Mitsubishi Electric MELSEC Q Series User Manual page 243

(5) Writing to buffer memory when using the block data assurance per station
function
To enable the Block Data Assurance per Station and write data to the buffer memory, follow the following
procedures.
Method
Automatic cyclic data
refresh
Manual cyclic data
refresh
Use the manual cyclic data refresh method if user program processing is to be continued during the waiting time which will
occur in the automatic cyclic data refresh.
(a) Automatic cyclic data refresh
1) Execute the QBF_ToBuf function with "automatic" specified for "CC-Link refresh method" of the third
argument (ulOffset).
2) In the timing of the next link scan, data are refreshed.
C Controller module
User
program
1)
)
2
• If execution of the QBF_ToBuf function is attempted before completion of the previous refresh, data writing
is suspended until completion of the refresh.
C Controller module
User
program
QBF_ToBuf (automatic)
QBF_ToBuf (automatic)
: User program is waiting
CHAPTER 13 FUNCTIONS ACCESSED VIA A NETWORK MODULE
Description
Data are automatically written by just executing the QBF_ToBuf
function in advance, and then they are automatically refreshed at the
time of next link scan.
Data are written with the QBF_ToBuf function, and then they are
manually refreshed by executing the QBF_RefreshLinkDevice
function.
Buffer memory
QBF_ToBuf (automatic)
Data writing
Buffer memory
Data (1) writing
Data (2) writing
CC-Link module
Link scan
Refresh request
Link scan
Refresh
CC-Link module
Link scan
Refresh request (1)
Link scan
Refresh
(Data (1))
Refresh request (2)
Link scan
Refresh
(Data (2))
Reference
Page 241, (5)(a) in this
section
Page 242, (5)(b) in this
section
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