Precautions When Using Iord; Iord Program Example - Omron C200HW Operation Manual

Reading Data with IORD

5-5-5 Precautions when Using IORD

5-5-6 IORD Program Example

Unit No.
112
IORD is an improvised instruction which transfers all data with a single instruc-
tion. It increases the transfer time for the data as well as the cycle time for the
ladder program. The monitoring time for the cycle time should be adjusted as
required.
The transfer time is influenced by such factors as the model of the Program-
mable Controller being used, the ladder program, and the status of the Position
Control Unit, and cannot be calculated easily. Refer to Appendix A Data Calcula-
tion Standards to transfer positioning sequences using a C200HX and a
C200HW-NC413. It can be used as a model for setting cycle time monitoring
time.
Using IORD, a maximum of 128 words of data in consecutive addresses can be
transferred at one 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 becomes three words consisting of addresses from 1000 to 1002. If the
transfer is started or ended part-way through, the ER Flag (25503) will be turned
ON.
In this example, speeds #0 and #1 written in 5-4 Writing Data with IOWR are
read. The conditions to be set are the same as those used in the example of writ-
ing the data. The beginning word for the DM area where the read data is to be
stored is set at DM 0500.
Data transfer
Note Depending on the execution timing of the IORD instruction, it is possible that
errors generated as a result of data check at the time of transfer may not be
reflected at the CPU Unit. (Refer to 5-1 Transferring and Saving Data.)
Position Control Unit (NC413, Unit #2)
Data area
Section 5-5
Speed #0
Speed #1