Marine anchor equipment PLC control system and control method thereof

Abstract

The invention discloses a marine anchor equipment PLC control system and a control method thereof, a control input unit, a detection alarm input unit, an execution relay, an alarm output unit and a state display output unit of the PLC control system are respectively connected with corresponding terminals of a PLC, and an output signal of a control cabinet of the PLC control system acts on a marine anchor equipment control object. And a measuring unit arranged on a control object is connected with the signal input end of the PLC. The control method of the PLC control system comprises three kinds of speed control and protection, emergency control, brake control, anchor chain speed measurement and length calculation and working state indication. The size of the control system is greatly reduced, reliability is higher, maintenance and later upgrading and reconstruction are facilitated, the automation degree of the marine anchor equipment is improved, and operation of the marine anchor equipment under different working conditions is safer and more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of marine anchor equipment control systems, and specifically to a PLC control system for marine anchor equipment and its control method. Background Art

[0002] As an important deck machinery, marine anchor equipment plays important functions such as assisting the ship in anchoring, berthing and unberthing at the dock, and mooring and unmooring from the buoy. At the same time, it also plays roles such as turning around in narrow channels in case of emergency, reducing the ship speed, and assisting in getting off the shoal when running aground, which is very important for ensuring the vitality of the ship. Therefore, it is crucial to improve the informatization and automation level of its control system. Most of the existing anchor equipment control systems still use the traditional relay contactor control system as the core. Compared with the traditional relay contactor control, the Programmable Logic Controller (PLC) control is more stable and reliable, and the PLC with a modular structure has a smaller volume, which greatly reduces the wiring difficulty and also greatly facilitates the later maintenance work. At the same time, the PLC control can also greatly optimize the space layout of the control cabinet, and has the advantages of monitoring data at any time, detecting faults in time and alarming. Applying the PLC control technology to the marine anchor equipment control system can greatly improve the informatization and automation level of the marine anchor equipment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a PLC control system for marine anchor equipment and its control method, which greatly reduces the volume of the control system, has stronger reliability, is convenient for maintenance and later upgrading and transformation, improves the automation level of the marine anchor equipment, and makes the operation of the marine anchor equipment safer and more reliable under different working conditions.

[0004] The technical solution of the present invention is as follows:

[0005] A PLC control system for marine anchor equipment includes a programmable logic controller, i.e., PLC, a control input unit, a detection and alarm input unit, an execution relay, a control cabinet, a control object of the marine anchor equipment, a measurement unit, an alarm output unit and a status display output unit. The control input unit, the detection and alarm input unit, the execution relay, the alarm output unit and the status display output unit are respectively connected to the corresponding terminals of the PLC. The control object of the marine anchor equipment is connected to the signal output end of the control cabinet. The measurement unit arranged on the control object is connected to the signal input end of the PLC;

[0006] The control object of the marine anchor device is the windlass. The windlass includes a motor, a transmission device, two clutch devices, an anchor chain wheel, and a mooring cable drum. The motor is connected to the input end of the transmission device. The input ends of the two clutch devices are respectively connected to the two output ends of the transmission device. The output ends of the two clutch devices are respectively connected to the anchor chain wheel and the mooring cable drum. A brake, a braking device, a chain stopper, and an anchor releasing and retrieving handle are arranged on the anchor chain wheel. A mooring cable releasing and retrieving handle is arranged on the mooring cable drum.

[0007] The measurement unit is used to measure the anchoring length and the anchoring speed of the windlass.

[0008] The measurement unit of the control object is an encoder arranged on the anchor chain wheel. The PLC calculates the anchoring length and the anchoring speed by using the encoder and a designed high-speed counter.

[0009] The PLC selected is of the S7-200 SMART type.

