Omron CJ - 09-2009 Operation Manual page 433

CPU Bus Unit Area
Forcing Bit Status
CPU Bus Unit Area
Initialization
1,2,3...
IOM Hold Bit Operation
Each CPU Bus Unit is allocated 25 words based on its unit number, as shown
in the following table.
Unit number Allocated words
0 CIO 1500 to CIO 1524
1 CIO 1525 to CIO 1549
2 CIO 1550 to CIO 1574
3 CIO 1575 to CIO 1599
4 CIO 1600 to CIO 1624
5 CIO 1625 to CIO 1649
6 CIO 1650 to CIO 1674
7 CIO 1675 to CIO 1699
8 CIO 1700 to CIO 1724
9 CIO 1725 to CIO 1749
A CIO 1750 to CIO 1774
B CIO 1775 to CIO 1799
C CIO 1800 to CIO 1824
D CIO 1825 to CIO 1849
E CIO 1850 to CIO 1874
F CIO 1875 to CIO 1899
The function of the 25 words depends upon the CPU Bus Unit being used. For
details, refer to the Unit's operation manual.
Words in the CPU Bus Unit Area that aren't allocated to CPU Bus Units can
be used only in the program.
Bits in the CPU Bus Unit Area can be force-set and force-reset.
The contents of the CPU Bus Unit Area will be cleared in the following cases:
1. The operating mode is changed from PROGRAM to RUN or MONITOR
mode or vice-versa and the IOM Hold Bit is OFF.
2. The PLC's power supply is cycled and the IOM Hold Bit is OFF or not pro-
tected in the PLC Setup.
3. The CPU Bus Unit Area is cleared from a Programming Device.
4. PLC operation is stopped when a fatal error other than an FALS(007) error
occurs. (The contents of the CPU Bus Unit Area will be retained when
FALS(007) is executed.)
If the IOM Hold BIt (A50012) is ON, the contents of the CPU Bus Unit Area
won't be cleared when a fatal error occurs or the operating mode is changed
from PROGRAM mode to RUN/MONITOR mode or vice-versa.
If the IOM Hold BIt (A50012) is ON and the PLC Setup's "IOM Hold Bit Status
at Startup" setting is set to protect the IOM Hold Bit, the contents of the CPU
Bus Unit Area won't be cleared when the PLC's power supply is cycled.
Section 9-5
385