I. Overview <br> Numerical Control (NC) is an automatic control technology developed in the 1950s. It is a method of using digital signals to control the movement and processing of machine tools. The introduction of computer technology in CNC technology is called CNC (Computer NumericalContr01). CNC has the characteristics of good flexibility, strong functions, high reliability, good economy, and easy realization of electromechanical integration, making CNC technology leap in quality. .
Second, technology introduction <br> Horizontal CNC machine tool consists of CNC controller, servo drive and motor, electrical cabinet and CNC machine tool rack four parts. The working principle is: through the special programming software configured in the CNC, the trajectory of the machined parts is expressed in the form of coordinates, and these information are converted into signals (pulse trains) with the power to drive the servo motor, and the servo is controlled. The motor drives the corresponding axis to achieve the trajectory. At the same time, the cutter holder is equipped with a numerically controlled lathe, and the corresponding workpiece is processed by cutting the machining material fixed on the spindle by configuring the corresponding cutter according to the machining material.
Third, the composition of the equipment <br> Horizontal CNC machine tools from the CNC system, servo drives and motors, electrical cabinets and machine tool bed four parts. CNC system: It mainly completes the computer program that implements the program in its memory to realize the numerical control function, and is equipped with an interface circuit and a servo drive device. It converts the information calculated by the system itself into a signal (pulse train) that drives the servo motor. ), Control each axis of the CNC machine tool to generate X, Y, Z three-axis path, and automatically process the workpiece according to a given machining program. Therefore, a computer numerical control system is a digital control system including a computer.
Fourth, the control line (CN2) wiring diagram and servo parameter settings 1) control line (CN2) wiring diagram
2) Description of parameter settings:
PA4=0 (control mode selection, 0: position control);
PA9=16 (motor model selection, different motor parameters are different);
PA11=3500 (position loop gain, range 500-8000);
PA27=0/1 (The pulse input logic is negated and can be used to change the direction of the motor);
PA31 (input command pulse multiplier);
PA32 (input command pulse multiplier and denominator);
Note: Electronic gear ratio = PA31/PA32 == Ppulse / P
Ppulse: The number of pulses per motor revolution refers to the number of pulses (pulse/turn) fed back by the motor's feedback element. Such as 2500-line incremental encoder, the number of pulses fed back to the driver is 2500×4=10000;
P: Refers to the upper computer command pulse (pulse/turn) that the servo must receive to make the motor rotate one revolution;
Fifth, debugging and precautions 1), debugging steps:
A, correctly connect the motor power line (U, V, W), encoder line (CN3), power line (L1, L2, R, S, T), connect the control line (CN2);
B. Run the motor at a low speed to see if the motor direction is correct (the direction of the motor can be changed by adjusting the PPA27 parameter);
C. Set the electronic gear ratio (PA31/PA32) of the servo driver as required;
D. After completing the above steps, run the motor to see if the motor sound is normal, whether the motor rigidity is satisfied, and the response time; (can be adjusted by: position loop parameters PA11, PA12, PA13; speed loop parameters PA14, PA15; current loop Parameters PA38, PA41).
E. After adjustment, turn a sample to see if it meets the requirements. If the sample is not good, repeat step D until the turning sample meets the requirements.
2) Notes:
A. When connecting power lines (U, V, W), they must be connected to the U, V, W terminals one by one. It is not possible to change the direction of the motor by changing the phase sequence of U, V and W. The direction of the motor can be changed by adjusting the parameters.
B. When connecting the control line (CN2), one end must be connected to the shielded cable. Avoid external interference with control signals.
C, wiring must be reasonable, AC and DC power supply must be strictly separated, the control line must be strictly separated from the motor power line, power line.
3) Result:
Compared to the customer's previous lathes, the use of servos not only greatly improved the speed, but also improved the positioning accuracy much more than before, the motor sound is much smaller than before, so that customers achieve maximum satisfaction.
Sixth, failure and exclusion methods 1), fault: the upper computer to the signal motor run away, the driver appeared on the 09th alarm;
Remedy: Check whether the phase sequence of the motor power line (U, V, W) is connected incorrectly. Check whether the driver PA9 (motor model selection) is set correctly.
2) Fault: The No. 27 alarm appears: Check if the motor encoder cable (CN3) is loose. After fixing it, try it.
3) Fault: The host computer sends a pulse and the motor does not run. Exclusion method: Check whether the signal line in the control line (CN2) is wrong. Check whether the servo driver PA64 is set correctly. The driver is internally enabled (PA64=64). Enable (PA64=0).
7. Summary <br> The CNC machine tool fully combines the EPS2 series of Dongneng servos with fast response, accurate positioning, short setting time and stable operation. So that customers achieve maximum satisfaction, not only improve customer's output, quality, but also save labor costs for customers. This equipment fully demonstrated the technical capabilities of Zhejiang Dongneng Technology Co., Ltd. to customers, and at the same time greatly enhanced the competitiveness of the lathe manufacturers in the market.