[0010] A control method for the PLC control system of a marine anchor device includes three-speed control, emergency control, and brake electric control. Specifically, it includes the following steps:

[0011] (1) S11. Three-speed control: It includes the operation control of the low speed (i.e., the first speed), medium speed (i.e., the second speed), and high speed (i.e., the third speed) of the windlass. When the motor of the windlass runs normally at low speed or medium speed, the states of the first-speed coil or the second-speed coil output by the PLC are maintained by a designed first-speed mark memory or a second-speed mark 1 memory. When the motor switches to the high-speed gear, it first maintains medium-speed operation, and the state of the second-speed coil is maintained by a designed second-speed mark 2 memory. The PLC uses a power-on delay timer for delay control. After reaching the set time, the motor automatically switches to the high-speed operation state.

[0012] S12. When the motor is blocked during high-speed movement and the current is too large to trigger an alarm, the PLC controls the motor to switch to medium-speed operation and maintain it, and at the same time gives an alarm.

[0013] (2) Emergency control: After the master controller of the windlass is placed in the zero position, press and hold the emergency operation button to keep it closed, thereby realizing emergency control. Emergency control is to parallel an emergency control circuit for the first speed on the normal operation line of the first-speed coil, parallel an emergency control circuit for the second speed on the normal operation line of the second-speed coil, and parallel an emergency control circuit for the third speed on the normal operation line of the third-speed coil.

[0014] (3) Brake electric control: The electric brake drives the brake device to loosen and tighten by controlling the brake motor. The brake conversion switch inputs an open brake instruction or a tighten brake instruction to the PLC, and then the PLC controls the open brake coil or the tighten brake coil to be energized, so that the brake device on the anchor chain wheel is loosened or tightened.

[0015] The control method also includes working status indication and alarm control. The working status indication includes a first clutch in-place indicator light, a second clutch in-place indicator light, a chain stopper open in-place indicator light, a chain stopper closed in-place indicator light, a manual brake indicator light, a medium and low speed overload alarm indicator light, a high speed overcurrent alarm indicator light, an anchor dropping too fast alarm indicator light, and a phase sequence normal indicator light. The PLC collects the on-state of the normally open contact of the first clutch in place, the on-state of the normally open contact of the second clutch in place, the on-state of the normally open contact of the chain stopper open in place, the on-state of the normally open contact of the chain stopper closed in place, the on-state of the normally open contact of the manual brake, the on-state of the normally open contact of the medium and low speed overload, the on-state of the normally open contact of the high speed overcurrent, the on-state of the normally open contact of the anchor dropping too fast, and the normal state of the phase sequence protection input instruction, and controls the corresponding indicator lights to be energized and lit; the alarm control is that when any one of the normally open contacts of the medium and low speed overload, the high speed overcurrent, and the anchor dropping too fast is closed, the PLC controls the buzzer coil to be energized, and at the same time, a buzzer alarm is carried out.

[0016] The control method also includes an anchor chain speed measurement function, that is, the calculation of the anchor dropping speed. The anchor chain speed measurement uses the high-speed counter of the PLC, and uses an encoder and the Frequency library to complete the speed measurement; the encoder sends a high-speed pulse signal to the high-speed counter, and then the high-speed pulse signal read by the high-speed counter is input into the count port of the Frequency instruction. The measurement unit time is set to obtain the real-time pulse frequency and store it. The real-time pulse frequency is divided by the number of signals per revolution to obtain the rotational speed in the set measurement unit time, and then multiplied by the anchor chain length corresponding to one revolution of the anchor chain wheel, that is, the anchor dropping speed in the set measurement unit time is obtained.

[0017] The control method also includes an anchor chain length calculation function, that is, the calculation of the anchor dropping length. Multiply the real-time pulse frequency recorded by the high-speed counter by the anchor chain length corresponding to a unit pulse, that is, the anchor dropping length is obtained.

[0018] The brake device also includes a manual brake. The manual brake handle inputs a manual brake instruction, and the normally closed contact of the manual brake connected to the PLC is disconnected. Then, the PLC controls the opening brake coil and the tightening brake coil to lose power, so that the manual brake operation has a higher priority than the electric brake control.

