Programming FCs (Functions) and FBs for S7 Ethernet CPs
168
SIMATIC NET NCM S7 for Industrial Ethernet
C79000-G8976-C129–06
User program
(CPU cycle)
Ethernet CP Communications Partner
LOCKED = 0
LOCKED = 0
AG_LOCK
AG_LOCK
AG_LOCK
LOCKED = 1
FETCH/WRITE
access to DB x
active
FETCH/WRITE
access to DB x
active
Time Time Time
Data
processing
in DB x
FETCH/WRITE
FETCH/WRITE rejected
AG_UNLOCK
STATUS = 700x
Cycle n
Cycle n+1
Cycle n+2
Cycle n+m
...
The lock job must first be monitored in the user program using the code in the
return parameter LOCKED. As long as LOCKED=0 is indicated, it must be
assumed that there is still a FETCH/WRITE access active.
If LOCKED=1 is indicated, this shows that the lock is active; data can now be
modified by the user program.
The status code is updated at each block call.
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