Omron SYSMAC C500-NC113, Operation Manual

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9-1 Section
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In particular, if a WRIT instruction is immediately followed in the program by
a READ instruction for reading the status, as shown in example (a) in the
above diagram, the READ instruction will not be executed after the WRIT
instruction is executed (i.e., the Equals Flag will not turn ON). In examples
(b) and (c), after the WRIT and READ instructions in the upper part of the
diagram have been executed, the WRIT and READ instructions in the lower
part of the diagram will be executed in subsequent cycles if the WRIT and
READ in the upper part are not executed.
2. Approximately every 10 ms, asynchronous with the CPU Unit, the Position
Control Unit carries out execution processing for commands from the
shared memory and data reading, as well as status writing to the shared
memory. While this processing is being carried out, the Position Control Unit
ignores any WRIT or READ instructions from the CPU Unit. Therefore, be
sure to insert WRIT and READ instructions into the program in such a way
that they fit within 10-ms intervals.
Create the program as shown in the following example:
Command set
Command transfer
9 words*
to
WRIT
Always ON
READ
* 5 words for the NC113
For details on transferring data and commands consecutively, refer to 10-3 Us-
ing Continuous Operation .