Omron CS1W-213 - REV 02-2008, Operation Manual

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Reading Data with IORD Section 5-5
5-5-5 Flags
When data is transferred using IORD, the Error Flag (word n+8, bit 12), the
ER Flag and the Equals Flag can be used to check whether the transfer has
been completed successfully. If the Error Flag (word n+8, bit 12) is ON, an
error code will be output to n+10 in the operating memory area. Check this
error code to determine the cause of the error and correct it.
5-5-6 Precautions when Using IORD
IORD is an instruction which transfers all specified data with a single execu-
tion. Therefore, it increases the cycle time for the ladder program by the time
required to transfer the data.
Refer to Appendix A Performance Characteristics for details on the times
required for transferring positioning sequences. Use them as reference values
for setting cycle time monitoring time.
When using IORD, be sure to transfer data in complete units, and do not start
or end transfer in the middle of data. For example, with X axis sequence #0,
the data unit consists of three words (addresses: 1000 to 1002). If the transfer
Flag ON Condition OFF Condition
ER • The number of transfer words set
in W is outside the range 0001 to
0080 Hex.
• The unit number set in W is out-
side the range 0000 to 005F Hex.
• A Special I/O Unit that is not com-
patible with the IORD instruction
has been specified.
• A Special I/O Unit for which a set-
ting error has been made or an
error is being generated has been
specified.
Anything else.
= The transfer has been completed
without error. • The address set in C, or the area
specified with this address and
the number of transfer words set-
ting, corresponds to only some,
and not all, of the words used to
store an item of data. For exam-
ple, the Equals Flag would turn
ON if the destination address set
for a speed, which is stored in 2
words, was set to an address that
corresponded to only the second
word.
• The address set in C, or the area
specified with this address and
the number of transfer words set-
ting, is outside the range of PCU
addresses.
• The number of transfer words is
set to 0.
• Another write process is being
executed.
• Data is being saved to flash
memory.
(Data is being saved for a SAVE
DATA bit or data is being saved
from the CX-Position.)
• The has just been turned ON or
restarted and is still performing
initial processing.