[0019] Advantages of the present invention:

[0020] Compared with the traditional contactor relay control system, the volume of the present invention is greatly reduced, and the control speed and accuracy are greatly improved. The protection function is relatively perfect, and the reliability is further improved.

[0021] The marine anchor equipment of the present invention is provided with an emergency control program, and an emergency control circuit is connected in parallel on the normal operation line of the motor coil, so as to skip the fault inspection and realize the rapid emergency control of the anchor winch.

[0022] When the brake of the present invention is controlled, the brake device is controlled to relax and tighten through a brake conversion switch, realizing the electric control of the anchor winch brake. At the same time, the function of manually controlling the brake is retained to ensure that the anchor winch brake can be manually controlled in case of electric control failure.

[0023] Various working status indicator lights are connected to the PLC of the present invention, enabling the staff to more clearly grasp the operating status of the equipment.

[0024] The present invention monitors the anchoring speed of the marine anchor equipment in real time to avoid accidents such as chain breakage and anchor loss caused by misoperation. The present invention also has the function of monitoring the length of the anchor chain thrown out in real time to more accurately grasp the working condition of the anchor equipment. Description of the Drawings

[0025] Figure 1 is the principle block diagram of the PLC control system of the marine anchor equipment of the present invention.

[0026] Figure 2 is the schematic diagram of the mechanical structure of the anchor winch of the present invention.

[0027] Figure 3 is the flow chart of the anchor winch anchoring operation of the present invention.

[0028] Figure 4 is the terminal wiring diagram of the PLC of the present invention.

[0029] Figure 5 is the ladder diagram of the first-speed marking function in the three-speed control of the PLC of the present invention.

[0030] Figure 6 is the ladder diagram of the second-speed marking 1 function in the three-speed control of the PLC of the present invention.

[0031] Figure 7 is the ladder diagram of the second-speed marking 2 function in the three-speed control of the PLC of the present invention.

[0032] Figure 8 is the ladder diagram of the third-speed marking function in the three-speed control of the PLC of the present invention.

[0033] Figure 9 is the ladder diagram of the normal operation and emergency control of the first-speed coil of the PLC control system of the present invention.

[0034] Figure 10 is the ladder diagram of the normal operation and emergency control of the second-speed coil of the PLC control system of the present invention.

[0035] Figure 11 is the ladder diagram of the normal operation and emergency control of the third-speed coil of the PLC control system of the present invention.

[0036] Figure 12 It is the ladder diagram of the high-speed overcurrent marking function in the three-speed control of the PLC of the present invention.

[0037] Figure 13 It is the ladder diagram for the PLC of the present invention to control the relaxation of the braking device.

[0038] Figure 14 It is the ladder diagram for the PLC of the present invention to control the tightening of the braking device.

[0039] Figure 15 It is the ladder diagram for the PLC of the present invention to measure the speed of the anchor chain.

[0040] Figure 16 It is the ladder diagram for the PLC of the present invention to calculate the length of the anchor thrown.

[0041] In the ladder diagram, represents a normally open contact, | / | represents a normally closed contact, and () represents a coil. Detailed implementation manner

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] See Figure 1 and Figure 2 A PLC control system for a marine anchor device includes a programmable logic controller, i.e., PLC 1 (S7-200 SMART type), a control input unit 2, a detection and alarm input unit 3, an execution relay 4, a control cabinet 5, a control object 6 of the marine anchor device, a measurement unit 7, an alarm output unit 8, and a status display output unit 9. The control input unit 2, the detection and alarm input unit 3, the execution relay 4, the alarm output unit 8, and the status display output unit 9 are respectively connected to the corresponding terminals of PLC 1. The control object 6 of the marine anchor device is an anchor winch, the control object 6 is connected to the signal output end of the control cabinet 5, the measurement unit 7 provided on the control object 6 is connected to the signal input end of PLC 1, the measurement unit is an encoder provided on the anchor sprocket of the anchor winch, and PLC 1 calculates the length and speed of the anchor thrown by using the encoder and the designed high-speed counter;

