1. Introduction
The automobile industry is developing rapidly, and the demand for automobile tires is also growing rapidly.At the same time, the rapid development of high-grade roads in our country has greatly improved the operating speed of automobiles, which puts forward higher requirements for the quality of automobile tires.As an important part of the tire, the steel wire plays an important role in the strength of the tire.The quality of the steel wire directly affects the quality, quality, and grade of the tire.As the main production equipment of steel wire, the straight-in wire drawing machine is also more and more widely used.In the early days, straight-in wire drawing machines were mainly imported, including imported wire drawing machines from Germany, Italy, South Korea, etc. These systems had DC speed regulation and AC frequency conversion speed regulation.Now these equipment are also used in some large steel wire production plants.In recent years, with the improvement of domestic machining capabilities and the development of automation control technology, the straight wire drawing machine has basically been localized.Several wire drawing machine production plants such as Jiangyin and Jingjiang have produced AC frequency conversion synchronous speed regulation straight wire drawing machines.
This application case is a supporting case of QMA Q9000 high-performance vector inverter for straight-in wire drawing machine produced in Jiangyin.
2. Introduction to the working principle of straight wire drawing machine
The straight-in wire drawing machine is a small continuous production equipment composed of multiple drawing heads, which can be drawn step by step, and the steel wire can be cold drawn to the required specifications at once, and the work efficiency is relatively high., After each stage of drawing, the wire diameter changes, and the working line speed of each drawing head should also change.
The drawing die configuration is different, and the drawing speed of each drawing head must also vary.The reference for drawing speed is that the flow rate and volume of the die-drawing steel wire per second remain unchanged at each time. The following formula is established：
πR2×V1= πr2×V2
Where R: the diameter of the incoming wire
V1: Wire speed of incoming wire
r: Diameter of outlet wire
V2: Outlet wire speed
The working speed of each drawing head of the straight wire drawing machine is based on the above formula to ensure the synchronous operation of each drawing head., The above description is based on the steady-state working process of the ideal state, mechanical transmission errors and mechanical transmission gaps, as well as dynamic working processes such as starting, acceleration, deceleration, and stopping, each drawing head cannot be kept in sync. , Most straight wire drawing machines now have tension sensors that dynamically measure the tension of the steel wire between the drawing heads, and then convert the tension into a standard signal (0~20mA or 0~10V), which is fed back to the speed-regulating inverter. The inverter uses this signal for closed-loop PID process control, and the PID is superimposed on the main speed to calculate the adjustment amount to keep the tension of each tension detection point constant. , Which also ensures the synchronous and constant tension working state of the straight wire drawing machine.
As explained above, the straight-in wire drawing machine puts forward high requirements for the performance of the inverter.The inverter should have the following properties.
1. The low-frequency starting torque is large, the overload capacity is strong, and the speed accuracy is high.
2. There is a built-in PID function and rich PID parameters
3. Fast dynamic response
We chose the QMA Q9000 series high-performance vector inverter as the drive device of the straight wire drawing machine. In actual use, the inverter also fully meets the requirements of the wire drawing machine, with fast response, large starting torque, strong overload capacity, and speed control accuracy of 0.2% (no PG) when vector control. , There is a built-in PID, and the PID parameters are rich, including PID gain, limiter, bias, etc.
3. Configuration and description
The electrical system configuration of the straight—in wire drawing machine is shown in the figure below, which mainly includes the following parts: touch screen—Siemens TP270, 10' true color, programmable controller (PLC)-Siemens S7-315—2DP, with Profibus fieldbus interface, inverter—Cool horse Q9000 series high-performance vector inverter, built-in PID, sensor-Turk linear sensor, 0~10V, or 4~20mA.The touch screen is connected to the PLCMPI bus, and the Profibus fieldbus is connected between the PLC and the inverter to form a high-speed fieldbus network. The data transmission rate reaches 1.5M, which greatly improves the response speed of the inverter, improves the synchronization accuracy, and basically achieves continuous synchronization during normal operation.This is very effective for improving work efficiency.
Parameter | Mame | Factory settings | Set |
21-01 | Frequency command selection | 1 | 1 |
21-02 | Run command selection | 1 | 1 |
21-03 | Stop method selection | 0 | 1 |
31-01 | Acceleration time 1 | 10.0 | 8 |
31-02 | Deceleration time 2 | 10.0 | 8 |
36-01 | The upper limit of the carrier frequency | 12.5 | 2 |
41-01 | Frequency instruction 1 | 0.00 | 50 |
51-01 | Setting of input voltage | 200 | 380 |
51-04 | Maximum output frequency | 60.0 | 80 |
51-05 | Maximum voltage | 200.0 | 380 |
51-06 | Base frequency | 60.0 | 50 |
51-08 | Medium output frequency voltage | 11.0 | 25.1 |
51-13 | Base voltage | 0.0 | 380 |
52-01 | Motor rated current | 1.90 | 29.6 |
52-02 | Motor rated slip | 2.90 | 0.82 |
52-03 | Motor no-load current | 1.20 | 13.8 |
52-05 | Inter-line resistance of the motor | 9.842 | 0.675 |
52-07 | The core saturation coefficient of the motor 1 | 0.50 | 0.42 |
52-08 | The core saturation coefficient of the motor 2 | 0.75 | 0.68 |
T2-01 | Function selection of terminal RA-RC | 0 | E |
T3-12 | Filter constant | 0.00 | 1 |
T5-01 | Delivery address | 1F | 3 |
T5-02 | Selection of transmission speed | 3 | 4 |
P3-04 | Selection of stall prevention function during deceleration | 1 | 0 |
The pilot speed of the entire system is determined by the last drawing inverter, and then the compression ratio and reduction ratio of each drawing die are calculated. The given speed of each other machine owner, mechanical errors and drawing die wear, make the given parameters and the actual value have a certain difference, this difference is corrected by the tension arm.In fact, a position sensor is connected under the tension arm. The sensor measures the rotation angle of the tension arm and outputs a 0~10V analog signal to the inverter. The inverter then sets the position value (a relative and 10V percentage value), PID calculation, and a correction amount is superimposed on the output frequency to eliminate the above differences.
In the system, the touch mold screen serves as the man-machine interface and plays the role of a man-machine interface. The compression ratio of each drawing mold is the input of the touch mold screen. The touch mold screen can also store several sets of different drawing mold parameters, which is convenient for users to quickly select a complete set of drawing mold parameters without having to enter parameters every time, which is convenient for users and improves efficiency.The touch-mode screen also displays the actual working parameters of each drawing mode at work, including voltage, current, speed, etc. When the system alarms, the system fault content is displayed on the touch-mode screen in time to facilitate users to diagnose in time and eliminate some simple faults.The touch screen is connected to the PLC by MPI, and the rate is: 187.5K.
PLC is the control center of the entire system, controlling the entire system workflow.Button operation controls the front linkage, rear linkage, jog of each machine, and the jog and automatic operation of the entire system.The touch screen inputs the compression ratio parameters of the drawing machine, calculates the synchronization speed of each machine, and transmits the Profibus bus to the inverter, which directly drives the motor of the machine to work.The PLC uses the Profibus bus to read the working parameters of the inverter from the inverter, deal with various working abnormalities of the inverter, and display it on the touch screen in time.
4. Conclusion
The inverter has been used on the straight-in wire drawing machine for a period of time, and customers have reported that the equipment is running smoothly, starting, stopping, accelerating, and decelerating smoothly and stably, with high synchronization accuracy, low starting current, and low noise. It has been widely recognized by end-use customers.
