1. Analysis of the original control system

1: Using controller and wire control operation mode: Due to the limitation of the control line, the operator must follow the object to the left and right or under the object to control the movement of the vehicle. Sometimes the line of sight is not so clear or the control line is When the objects are mixed together, it brings great inconvenience to the operator's work, and there is also a safety hazard.

When the area of ​​the object is too large or the wire control is not so flexible during the operation, several people are needed to complete the operation. If the communication is not very tacit during the operation, the accuracy of the operation will be greatly reduced, and the production efficiency will also be reduced. Great discount.

2: Using the cab operation mode: the crane is controlled by the driver through the cam controller or linkage platform. When in use, personnel with an operating license must climb onto the crane cab to operate, and the dedicated auxiliary personnel under the crane hang ropes and command. During operation, the driver must use the commander's gestures on the ground to operate. If there is a blind spot in the viewing angle or the driver misunderstands the meaning of the command improperly, operation errors will occur, which has a relatively large potential for danger.

Second, the improvement after the modification of the remote control

Original functions: The functions and usage of the original system are still retained;

Modification system: The functions after the modification of the remote control can meet all the original functions;

System conversion: The room control and remote control can be easily converted in the cab, which is flexible and convenient;

Improve production efficiency: The control is in the hands of the operator, so that the author can judge independently, with consistency, and the output naturally increases.

Reduced human resources: One driver can reduce the operation, the user can independently hook the head, and one person can operate independently without command.

Away from the danger zone: For operations such as high temperature, strong acid, strong alkali, or unclear vision, the operator can stand in a safe place with good visibility.

Reduce maintenance costs: The remote control can completely replace the cab function, allowing the "cab" to perform mobility functions.

3. Features of remote control

Security key: a security key switch to prevent unauthorized persons from using or accidentally touching the buttons;

Master stop switch: Press the master stop switch in an emergency, and the crane will all stop, emphasizing the overall safety factor;

Up and down buttons: up and down the hook has up to 2 speeds, and up to 5 speeds through the time relay.

East-West button: The cart has up to 2 speeds when traveling, and up to 5 speeds through the time relay.

North-south button: The trolley has 2 speeds for walking, and up to 5 speeds through the time relay.

Button security: up/down, east/west, south/north can inhibit each other without conflict;

Control distance: up to 100 meters to ensure that the crane is used within sight;

Security codes: as many as tens of millions or even hundreds of billions of security codes to ensure that when multiple remote controls are used in the same place, they will not change codes and affect the use of other machines;

Four, system protection function

1. In the remote control system, the inverter itself has various protection and fault output functions such as short circuit, overload, overvoltage, phase loss, stall, etc. For the main hoisting mechanism, the inverter drives a motor, so the output of the inverter can be Connect the motor directly without connecting the thermal relay for overload protection. The main circuit of the line is connected with the main contactor and the sub-contactor. In addition to the function of making and breaking the line, they also have multiple protections such as short circuit, overload and undervoltage. The driver can control the main contactor through the start-stop button in the linkage platform to control the on-off of the main power supply. When the contactor cannot be used to make and break the circuit, the shunt trip coil of the main circuit breaker can be turned on through the emergency stop switch To disconnect the power circuit. In addition, there are door limit switches and key switches in series in the main power control loop as safety protection measures.

2. The system is equipped with the following protections: upper and lower limit protection, upper and lower pre-limit protection, overspeed protection, overload protection, zero protection, power supply voltage phase failure protection, motor phase loss protection, voltage loss protection, device overcurrent protection, grounding At the same time, the inverter device itself should also have the status and fault indication. The fault signal is stored in the memory unit, and the fault signal can be saved even when the power supply has a problem. After the protection is activated, it is necessary to ensure the safety of the lifting object. Dangerous conditions such as slipping hooks.

3. Emergency power-off switch. Emergency power-off buttons are installed on the crane's power distribution protection cabinet and the linkage platform of the driver's cab, which can conveniently cut off the crane's total power and control power in an emergency. The remote control button signal should be sent to the PLC device for monitoring and action recording.

4. Zero-position protection. Zero-position contacts are provided on the crane's driver's cab console and remote control handle. Through its interlocking relationship with the PLC, the purpose of zero-position protection is achieved. When the mechanism starts to operate and the power supply is restored after the voltage loss, the controller handle must be set to the zero position before the motor of the mechanism can be started:

5. Travel switch, travel switch is provided in the crane's cart operating mechanism, trolley operating mechanism, and hoisting mechanism; each mechanism is controlled by the travel switch through PLC; the lifting mechanism is also equipped with upper and lower pre-limit switches , When the hook reaches a certain distance before the limit position, the pre-limit switch will act, and the running speed of the hook will automatically decelerate to reduce the impact of the end limit position;

6. Ascending limit position limit protection, equipped with a lifting mechanism to set an ascending limit position limiter to ensure that when the spreader is lifted to the limit position, the lifting power supply is automatically cut off, and an alarm signal is issued through the PLC;

Five, advantages

After the remote control is installed, there is strong support from PLC and frequency converter with complete functions, stable and reliable performance. The whole machine is greatly compared with traditional bridge cranes in terms of reliability, speed control performance, energy saving and operating efficiency. Improve, make the performance of the whole machine more safe and reliable.