What kind of pulse does the servo drive need?

What kind of pulse does the servo drive need?

Positive and negative pulse control (CW+CCW); pulse plus direction control (pulse+direction); AB phase input (phase difference control, commonly used in handwheel control).

The main program of the servo drive is mainly used to complete the initialization of the system, the LO interface control signal, and the setting of each control module register in the DSP.

After all the initialization work of the servo drive is completed, the main program enters the waiting state and waits for the occurrence of interruption to adjust the current loop and speed loop.

The interrupt service program mainly includes the four M timing interrupt program, the photoelectric encoder zero pulse capture interrupt program, the power drive protection interrupt program, and the communication interrupt program.

Techniques for handling other problems of servo motors

(1) Motor movement: movement occurs during feeding, and the speed measurement signal is unstable, such as a crack in the encoder; poor contact of the terminal, such as loose screws, etc.; when the movement occurs in the positive direction and the reverse direction At the moment of commutation, it is usually caused by the reverse gap of the feed transmission chain or the servo drive gain is too large;

(2) Motor crawling: mostly occurs in the start acceleration section or low-speed feed, generally due to poor lubrication of the feed transmission chain, low servo system gain and excessive external load. In particular, it should be noted that the coupling used for the connection of the servo motor and the ball screw, due to the loose connection or the defect of the coupling itself, such as cracks, causes the rotation of the ball screw and the servo motor to be out of synchronization, which makes the feed The movement is fast and slow;

(3) Motor vibration: When the machine tool is running at high speed, vibration may occur, and an over-current alarm will be generated at this time. Machine vibration problems are generally speed problems, so you should look for speed loop problems;

(4) Motor torque reduction: When the servo motor is running from the rated locked-rotor torque to high-speed operation, it is found that the torque will suddenly decrease, which is caused by the heat dissipation damage of the motor winding and the heat of the mechanical part. At high speed, the temperature rise of the motor becomes larger, therefore, the load of the motor must be checked before using the servo motor correctly;

(5) Motor position error: When the servo axis movement exceeds the position tolerance range (KNDSD100 factory standard setting PA17: 400, position out of tolerance detection range), the servo drive will appear “4″ position out of tolerance alarm. The main reasons are: the tolerance range of the system setting is small; the servo system gain setting is improper; the position detection device is polluted; the cumulative error of the feed transmission chain is too large;

(6) The motor does not rotate: In addition to connecting the pulse + direction signal from the CNC system to the servo drive, there is also an enable control signal, which is generally DC+24 V relay coil voltage. Servo motor does not turn, the common diagnostic methods are: check whether the CNC system has pulse signal output; check whether the enable signal is turned on; observe whether the input/output status of the system meets the starting conditions of the feed axis through the LCD screen; for those with electromagnetic brakes The servo motor confirms that the brake has been opened; the drive is faulty; the servo motor is faulty; the servo motor and the ball screw connection coupling failure or key disconnection, etc.

To sum up

To sum up, the correct use of the CNC machine tool servo drive should not only set the parameters correctly according to the user manual, but also combine the use of site and load conditions for flexible operation. In actual work, only with strong parameter understanding and practical skills, users can find out the skills of debugging drives and motors, and use servo drives and servo motors well.