ADLINK Technology PCI-8102, User Manual, Page: 87 / 210

Operation Theory 77
tion and current motion command’s target position in order to
calculate relative pulses of current command then send results
into pre-register. Please check if the target position is the same
with current command position before continuous motion. Espe-
cially after the home function and stop function.
4.6 Comparaters
There are 5 counter comparators of each axis. Each comparater
has dedicated functions. They are:
1. Positive soft end-limit comparator to command counter
2. Negative soft end-limit comparator to command counter
3. Command and feedback error counter comparator
4. General comparator for all counters
5. Trigger comparator for all command and feedback coun-
ters
4.6.1 Soft End-Limit Comparators
There are two comparators for end-limit function of each axis. We
call them for the soft end-limit comparators. One is for plus or pos-
itive end-limit and the other is for minus or negative end-limit. The
end-limit is to prevent machine crash when over traveling. We can
use the soft limit instead of a real end-limit switch. Notice that
these two comparators only compare the command position coun-
ter. Once the command position is over the limited set inside the
positive or negative comparators, it will stop moving as it touches
the end-limit switch.
4.6.2 Command and Feedback Error Counter Compara-
tors
This comparator is only for command and feedback counter error.
Users can use this comparator to check if the error is too big. It
can be set a action when this condition is met. The actions include
generating interrupt, immediately stop, and deceleration to stop.