[0044] The windlass includes a motor 61, a transmission device 62, two clutch devices 63, an anchor chain wheel 64 and a mooring drum 65. The motor 61 is connected to the input end of the transmission device 62. The input ends of the two clutch devices 63 are respectively connected to the two output ends of the transmission device 62. The output ends of the two clutch devices 63 are respectively connected to the anchor chain wheel 64 and the mooring drum 65. A brake, a braking device, a chain stopper and an anchor handling lever are provided on the anchor chain wheel 64. A mooring cable handling lever is provided on the mooring drum. When the anchor is being dropped, the process is shown in Figure 3 as follows.

[0045] See Figure 4 , there are multiple digital input terminals, multiple digital output terminals and two analog output terminals provided on the PLC 1. The functions of each terminal are specifically shown in Table 1 below:

[0046] Table 1

[0047]

[0048]

[0049] A control method for the PLC control system of a marine anchor device includes three-speed control, emergency control, brake electric control, working state indication and alarm control, anchor chain speed measurement, and calculation of the anchor dropping speed. Specifically, it includes the following steps:

[0050] (1). S11. Three-speed control: See Figures 5 to 10 , including the operation control of the low speed (first speed), medium speed (second speed), and high speed (third speed) of the windlass. When the motor of the windlass runs normally at low speed or medium speed, the states of the first-speed coil or the second-speed coil output by the PLC are maintained by the first-speed mark memory M0.1 or the second-speed mark 1 memory M0.3 inside the PLC. When the motor switches to the high-speed gear, it first maintains medium-speed operation, and the state of the second-speed coil is maintained by the designed second-speed mark 2 memory M0.4. The PLC uses a power-on delay timer for delay control. After reaching the set time, the motor automatically switches to the high-speed operation state;

[0051] S12. When the motor is blocked during high-speed movement, the excessive current triggers an alarm, controls the I9.0 contact to act, makes the high-speed overcurrent memory M0.6 get powered, the PLC controls the motor to switch to medium-speed operation and maintain it, and at the same time gives an alarm;

[0052] The PLC also designs a reset function before system startup, a phase sequence indication function, a system power-on function, an anchor winch anchor retrieval (i.e., motor reverse) function, an anchor winch anchor dropping (i.e., motor forward) function, and an anchor winch brake opening function for three-speed control.

[0053] See Figure 5 andFigure 9 For the low-speed (first speed) operation function of the windlass, the first-speed flag memory M0.1 is used. When the system is powered on, the normally open contact of M3.0 is closed. When the forward rotation Q0.0 or reverse rotation Q0.1 function and the low-speed instruction I8.4 are turned on, the first-speed flag memory M0.1 is powered on, the normally open contact of M0.1 is closed, the first-speed coil Q0.2 is powered on, and the motor runs at low speed.

[0054] See Figure 6 、 Figure 7 and 10 For the medium-speed (second speed) operation function of the windlass, the second-speed flag 1 memory M0.3 and the second-speed flag 2 memory M0.4 are used. When the forward rotation Q0.0 or reverse rotation Q0.1 function and the medium-speed instruction I8.5 are turned on, the second-speed flag 1 memory M0.3 is powered on. When the medium-speed instruction I8.5 and the high-speed instruction I8.6 are turned on, the second-speed flag 2 memory M0.4 is powered on. When M0.4 is powered on, the power-on delay timer T97 is turned on. After 2s, the normally open contact of T97 is closed, realizing the function that the conversion from medium speed to high speed operation will be delayed by 2s. When medium-low speed overload or high-speed overcurrent occurs, the normally closed contact of the medium-low speed overload protection I9.1 or the high-speed overcurrent memory M0.6 is opened, and the second-speed flag 2 memory M0.4 and the power-on delay timer T97 lose power; when the normally open contact of the second-speed flag 1 memory M0.3 or the normally open contact of the second-speed flag 2 memory M0.4 is turned on, the second-speed coil Q0.3 is powered on, and the motor runs at medium speed; when overcurrent occurs during the high-speed operation of the windlass, the normally open contact of the high-speed overcurrent memory M0.6 is closed, and the second-speed coil Q0.3 will also be powered on and switched to medium-speed operation; when medium-low speed overload or the three-speed flag memory M0.0 is powered on, the normally closed contact of I9.1 or the normally closed contact of M0.0 is opened, and the second-speed coil Q0.3 loses power.

