Omron SYSMAC CJ Operation Manual page 310

How-to's
Note
298
Driver inputs mapped to the same number. However, the command
INVERT_IN(22) inverts the status of input 22 read by the controller. It affects
not only the unique software input 22, which is accessible with the IN
command, but all axis-specific inputs 22, which in this example are the EXT1
inputs of the connected Servo Drivers.
If a forward limit, reverse limit and origin input signal are used for an axis, it is strongly
recommended to use the following settings for the axis:
BASE(axis_number)
DAT_IN=18
' /DEC input in the corresponding Servo Driver is
' assigned
FWD_IN=16
INVERT_IN(16,ON)
' P_OT input in the corresponding Servo Driver is
' assigned. It is necessary to invert the signal
' because a Normally Closed input is expected.
REV_IN=17
INVERT_IN(17,ON)
' N_OT input in the corresponding Servo Driver is
' assigned. It is necessary to invert the signal
' because a Normally Closed input is expected
Also note that INVERT_IN inverts the selected input in all axes.
Section 5-1