Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 975

Basic I/O Unit Instructions
Flags
Precautions
Example
Name Label
Error Flag ER
Equals Flag =
I/O refreshing will not be performed if a CPU Bus Unit Error (A40207) or CPU
Bus Unit Setup Error (A40203) has occurred in the specified CPU Bus Unit.
I/O refreshing will be stopped if an I/O Bus Error occurs while I/O refreshing is
being performed by DLNK(226).
DLNK(226) refreshes data between the CPU Unit and specified CPU Bus
Unit. Some time is required for the data exchange with the CPU Bus Unit (for
example, a data link with a Controller Link Unit).
If the specified CPU Bus Unit is exchanging data, DLNK(226) will not be exe-
cuted and the Equals Flag will be turned OFF. We recommend programming
the execution conditions shown below so that the execution of DLNK(226) will
be retried automatically.
Execution
condition
b
a
When CIO 000000 is ON in the following example, DLNK(226) performs
immediate I/O refreshing (in this case, data link refreshing within the PLC) for
the CPU Bus Unit with unit number 1 (in this case, a Controller Link Unit).If I/O
refreshing cannot be performed because the Controller Link Unit is refreshing
data, the Equals Flag will be turned OFF causing W001 to be turned ON so
that the instruction execution will be retried in the next cycle. When the I/O
refreshing is completed normally, the Equals Flag will be turned ON and the
instruction will not be retried in the next cycle.
Operation
ON if the specified unit number is not between 0000 and
000F hex (between 0 and 15 decimal).
ON if the PLC does not have a CPU Bus Unit with the
specified unit number.
With the CS1D CPU Units: ON if the active and standby
CPU Units could not be synchronized.
OFF in all other cases.
OFF if the I/O refreshing could not be performed because
the CPU Bus Unit was refreshing data.
OFF if there was a CPU Bus Unit Error or CPU Bus Unit
Setup Error in the specified CPU Bus Unit.
OFF if DLNK(226) was executed in an interrupt task,
there was a conflict with regular I/O refreshing, and over-
lapping refreshing occurred.
ON if the I/O refreshing was completed normally.
DLNK
Equals Flag
Equals Flag
Section 3-23
N
a
b
935