Question 1:
When the servo motor vibrates at zero speed, it should be because the gain is set too high, and the gain value can be reduced. If there is a slight vibration during startup, indicating that the alarm has stopped, it is most likely that the phase sequence of the servo motor is incorrect. Check if the wiring of the servo motors U, V, W, and PE is correct.
Question 2:
1. When the PID gain adjustment is too large, it is easy to cause servo motor vibration, especially after adding D, which is particularly severe. Therefore, try to increase P and reduce I as much as possible, and it is best not to add D;
2. Vibration can also occur when the servo motor encoder is wired incorrectly;
3. The load inertia is too large, replace with larger servo motors and servo drivers;
4. Analog input port interference causes vibration, and magnetic rings are added to the servo motor input line and servo driver power input line to keep the signal line away from the power line;
5. Another type is a rotary encoder interface motor, and poor grounding can easily cause vibration.
Question 3:
① Servo wiring:
a. Use standard power cables, encoder cables, control cables, and check for any damage to the cables;
b. Check if there is any disturbance source near the control line, and if it is parallel or too close to the nearby high current power cable line;
c. Check if there is any change in the potential of the grounding terminal to ensure good grounding.
② Servo parameters:
a. The servo gain setting is too large. It is recommended to manually or automatically readjust the servo driver parameters;
b. Confirm the setting of the time constant for the speed feedback filter, with an initial value of 0. You can try increasing the setting value;
c. The electronic gear ratio setting is too large, it is recommended to restore it to the factory setting value;
d. Resonance between servo system and mechanical system, attempting to adjust the frequency and amplitude of the notch filter.
③ Mechanical system:
a. The coupling connecting the servo motor shaft and the equipment system is offset, and the installation screws are not tightened;
b. Poor meshing of pulleys or gears can also cause changes in load torque. Try running without load, and if it is normal during no-load operation, check if there are any abnormalities in the joint parts of the mechanical system;
c. Confirm if the load inertia, torque, and speed are too high, try running without load. If the no-load operation is normal, reduce the load or replace the servo motor driver and servo motor with a higher inertia.

Question 4:
Servo motor vibration is caused by mechanical structure, speed loop, compensation board and servo amplifier of servo system, load inertia, electrical components and other faults:
The vibration caused by mechanical structure can be divided into three situations:
1) No load vibration:
a. The foundation of the servo motor is not firm, the stiffness is insufficient, or the fixation is not tight enough;
b. The servo motor fan blades are damaged, which disrupts the mechanical balance of the rotor;
c. The output shaft of the servo motor is bent or cracked, which can be treated by tightening screws, replacing fan blades, replacing the output shaft of the servo motor, and other methods.
2) If there is vibration after adding load, it is usually caused by a problem with the transmission device, and the following defects can be identified:
a. Unbalanced operation of tape roller or coupling;
b. The coupling is not concentric, causing the servo motor motor and the mechanical shaft of the transmission to be not concentric;
c. The unbalanced joint of the transmission tape can be treated by correcting the transmission device to make it balanced.
2. Vibration caused by speed loop issues:
Improper setting of parameters such as speed loop integral gain, speed loop proportional gain, acceleration feedback gain, etc. The larger the gain, the faster the speed, the greater the inertia force, the smaller the deviation, and the more likely it is to produce vibration. Setting a smaller gain can maintain the speed response and reduce the likelihood of vibration.
3. Vibration caused by faults in the compensation board and servo drive of the servo system:
The sudden power outage during the movement of the servo motor results in significant vibration, which is related to improper wiring terminals and parameter settings of the servo drive BRK. The acceleration and deceleration time constant can be increased, and the servo motor can be slowly started or stopped using a PLC to prevent vibration.
4. Vibration caused by load inertia:
The problems with the guide rail and screw lead to an increase in load inertia, and the motion inertia of the guide rail and screw lead has a significant impact on the rigidity of the servo motor transmission system. Under fixed gain, the greater the motion inertia and rigidity, the more likely it is to cause servo motor vibration; The smaller the inertia and rigidity of the motion, the less likely the servo motor is to vibrate. By replacing the guide rail and screw with a smaller diameter, the inertia of the motion can be reduced, thereby reducing the load inertia and achieving the servo motor without vibration.
5. Vibration caused by electrical components:
a. The power-off brake is not turned on due to factors such as unstable feedback voltage. Check if the power-off brake is turned on, and use the encoder vector control zero servo function to output a certain torque by reducing the torque to solve the vibration. If the feedback voltage is abnormal, first check whether the vibration period is related to the speed. If it is related, then check whether there is a fault in the connection between the spindle and the spindle motor, whether the spindle and the pulse generator installed at the tail of the spindle motor are damaged, etc. If it is not related, then check whether there is a fault on the circuit board. It is necessary to check the circuit board or readjust it.
b. Sudden vibration during servo motor operation is mostly caused by phase loss. It is important to check whether the fuse melt is blown, whether the switch touch is good, and measure whether there is electricity in each phase of the power grid.

