Mitsubishi MELSEC Q Series User Manual

4
FUNCTIONS
4.3 CC-Link Module Access Function
4.3.1 Block guarantee of cyclic data per station
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1
OVERVIEW
2
SYSTEM CONFIGURATION
3
SPECIFICATIONS
4
FUNCTIONS
5
SETTING AND PROCEDURES
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I/O NUMBER ASSIGNMENT
7
MEMORIES AND FILES
8
INSTALLING / UNINSTALLING
(3) How to read out cyclic data (buffer memory)
Cyclic data can be read out from the buffer memory using the functionality of the block
guarantee of cyclic data per station as described below.
If any other method is used, cyclic data per station are not be guaranteed.
1) With the CC-Link utility, make setting to enable the Block guarantee of
cyclic data per station. ( Section 9.3.5)
2) Select either of the following.
(a) Automatically refreshing cyclic data
1) Execute the QBF_FromBuf function with "automatic" specified for "The
link refreshing method of the CC-Link link" of the third argument
(ulOffset).
2) In the timing of the next link scan, refreshed cyclic data (buffer memory)
are read out.
Processing of the user program is suspended until the reading is
completed.
3) Upon completion of the reading, processing of the user program is
resumed.
POINT
During execution of the QBF_FromBuf function, a time of up to one link scan may
be spent for standby.
Table4.4 Reading out cyclic data (buffer memory)
Method Description
Reference
section
Automatic cyclic data
refresh method
Only by executing the QBF_FromBuf function, data are
automatically refreshed and read out (at the next link scan).
(a)
Manual cyclic data
refresh method
Data are manually refreshed in advance with the
QBF_RefreshLinkDevice function, and then they are read out
by executing the QBF_FromBuf function.
(b)
Figure 4.3 Readout operation
User program
Buffer memory
Link scan
C Controller module CC-Link module
Refresh
:User program is in standby state.
Link scan
Refresh request
1)
2)
3)
Reading data
QBF_FromBuf function (Auto)

Mitsubishi MELSEC Q Series Specifications

General

Brand	Mitsubishi
Model	MELSEC Q Series
Category	Controller
Language	English