Omron TJ1-MC04 - PROGRAMMING 1 Programming Manual page 255

Examples and tips
Absolute switch origin search plus limit switches
The origin search function is performed by searching for an
external limit switch that is positioned absolutely and the position of
which defines the origin position. The example for this homing
procedure is shown in the figure.
The figure shows the possible scenarios for absolute origin search
plus limit switches. These scenarios depend on the position of the
moving part when the power comes on.
The program example that does this origin search sequence is
given below.
'Absolute origin switch: IN0
'Left limit switch: IN1
'Right limit switch: IN2
BASE(0)
DATUM_IN=0
FW_IN=2
RV_IN=1
SERVO=ON
WDOG=ON
DATUM(4)
WA(1)
WAIT UNTIL MTYPE=0 OR IN(1)=OFF
IF IN(1)=ON
FORWARD
WAIT UNTIL IN(0)=ON
WAIT UNTIL IN(0)=OFF
CANCEL
DATUM(4)
PROGRAMMING MANUAL
fig. 26
OFF ON OFF origin limit switch
moving part
min. limit switch ON OFF OFF ON
fig. 27
REVERSE FORWARD
max. limit switch
min limit switch
origin limit switch
max limit switch
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