyards. In particular, absolute encoders are widely and maturely used in the crane field. Due to their power-off retention capability, absolute encoders are often used as a necessary means of reading position and angle. Furthermore, the development of weighing systems has led to new applications, greatly facilitating management and control for production enterprises. Steel plate flow control systems are increasingly used in shipbuilding and repair companies. Currently, electromagnetic crane steel plate flow control systems rely on manual weight reading, requiring at least three people: a driver, someone to measure and mark the weight of the steel plate, and someone to operate the drive motor system. Because steel plates vary in size and weight, inaccurate readings occur frequently. To reduce the costs associated with manual control, the demand for flow statistics for electromagnetic cranes is increasing.

[0003] Although CN105398933B, a method for lifting steel plates, has been published, it involves cutting off the connection to the power supply by switching on and off, allowing the worker to move the hook to a suitable position on both sides of the steel plate and hook it; a distance sensor detects the distance between the electromagnetic lifting unit and the steel plate being lifted and transmits the detection signal to the control unit. However, this method still cannot improve the overall efficiency of the crane. During the crane's operation, if the rotation area is small, the lifting device sways left and right due to the operator's movements, causing frequent triggering of the mechanical contact switch. This can sometimes result in over-reporting, making it impossible to accurately determine the actual quantity of material. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an electromagnetic steel plate flow control system and its operation method that requires only one operator, accurately collects weight, and improves work efficiency.

[0005] To address the above technical problems, this invention provides an electromagnetic steel plate flow control system, including a controller, a rotary absolute encoder, an interface module, a lifting absolute encoder, a weight sensor, and a human-machine interface. The rotary absolute encoder, lifting absolute encoder, and weight sensor are connected to the controller via the interface module and a DP fieldbus, using the MODBUS RTU protocol for communication. The controller performs calculations and transmits the data to the human-machine interface for display and storage, while simultaneously controlling the operation of the rotary absolute encoder and the lifting absolute encoder. The human-machine interface communicates with the controller via Ethernet.

[0006] By adopting the above technical solution, the entire control system communicates based on DP fieldbus and MODBUS RTU protocol. The controller reads the rotary absolute encoder and the hoisting absolute encoder, and then reads the weight sensor data after the position is stable. This effectively improves the accuracy of weight data acquisition, and only requires one person to operate, which improves work efficiency and reduces the cost caused by inaccurate readings due to the weight changing from time to time when reading manually.

[0007] Preferably, the rotary absolute encoder is installed on the shaft of the pinion in the rotary mechanism of the electromagnetic crane.

[0008] By adopting the above technical solution, the rotary absolute encoder is installed on the pinion of the rotary mechanism. The large gear has a slow speed and a long circumference, while the small gear has a fast speed and a small circumference. In order to obtain a more accurate angle reading, it is installed on the small gear. The faster the small gear is, the more the rotary absolute encoder changes values. Compared with the large gear, the stroke is shorter, and the angle it reads is more accurate.

[0009] Preferably, the lifting absolute encoder is installed on the shaft of the large gear on the side of the lifting winch of the electromagnetic crane.

[0010] By adopting the above technical solution, the lifting absolute encoder is installed on the shaft connected to the large gear, and its speed is the same as that of the large gear. The small gear of the lifting winch is connected to the motor shaft. The small gear rotates faster than the large gear. Because the lifting height does not change quickly, the lifting absolute encoder is installed on the shaft of the large gear and connected coaxially, so that the stroke of the large gear is the same as the actual height change. Many mechanical structural errors can be ignored in the middle, resulting in a more accurate lifting height.

[0011] Preferably, there are two weight sensors, which are respectively installed at the lower ends of the two wire ropes of the electromagnetic crane; two wire ropes are installed on the lifting device of the electromagnetic crane, and weight sensors are installed at the lower ends of the wire ropes, with the lower ends of the weight sensors connected to electromagnetic chucks.

[0012] By adopting the above technical solution, the electromagnetic chuck lifts the steel plate, and two weight sensors read a weight value from each sensor. The weight value is transmitted to the controller for calculation via DP fieldbus, which reduces the situation where the electromagnetic chuck shakes and causes weight fluctuations during weight acquisition, resulting in inaccurate readings.

[0013] An operation method for an electromagnetic steel plate flow control system includes the following steps: 1. The operator starts the system power supply. The controller detects whether the communication status of each substation of the system is normal through the interface module. The lifting absolute encoder and the slewing absolute encoder provide real-time position feedback to the controller due to their holding function.

