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MELSEC-Q
4 FUNCTIONS
4.1.1 Exchange flow
The I/O data exchange flow with slave station is shown below.
The refresh between the CPU and QJ71PB92D and the refresh of buffer memory of
QJ71PB92D are executed asynchronously with each other.
The input data will be read from
the input area to the device of the
CPU specified by the auto refresh
setting.
The output data from the device of
the CPU specified by the auto
refresh setting will be written to the
output area in the buffer memory.
Turn ON the dedicated instruction
valid signal (Y0C).
Read the input data from the input
area using the dedicated
instruction (BBLKRD).
Using the dedicated instruction
(BBLKWR), write the output data
to the output area in the buffer
memory.
Set the slave trouble information
cancel area. (Setting is
unnecessary if the default value
can be left unchanged.)
Communication trouble area type
selection (This setting is
unnecessary if the default value
can be left unchanged.)
Check that the exchange start/end
signal (X00) is ON.
Read the input data from the input
area using the FROM instruction.
Write the OUTPUT data in the
output areain the buffer memory
using the TO instruction.
Write the initial OUTPUT data
value in the output area.
Turn ON the exchange start
request signal (Y00).
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