Siemens SIMATIC ET 200pro - Page 50

Basics of program execution
6.1 Events and OBs
CPU 1516pro-2 PN (6ES7516-2PN00-0AB0)
Operating Instructions, 11/2019, A5E35873416-AC
49
Types of event sources
Possible priorities (default
priority)
Possible OB
numbers
Default system
reaction
1)
Number of OBs
Rack error
2 to 26 (6)
86
Ignore
0 or 1
MC servo
5)
17 to 26 (25)
91
Not applicable
0 or 1
MC pre-servo
5)
17 to 26 (25)
67
Not applicable
0 or 1
MC post-servo
5)
17 to 26 (25) 95 Not applicable 0 or 1
MC interpolator
5)
16 to 26 (24)
92
Not applicable
0 or 1
Programming error (only for global
error handling)
2 to 26 (7) 121 STOP 0 or 1
I/O access error (only for global error
handling)
2 to 26 (7) 122 Ignore 0 or 1
1)
If you have not configured the OB.
2)
For these event sources, apart from the permanently assigned OB numbers (see column: possible OB numbers), you
can also assign OB numbers in STEP 7 from the range ≥ 123.
3)
You can assign a maximum of one hardware interrupt OB to each I/O module in STEP 7.
The start information is displayed in the hardware interrupt OB in the TIA Portal the same as in S7-300/S7-400. You can
find additional information on the start information in the STEP 7 online help.
4)
If the maximum cycle time has been exceeded twice within a cycle, the CPU always switches to STOP regardless of
whether you have configured OB 80.
5)
You can find additional information about these event sources and the runtime behavior in the S7-1500 Motion Control
function manual.
Assignment between event source and OBs
The type of OB determines where you make the assignment between OB and event source:
● With hardware interrupts and isochronous mode interrupts, the assignment is made
during the configuration of the hardware or when the OB is created.
● For MC-Servo, MC-PreServo, MC-PostServo and MC-Interpolator, STEP 7 automatically
assigns OBs 91/92 as soon as a technology object is added.
● For all other types of OB, the assignment is made when the OB is created or after you
have configured the event source.
For hardware interrupts, you can change an assignment which has already been made
during runtime with the instructions ATTACH and DETACH. In this case, only the actually
effective assignment changes, and not the configured assignment. The configured
assignment takes effect after loading, and upon each startup.
The CPU ignores hardware interrupts to which you did not assign an OB in your
configuration or which occur after the DETACH instruction. The CPU does not check
whether an OB is assigned to this event when the event arrives, but only before the actual
processing of the hardware interrupt.