[0014] 2. Start timing from the moment the driver powers on the start, read the angle of the absolute value encoder of the slewing and the height of the lifting encoder, and comprehensively determine the location of the crane boom on the side of the cabin. 3. When the lifting device reaches the specified lifting height, the weight sensor's curve tends to stabilize. The controller completes one cycle from the first lifting height to the next lifting height, which is counted as one lifting operation. Fourth, the controller subtracts the net weight from the values ​​displayed by the crane sensors in each cycle and converts them into the actual weight lifted by the crane in this cycle. This value is then stored in the controller's storage unit and simultaneously sent to the human-machine interface. Finally, the controller accumulates and calculates the total weight of the steel plate over a period of time. 5. The tonnage calculated by the controller determines whether the alarm threshold has been reached, thereby controlling the operating condition of the rear conveyor belt.

[0015] By adopting the above technical solution, after the lifting absolute encoder and slewing absolute encoder are started, the weight sensor collects the weight at the stable weight position based on the number of lifting operations according to the lifting height gauge, and the readings are more accurate. The position of the lifting device is determined by the angular rotation position of the slewing absolute encoder. There is no need for the cooperation of the driver, the person measuring and marking the weight of the steel plate, and the person driving the absolute encoder. Only one driver is needed to operate it, which improves the work efficiency and reduces personnel costs.

[0016] Preferably, in step three, the weight sensor collects the weight when the spreader is stabilized at the same level as the dock.

[0017] By adopting the above technical solution, a comprehensive comparison of the crane's entire lifting operation at the level of the dock revealed that the crane structure is most stable when it is lifted from the ship on the river side to the level of the dock. At this time, the weight sensor values ​​are stable, the error is small, and the reading accuracy is improved.

[0018] Preferably, in step four, the formula for calculating the actual weight lifted by the crane is as follows: ; a1 and a2 are analog signals transmitted from the weight sensors mounted on both sides of the lifting device, and k is a proportional constant.

[0019] By adopting the above technical solution, the weights of the two weight sensors are compared and their average value is taken, thereby reducing the shaking error.

[0020] Preferably, in step four, the controller subtracts the net weight of the spreader from the weight when the spreader reaches the level position with the pier in each cycle, and then accumulates the weights.

[0021] By adopting the above technical solution, the system calculates the total weight of the steel plate accumulated over a period of time through the controller, avoiding the error in lifting tonnage caused by fluctuations in the steel plate, and more accurately describing the real-time lifting weight.

[0022] Compared with the prior art, the present invention has the following advantages: 1. The entire control system of this invention is based on DP fieldbus and MODBUS RTU protocol communication. The controller reads the rotary absolute encoder and the hoisting absolute encoder. After the position is stable, it reads the weight sensor data, which effectively improves the accuracy of weight data acquisition. Moreover, it only requires one person to operate, which improves the work efficiency and reduces the cost caused by inaccurate readings due to the weight changing from time to time when reading manually.

[0023] 2. The rotary absolute encoder of the present invention is mounted on the small gear of the rotary mechanism. The large gear has a slow rotation speed and a long circumference, while the small gear has a fast rotation speed and a small circumference. In order to obtain a more accurate angle reading, it is mounted on the small gear. The faster the small gear is, the more the rotary absolute encoder changes values. Compared with the large gear, the stroke is shorter, and the angle read is more accurate.

[0024] 3. The lifting absolute encoder of this invention is installed on the shaft connected to the large gear. Its speed is the same as that of the large gear. The small gear of the lifting winch is connected to the motor shaft. The small gear rotates faster than the large gear. Since the lifting height does not change quickly, the lifting absolute encoder is installed on the shaft of the large gear and connected coaxially, so that the stroke of the large gear is the same as the actual height change. Many mechanical errors can be ignored in the middle, resulting in a more accurate lifting height.

[0025] 4. After the lifting absolute encoder and slewing absolute encoder of this invention are started, the weight sensor collects the weight at the stable weight position according to the number of lifting times of the lifting height gauge, and the reading is more accurate. The position of the lifting device is determined by the angular rotation position of the slewing absolute encoder. It does not require the cooperation of the driver, the person measuring and marking the weight of the steel plate, and the person driving the absolute encoder. Only one driver is needed to operate it, which improves the work efficiency and reduces personnel costs. Attached Figure Description

[0026] Figure 1 This is a system distribution diagram of the present invention.