[0055] See Figure 8 and Figure 11 For the high-speed (third speed) operation function of the windlass, the three-speed flag memory M0.0 is used. After the system is powered on, the normally open contact of the three-speed flag memory M0.0 is closed, the three-speed coil Q0.4 is powered on, and the motor runs at high speed; when high-speed overcurrent protection occurs, the normally closed contact of the high-speed overcurrent protection I9.0 is opened, and the three-speed coil Q0.4 loses power;

[0056] See Figure 12 The windlass is designed with a high-speed overcurrent flag function. When running at high speed, the medium-speed instruction I8.5 and the high-speed instruction I8.6 are turned on at the same time. When high-speed overcurrent protection occurs, the normally open contact of the high-speed overcurrent protection I9.0 is turned on, and the high-speed overcurrent memory M0.6 is powered on.

[0057] (2) Emergency control: After the master controller of the wildcat winch is placed in the zero position, press and hold the emergency operation button to close it, thereby realizing emergency control; the emergency control is to parallel the first-speed emergency control circuit on the line where the first-speed coil operates normally, parallel the second-speed emergency control circuit on the line where the second-speed coil operates normally, and parallel the third-speed emergency control circuit on the line where the third-speed coil operates normally;

[0058] See Figure 9 , when the wildcat winch runs at low speed (first speed), the emergency control of low speed is realized by paralleling the normally open contact of the first-speed emergency M0.2; see Figure 10 , when the wildcat winch runs at medium speed (second speed), the emergency control of medium speed is realized by paralleling the normally open contact of the second-speed emergency M0.7; see Figure 11 , when the wildcat winch runs at high speed (third speed), the emergency control of high speed is realized by paralleling the normally open contact of the third-speed emergency M1.1;

[0059] (3) Electric control of the brake: The electric brake drives the brake device to relax and tighten by controlling the brake motor. The brake conversion switch inputs the open brake command or the tighten brake command to the PLC, and then the PLC controls the open brake coil or the tighten brake coil to be energized, so that the brake device on the wildcat wheel is relaxed or tightened; the brake device includes a manual brake and an electric brake. The manual brake handle inputs the manual brake command, and the normally closed contact of the manual brake connected to the PLC is disconnected. Then the PLC controls the open brake coil and the tighten brake coil to lose power, so that the manual brake operation has a higher priority than the electric brake operation;

[0060] See Figure 13 , when the brake device relaxation function is running, connect the normally open contact of the open brake command I8.2, and the coil of the open brake Q0.6 is energized, and the brake device performs the relaxation operation; see Figure 14 , when the brake device tightening function is running, connect the normally open contact of the tighten brake command I8.3, and the coil of the tighten brake Q0.7 is energized, and the brake device performs the tightening operation; when using the manual brake, the normally closed contact of the manual brake I1.2 is disconnected, disconnecting the coils Q0.6 and Q0.7, and the electric brake fails;

[0061] (4) Working status indication and alarm control: The working status indication includes the first clutch in-place indicator light, the second clutch in-place indicator light, the chain stopper open in-place indicator light, the chain stopper closed in-place indicator light, the manual brake indicator light, the medium and low speed overload alarm indicator light, the high speed overcurrent alarm indicator light, the anchor dropping too fast alarm indicator light, and the phase sequence normal indicator light. The PLC collects the on-state of the normally open contacts of the first clutch in-place, the second clutch in-place, the chain stopper open in-place, the chain stopper closed in-place, the manual brake, the medium and low speed overload, the high speed overcurrent, the anchor dropping too fast, and the normal state of the phase sequence protection input instruction, and controls the corresponding indicator lights to be energized and lit; The alarm control is that when any of the normally open contacts of the medium and low speed overload, the high speed overcurrent, and the anchor dropping too fast is closed, the PLC controls the buzzer coil to be energized, and at the same time, a buzzer alarm is carried out;

