240
Cycle Time/High-speed Processing Section 6-1
refreshing, but this cyclic refreshing can be disabled for individual Units in the
PLC Setup.
There are basically three reasons to disable cyclic refreshing:
1,2,3... 1. Cyclic refreshing for Special I/O Units can be disabled when the cycle time
is too long because so many Special I/O Units are installed.
2. If the I/O refreshing time is too short, the Unit’s internal processing may not
be able to keep pace, the Special I/O Unit Error Flag (A40206) will be
turned ON, and the Special I/O Unit will not operate properly.
In this case, the cycle time can be extended by setting a minimum cycle
time in the PLC Setup or cyclic I/O refreshing with the Special I/O Unit can
be disabled.
3. Always disable cyclic refreshing for a Special I/O Unit when it will be re-
freshed in an interrupt task by IORF(097). An interrupt task error will occur
and the Interrupt Task Error Flag (A40213) will be turned ON if cyclic re-
freshing and IORF(097) refreshing are performed simultaneously for the
same Unit.
When cyclic refreshing has been disabled, the Special I/O Unit’s data can be
refreshed during program execution with IORF(097).
PLC Setup
The Cyclic Refreshing Disable Bits for Special I/O Units 0 to 95 correspond
directly to the 96 bits in addresses 226 through 231.
6-1-8 Improving Refresh Response for CPU Bus Unit Data
This function is supported only by CS1-H, CJ1-H, or CJ1M CPU Units.
Normally, data links and other special data for CPU Bus Units are refreshed
along with the CIO and DM Area words allocated to the Units during the I/O
refresh period following program execution.
The following table lists some example of special data for CPU Bus Units.
The following functions can be used to improve the refresh response for spe-
cial CPU Bus Unit data with CS1-H, CJ1-H, or CJ1M CPU Units.
• Reducing the cycle time by using parallel processing mode or high-speed
instructions (Parallel processing mode is not supported by CJ1M CPU
Units.)
• Executing DLNK(226) to refresh specific CPU Bus Units by specifying
their unit numbers (DLNK(226) can be used more than once in the pro-
gram.)
Address Name Setting Default
226 bit 0 Cyclic Refreshing Disable Bit
for Special I/O Unit 0
0: Enabled
1: Disabled
0 (Enabled)
:: ::
231 bit 15 Cyclic Refreshing Disable Bit
for Special I/O Unit 95
0: Enabled
1: Disabled
0 (Enabled)
Units Special data
Controller Link Units and
SYSMAC LINK Units
Controller Link and SYSMAC LINK data links (includ-
ing automatically and user-set links)
CS/CJ-series DeviceNet
Units
DeviceNet remote I/O communications (including
fixed allocations and user-set allocations)
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