[0027] Figure 2 This is a schematic diagram of the installation of the rotary absolute encoder of the present invention.

[0028] Figure 3 This is a schematic diagram of the installation of the lifting absolute encoder of the present invention.

[0029] Figure 4This is a schematic diagram of the installation of the weight sensor of the present invention.

[0030] In the diagram, 1. Rotary absolute encoder, 2. Interface module, 3. Lifting absolute encoder, 4. Controller, 5. Weight sensor, 6. DP fieldbus, 7. Human-machine interface, 8. Motor drive system, and 9. Wire rope. Implementation

[0031] like Figure 1 As shown, an electromagnetic steel plate flow control system includes a rotary absolute encoder 1, an interface module 2, a lifting absolute encoder 3, a SIMATIC S7-1500 controller 4, a weight sensor 5, a DP fieldbus 6, a human-machine interface 7, and a motor drive system 8. The rotary absolute encoder 1 and the lifting absolute encoder 3 are both PVM58 models, and the weight sensor 5 is a WT-PY model. The motor drive system 8 includes a system belt, a lifting motor, a rotary motor, and their respective drivers. The SIMATIC S7-1500 controller 4 is installed in the ship's bridge. The PVM58 rotary absolute encoder 1, PVM58 lifting absolute encoder 3, and WT-PY weight sensor 5 are connected to the controller 4 via interface module 2 and DP fieldbus 6, using the MODBUS RTU protocol for communication. The controller 4 performs calculations and transmits the data to the human-machine interface 7 for display and storage, while simultaneously controlling the operation of the PVM58 rotary absolute encoder 1 and PVM58 lifting absolute encoder 3. The human-machine interface 7 communicates with the controller 4 via Ethernet. This entire control system is based on DP fieldbus 6 and MODBUS RTU protocol communication, offering good real-time performance over short distances. The controller 4 reads data from the PVM58 rotary absolute encoder 1 and PVM58 lifting absolute encoder 3, and then reads data from the WT-PY weight sensor 5 after the position has stabilized. This effectively improves the accuracy of weight data acquisition, requires only one operator, increases work efficiency, and reduces costs associated with inaccurate readings due to fluctuating weight.

[0032] The SIMATIC S7-1500 controller 4 reads data through interface module 2, first judging the values ​​of the PVM58 lifting absolute encoder 1 and the PVM58 slewing absolute encoder 1; it determines whether the lifting height is level with the dock, and whether the rotation angle of the slewing absolute encoder PVM58 has turned to the river side, i.e., whether the rotation angle is less than 0°. If both are true, the current lifting operation is recorded as one start. This data is stored in the register of the SIMATIC S7-1500 controller 4. The SIMATIC S7-1500 controller 4 uses addition to accumulate the weight, and finally transmits the result to the human-machine interface 7. The human-machine interface 7 can set the alarm cycle threshold. The SIMATIC S7-1500 controller 4 compares and processes the collected data, and sends feedback to the belt conveyor control system each time the threshold is triggered.

[0033] like Figure 2 As shown, the PVM58 rotary absolute encoder 1 is installed on the shaft of the pinion in the slewing mechanism of the electromagnetic crane. The large gear rotates slowly and has a long circumference, while the small gear rotates quickly and has a small circumference. To obtain more accurate angle readings, it is installed on the small gear. The faster the small gear moves, the more changes the PVM58 rotary absolute encoder 1 will make. Correspondingly, the stroke of the large gear is short, and its angle reading is more accurate.

[0034] like Figure 3 As shown, the PVM58 lifting absolute encoder 3 is installed on the shaft of the large gear on the side of the lifting winch of the electromagnetic crane in this application. Its speed is the same as that of the large gear. The small gear is connected to the shaft of the lifting motor. The small gear rotates faster and the large gear rotates slower. Because the lifting height does not change quickly, the PVM58 lifting absolute encoder 3 is installed on the shaft of the large gear and connected coaxially, so that the stroke of the large gear is the same as the actual height change. Many mechanical errors can be ignored in the middle, resulting in a more accurate lifting height.

