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1、 Explanation of the Transformation of the Electric Control System for Mine Hoists

 

1. Overall renovation content

 

1) Increase networked intelligent unmanned operation consoles;

 

2) Add a new digital brake shoe clearance online detection system;

 

3) Add a four quadrant variable frequency cabinet.

 

4) Add Taiwan Advantech industrial computer and 24 inch LCD display

 

3. Brief technical description

 

Performance of fully automatic networked intelligent unmanned variable frequency control technology scheme

 

1. Technical parameters of the hoist:

 

Elevator model:

 

Maximum static tension of steel wire rope:

 

Wire rope diameter:

 

Increase speed:

 

Improvement level:

 

Supporting AC motor:

 

2. Environmental conditions for use:

 

1) The ambient temperature shall not exceed 40 ℃ and shall not be lower than -10 ℃.

 

2) The relative humidity shall not exceed 85% (+25 ℃).

 

3) There are no conductive dust or gases that can damage metals and insulation.

 

4) There is no severe vibration or turbulence.

 

5) Places that do not require explosion-proof measures.

 

6) Power supply voltage level: 380V

 

3. Technical description of electronic control system:

 

3.1 Overall Technical Description

 

The entire electronic control system is divided into three parts: a fully digital variable frequency speed control system, a networked operating system, and a real-time monitoring system for brake clearance.

 

3.2 System Description

 

1) According to the improvement requirements, a fully digital variable frequency speed control system is selected, and feedback braking mode is adopted.

 

2) The use of fully digital speed, current, and position closed-loop control ensures stable and reliable operation of the hoist at any speed while maintaining a constant crawling distance, resulting in high operational efficiency of the hoist.

 

3) Two sets of programmable controllers (PLCs) are selected for the operation and safety protection system. The main and auxiliary PLCs communicate and monitor each other, and the operation process adopts a dual line control method. Multiple protection measures are adopted for key signals of the hoist operation (such as speed, container position, safety, deceleration, over winding, etc.), which are redundant to each other.

 

4) The PLC operation control system can meet the control requirements of various operation modes such as fully automatic, semi-automatic, manual, maintenance, emergency, and manual overwinding of the hoist. The control system automatically selects the maximum operating speed based on the position and direction of the lifting container, as well as the type of lifting, to improve the system's operational efficiency.

 

Fully automatic operation: i.e. unmanned mode. When the automatic operation logic is normal, upon receiving the signal sent by the signal system, the system begins to automatically complete a lifting cycle; It has functions such as automatic direction selection, determining operating speed, automatic deceleration, and automatic parking.

 

Semi automatic operation: When the semi-automatic operation logic is normal, upon receiving a signal from the signal system, the driver presses the start button once, and the system begins to automatically complete a lifting cycle; It has functions such as automatic direction selection, determining operating speed, automatic deceleration, and automatic parking.

 

Manual operation: The driver controls the hoist to operate at any speed below the rated speed through a speed setting device based on the signal system situation, automatically accelerating, decelerating, and accurately stopping, while also being limited by the travel controller.

 

Maintenance operation: Maintenance speed: 0.3~0.5m/s, used for inspecting the wellbore and rope. Manually drive during maintenance.

 

Manual overwinding operation: During maintenance, a switching switch can be used to manually overwind and limit the operating speed to below 0.3m/s. When lifting normally, the manual overwind switch cannot be reset and cannot be driven.

 

Emergency operation: In any operating mode, the driver can implement an emergency stop operation through the emergency stop button or foot switch.

 

Fault operation: In the event of both PLCs malfunctioning, the lifting function can achieve low-speed fault operation through the relay system, with a speed of less than 2 meters per second, and the system can still meet the requirements for operation and operation; And it has all the protections stipulated in the Coal Mine Safety Regulations.

 

5) It has three safety protection circuits, two software safety circuits, and one hardware safety circuit. Key links adopt triple or multiple protections, such as over winding, overspeed, and 2-meter fixed-point overspeed. Multiple safety protection circuits are redundant to ensure the efficient and safe operation of mining equipment. The hardware safety circuit includes protections such as overspeed, speed limit, and over winding.

