ADLINK Technology cPCI-8168, User Manual

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54 Operation Theory
4.2.10 Home Return Mode
Home return means searching a zero position point on the coordi-
nate. Sometimes, users use a ORG, EZ or EL pin as a zero posi-
tion on the coordinate. When a machine is starting up, the
program needs to find a zero point. Our motion controller provides
a home return mode to set the zero point.
We have many home modes and each mode contains many con-
trol phases. All of these phases are done by ASIC, requiring no
software efforts or CPU loading. After home return is complete, the
target counter will be reset to zero as the desired position of home
mode. Consider a raising edge when in ORG input. Sometimes,
the motion controller will still output pulses to make the machine
slow down after reseting the counter. When the motor stops, the
counter may not be at the zero point, but the home return proce-
dure is finished. The counter value you see is a reference position
from the mahcine’s existing zero point.
The following diagrams show the various home modes: R means
counter reset ( command and position counter ). E means ERC
signal output.