Emerson Control Techniques Epsilon Eb Series Reference Manual page 184

There are two steps in interfacing the encoder signals:
1. Determine whether your encoder has all the required signals to operate with a drive.
Some encoders, for example, do not provide a marker pulse or the marker pulse may not
have a fixed phase relationship to the commutation tracks.
2. Determine the mapping from the motor encoder signals to the drive. To help with this
second step we have provided a description of the required characteristics of the A, B, Z,
U, V and W encoder signals.
The signal relationships of A, B, U, V and W required by the drive are shown in the phase
plots below. For clarity the time scale against which A and B are plotted is different from that
which U, V and W are plotted. Note that A leads B and U leads V and V leads W.
Plots like these are obtained by powering the encoder then rotating the motor while observing
the signals on an oscilloscope. It is important to note which direction of motor rotation (CW
or CCW) generates the phasing shown in the figures below.
Figure 121: Phase Plot of A and B Encoder Channels
Figure 122: Phase Plot of U, V and W Encoder Signals with CCW Rotation
If the signal phasing in the figure above is obtained by rotating the motor -, the Motor Encoder
Reference Motion is defined as - and the Motor Encoder Reference Motion parameter is set
to 0. If the signal phasing in the figure above is obtained by rotating the motor +, then the
Motor Encoder Reference Motion is defined as + and the Motor Encoder Reference Motion
is set to 1.
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