Mitsubishi Electric Melsec Q Series User Manual page 131

4
FUNCTIONS
(b) Data consistency function by dedicated instructions
Remark
(3) Precautions
(a) Applicable QCPUs
(b) Transmission delay time when the data consistency function is used
(c) When the data consistency function is enabled in the automatic refresh setting
(d) MOV or FROM/TO instruction.
Use the BBLKRD (read) and BBLKWR (write) instructions as dedicated
instructions for reading/writing QJ71PB92V buffer memory to execute the data
consistency function.
For details on dedicated instructions, refer to Chapter 8.
For program examples on the I/O data exchange using dedicated instructions,
refer to the following:
• Single CPU system:
• Redundant system:
For QCPUs supporting the data consistency function, refer to Section 2.1.
When the data consistency function is used, the transmission delay time between
the QCPU and DP-Slaves increases because the time waiting for read/write from
the QCPU or data transfer from/to DP-Slaves arises. (
The data consistency function can be disabled in the automatic refresh setting.
If this function is unnecessary, disable it.
Dedicated instructions are not executable. (They are not processed.)
Dedicated instructions are executable if the data consistency function is disabled
in the automatic refresh setting.
The data consistency function is not usable when data refresh are performed
between the QCPU and the QJ71PB92V buffer memory by the MOV or FROM/TO
instruction.
4.5 Data Consistency Function
Section 7.1.2
Section 7.9.1
Section 3.5.2)
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