Omron trajexia CJ1W-MCH72 Operation Manual page 48

Unit components
2-1-2 Unit number selector switch
2-1-2-1 Word allocations for CPU bus units
2-1-3 Battery
For example: if the command DISPLAY=1 is executed, LED 5 reflects the
activity of input IN13 (pin 16) of the 28-pin I/O connector.
The unit number identifies each individual CPU bus unit when more than one
CPU bus unit is connected to the same PLC. The unit number must be unique
for each CPU bus unit. If the unit number is not unique, the PLC system
cannot start correctly.
The unit number can range from 0 hex to F hex.
Words are automatically allocated in the CIO area of CJ-series PLC systems.
The CJ1W-MCH72 uses these words to receive control data from the CPU
and to notify the CPU of its status and the status of the communication.
The word addresses in the allocated areas depend on the unit number.
Because the word addresses are hard-coded in user programs, a user
program becomes invalid when the unit number is changed.
The table below gives the relation between the unit number and the allocated
CIO area words.
/i
Unit number Allocated words
0 hex (0) CIO1500..CIO1524
1 hex (1) CIO1525..CIO1549
2 hex (2) CIO1550..CIO1574
3 hex (3) CIO1575..CIO1599
4 hex (4) CIO1600..CIO1624
5 hex (5) CIO1625..CIO1649
6 hex (6) CIO1650..CIO1674
7 hex (7) CIO1675..CIO1699
The battery makes sure that the following RAM data is preserved when the
power supply is off:
• User programs
• VR variables
• Table memory
If the battery is not installed, or the battery voltage is too low, the RAM data is
lost when the power supply is off.
User programs, VR variables and TABLE memory can be stored into flash
memory, which do not need battery back up, on user request using the BASIC
commands EPROM and FLASHVR.
UNIT
No.
Unit number selector switch
Unit number
8 hex (8)
9 hex (9)
A hex (10)
B hex (11)
C hex (12)
D hex (13)
E hex (14)
F hex (15)
Section 2-1
Allocated words
CIO1700..CIO1724
CIO1725..CIO1749
CIO1750..CIO1774
CIO1775..CIO1799
CIO1800..CIO1824
CIO1825..CIO1849
CIO1850..CIO1874
CIO1875..CIO1899
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