Omron CJ - PROGRAMMING MANUAL 12-2009 Programming Manual page 307

Cycle Time/High-speed Processing
1. Cyclic Refreshing
2. Immediate Refreshing
Note
I/O refreshing is performed after all of the instructions in executable tasks
have been executed. (The PLC Setup can be set to disable cyclic refreshing
of individual Special I/O Units.)
END
END
END
I/O refreshing
Using the Instruction's Immediate Refresh Variation
When an address in the I/O Area is specified as an operand in the immediate-
refreshing variation of an instruction, that operand data will be refreshed when
the instruction is executed. Immediate-refreshing instructions can refresh data
allocated to Basic I/O Units.
Immediate refreshing is also possible for the built-in I/O on CJ1M CPU Units.
Immediate refreshing
Operand
specification
Operand
type
Input or source
Output or destination
1. The execution times for immediate-refreshing variations are longer than
the regular variations of instructions, so the cycle time will be longer. Refer
to 10-5 Instruction Execution Times and Number of Steps in the Operation
Manual for details.
Task
Task
Task
CIO 0001
CIO 0002
CIO 0003
CIO 0004
Bit address specification
The entire word containing
the specified bit will be
refreshed just before the
instruction is executed (input
refreshing).
The entire word containing
the specified bit will be
refreshed just after the
instruction is executed (out-
put refreshing).
Section 6-1
Actual I/O data
Actual I/O data
Word address
specification
The specified word (16 bits)
will be refreshed just before
the instruction is executed
(input refreshing).
The specified word (16 bits)
will be refreshed just after
the instruction is executed
(output refreshing).
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