Omron CJ - REFERENCE MANUAL 10-2009 Reference Manual page 999

Hint
• When another file memory related operation (file memory format, file copy, file delete, etc.) is
executed from the ladder program, send the file memory related FINS command to the local CPU
Unit with a CMND(490) instruction.
Precaution
• During normal instruction processing, FWRIT(701) is used only to start writing of the file memory.
The instruction execution times given toward the end of this manual are thus the times required to
start writing, not to complete it. Actual writing (transfer) is performed by the file access processing in
peripheral servicing. Therefore, once FWRIT(701) has been executed, writing is continuously
executed even if the execution condition is OFF in following cycles.
The time required to complete data transfer for FWRIT(701) will depend on the amount of data being
transferred, the service time allocated to file access processing, and other conditions. As a guideline,
the transfer times for a cycle time of 10 ms for a file in the root directory with the default service time
settings will be 1.97 s (new file) or 1.33 s (existing file) for 1,024 words and 6.64 s (new file) or 6.12 s
(existing file) for 9,999 words.
• When transfer has been completed, the File Memory Operation Flag (A343.13) will turn OFF. This
flag can be used for exclusive control of file memory instructions.
• The source data is read from absolute internal memory addresses in RAM, so the entire block of data
will be read even if the data spans two or more data areas. For example, if the first destination
address is in the Work Area but the amount of data exceeds the capacity of this area, FWRIT(701)
will continue reading data at the beginning of the next area (in this case, the Timer Area). When
FWRIT(701) is executed, the number of words or fields specified in D1 and D1+1 is written to A346
and A347 (Number of Data to Transfer) and this value is decremented by 1 as each word or field is
transferred. The content of these words can be checked to verify that the expected number of words
or fields were transferred.
• The File Memory Operation Flag (A343.13) is turned ON when FWRIT(701) is executed. An error will
occur and the instruction will not be executed if A343.13 is already ON.
• If the specified starting word exceeds the number of words in the data file, the File Write Error Flag
(A343.08) will be turned ON and the data will not be written.
• The File Write Impossible Flag (A343.09) will be turned ON and the instruction will not be executed if
data could not be written because the file was write-protected or there was not enough free memory.
• The File Write Error Flag (A343.08) will be turned ON and the instruction will not be executed if the
specified file is not the correct data type or the file data has been corrupted.
• A few seconds is required for the CPU Unit to detect a Memory Card after it has been inserted. If a
Memory Card is going to be accessed soon after power is turned ON or after a Memory Card is
inserted, use the Memory Card Detected Flag (A343.15) in a NO input condition as shown below to
be sure that the Memory Card has been detected.
Execution
A343.15
condition
Memory Card
Detected Flag
• The source data words starting at S are accessed and read during the peripheral servicing after
FWRIT(701) is executed. If the source data is changed before the file memory write processing is
completed, the changed data may be written to the file.
CS/CJ/NSJ Series Instructions Reference Manual (W474)
A343.13
File Memory
Operation Flag
@FWRIT
C
D1
D2
S
3. Instructions
3
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