 

6) Light and serious faults have sound and light alarms or pre alarms.

 

7) Each subsystem exchanges data and signals through the network to achieve networked distributed control, greatly reducing the external wiring of the entire system.

 

8) Take necessary hardware and software anti-interference measures (isolation, filtering, reasonable structure and wiring) to ensure that the entire system is not affected by electromagnetic interference, power supply interference, and does not cause harmful interference to other equipment;

 

9) Through optimized design, the performance of the equipment has become more powerful, and the hardware, including wiring, has become cleaner.

 

 

4. Networked control panel:

 

 

Networked PLC control system

 

◆ Select dual sets of Siemens series programmable controllers. There are both software and hardware interlocks between dual PLCs, which monitor the operation of the PLC to prevent PLC failures caused by PLC crashes or other unexpected reasons, and can monitor and participate in safety protection in a timely manner.

 

The programmable controllers adopt network communication mode, and the main control PLC has a fiber optic industrial Ethernet interface, which is used for fiber optic communication with the signal system.

 

The main control PLC consists of a mainframe, power board, CPU board, communication board, high-speed counting board, analog I/O board, digital I/O board, modem and other hardware components, with a 10% margin left for the total number of input and output ports.

 

The main control PLC application software can meet the control requirements for automatic, semi-automatic, manual, maintenance, layer changing, slow motion, deceleration parking, emergency control driving and other operating modes of the hoist. Control and monitor all power sources of the lifting system. And achieve sequential interlocking control for forced ventilation fans;

 

◆ Implement control over the given travel speed of the speed control system, with automatic deceleration protection for three or more lanes, and automatic brake holding when parking.

 

The lifting signal between the signal system is locked, and the vehicle cannot be driven without a signal. It is equipped with a locking release function.

 

◆ Implement comprehensive protection functions, with multiple independent protections for safety protection such as full envelope line overspeed, over winding, and deceleration. At the same time, it can also complete monitoring and protection functions such as fixed-point speed monitoring, overload, undervoltage, deceleration over speed, constant speed over speed, motor temperature detection, brake shoe wear, spring fatigue, signal system interlocking, hydraulic station oil pressure and temperature, and interlock with safety circuits or primary driving circuits, alarm and automatic protection.

 

◆ Implement the function of digital stroke setting, with a positioning accuracy of ≤ | 1 | cm, and display the position of the digital stroke tank. Set a synchronization switch in the wellbore to synchronize and correct the photoelectric encoder.

 

◆ Implement low-speed fault driving function in PLC fault state.

 

◆ Protection functions can be set according to the following three categories:

 

Immediate brake failure: high and low voltage power outage failure, frequency conversion system failure, lifting container over winding, regulation and control circuit failure, brake system oil pressure failure, lifting system exceeding maximum speed by 15% and deceleration section exceeding speed by 10%, 2m/s fixed point overspeed, misoperation, pressing safety brake button, power outage, main circuit overvoltage, overcurrent, main circuit voltage loss, etc.

 

The faults of first decelerating according to the set speed and then emergency stopping include overheating of the main engine bearing, high temperature of the transformer, ventilation fan failure during operation, undervoltage of the signal power supply, high oil temperature of the hydraulic braking system, low oil level of the hydraulic braking system, brake shoe wear, brake disc deviation, spring fatigue, loss of safety door locking signal, loss of shaking table locking signal, and loss of blocking signal of the car stopper.

 

After completing this upgrade, faults that are not allowed to drive again include overheating of the main motor, grounding and other grounding faults of the signal power supply, high room temperature, and high temperature of the control cabinet.

 

◆ Realize automatic calculation of the diameter of the hoist drum, automatically correct the position of the system, complete closed-loop control of the hoist position, and achieve multiple synchronous monitoring and verification functions of the position.

 

◆ Fault self diagnosis function of the main control PLC.

 

Implement real-time monitoring and recording of PLC programs, safety faults, and events.

