Incremental rotary encoder output signal for the square wave signal, and can be divided into belt in believe, incremental rotary encoder type and ordinary type incremental rotary encoder, the ordinary type of incremental rotary encoder has two phase is sores on wave pulse output signal A and B, and zero signal Z;
Belt type in believe, incremental rotary encoder in addition to the output signal has A/B/Z, has sent 120 degrees each electron number in believe U/V/W, U/V/W their every turn the logarithmic cycles and motor rotor poles.
With incremental change believe U/V/W type rotary encoder electronics in believe in phase with the rotor magnetic pole phase, or electric Angle between phase alignment method is as follows: 1.
Use a U/V dc power to the motor winding to less than the rated current of dc, U, V, the motor shaft orientation to a balanced position.
Use the oscilloscope to observe U believe and Z signal of encoder.
The relative position of adjust the encoder shaft and motor shaft.
Adjustment, while observing the encoder believe U and Z, jump down, until the signal stability on high level (Z
In the default Z signal of the norm for low level)
The relative position relations, lock encoder and motor.
Back and forth to reverse the motor shaft, after, if every time the motor shaft free to return to balance position, Z signal can be stable at a high level, the alignment is effective.
Removed after the dc power supply, validation is as follows: 1.
Using oscilloscope to observe motor encoder U believe in number and U/V line back emf waveform.
Rotate the motor shaft, encoder U believe U/V line rise along with the motor of the back emf waveform from low to high passing zero overlap, Z of encoder signal also appear in the zero point.
This verification method, also can be used as alignment method.
It is important to note that the number U believe in the phase of incremental rotary encoder and motor UV line zero phase zero alignment of back emf, potential due to U instead of the motor, and UV line between the potential difference between 30 degrees, so that after alignment, incremental rotary encoder number U believe the phase zero point - in contrast to the motor U electric potential
Point at 30 degrees phase alignment, and motor phase Angle in contrast to the U potential waveform phase, so the incremental rotary encoder U believe that number of mechanical and electrical Angle of phase - phase zero and electricity
30 degrees point alignment.
Some servo enterprises are accustomed to the encoder U believe that number zero aligned with the zero point directly to the motor Angle, to achieve this purpose, can: 1.
With equal three resistances into a star, and then the three resistance of star join separately UVW three-phase winding wire connected to the motor;
U to oscilloscope to observe motor phase input to the halfway point of the star resistance, can approximate to get U instead of the motor voltage waveform.
According to the convenience of operation, adjust the relative position of encoder shaft and motor shaft, or the relative position of encoder housing and motor shell.
Adjustment, while observing the encoder number U believe U instead rise along with motor voltage waveform from low to high passing zero, eventually make up along and zero overlap, locking relationship between encoder and the relative position of the motor, complete alignment.
Because ordinary incremental rotary encoder does not have the U/V/W phase information, and Z signal can only reflect a point of a circle, do not have direct potential phase alignment.