Omron CJ - 08-2008 - I;O Refreshing and Peripheral Servicing

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CPU Unit Operation Section 10-1
10-1-2 I/O Refreshing and Peripheral Servicing
I/O Refreshing
I/O refreshing involves cyclically transferring data with external devices using
preset words in memory. I/O refreshing includes the following:
• Refreshing between Basic I/O Units and I/O words in the CIO Area
• Refreshing between Special I/O Units and CPU Bus Units, and the words
allocated to these in the CIO Area (and for CPU Bus Units, words allo-
cated in the DM Area)
• Refreshing Unit-specific data for Special I/O Units and CPU Bus Units.
All I/O refreshing is performed in the same cycle (i.e., time slicing is not used).
I/O refreshing is always performed after program execution (even in a Parallel
Processing Mode for CJ1-H CPU Units).
Units Max. data
exchange
Data exchange area
Basic I/O Units Depends on the
Unit.
I/O Bit Area
Special I/O
Units
Words allocated in CIO
Area
10 words/Unit
(Depends on the
Unit.)
Special I/O Unit Area
Unit-
specific
data
DeviceNet Mas-
ter Unit
Depends on the
Unit.
Words set for remote I/O
communications (for
either fixed or user-set
allocations)
CompoBus/S
Master Unit
Depends on the
Unit.
Special I/O Units Area
CPU Bus
Units
Words allocated in CIO
Area
25 words/Unit CJ-series CPU Bus Unit
Area
Words allocated in DM
Area
100 words/Unit CJ-series CPU Bus Unit
Area
Unit-
specific
data
Controller Link
Unit and SYS-
MAC LINK Unit
Depends on the
Unit.
Words set for data links
(for either fixed or user-
set allocations)
DeviceNet Unit Depends on the
Unit.
Words set for remote I/O
communications (for
either fixed or user-set
allocations)
Serial Communi-
cations Unit
Depends on the
protocol macros.
Communications data
set for protocol macros
Ethernet Unit Depends on the
Unit.
Communications data for
socket services initiated
by specific control bit
operations.