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S5-115U Manual
The SYNCHRON Block- FB249 -
Each time the PLC is restarted, FB249 initializes the interface on a module with page addressing
for communication with the control program. This synchronization is essential for proper execu-
tion of the data handling blocks.
Calling FB249 (Example)
STL
: JU
NAME
: SYNCHRON
SSNR
:
BLGR
:
PAFE
:
:
***
Parameter Description
FB249 requires the following parameters:
•
SSNR
-
interface number
•
BLGR
-
frame size
•
PAFE
-
parameter assignment error byte
SYNCHRON Function Description
After you enter the desired frame size for the BLGR parameter, the CP checks this value according
to module-specific criteria and determines the final frame size.
In certain cases, this means that the frame size specified in the parameter is invalid.
The final frame size specifies how much data (bytes) can be transferred directly when the SEND
and RECEIVE blocks are called. For larger amounts of data, continuation frames are generated
and transferred with the ALL functions of these blocks.
FB249 synchronizes the PLC and the CP on each PLC restart. Consequently, FB249 should be called
in RESTART blocks OB21 and OB22. FB249 executes when it receives RLO "1".
EWA 4NEB 811 6130-02b
FB
249
KY
0,1
KY
0,5
FY
100
Integral Blocks
CSF/LAD
FB249
SYNCHRON
SSNR
PAFE
BLGR
11-27
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