ADLINK PCI-8158 - Manual (Page 78)

68 Operation Theory
respectively. The numbers of pulse represent distance in pulse.
The frequency of the pulse represents speed in pulse per second.
Pulses output from the CW pin makes the motor move in positive
direction, whereas pulse output from the CCW pin makes the
motor move in negative direction. The following diagram shows
the output waveform of positive (+) commands and negative (-)
commands.
The command pulses are counted by a 28-bit command counter.
The command counter can store a value of total pulses outputting
from controller.
4.3.2 Pulse feedback input interface
Our motion controller provides one 28-bit up/down counter of each
axis for pulse feedback counting. This counter is called position
counter. The position counter counts pulses from the EA and EB
signal which have plus and minus pins on connector for differential
signal inputs. It accepts two kinds of pulse types: dual pulse input
(CW/CCW mode) and AB phase input. The AB phase input can be
multiplied by 1, 2 or 4. Multiply by 4 AB phase mode is the most
commonly used in incremental encoder inputs.
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.