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3-6-1 Expansion DM Area
The expansion DM area is designed to provide memory space for storing oper-
ating parameters and other operating data for Link Units and Special I/O Units.
Up to 3,000 words of UM can be allocated as Expansion DM (in 1K-word incre-
ments) using the UM ALLOCATION operation in the Programming Console or
LSS. Expansion DM area addresses run from DM 7000 to DM 9999.
The data in the expansion DM area can be transferred to the Special I/O Unit
Default Area (DM 1000 to DM 1999) when starting the PC or via programming
instruction to easily change operating parameters, enabling rapid switching be-
tween control processes. The expansion DM area can also be used to store pa-
rameters for other devices connected in the PC system, e.g., Programmable
Terminal character string or numeral tables.
The expansion DM area is used to store operating parameters and cannot be
used in programming like the normal DM area. Expansion DM can only be over-
written from a Peripheral Device, retains status during power interruptions, and
cannot be used for indirect addressing.
The UM area can be allocated as expansion DM area in increments of 1K words.
Once expansion DM area has been created, it is saved and transferred as part of
the program, i.e., no special procedures are required when saving or transfer-
ring the program.
UM ALLOCATION Operation The procedure for the Programming Console’s UM ALLOCATION operation is
shown below. Refer to

1-8-10 New Programming Console Operations

for details
on the DATA CLEAR and UM ALLOCATION instructions.
1, 2, 3...
1. Clear memory.
CLR RESETSET NOT EXT MONTR
Note UM allocation is not possible unless memory is cleared first.
2. The expansion DM area can be set to 0, 1, 2, or 3 K words. The following key
sequence creates a 2-KW expansion DM area (DM 7000 to DM 8999).
WRITECLR FUN VER CHG 2 SET 9 7 1 3
Press the 0 Key to eliminate the expansion DM area (0 KW).
or Press the 1 Key to allocate DM 7000 to DM 7999 (1 KW).
or Press the 2 Key to allocate DM 7000 to DM 8999 (2 KW).
or Press the 3 Key to allocate DM 7000 to DM 9999 (3 KW).
3-6-2 Special I/O Unit Data
Special I/O Units are allocated 1000 words in the DM Area as shown in the fol-
lowing table. The value set in the PC Setup (DM 6602 bits 08 to 15) determines
DM Area Section 3-6