Serial Plc Link Area - Omron CJ2 CPU UNIT SOFTWARE User Manual

6 I/O Memory Areas
6-8

Serial PLC Link Area

Serial PLC Link Area addresses range from CIO 3100 to CIO 3189 for words and CIO 3100.00 to CIO
3189.15 for bits.
The Serial PLC Link Area is used for Serial PLC Links. They can be used for data links to other PLCs.
For Serial PLC Links, data is exchanged between CPU Units using serial ports without communications
programming.
The words in the Serial PLC Link Area are allocated automatically according to the settings made in the
PLC Setup of the polling PLC.
• Serial PLC Link mode
• Serial PLC Link number of send words
• Serial PLC Link maximum unit number
CJ2M CPU Unit
Serial port
Words in the Serial PLC Link Area that are not allocated to Serial PLC Links can be used only in the
program as work bits. Bits in the Serial PLC Link Area can be force-set and force-reset.
The contents of this area will be cleared in the following cases:
• The operating mode is changed from PROGRAM mode to RUN/MONITOR mode or vice-versa.
• When the PLC power is reset
• When the area is cleared from the CX-Programmer
• When operation stops due to a fatal error (except that the area is not cleared when stopping opera-
tion due to execution of a FALS(007) instruction)
Setting the IOM Hold Bit (A500.12) to ON
If the IOM Hold Bit (A500.12) is ON, the contents of this area will be retained when a fatal error
occurs or the operating mode is changed from PROGRAM mode to RUN or MONITOR mode or
vice-versa. However, the contents will be cleared when power is cycled.
Setting the IOM Hold Bit (A500.12) to ON and Protecting the IOM Hold Bit
itself in the PLC Setup
The contents of this area will be maintained even when the power is cycled.
6-18
CJ2M CPU Unit CJ2M CPU Unit
Serial port Serial port
Serial PLC Links

Serial PLC Link Area

CJ2 CPU Unit Software User's Manual