[0035] like Figure 4As shown, there are two WT-PY weight sensors 5, each installed at the lower end of one of the two wire ropes 9 of the electromagnetic crane. Two wire ropes 9 are installed on the lifting device of the electromagnetic crane, with the WT-PY weight sensors 5 installed at the lower end of each wire rope 9. The lower ends of the WT-PY weight sensors 5 are connected to the electromagnetic chuck. The value measured by the WT-PY weight sensors 5 is related to the tension of the wire ropes 9. The two sensors are installed on the lower side of the two lifting wire ropes 9 respectively. The deformation caused by the pressure on the wire ropes 9 results in a change in the value. The greater the pressure, the larger the analog current signal output by the sensor; the two are approximately directly proportional. In this application, the electromagnetic chuck lifts a steel plate, and each of the two WT-PY weight sensors 5 reads a weight value. The weight value is transmitted to the controller 4 via the DP fieldbus 6 for calculation, reducing the inaccurate readings caused by weight fluctuations due to electromagnetic chuck movement during weight acquisition.

[0036] An electromagnetic steel plate flow control system includes the following steps: 1. When the operator powers on the system, the SIMATIC S7-1500 controller 4 reads the communication status of all substations in the system through interface module 2 to determine whether each substation is functioning normally. The PVM58 lifting absolute encoder 3 and the PVM58 slewing absolute encoder 1, due to their holding properties, can provide real-time position feedback to the SIMATIC S7-1500 controller 4.

[0037] 2. The SIMATIC S7-1500 controller 4 starts timing from the moment the operator starts the machine, reads the angle of the PVM58 rotary absolute encoder 1 and the height of the PVM58 lifting absolute encoder 3, and comprehensively judges that the crane lifting device is located on the side of the cabin.

[0038] 3. When the spreader reaches the level with the dock, the change curve of the weight sensor WT-PY (5) tends to stabilize. The SIMATIC S7-1500 controller 4 counts one cycle from when the spreader reaches the horizon of the lifting height to when the next lift reaches the horizon of the lifting height. The system of this application is a mechanism that works on the dock. The electromagnetic crane mechanism can extend to the river side. The steel plate is on the ship on the river side. When the spreader is lifted from the ship on the river to the level with the dock, the WT-PY weight sensor 5 collects the weight. At this time, the weight sensor 5 tends to stabilize. This position is selected because the entire lifting operation of the crane is compared. It is found that when the crane is lifted from the ship on the river side to the level with the dock, the entire crane structure tends to be the most stable. At this time, the value of the weight sensor 5 is stable and the error is small, which effectively improves the accuracy of the reading.

[0039] IV. The SIMATIC S7-1500 controller 4 subtracts the net weight of the spreader from the weight of the steel plate when it reaches the dock level position in each cycle, then accumulates the weights and stores them in the storage unit of the SIMATIC S7-1500 controller 4, and simultaneously sends them to the human-machine interface 7. Finally, the SIMATIC S7-1500 controller calculates the total weight of the steel plate over a period of time. The WT-PY weight sensor 5 transmits the weight to the controller 4 via a weight transmitter, through SSI to MODBUS RTU, and via DP fieldbus 6. This application's system calculates the cumulative total weight of the steel plate over a period of time using the SIMATIC S7-1500 controller 4, avoiding errors in lifting tonnage caused by steel plate fluctuations, and more accurately describing the real-time lifting weight.

[0040] The formula for calculating the actual weight lifted by the crane is as follows: ; a1 and a2 are analog signals transmitted from the WT-PY weight sensors 5 mounted on both sides of the lifting device, respectively, and k is a proportionality constant. The weights of the two sensors are compared and their average value is taken to reduce sway error.

[0041] 5. The alarm threshold is determined by the tonnage calculated by the SIMATIC S7-1500 controller 4, and the operation of the rear drive is controlled by the DP fieldbus 6.

[0042] After the PVM58 lifting absolute encoder 3 and PVM58 slewing absolute encoder 1 of this application are started, the weight is collected by the WT-PY weight sensor 5 at the weight stable position according to the number of lifting times of the lifting height gauge, and the reading is more accurate. The position of the lifting device is determined by the angular rotation position of the PVM58 slewing absolute encoder 1. There is no need for the cooperation of the driver, the person measuring and marking the weight of the steel plate, and the person driving the absolute encoder. Only one person, the driver, is needed to operate it, which improves the work efficiency and reduces personnel costs.

[0043] The specific steps are as follows: a: The operator starts the system power supply. The controller detects whether the communication status of each substation of the system is normal through the interface module. The PVM58 lifting absolute encoder 3 and PVM58 slewing absolute encoder 1 provide real-time position feedback to the controller due to their holding feedback.

