Siemens Simatic S7-1500H - Page 222

The figure below shows the behavior of the two OBs during system state transitions from
RUN-Solo to RUN-Redundant and vice versa.
2%b5DFNIDLOXUH2%b&38UHGXQGDQF\HUURU
)DLOXUHDODUP2%LQFRPLQJIRU,2
GHYLFHRU
)DLOXUHDODUPZLWKRXW2%FDOOIRU,2
GHYLFHRU
'HOD\HGH[HFXWLRQRI2%LIDODUPFDQQRWEH
SURFHVVHGGLUHFWO\7KHEHKDYLRULVSRVVLEOHIRUERWK
IDLOXUHDQGUHWXUQ
7LPHU
2%LQFRPLQJ
5HWXUQDODUP2%RXWJRLQJIRU,2
GHYLFHRU
5HWXUQDODUPZLWKRXW2%FDOOIRU,2
GHYLFHRU
2%RXWJRLQJ2%LQFRPLQJ
'LDJQRVWLF
HYHQWVDUH
VLJQDOHGEXW
QRW\HW
SURFHVVHG
&RS\LQJWKHZRUNPHPRU\0DNLQJXSWKHODJ
5816ROR
5815HGXQGDQW
5816ROR
,2GHYLFHV
2%
2%
6<1&83

Figure 9-1OB72 and OB86 during system state transitions
OB 86
There are three IO devices in the example. Each failure of one of the three IO devices is
followed by recovery of the IO device. Each IO device failure/IO device recovery is signaled.
Cyclic program execution is interrupted with an OB86 call.
In the "Copy main memory" phase of the SYNCUP system state those OBs that interrupt the
cyclic program processing are processed. New diagnostic events are signaled but the OBs are
not yet processed. In the example, the failure of IO device 2 and the recovery of IO device 3
are signaled. However, the OB86 are not processed until the following phase, "Making up
backup CPU lag".
NOTE
Order of execution of OB86
Please note that the order of processing of the OB 86 may differ from the order of processing
of the associated diagnostic events.
222
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
Basics of program execution
9.3 Events and OBs