Yaskawa MP2000 Series: User's Manual for Motion Programming - Manual (Page 149)

8 Command Reference
8.1.9 Interpolation Acceleration Time Change (IAC)
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(5) Supplemental Information on IAC Command
(a) Related Motion Parameters
There is no motion setting parameter related to the IAC command.
The interpolation acceleration time specified by executing the IAC command is the control data exclusively
reserved for motion programs, and cannot be specified by using a motion setting parameter.