ADLINK PCI-8124-C - Manual (Page 40)

30 Operation Theory
90° phase shifted signals (AB phase Mode)
In this mode, EA signal is a 90° phase leading or lagging to EB
signal. “Lead” or “lag” of phase difference between two signals is
caused by the turning direction of the motor. The up/down coun-
ters counts up when the phase of EA signal leads the phase of EB
signal.
The following diagram shows the waveform.
4.1.2 Index Input (EZ)
The index input (EZ) signals of the encoders are used as the
“ZERO” reference. This signal is common on most rotational
motors. EZ can be used to define the absolute position of the
mechanism. The input logic polarity of the EZ signals is program-
mable with ADLINK library.
With EZ signal, users can realize the homing procedure and clear
the counter as zero.