ADLINK PCI-8124-C - Manual (Page 39)

Operation Theory 29
Dual Pulse Mode (CW/CCW Mode)
In this mode, EA is dedicated to count the pulses from external
source and view it as clockwise direction (CW). EB is dedicated to
count the pulses from external source and view it as counterclock-
wise direction (CCW). Simply put, EA counts up and EB counts
down. User can decide the normal high or normal low for those
two channels according to users’ devices. The following diagrams
show the normal high and normal low cases individually.