Yaskawa LEGEND-MC - Manual (Page 332)

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LEGEND-MC User’s Manual
Homing Example (FE and FI method)
This example demonstrates how to home servos with a home sensor in the middle of a slide where it is
possible for the servo to be on either side of the home sensor at power-up. If the servo is already past the
sensor, it will hit a limit switch first, and the #LIMSWI special label subroutine will reverse the CN
command and turn the servo around. The #BACKUP subroutine is used to make the servo come back to
the home input and go a small distance past it, so the #HOMING routine can always hit the same side of
the home sensor.
Ideally, the home sensor is a photo device. If there is a white and black strip along the slide, the photo eye
will see either light or dark, and the value of _HMX will be “1” or “0”. Under this design, the FEX
command can automatically determine the direction to find the transition point of the black and white
strip. You need not account for the limit switch or the #BACKUP routine in that case
Instruction Interpretation
#TEST
SPX=10000
ACX=1000000
DCX=1000000
CN,1
TRUE=1
FALSE=0
HOMING=FALSE
SHX; WT 2000
#HOMING
MG “Attempting to find
home” {N}
MG “(normal direction)”
FLX
BLX
HOMING=TRUE
JGX=8192;
FEX;BGX;AMX
HOMING=FALSE
JG*=500; FIX; BGX;
MCX (MCX because the controller will automatically define the position
as zero when the index is found)
MG “Homed O.K!” EN
#BACKUP
MG “Going back to the
{N}
MG “home input..”
CN,-1