Common types of interference in servo motor applications

We have learned about the faults and maintenance methods of servo motors before. From this, we can understand that servo motors will cause some faults after being used for a long time. In the face of these faults, we should adopt correct maintenance methods. At the same time, in our daily use and debugging of servo systems, various unexpected interferences may occur from time to time, especially for the application of pulse-generating servo motors. The following mainly analyzes the application of servo motors from several aspects. Common types of interference, I hope it can help everyone solve their problems.

1. Radiation interference from space

The effective measure against radiation interference is metal shielding. Space radiated electromagnetic fields are mainly generated by power networks, lightning, radio broadcasts, radars, etc., and are often called radiated interference.

Its influence mainly passes through two paths: one is direct radiation inside the servo, which is induced by the circuit and causes interference; the other is radiation on the servo communication network, which is induced by the communication line and causes interference. The probability of such interference occurring is relatively small, and shielded cables are generally provided for corresponding protection.

An effective measure against conducted interference is to use power filters, isolated power supplies, shielded cables, and reasonable and reliable grounding to solve the problem.

2. Three main types of conducted interference

① Interference from power supply

Practice has proved that there are many situations where servo control system failures are caused by interference introduced by the power supply, which are generally solved by adding equipment such as voltage regulators and isolation transformers.

② Interference introduced from signal lines

This type of interference mainly has two information channels: one is the interference from the power grid connected in series through the power supply of the transmitter or the power supply of the shared signal instrument, but this type of interference is often ignored; the other is the interference of the signal line induced by space electromagnetic radiation. , that is, external induced interference on the signal line, which is often very serious.

The interference introduced by the signal will cause the circuit board components to work abnormally, and in severe cases, it will cause damage to the components. For systems with poor isolation performance, it will also cause mutual interference between signals, causing backflow of the common ground system bus, causing changes in logical data, malfunctions and crashes.

There are many situations where internal components of the control system are damaged due to interference introduced by signals, resulting in system failure. This kind of interference often occurs in applications with long signal distances. We often use the method of adding relay isolation to shield the induced voltage and solve the interference problem.

③ Interference from chaotic grounding system

As we all know, grounding is one of the effective means to improve the anti-interference of electronic equipment. Correct grounding can inhibit the interference from the equipment; but incorrect grounding will introduce serious interference signals, making the system unable to work normally.

Generally speaking, the ground wires of the control system include system ground, shielding ground, AC ground, protective ground, etc. If the grounding system is chaotic, the main interference to the servo motor system will be uneven distribution of potentials at each grounding point, and there will be differences between different grounding points. The ground potential difference causes ground loop current and affects the normal operation of the system.

If the system ground and other grounding are messed up, the resulting ground circulation may produce unequal potential distribution on the ground wire, thus affecting the normal operation of the servo motor circuit. The key to solving this kind of interference is to distinguish the grounding method and provide good grounding performance for the system.

3. Interference from within the system

This type of interference is mainly caused by mutual electromagnetic radiation between internal components and circuits in the system, such as mutual radiation between logic circuits, the interaction between analog ground and logic ground, and the mismatched use of components.