Emerson Control Techniques Epsilon Eb Series Reference Manual page 185

Epsilon Eb and EN Drives Reference Manual
Note
It is important that all the encoder phases match the phase plot in the figure above. (i.e.,
A leads B, U leads V and V leads W. No particular phase relationship is required between
the A and B pari and the U, V, W signals.
Drive signal names are relatively standard. Your encoder signals may be named differently
or they may have the same names but the signals may be functionally different. You must
determine the proper encoder signal mapping to correctly wire your encoder to a drive.
Encoder signals are used for commutation. Incorrectly wired encoder signals can cause
damage to the drive.
Step 3: Determine Encoder Alignment
In order for the drive to commutate with a motor correctly, it must know how the encoder
commutation tracks and how the marker pulses are aligned with respect to the R, S and T
windings in the stator. The drive does not require any particular alignment position but
instead allows the alignment to be specified using the Motor Encoder U Angle and Motor
Encoder Marker Angle parameters.
If the motor under test has a defined encoder alignment which is repeated on all similar
motors, simply determine the proper angles then use the same settings on all similar motors.
If the motor under test does not have a specific encoder alignment, you should establish some
standard mechanical alignment before determining and setting the encoder electrical angles.
This will allow you to replace the motor with another one in the same alignment without
going through this procedure each time.
Reading Encoder Alignment
The reference motion for this test can be either CW or CCW. We will first use CCW. An
oscilloscope will be used to monitor the signals. This procedure must be performed with the
motor disconnected from the drive with the exception of the encoder power supply.
Be careful when using the drive encoder power supply for testing a motor. Shorting the 5
V drives encoder power supply will blow an internal fuse which can only be replaced at
the factory.
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