Reason inspection for abnormal operation of stepper motor:
1. Is the motor torque large enough to drive the load? Therefore, we generally recommend that users choose a motor with a torque that is 50% to 100% greater than the actual requirement when selecting, because stepper motors cannot operate under overload, even for a moment, which can cause step loss, and in severe cases, stop or irregularly repeat.
2. Is the current of the input step pulse from the upper controller large enough (generally>10mA) to ensure stable conduction of the optocoupler? Is the input frequency too high to receive it? If the output circuit of the upper controller is a CMOS circuit, a CMOS input type driver should also be selected.
3. Is the startup frequency too high, and is there an acceleration process set in the startup program? It is best to start accelerating from within the specified startup frequency of the motor to the set frequency, even if the acceleration time is short, otherwise it may be unstable or even in an idle state.

1、 How to control the direction of the stepper motor?
1. The direction level signal of the control system can be changed.
2. The wiring of the motor can be adjusted to change direction, as follows:
For two-phase motors, simply swap the motor wires of one phase and connect them to the driver, such as swapping A+and A -.
For three-phase motors, swap the motor wires of adjacent phases, such as A, B, and C phases, and swap A and B phases
2、 What are the reasons for the large vibration and noise of stepper motors?
The reason for encountering this situation is that the stepper motor operates in the oscillation zone. Solution:
1. Change the input signal frequency CP to avoid the oscillation region.
2. Using a subdivision driver to reduce the step angle and ensure smoother operation.
3、 Why does the stepper motor not run after being powered on?
There are several reasons that can cause the motor to not rotate:
1. Overload blockage (at this time, the motor makes a whistling sound)
2. Is the motor offline
3. Is there a pulse signal from the control system to the stepper motor driver, and is there a problem with the wiring
4、 What should I do if the stepper motor shakes and cannot run continuously?
In this situation, first check if the winding of the motor is connected to the driver incorrectly
Check if the input pulse signal frequency is too high and if the frequency up and down design is unreasonable.

