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I/O Memory Allocations Section 2-3
• When the Port 1 Port Settings Change Bit (a bit between A62001 to
A63501 (see note a)) or Port 2 Port Settings Change Bit (a bit between
A62002 to A63502 (see note b)) is turned ON.
Note a) Bits are allocated in the following order: Unit number 0: A62001,
unit number 1: A62101, unit number 2: A62201, and so on through
unit number F: A63501.
b) Bits are allocated in the following order: Unit number 0: A62002,
unit number 1: A62102, unit number 2: A62202 and so on through
unit number F: A63502.
2. When STUP(237) is executed, the CPU Unit automatically turns ON the
Port 1 or Port 2 Port Settings Change Bit and updates the System Setup.
For details on the STUP(237) instruction, see Appendix O Changing Com-
munications Port Settings Using STUP(237).
2-3 I/O Memory Allocations
This section explains the DM Area, CIO Area, and Auxiliary Area allocations
to the Serial Communications Boards and Serial Communications Units. The
Serial Communications Board uses the allocations for the Inner Board of the
CPU Unit. The Serial Communications Unit is allocated I/O memory as a CPU
Bus Unit according to the unit number setting.
2-3-1 DM Area
Serial Communications
Boards (CS Series Only)
The Setup Area allocated in the DM Area consists of 20 words between
D32000 and D32767, except for the Modbus-RTU slave mode, which uses 40
words for the Setup Area. These words are used to set the serial communica-
tions mode, communications specifications, and other settings for the Serial
Communications Board.
The 20 words from D32000 to D32009 and D32020 to D32029 are used for
port 1, and the 20 words from D32010 to D32019 and D32030 to D32039 are
used for port 2. The remaining words are reserved for the system.
Setup Area Allocated in the DM Area
D32000 to D32767
Words Usage
D32000 to D32009 Port 1 Settings
D32010 to D32019 Port 2 Settings
D32020 to D32029 Port 1 Settings for Modbus-RTU slave mode
D32030 to D32039 Port 2 Settings for Modbus-RTU slave mode
D32040 to D32767 Reserved for the system
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