How to solve the interference problem in the application of high speed motor encoder

High speed motor encoder has applied in many fields,including in the motion control system as the core part of automation equipment,is a common application of high-speed motor encoder.High-speed motor encoder reliability and stability directly affect the performance of the equipment,and is one of the main factors that influence the reliability and stability anti-interference problem,this paper said that the interference problem,and how to solve the problem of interference.

Interference of high-speed motor encoder

In the application,there are several main disturbances:

When the control system fails to send instructions,the motor spins without rules.

2,the equipment that shares the same power with the ac servo system(such as display etc.)is not working properly.

When the servo motor stops moving and the motor controller reads the motor position,the speed motor encoder of the motor's end of the motor is not random.

When the servo motor runs,the value of the high-speed motor encoder that is read does not match the value of the instruction,and the error value is random and irregular.

When the servo motor runs,the value of the high-speed motor encoder that is read is a stable value or periodic variation of the value of the command value.

Interference source analysis of high-speed motor encoder

There are two main types of interference into the movement control system:

One is that the signal transmission channel interferes,and the interference passes through the input channel and the output channel of the signal input channel.The second is the interference of the power supply system.

Signal transmission channel is a control system or device receives the feedback signal and the signal control way,because the pulse on a transmission line appear delay,attenuation and distortion,channel interference,in the process of transmission,long-term interference are the main factors.

Any power source and transmission line are existing internal resistance,it is the resistance to the power supply noise,if there is no resistance,no matter what kind of noise will be absorbed by the power supply circuit,the circuit will not establish any interfering voltage,in addition,the ac servo drive system itself is also a strong interference source,it can pass the power interference to other equipment.

Three,high-speed motor encoder anti-interference measures

Design of anti-interference of power supply system

(1)power supply of power supply,for example,the drive power supply of the motor is separated from the control power to prevent interference between the equipment.

(2)noise filters can also effectively inhibit the interference of other devices.The measures can be effectively inhibited by several kinds of disturbances.

(3)using isolation transformer,considering the high frequency noise by main transformer was not on the first level of mutual inductance coupling coil,but by parasitic capacitance coupling level for the first time,so the isolation transformer between the first level of shielding layer isolation,reduce the distributed capacitance,in order to improve the ability to resist common mode interference.

Anti-interference design of signal transmission channel

(1)photocoupled isolation measures

In the process of long distance transmission,adopting photoelectric coupler,can control systems with input channel,output channel and servo drives the connection between the input and output channels to cut off the circuit.If the electrical isolation is not applied in the circuit,the external peak interference signal enters the system or enters the servo driver directly,causing the first disturbance.

(2)the double stranded wire for long line transmission

The signal is affected by interference factors such as electric field,magnetic field and earth impedance during transmission,and the interference of electric field can be reduced by grounding wire.Twisted-pair compared with coaxial cable,although the low frequency band,but wave impedance is high,the common mode noise resistance is strong,can make the electromagnetic interference of each little link cancel each other out.In addition,during long distance transmission,the difference signal transmission is used to improve the anti-interference performance.The use of double-stranded cable for long lines can effectively inhibit the production of second,third and fourth disturbances.

(3)ground

Grounding can eliminate noise produced during the current flows through the ground voltage,in addition to the servo system to connect the earth,signal shielding wire to ground,also prevent electrostatic induction and electromagnetic interference.If there is no proper grounding,there may be a second disturbance.

To sum up,there are two main types of interference sources of high-speed motor encoder,the same anti-interference measures also have two kinds,the anti-jamming design of the power supply system and signal transmission channel anti-interference design.