5、 Under what circumstances is the offline signal FREE of a hybrid stepper motor driver generally used?
When the offline signal FREE is low, the current output from the driver to the motor is cut off, and the motor rotor is in a free state (offline state). In some automation equipment, if it is required to operate the drive without power supply
By directly rotating the motor shaft (manual mode), the FREE signal can be set low to take the motor offline for manual operation or adjustment. After manual completion, set the FREE signal high to continue automatic control.
6、 How to choose a power supply for stepper motor drivers?
Determine the power supply voltage of the driver and then determine the operating current; The current of the power supply is generally determined based on the output phase current I of the driver. If a linear power supply is used, the power supply current can generally be 1.1-1.3 times that of I; If a switch mode power supply is used, the power supply current can generally be taken as 1.5 to 2.0 times I.
7、 How to choose the power supply voltage for stepper motor drivers?
Our company's stepper motor drivers are all wide voltage inputs, with a wide range of input voltages to choose from; The power supply voltage is usually selected based on the operating speed and response requirements of the motor. If the motor operates at a high speed or responds quickly, the voltage value will also be high. However, it is important to note that the ripple of the power supply voltage should not exceed the maximum input voltage of the driver, otherwise it may damage the driver. If a lower voltage is chosen, it is beneficial for the smooth operation of the stepper motor and reduces vibration.
8、 Can the subdivision score of the subdivision driver represent accuracy?
Subdivision, also known as micro stepping, is mainly aimed at reducing or eliminating low-frequency vibrations of stepper motors, and improving the operational accuracy of motors is just an additional function of subdivision technology. For example, for a two-phase hybrid stepper motor with a step angle of 1.8 degrees, if the subdivision number of the subdivision driver is set to 4, the operating resolution of the motor is 0.45 degrees per pulse. Whether the accuracy of the motor can reach or approach 0.45 degrees also depends on other factors such as the subdivision current control accuracy of the subdivision driver. The precision of segmented drivers from different manufacturers may vary greatly; The larger the fine score, the more difficult it is to control the accuracy.
9、 Why does the torque of a stepper motor decrease with increasing speed?
When the stepper motor rotates, the inductance of each phase winding of the motor will form a reverse electromotive force; The higher the frequency, the greater the reverse electromotive force. Under its action, the phase current of the motor decreases with the increase of frequency (or speed), resulting in a decrease in torque.

A stepper motor is an induction motor that works by using electronic circuits to convert direct current into alternating current. It controls the current in a multi-phase timing system, and only when this current is used to power the stepper motor can it work properly. The driver is a multi-phase timing controller that supplies power to the stepper motor in a time-sharing manner.
A stepper motor is an open-loop control element that converts electrical pulse signals into angular displacement or linear displacement. In non overloaded situations, the speed and stopping position of the motor depend only on the frequency and number of pulses of the pulse signal, and are not affected by load changes. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle in the set direction, called the "step angle", and its rotation runs step by step at a fixed angle. By controlling the number of pulses, the angular displacement can be controlled to achieve accurate positioning; At the same time, the speed and acceleration of the motor can be controlled by controlling the pulse frequency, thus achieving the purpose of speed regulation.
1、 When changing direction, the pulse is lost, which is manifested as being accurate in any direction, but the deviation accumulates as soon as the direction is changed, and the more times it is changed, the more deviation it will be;
2、 The initial speed is too high and the acceleration is too large, causing occasional step loss;
3、 Too much or too little software compensation when using synchronous belts;
4、 Insufficient motor power;
5、 Controller misoperation caused by interference;
6、 Driver interference caused;
7、 Software defects;

There are several solutions available:
1) Generally, stepper motor drivers have certain requirements for direction and pulse signals. For example, the direction signal is determined several microseconds before the first pulse rising or falling edge (different drivers have different requirements) arrives. Otherwise, a pulse will rotate at an angle opposite to the actual required direction, and the fault phenomenon will become more and more deviated as it moves, and the subdivision will become smaller and more obvious. The solution is mainly to use software to change the logic of the pulse or add delay.
2) Due to the characteristics of stepper motors, the initial speed should not be too high, especially when carrying a large load inertia. It is recommended that the initial speed be below 1r/s to minimize the impact. Similarly, if the acceleration is too large, it will also have a significant impact on the system, which can lead to overshoot and inaccurate positioning. There should be a certain pause time between the forward and reverse rotation of the motor. If there is no pause time, overshoot may occur due to excessive reverse acceleration.
3) Adjust the compensated parameter values according to the actual situation (due to the large elastic deformation of the synchronous belt, some compensation needs to be added when changing direction).
4) Appropriately increase the motor current, increase the driver voltage (pay attention to selecting a motor driver), and choose a motor with higher torque.
5) System interference can cause controller or driver misoperation. We can only find ways to identify the interference source, reduce its interference capability (such as shielding, increasing the distance between them, etc.), cut off the propagation path, and improve our anti-interference ability. Common measures include:
① Replace ordinary wires with double shielded wires, and separate the signal wires from high current or high voltage change wires in the system to reduce electromagnetic interference capability.
② Filter out the interference waves from the power grid with a power filter, and if conditions permit, add power filters to the input terminals of major electrical equipment to reduce interference between devices in the system.
③ It is best to use optoelectronic isolation devices for signal transmission between devices. If conditions permit, pulse and directional signals are best transmitted using differential methods with optoelectronic isolation. By adding resistance capacitance absorption or rapid discharge circuits at both ends of inductive loads (such as electromagnetic relays and solenoid valves), the inductive load can generate a peak voltage of 10-100 times at the beginning, if the operating frequency is above 20KHZ.
6) Software should perform some fault-tolerant processing to eliminate the impact of interference.