 

◆ Software and hardware redundant safety loops.

 

After the on-site safety accident signal is isolated, it enters the PLC and utilizes both the internal safety circuit and external hardware safety circuit of the PLC to form a dual safety protection. Multiple protection circuits can also be installed inside the PLC to achieve comprehensive judgment of various faults. Having various protections as required.

 

◆ Gate control system: The working gate adopts PLC calculation control, which can be automatically and manually adjusted. When manually operated, the brake oil pressure is adjusted by the brake control handle; When in automatic mode, the transmission torque is matched, and the command is given to release the brake, pre apply the brake skin, and apply the brake control signal. And there is hardware and software interlocking with the safety circuit in the gate control circuit.

 

The cabinet is equipped with hardwired safety protection relays to achieve redundant functions with the PLC software safety circuit, as well as interface circuits for PLC control input/output and hydraulic station control.

 

Network control, modular components, and combination cabinet structure simplify the connection between equipment and shorten the installation period.

 

In addition to having the function of an electronic digital monitor, the auxiliary PLC on the control panel that needs to be wired from the PLC input and output ports are all wired from the nearby auxiliary PLC. The auxiliary PLC is installed inside the control panel and communicates with the main PLC through network communication. Various signal lines are completed through communication cables to achieve networked control. The control panel is equipped with indicator lights, instruments, selection switches, buttons, audio equipment, digital depth indicators, etc., which can meet the requirements of various control processes for the operation of the hoist.

 

The auxiliary control PLC consists of a main frame, power supply, CPU, communication, high-speed counting, analog I/O, digital I/O board and other templates. There is an independent security protection link that monitors and works collaboratively with the main control PLC.

 

The instrument mainly displays contents such as tank level digital depth indicator, lifting speed, motor current, brake oil pressure, adjustable brake current, high-voltage power supply voltage, etc.

 

The content of the combination indicator light includes two categories: hoist operation status indication, signal indication, and safety status indication.

 

The control console is designed with a user-friendly design, with a compact and generous structure that is easy to operate and observe, making the driver's work more comfortable.

 

 

Set up an independent gate detection system that integrates detection, computation, control, and monitoring. The main controller of the system adopts Siemens PLC products, which collect and process external variables through PLC modules, and complete parameter correction and zero calibration, protection and alarm function output through logical operations. It can achieve dynamic detection of the clearance, temperature, deflection, and brake oil pressure of the hoist brake disc. At the same time, the process variables detected by the system are visually displayed through the human-machine interface, making it easy to observe and operate.

 

The sensors of the intelligent gate detection system are the front-end measurement components of the system, mainly including displacement sensors and non-contact temperature sensors.

 

A. Displacement sensor; By compressing and extending the probe, displacement is generated, and the internal electronic circuit converts the displacement signal into a linearly changing 4-20mA current signal, completing the detection of the gap value between the brake shoe and the brake disc during opening and closing. Each brake head is equipped with one displacement sensor. The main technical parameters of the sensor are as follows:

 

① Range: 0-10mm

 

② Output signal: 0-10V

 

③ Working section accuracy: ± 2%, (4-20 mA/0-10mm linear variation)

 

④ Operating environment temperature range: -20~60 ℃

 

⑤ Power supply: 15~24V DC

 

⑥ Lifetime ⑦:>5 × 106 times

 

 

B. Infrared temperature sensor: installed on a specific position of the gate seat through a bracket, using a non-contact temperature sensor. By adjusting the appropriate distance between the probe and the gate disc, the temperature of the gate disc is dynamically and continuously monitored, completing the detection of the gate disc temperature. One brake disc is equipped with one temperature sensor. The main technical parameters of temperature sensors are as follows:

 

① Power supply: DC 24V

 

② Output signal: Voltage DC 0-5V

 

③ Detection range: 0-150 ° C

 

④ Detection accuracy: 1 ° C

 

⑤ Self temperature resistance range: -15 ℃~+55 ℃

 

⑥ Detection form: infrared type