ADLINK Technology cPCI-8168, Руководство пользователя

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Operation Theory 67
For example, if a rotary encoder has 2000 pulses per rotation,
then the counter value read from the position counter will be 8000
pulses per rotation when the AB phase is multiplied by four.
If users don’t use an encoder for motion controller, the feedback
source for this counter must be set as a pulse command output or
the counter value will always be zero. If it is set as a puse com-
mand output, users can get the position counter value from pulse
command output counter because the feedback pulses are inter-
nally counted from command output pulses.
The following diagrams show these two types of pulse feedback
signals.
Plus and Minus Pulses Input Mode (CW/CCW Mode)
The pattern of pulses in this mode is the same as the Dual
Pulse Output Mode in the Pulse Command Output section,
except that the input pins are EA and EB.
In this mode, pulses from EA pins cause the counter to count
up, whereas EB pin caused the counter to count down.
90° phase difference signals Input Mode (AB phase Mode)
In this mode, the EA signal is a 90° phase leading or lagging in
comparison to the EB signal. “Lead” or “lag” of phase differ-
ence between two signals is caused by the turning direction of
the motor. The up/down counter counts up when the phase of
the EA signal leads the phase of the EB signal.