[0062] (5) Anchor chain speed measurement: That is, the calculation of the anchor dropping speed. The anchor chain speed measurement uses the high-speed counter of the PLC and completes the speed measurement by using the AB item encoder and the Frequency library; First, set the filtering frequency of the HSC4 clock signal input port. When the program is scanned for the first time, call the high-speed counter initialization program to define the control bit of the high-speed counter. Then, set the initial value of the HSC4 clock signal input port to 0 and start HSC4. After the Frequency instruction starts to work, the encoder sends a high-speed pulse signal to the high-speed counter. The high-speed pulse signal read by the high-speed counter is transmitted to the count port of the Frequency instruction. Set the measurement unit time, obtain the real-time pulse frequency and store it. Divide the real-time pulse frequency by the number of signals per revolution to get the rotational speed in the set measurement unit time, and then multiply it by the anchor chain length corresponding to one revolution of the anchor sprocket movement, that is, the anchor dropping speed in the set measurement unit time is obtained;

[0063] See Figure 15 , using the Frequency library function, the real-time pulse frequency will be transmitted to the variable memory VD0 for storage. After the variable memory VD0 goes through integer calculation instructions, the frequency value is converted into a speed value (anchor dropping speed) and stored in the analog output unit AQW34;

[0064] (6) Calculation of the anchor chain length: That is, the calculation of the anchor dropping length. Multiply the real-time pulse frequency recorded by the high-speed counter by the anchor chain length corresponding to a unit pulse, that is, the anchor dropping length is obtained; When the master controller of the anchor windlass is placed in the zero position, the high-speed counter is reset to achieve the function of resetting the anchor chain length.

[0065] See Figure 16 The value of the high-speed counter HC0 is transformed through integer calculation instructions, rounding instructions, and conversion instructions, and the anchor chain length value is transmitted to the analog output unit AQW32.

[0066] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PLC control system for marine anchor equipment, characterized in that : It includes a programmable logic controller, i.e., a PLC, a control input unit, a detection alarm input unit, an execution relay, a control cabinet, a control object of the marine anchor equipment, a measuring unit, an alarm output unit, and a status display output unit. The control input unit, the detection alarm input unit, the execution relay, the alarm output unit, and the status display output unit are respectively connected to the corresponding terminals of the PLC, the marine anchor equipment control object is connected to the signal output terminal of the control cabinet, and the measuring unit arranged on the control object is connected to the signal input terminal of the PLC; The control object of the marine anchor equipment is an anchor winch, which includes an electric motor, a transmission device, two clutch devices, an anchor chain wheel and a cable drum. The electric motor is connected to the input end of the transmission device, the input ends of the two clutch devices are respectively connected to the two output ends of the transmission device, the output ends of the two clutch devices are respectively connected to the anchor chain wheel and the cable drum, the anchor chain wheel is provided with a brake, a braking device, a chain stopper and an anchor releasing and collecting handle, and the cable drum is provided with a cable releasing and collecting handle; The measuring unit is used to measure the anchor length and anchor speed of the anchor winch.

2. A PLC control system for marine anchor equipment according to claim 1, characterized in that The measuring unit of the control object is an encoder arranged on the anchor chain wheel. The PLC uses the encoder and a designed high-speed counter to calculate the anchor length and anchor speed.

3. A PLC control system for marine anchor equipment according to claim 1, characterized in that The PLC used is S7-200 SMART type PLC.

