Omron CJ - PROGRAMMING MANUAL 08-2008 Programming Manual page 304

Cycle Time/High-speed Processing
266
2. CS1D CPU Units for Duplex-CPU Systems do not support immediate re-
freshing.
■ IORF(097): I/O REFRESH
IORF(097) can be used to refresh a range of I/O words upon execution of the
instruction. IORF(097) can refresh data allocated to Basic I/O Units and Spe-
cial I/O Units.
The following example shows IORF(097) used to refresh 8 words of I/O data.
When a high-speed response is needed from a calculation that uses input
data from a Basic I/O Unit or outputs data to a Basic I/O Unit, use IORF(097)
just before and just after the calculation instruction.
Note IORF(097) has a relatively long instruction execution time and that execution
time increases proportionally with the number of words being refreshed, so it
can significantly increase the cycle time. Refer to 10-5 Instruction Execution
Times and Number of Steps in the Operation Manual for more details.
■ FIORF(225): SPECIAL I/O UNIT I/O REFRESH (CJ1-H-R CPU Units Only)
FIORF(225) can be used to refresh the following data in a Special I/O Unit
with the specified unit number, only when necessary.
• Allocated CIO Area words
• Allocated DM Area words
FIORF(225)
N
Example:
FIORF(225)
&20
A Special I/O Unit's regular cyclic I/O refreshing can be disabled in the PLC
Setup (by turning ON the Unit's Special I/O Unit Cyclic Refresh Disable Bit),
and I/O refreshing can be performed with the Unit only when necessary by
executing FIORF(225). This function can prevent the PLC's cycle time from
increasing when a Special I/O Unit is mounted.
Note IORF(097) can immediately refresh a specified range of I/O words (in the CIO
Area only) allocated to Basic I/O Units or Special I/O Units. In contrast,
FIORF(225) immediately refreshes all of the CIO Area words and DM Area
words allocated to a specified Special I/O Unit.
■ Using DLNK(226): CPU Bus Unit I/O Refresh
DLNK(226) is used to refresh data for a CPU Bus Unit of a specified unit num-
ber. The following data is refreshed.
St: Start word
E: End word
St
The data in all words from St through E are
refreshed when IORF(097) is executed.
E
The 7 words from CIO 0010 through CIO 0016
are refreshed when IORF(097) is executed.
0016
N: Special I/O Unit's unit number
Refreshes the CIO words and DM words allocated to
the Special I/O Unit with unit number &20.
Section 6-1