[0044] b: Judge the values ​​of the two absolute encoders to determine whether the lifting height is level with the dock, whether the angle rotation position of the PVM58 rotary absolute encoder 1 has turned to the river side, and determine whether the position of the spreader is on the side of the cabin. c: Plot the change curve of the lifting weight within a cycle. Determine that when the lifting device reaches the same height as the dock within the lifting cycle, the change curve of the WT-PY weight sensor 5 tends to stabilize. The SIMATIC S7-1500 controller counts one cycle as the time from the first lifting height position at the same height as the dock to the next lifting height position at the same height as the dock. d: The SIMATIC S7-1500 controller 4 calculates the weight of the crane at the WT-PY weight sensor 5 when it reaches the dock level position within each cycle, subtracts the net weight of the lifting gear, accumulates the weights, stores them in the storage unit of the SIMATIC S7-1500 controller 4, and simultaneously sends them to the human-machine interface 7. Finally, the SIMATIC S7-1500 controller calculates the total weight of the steel plate over a period of time. This method avoids errors in lifting tonnage caused by fluctuations in the steel plate and provides a more accurate description of the real-time lifting weight. e: The SIMATIC S7-1500 controller 4 analyzes and processes the collected data, judges the total tonnage calculated, and controls the operation of the back-end DP fieldbus 6 if the alarm threshold exceeds the requirements.

Claims

1. An operation method for an electromagnetic steel plate flow control system, the system comprising a controller (4), characterized in that: It also includes a rotary absolute encoder (1), an interface module (2), a lifting absolute encoder (3), a weight sensor (5), and a human-machine interface (7); the rotary absolute encoder (1) and the lifting absolute encoder (3) are connected to the interface module (2) via a DP fieldbus (6); the interface module (2) is connected to the controller (4) via the MODBUS RTU protocol; the weight sensor (5) is connected to the controller (4) via the MODBUS RTU protocol; the controller (4) performs calculations and transmits the data to the human-machine interface (7) for display and storage, while controlling the operation of the rotary absolute encoder (1) and the lifting absolute encoder (3); the human-machine interface (7) communicates with the controller (4) via Ethernet; There are two weight sensors (5), which are installed at the lower ends of the two steel wire ropes (9) of the electromagnetic crane respectively; two steel wire ropes (9) are installed on the lifting device of the electromagnetic crane, and weight sensors are installed at the lower ends of the steel wire ropes (9). The lower ends of the weight sensors (5) are connected to the electromagnetic chuck. The method includes the following steps:

1. When the operator starts the system power, the controller (4) detects whether the communication status of each substation of the system is normal through the interface module (2). The lifting absolute encoder (3) and the slewing absolute encoder (1) provide real-time position feedback to the controller (4) because they have a holding function.

2. Starting from the moment the operator powers on the machine, read the angle of the rotary absolute encoder (1) and the height of the hoisting absolute encoder (3) to comprehensively determine that the electromagnetic crane boom is located on the side of the cabin.

3. When the lifting device reaches the specified lifting height, the change curve of the weight sensor (5) tends to stabilize. The controller (4) completes one cycle from the first lifting height to the next lifting height, which is counted as one lifting operation. IV. The controller (4) converts the value displayed by the weight sensor (5) in each cycle into the actual weight lifted by the electromagnetic crane in this cycle after removing the net weight, stores it in the storage unit of the controller (4), and sends it to the human-machine interface (7) at the same time. Finally, the controller (4) accumulates and calculates the total weight of the steel plate in a period of time.

5. The alarm threshold is determined by the tonnage calculated by the controller (4) to control the operation of the rear conveyor belt; In step three, the weight sensor (5) collects the weight when the spreader is stable at the same level as the dock; In step four, the controller (4) removes the net weight of the spreader from the weight when the spreader reaches the level position with the dock in each cycle, and then adds up the weight.

2. The operating method of the electromagnetic steel plate flow control system according to claim 1, characterized in that: The rotary absolute encoder (1) is installed on the shaft of the pinion in the rotary mechanism of the electromagnetic crane.

3. The operating method of the electromagnetic steel plate flow control system according to claim 1, characterized in that: The lifting absolute encoder (3) is installed on the shaft of the large gear on the side of the lifting winch of the electromagnetic crane.

4. The operating method of the electromagnetic steel plate flow control system according to claim 1, characterized in that: In step four, the formula for calculating the actual weight lifted by the electromagnetic crane is as follows: ； and These refer to the analog signals transmitted by the weight sensors (5) on both sides of the lifting device, where k is a proportional constant.

Images