1、 Driver current:
Current is the basis for determining the capacity of a driver and is one of the important indicators for selecting a driver. Typically, the maximum current of a driver is 2.2A/3.2A/4.5A/6.0A/8.2A and other specifications.
2、 Power supply voltage of the driver:
The power supply voltage is a sign of the driver's ability to increase or decrease, and the conventional power supply voltage includes VDC/48VDC/50VA
3、 Subdivision of Drivers:
Subdivision is a sign of controlling accuracy, and increasing subdivision can improve accuracy. Stepper motors (especially reactive stepper motors) need to operate in the low-frequency resonance region, so subdivision drivers are a good choice. In addition, subdivision ratios do not require subdivision, and the output torque is proportional to each other

Phenomenon 1: The motor does not rotate
Possible situation 1: The power light is not on - check the power supply circuit and ensure normal power supply.
Possible situation 2: The motor locks the shaft but does not rotate - the pulse signal is weak and the signal current increases.
Possible situation 3, too slow - choose the right segmentation.
Possible situation 4: The drive is protected - power on again.
Possible situation 5: Enable signal issue - pull the enable signal high or not connect it.
Possible situation 6: Incorrect command pulse - check if there is a pulse output from the upper position.
Phenomenon 2: Motor Rotation Error
Possible situation 1: The motor rotates in the opposite direction - replace the motor wiring sequence or adjust the command direction.
Possible situation 2: There is an open circuit in the motor wire - check for poor contact in the wiring.
Possible situation 3: The motor has only one direction - pulse mode error or DIR port damage.
Phenomenon 3: Alarm indicator light on
Possible situation 1: Incorrect connection of motor wires - check the wiring.
Possible situation 2: Voltage too high or too low - check the power supply.
Possible situation 3: Motor or driver damage - replace the motor or driver.
Phenomenon 4: Position or speed error
Possible situation 1: Signal interference - eliminate interference and ensure reliable grounding.
Possible situation 2: Incorrect command input - check the machine command to ensure correct output.
Possible situation 3: No pulse setting error - check the status of the dip switch and connect it correctly.
Possible situation 4: Motor step loss - check if the command speed is too high and if the motor selection is too small.
Phenomenon 5: Driver Terminal Burnout
Possible situation 1: Terminal short circuit - check the polarity of the power supply or external short circuit.
Possible situation 2: Excessive internal resistance between terminals - check if there is excessive soldering at the wire to wire connections to form solder balls.
Phenomenon 6: Motor stalling
Possible situation 1: The acceleration time is too short - reduce the instruction acceleration or increase the driver filtering parameters.
Possible situation 2: The motor torque is too small - choose a high torque motor.
Possible situation 3: The load is too heavy - check the weight and quality of the load, and adjust the mechanical structure.
Possible situation 4: The current is too low - check the dip code and increase the output current of the driver.