Omron CPM1 Programming Manual page 162

CQM1 Memory Area Functions
3-1-9 DM Area
!Caution Although the CQM1-CPU11-E and CQM1-CPU21-E do not support DM 1024
3-1-10 UM Area
one for the timer instruction, but rather is reset only when the reset input
goes ON.
Data is accessed in word units. As shown below, the DM area contains both
an area that can be freely used and areas with specific functions.
DM0000
DM1024
(see note 1)
DM6144
Fixed DM
(see note 2)
DM6569
Error Log
DM6600
PC Setup
(see note 2)
DM6655
Note 1. The CQM1-CPU11-E and CQM1-CPU21-E do not support DM 1024
through DM 6143.
2. Turning ON pin 1 of the DIP switch on the CPU Unit will prevent writing
even by means of peripheral devices.
Fixed DM contents, the PC Setup, the user program, and the instructions
table can all be saved to and loaded from a Memory Cassette as a single unit.
Refer to page 149 for details.
through DM 6143, an error will not occur if they are addressed. Any attempt to
write to these words will have no effect and any reads will produce all zeros.
The UM area stores the user's program. UM area contents can be read and
written only as program data, and not as words. The following table shows the
size of the UM area in the CQM1 CPU Units.
CPU Unit Model
CQM1-CPU11/21-E
CQM1-CPU4@-EV1
This area has no specific functions and can be used
freely. Both reading and writing are possible from the
program.
This area cannot be written from the program. It is used
for storing information that is not to be changed. Writing
can be executed by means of peripheral devices only.
This area stores the error log. The user can only read this
area, and cannot write into it.
This area stores information related to CQM1 operation.
The settings are made by means of peripheral devices.
UM area size
3.2 KW
7.2 KW
Section 3-1
141