Omron CJ1W-SCU32 Operation Manual page 452

A Standard System Protocol
Note The hexadecimal equivalents of sequences numbers are given in parentheses.
Ladder Interface Settings
YES: User settings are required for the 3rd and 4th operands of PMCR(260).
NO: Send word allocation: Set the constant #0000 for the 3rd operand (S).
Receive word allocation: Set the constant #0000 for the 4th operand (D).
R-118 CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)