Basics of program execution
10.3 Events and OBs
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
323
10.3 Events and OBs
Start events
The table below gives an overview of the possible event sources for start events and their
OBs:
Table 10- 3 Start events
Event sources Possible priorities (default
Possible OB
Default system
1)
Number of OBs
2 to 24 (8 to 17, frequency
dependent)
Manufacturer-specific or
profile-specific interrupt
22 80
0 or 1
Maximum cycle time exceed-
ed
2)
Removal/insertion of modules
Programming error (only for
global error handling)
I/O access error (only for
global error handling)
1)
If you have not configured the OB.
2)
See section "Response of S7-1500R/H redundant system when cycle time is exceeded"