ADLINK Technology cPCI-8168, User Manual

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72 Operation Theory
4.4.5 Counter Clear switch
The counter clear switch is an input signal used to reset the
counters of the motion controller. If a counter needs to be reset
according to an external command, this pin can be used as a con-
trol source.
4.4.6 Counter Latch switch
The counter latch switch is an input singal used to tell the counter
value at the active moment of one input.
4.4.7 Emergency stop input
cPCI-8168 has a global digital input that can stop all axes motion
immediately to prevent machine damage in emergeny situations.
Users can connect an emergency stop button to this input on their
machine, although it is suggested that this input is kept as a nor-
mal closed type for safety.
4.5 The Counters
There are four counters per axis on the cPCI-8168. They are as
follows:
X Command position counter : counts the number of output
pulses
X Feedback position counter : counts the number of input
pulses
X
Position error counter : counts the error between com-
mand and feedback pulse numbers.
X
General purpose counter : can be configured as command
position, feedback position, manual pulser, or half of ASIC
clock.
X
Target position recorder : A software-maintained target
position value of latest motion command.