Omron ZS Series Communication Command Reference page 63

[About Continual Data Obtaining]
Note that sending a request command is necessary after starting the data
reception until the next data accumulation is completed as described in "How
to obtain flow data."
Calculate the time for the completion of the accumulation using the formula
specified in the step above: measurement cycle x number of data items to be
accumulated, and send the next request command until the calculated time
expires.
Example: When measurement cycle=269 µs and the number of data items to
be accumulated=500:
It will take 134.5 ms (=269 µs x 500) until the accumulation is
completed.
Sending the next request command before the time above expires
is necessary.
The "flow data overflow bit," which is described in Section, "Data
Composition of Flow Data" and other sections, is enabled when sending a
command is delayed due to the delay of processing at the master side of the
communication devices, such as a personal computer.
(In this case, the continuity of data is lost.) Check the processing delay if the
bit is enabled or not.
When the processing delay occurred due to the personal computer
specification, adjustments below must be performed:
•
Increase the buffer interval and decrease the number of data items
per unit time.
•
Increase the number of data items to be accumulated and lessen the
frequency of communication processing.
Flow data is returned from controller upon completion of the data
accumulation. Therefore, flow data is immediately returned after sending a
command when data accumulation has already been completed upon
sending a command. Response is not performed unless the data
accumulation is completed upon sending a command.
Setting Procesures for Data Obtaining Conditions
CompoWay/F Communication Command Reference
Section 4
How to Obtain Flow Data
4-7
ZS Series