Incremental rotary encoder output signal is a square wave signal, and can be divided with commutation signals of incremental rotary encoders and ordinary incremental rotary encoder, Common incremental rotary encoder with two-phase quadrature square wave pulse output signals a and B, as well as the zero signal Z; with commutation signals of incremental rotary encoders except with a / B / Z output signal, but also with each other electronically commutated difference of 120 degrees in-phase signal U / V / W, U / V / W are each the number of periods per revolution to be consistent with the number of rotor poles.
　　With commutation signals of incremental rotary encoder U / V / W commutation signal of electronic phase and phase rotor poles, or say an electrical angle phase alignment method is as follows:
　　1. Use a DC power supply to the motor of the U / V winding through a less than rated current DC, U into, V out, the motor shaft will be directed to a balanced position.
　　2. oscilloscope encoder U-phase signal and Z signal.
　　3. Adjust the relative position of the encoder shaft and the motor shaft.
　　4. The side adjustment, while observing the encoder Z-phase signal U and hopping along until the Z signal is stable at a high level (in this default normal Z signal is low), the lock relative positional relationship between the encoder and motor .
　　5. The motor shaft twisting back and forth, after doing nothing, if every time the motor shaft freely return to equilibrium position, Z signal can be stabilized at a high level, then the effective alignment.
　　After removed the DC power supply to verify the following:
　　1. Use an oscilloscope to observe the encoder and motor U-phase signal U / V line back EMF waveform.
　　2. Turn the motor shaft, the encoder U believe U / V line with the rising number of motor back EMF from low to high zero crossing coincidence, Z signal of the encoder also appears on the crossings.
　　The verification method, the method can also be used as the alignment. Note that, at this incremental rotary encoder U believe phase number zero that is the motor UV line EMF phase zeros aligned, since the motor's U EMF, a difference of 30 degrees with the UV line back EMF between, Thus after this alignment, incremental rotary encoder U believe that number zero phase motor U EMF phase point of -30 degrees aligned and consistent with the phase angle motor phase U EMF waveform, so at this time increment type rotary encoder U believe numbers zero and phase Motor phase angle of 30 degrees point alignment.
　　Some companies are accustomed to the servo encoder Zero U believed directly aligned with the number zero Motor angle, for this purpose, you can:
　　1. three equal-value resistors connected into a star, and then the three star-connected resistors respectively connected UVW three-phase motor winding leads; 　　2. oscilloscope to observe the midpoint of U-phase motor with star-shaped input resistance, it can be approximated waveform EMF motor U.
　　3. The ease of operation is based on the relative position adjustment encoder shaft with the motor shaft, or the relative position of the encoder housing and the motor housing.
　　4. The side adjustment, while observing the encoder U believe the rising number and motor U EMF waveform from low to high zero crossing, eventually rising and zero crossings coincide, the lock relative positional relationship between the encoder and the motor, complete alignment .
　　Since 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 the direct phase-aligned potential.