173
DM Area
Section 3-9
Note
1.
The read-only area ranges from DM 6144 to DM 6568.
2.
The read-only area, PC Setup, program, and expansion instruction assign-
ments can be transferred to and from the Memory Cassette as a single
block of data. See
3-11 Using Memory Cassettes
for details.
Read/Write DM Area
The read/write area has no particular functions assigned to it and can be used
freely. It can be read and written from the program or Programming Devices.
The size of the read/write area depends upon the model of CPU Unit, as
shown in the following table.
Read-only Area
(DM 6144 to DM 6568)
DM addresses from DM 6144 to DM 6568 make up the read-only area. Data
in the read-only area can be read from instructions (not overwritten) and it can
be read and overwritten from Programming Devices. Use the read-only area
to store data that you don’t want to be changed from the program.
To prevent data from being overwritten by Programming Devices, turn ON pin
1 on the DIP switch on the front of the CPU Unit.
When a Controller Link Unit or Serial Communications Board is being used,
part of the read-only area is used for the Controller Link parameters/routing
table or Serial Communications Board settings, as shown in the following
table.
Note
Data cannot be overwritten from Programming Devices when pin 1 on the DIP
switch on the front of the CPU Unit is ON.
Error Log Area
(DM 6569 to DM 6599)
The CPU Unit automatically records the error code and date/time of up to 10
errors (fatal and non-fatal) in the error log area.
Error log area
DM 6569 to DM 6599
PC Setup (see note 2)
DM 6600 to DM 6655
Name
Range
CPU Unit
Range
Access from
instructions
Access from
Programming Devices
Read
Write
Read
Write
CQM1H-CPU11
DM 0000 to
DM 3071
YES
YES
YES
YES
CQM1H-CPU21
CQM1H-CPU51
DM 0000 to
DM 6143
CQM1H-CPU61
Name
Range
Access from
instructions
Access from
Programming Devices
Read
Write
Read
Write
Controller Link DM
parameters area
DM 6400 to
DM 6409
YES
No
YES
YES
(See note.)
Routing table area
DM 6450 to
DM 6499
Serial Communications
Board settings
DM 6550 to
DM 6559
Access from instructions
Access from Programming Devices
Read
Write
Read
Write
YES
No
YES
No
