Basics Of Program Processing; Events And Obs - Siemens SIMATIC S7-1500 System Manual

Basics of program processing

14.1

Events and OBs

Start events
The occurrence of a start event results in the following reaction:
● If the event comes from an event source to which you have assigned an OB, this event
● If the event comes from an event source to which you have not assigned an OB, the
The table below provides an overview of the start events, including the possible values for
OB priority, possible OB numbers, default system reaction and number of OBs. The table is
sorted in ascending order by OB numbers.
Types of event sources
Startup**
Cyclic program**
Time-of-day interrupt**
Time-delay interrupt**
Cyclic interrupt**
Hardware interrupt**
Status interrupt
Update interrupt
Manufacturer-specific or
profile-specific interrupt
Isochronous mode interrupt
Time error***
Maximum cycle time
exceeded once
Diagnostics interrupt
Pull/plug interrupt for
modules
Rack error
S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB
triggers the execution of the assigned OB. This means that the event is positioned in a
queue that corresponds to its priority.
default system reaction is executed.
Note
Some event sources, such as startup, pull/plug, exist even if you do not configure them.
Possible priorities
(default priority)
1
1
2 to 24 (2)
2 to 24 (3)
2 to 24 (8 to 17, frequency
dependent)
2 to 26 (18)
2 to 24 (4)
2 to 24 (4)
2 to 24 (4)
16 to 26 (21)
22
2 to 26 (5)
2 to 26 (6)
2 to 26 (6)
Possible OB Default system
numbers reaction*
100, ≥ 123 Ignore
1, ≥ 123 Ignore
10 to 17, ≥ 123 not applicable
20 to 23, ≥ 123 not applicable
30 to 38, ≥ 123 not applicable
40 to 47, ≥ 123 Ignore
55 Ignore
56 Ignore
57 Ignore
61 to 64, ≥ 123 Ignore
80 Ignore
STOP
82 Ignore
83 Ignore
86 Ignore
14
Number of OBs
0 to 100
0 to 100
0 to 20
0 to 20
0 to 20
0 to 50
0 or 1
0 or 1
0 or 1
0 to 2
0 or 1
0 or 1
0 or 1
0 or 1
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