4. The control method of a PLC control system for a marine anchor equipment according to claim 1, characterized in that : It includes three speed controls, emergency control and electric brake control, and specifically includes the following steps: (1) S11, three speed controls: including the operation control of the anchor winch at low speed (i.e., first speed), medium speed (i.e., second speed), and high speed (i.e., third speed). When the motor of the anchor winch is operating normally at low speed or medium speed, the state of the first speed coil or second speed coil output by the PLC is maintained by the designed first speed mark memory or second speed mark 1 memory; when the motor is switched to the high speed gear, the medium speed operation is maintained first, and the state of the second speed coil is maintained by the designed second speed mark 2 memory. The PLC power-on delay timer is used for delay control. After the set time is reached, the motor automatically switches to the high speed operation state; S12: When the motor is stalled at high speed, the current is too large and triggers an alarm. The PLC controls the motor to run at medium speed and maintains it, while giving an alarm. (2) Emergency control: After the main controller of the anchor winch is set to zero, press the emergency operation button and keep it closed to achieve emergency control; emergency control is to connect a first-speed emergency control circuit in parallel to the normal operation line of the first-speed coil, a second-speed emergency control circuit in parallel to the normal operation line of the second-speed coil, and a third-speed emergency control circuit in parallel to the normal operation line of the third-speed coil; (3) Electric brake control: The electric brake controls the brake motor to loosen or tighten the brake device. The brake conversion switch inputs the brake opening command or brake tightening command to the PLC, and then the PLC controls the brake coil to open or tighten the brake coil to energize, so that the brake device on the anchor chain wheel is loosened or tightened.

5. The control method according to claim 4, characterized in that : It also includes working status indication and alarm control. The working status indication includes a No. 1 clutch in place indicator light, a No. 2 clutch in place indicator light, a chain stopper open in place indicator light, a chain stopper closed in place indicator light, a manual brake indicator light, a medium and low speed overload alarm indicator light, a high speed overcurrent alarm indicator light, a too fast anchoring alarm indicator light and a normal phase sequence indicator light. The PLC collects the connection status of the No. 1 clutch in place normally open contact, the connection status of the No. 2 clutch in place normally open contact, the connection status of the chain stopper open in place normally open contact, the connection status of the chain stopper closed in place normally open contact, the connection status of the manual brake normally open contact, the connection status of the medium and low speed overload normally open contact, the connection status of the high speed overcurrent normally open contact, the connection status of the too fast anchoring normally open contact, and the normal status of the phase sequence protection input instruction, and controls the corresponding indicator lights to be energized and lit; the alarm control is that when any of the medium and low speed overload normally open contacts, the high speed overcurrent normally open contacts, and the too fast anchoring normally open contacts are connected, the PLC controls the buzzer coil to be energized and the buzzer alarm is sounded at the same time.

6. The control method according to claim 4, characterized in that : It also includes the anchor chain speed measurement function, that is, the calculation of the anchoring speed. The anchor chain speed measurement uses the PLC's high-speed counter, and uses the encoder and Frequency library to complete the speed measurement; the encoder sends a high-speed pulse signal to the high-number counter, and then the high-speed pulse signal read by the high-number counter is transmitted to the count port of the Frequency instruction, and the measurement unit time is set to obtain the real-time pulse frequency and store it. The real-time pulse frequency is divided by the number of signals per circle to obtain the rotation speed for the set measurement unit time, and then multiplied by the anchor chain length corresponding to one circle of the anchor chain wheel, that is, the anchoring speed for the set measurement unit time is obtained.

7. The control method according to claim 6, characterized in that : It also includes the function of calculating the length of the anchor chain, that is, calculating the length of the anchor. The real-time pulse frequency recorded by the high-frequency counter is multiplied by the length of the anchor chain corresponding to the unit pulse to obtain the anchor length.

8. The control method according to claim 4, characterized in that :The braking device also includes a manual brake. The manual brake handle inputs a manual brake command, and the normally closed contact of the manual brake connected to the PLC is disconnected. Then the PLC controls the opening brake coil and the tightening brake coil to lose power, so that the manual brake operation has a higher priority than the electric brake control.

Images