Omron CPM1

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CPM1/CPM1A Memory Area Functions Section 3-2
3-2 CPM1/CPM1A Memory Area Functions
3-2-1 Memory Area Structure
The following memory areas can be used with the CPM1/CPM1A.
Note 1. IR and LR bits that are not used for their allocated functions can be used
as work bits.
2. The contents of the HR area, LR area, Counter area, and read/write DM
area are backed up by a capacitor. The backup time varies with the ambi-
ent temperature, but at 25
°C, the capacitor will back up memory for 20
days. If the power supply is off longer than the backup time, memory con-
tents will be cleared and AR1314 will turn ON. (This flag turns ON when
data can no longer be retained by the built-in capacitor.) Refer to 2-1-2
Characteristics in the CPM1 and CPM1A Operation Manual for a graph
showing the backup time vs. temperature.
3. When accessing a PV, TC numbers are used as word data; when access-
ing Completion Flags, they are used as bit data.
4. Data in DM 6144 to DM 6655 cannot be overwritten from the program, but
they can be changed from a Peripheral Device.
Data area Words Bits Function
IR area
1
Input area IR 000 to IR 009
(10 words)
IR 00000 to IR 00915
(160 bits)
These bits can be allocated to the external
I/O terminals.
Output area IR 010 to IR 019
(10 words)
IR 01000 to IR 01915
(160 bits)
Work area IR 200 to IR 231
(32 words)
IR 20000 to IR 23115
(512 bits)
Work bits can be freely used within the pro-
gram.
SR area SR 232 to SR 255
(24 words)
SR 23200 to SR 25515
(384 bits)
These bits serve specific functions such as
flags and control bits.
TR area --- TR 0 to TR 7
(8 bits)
These bits are used to temporarily store ON/
OFF status at program branches.
HR area
2
HR 00 to HR 19
(20 words)
HR 0000 to HR 1915
(320 bits)
These bits store data and retain their ON/
OFF status when power is turned off.
AR area
2
AR 00 to AR 15
(16 words)
AR 0000 to AR 1515
(256 bits)
These bits serve specific functions such as
flags and control bits.
LR area
1
LR 00 to LR 15
(16 words)
LR 0000 to LR 1515
(256 bits)
Used for a 1:1 data link with another PC.
Timer/Counter area
2
TC 000 to TC 127 (timer/counter numbers)
3
The same numbers are used for both timers
and counters.
DM area
Read/write
2
DM 0000 to DM 0999
DM 1022 to DM 1023
(1,002 words)
--- DM area data can be accessed in word units
only. Word values are retained when the
power is turned off.
Error log DM 1000 to DM 1021
(22 words)
--- Used to store the time of occurrence and
error code of errors that occur. These words
can be used as ordinary read/write DM when
the error log function isn’t being used.
Read-only
4
DM 6144 to DM 6599
(456 words)
--- Cannot be overwritten from program.
PC Setup
4
DM 6600 to DM 6655
(56 words)
--- Used to store various parameters that con-
trol PC operation.