Electromagnetic crane is a kind of heavy duty crane, manufactured from our Overhead Bridge Crane Factory, right here below, the company introduces some key technologies that have been employed in our overhead crane system. Any questions, our crane engineer experts are ready to reply to you as soon as possible. The following includes two parts, the first part is the overhead cranes’ magnetic sucker technology introduction, and the second part is the overhead cranes’ control system technology introduction.
Two categories and uses of magnetic chucks that you don’t know
The two categories and uses of magnetic chucks are the factors that must be taken into consideration when purchasing electromagnetic cranes. Excellent lifting machinery here tells you two categories and uses of magnetic sucker: Magnetic sucker family has automatic magnetic chuck and manual magnetic chuck.
Automatic magnetic chuck is usually used when lifting steel plate and can be freely assembled according to the size of steel plate.The automatic magnetic chuck has the advantages of light structure, convenient operation, strong holding power, no power consumption, safety and reliability, etc..Magnetic chuck helps to improve the working conditions of material conveying operation and improve labor productivity.Therefore, as a kind of efficient, safe, energy-saving new magnetic sling, it has been widely used in shipbuilding, construction machinery and mold manufacturing and other industries.The use of permanent magnet lifting operation does not need an external power supply and electric control parts, the operation is simple and convenient, safe and reliable use, automatically sucking and discharging action.The permanent magnet can be associated with trolleys, cranes and other equipment, which can be used in the single machine, and multiple suction steel billet or another type of steel, durable, easy maintenance, and is an ideal energy saving magnetic suspension.
Manual magnetic sucker is normally used in lifting the workpiece. It is often for the single user, and can also be used in combination with other lifting equipment. The manual permanent magnet lifter has the advantages of small volume, so it has a higher requirement on the thickness of the steel plate.
Application of wireless communication technology in crane linkage control
Through in-depth study of wireless communication technology, in the multi crane linkage control, our Crane Machinery adopts wireless communication technology.Our company produced 4 cranes for a steel plant, 4 cranes need linkage control, lifting several fixed length objects together, and sometimes need 2 cranes linkage control, and sometimes need 3 cranes linkage control, and sometimes need 4 cranes linkage control.
Overhead crane drawing design
The crane inverter drive and PLC control between PLC and inverter using Profibus-DP communication between a crane and a crane with a wireless communication module for data exchange, using the encoder as the feedback signal, feedback mechanism of each operation distance of each crane, to achieve the purpose of the synchronous running of the multi crane.
- Lifting mechanism inverter using SIEMENS’s S120 series, operating agencies, frequency converter using internationally renowned lifting accessories brand.
- PLC uses SIEMENS’s S7-300 series, with Ethernet communication module.
- The wireless communication module uses SIEMENS’s W788 series.
- The encoder uses P+F absolute encoder with Profibus-DP communication port.
- Overhead crane design drawings include active control switch, single control switch, linkage control switch and wing control switches can control the other 3 cars; the crane machine start button, a stop button, bell switch, lighting switch and various institutions switches.
- The buttons and switches of the machine are used to control the operation and stop of the machine, that is, the single crane.
- Active control switch and driven control switch are interlocked.
- The active control switch is used for the crane to call the car and send control commands to the vehicle.
- The slave control switch is used for the crane to do the slave car and receive the control command of the main vehicle.
- Single action control switch and linkage control switch interlock each other,
- The single action control switch is used to control the individual work of the machine,
- The linkage control switch is used to control the linkage and work with other cranes.
single action control switches are installed on the machine used separately to operate the other 3 cranes on the machine.
configure the hardware of PLC control system: the control system uses SIEMENS STEP7 programming software on the hardware configuration, opens the STEP7 programming software, inserts 300PLC rail, power supply, CPU, Ethernet module, input, and output module, SIEMENS inverter S120 hardware, Yaskawa inverter A1000 hardware, P+F hardware, to save and compile the crane hardware .In this project, the PLC used in the other 3 cars is inserted separately, and the PLC used for each car is saved and compiled respectively.In the configuration network, the 4 PLC constitute the ISO-on-TCP connection network to save and compile the machine configuration.So the hardware configuration is completed.
Compile the communication control program of the machine
This machine communication control program using SIEMENS SFC14 programming software and SFC15 function block, read and write operations on the hardware configuration of S120 inverter; inverter with STARTER software, the communication message using standard message mechanism; the start command, stop and speed command with the given command control and status word S120 converter, and to monitor the state of the word, to realize the protection function; the start command, stop and speed command with the given command control and status word Yaskawa inverter, and to monitor the state of the word, to realize the protection function.
Programming communication control program between 4 sets of PLC
In the STEP7 programming software call FC5 and FC6 function block, through the function block of 4 cranes PLC between sending and receiving data programming.The data of one trolley is sent to another 3 cranes respectively, and the data of 3 other cranes are also received. The data include control commands, speed commands and the distance of each mechanism.
Compile the synchronous control program for each crane of 4 cranes
Using the calculated encoder running distance to various agencies, institutions of a crane running distance as a benchmark, the distance and the reference distance in the other 3 agencies crane operation were compared, if the distance is larger than the reference distance and shows the running speed of the crane of the agency quickly, the operation speed is reduced, given the inverter speed value is small, otherwise, given the speed value, to ensure the synchronization of each mechanism of multi crane.
linkage control program
According to the PLC data transmission, the linkage control switch and single control switch, in the preparation of the control procedures, if the linkage control switch point is closed, the crane in the state; if the single point control switch is closed, the crane work alone, without any control of a crane.Active control switch and the driven control switch plays a role in the linkage control switches closed, the active control switch and the driven control switch, in the preparation of the control program, active control switch point is closed, the crane for active crane can be controlled by the moving crane; closing driven control switch. The crane is driven only by active control of crane, crane, from the train master operation does not work; in the linkage condition, through the operation of the other 3 crane single switch, can control any one of the 1 cranes working alone.
Programming communication interruption program
The clock memory in the cycle/clock memory with the CPU attribute has different scanning periods in each byte of the clock memory, and the timing programming is carried out according to its scanning period.If the wireless communication is interrupted, the clock scanning cycle of CPU will be interrupted, then the timer will be switched on, so as to ensure the normal operation of the interrupt program.
According to the characteristics of Profibus-DP communication, according to the hardware configuration, set the DP address of each frequency, set the encoder address, then according to the software, using the online function, whether each from the station are in the online state, put each site hanging in the Profibus-DP communication line.
Frequency converter debugging
First of all, the lifting mechanism of the inverter debugging, the use of STARTER software to debug the inverter, the motor self selective learning, set its control mode for PG loss control.Then the frequency converter of the operating mechanism is debugged, and the control mode is set as PG voltage frequency control mode.Finally, the direction of the motor controlled by the inverter is debugged, and the direction of the motor is consistent with the control direction of the main command.
W788 configuration for wireless communication module: according to the configuration of PLC network, W788 configuration and PLC configuration in the same network segment, only in this way, can exchange data between 4 PLC.
Debugging the program
According to the pulse number of absolute encoder rotation, the number of pulses corresponding to the unit distance is calculated. According to the distance of each mechanism of the crane, the speed is adjusted, and the size of the given speed value is adjusted.At the same time, the communication interrupt protection program should be debugged so as to make the crane stop completely after the wireless communication interruption, and prevent the occurrence of the safety accident.
Through the electrical control design and debugging of 4 cranes, wireless communication can meet the needs of synchronous crane control, and in the case of wireless communication failure, crane safety parking requirements.It is feasible to run the wireless communication module on the special equipment of the crane.