ADLINK Technology PCI-8136, Руководство пользователя

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Operation Theory 33
90° phase difference signals Input Mode(AB phase Mode)
In this mode, the EA signal is 90° phase leading or lagging in com-
parison to the EB signal. Where “lead” or “lag' of phase difference
between two signals is caused by the turning direction of motors.
The up/down counter counts up when the phase of EA signal
leads the phase of EB signal.
The following diagram shows the waveform.
Pulse and direction input (Pulse/DIR)
In this mode, the high / low status of EB will cause the counter
value to increase or decrease (Direction), whereas the high/low
status of EA will cause the count number to increase or decrease
(Pulse).
4.4.2 Encoder Counter Value Capture (latch)
The EZ (index signal) of each pulse input channel doesn't affect
counter value. It can capture (latch) the current counter value by
proper setting, and generate an interrupt signal when receiving a
rising edge. The counter value capture function is very useful to
sensing the position of a moving object.