Siemens SIMATIC S7-1200

PLC concepts
5.1 Execution of the user program
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
97
Time error interrupt OB includes start information that helps you determine which event and
OB generated the time error. You can program instructions inside the OB to examine these
start values and to take appropriate action.
Table 5- 6 Start information for the time error OB (OB 80)
Input
Data type
Description
fault_id BYTE 16#01 - maximum cycle time exceeded
16#02 - requested OB cannot be started
16#07 and 16#09 - queue overflow occurred
csg_OBnr OB_ANY Number of the OB which was being executed when the error oc-
curred
csg_prio
UINT
Priority of the OB causing the error
To include a time error interrupt OB in your project, you must add a time error interrupt by
double-clicking "Add new block" under "Program blocks" in the tree, then choose
"Organization block", and then "Time error interrupt".
The priority for a new V4.0 CPU is 22. If you exchange a V3.0 CPU for a V4.0 CPU
(Page 1571), the priority is 26, the priority that was in effect for V3.0. In either case, the
priority field is editable and you can set the priority to any value in the range 22 to 26.
5.1.3.7
Diagnostic error interrupt OB
The diagnostic error interrupt OB executes when the CPU detects a diagnostic error, or if a
diagnostics-capable module recognizes an error and you have enabled the diagnostic error
interrupt for the module. The diagnostic error interrupt OB interrupts the normal cyclic
program execution. You can include an STP instruction in the diagnostic error interrupt OB to
put the CPU in STOP mode if you desire your CPU to enter STOP mode upon receiving this
type of error.
If you do not include a diagnostic error interrupt OB in your program, the CPU ignores the
error and stays in RUN mode.
Diagnostic error events
Analog (local), PROFINET, PROFIBUS, and some digital (local) devices are capable of
detecting and reporting diagnostic errors. The occurrence or removal of any of several
different diagnostic error conditions results in a diagnostic error event. The following
diagnostic errors are supported:
● No user power
● High limit exceeded
● Low limit exceeded
● Wire break
● Short circuit
Diagnostic error events trigger the execution of the diagnostic error interrupt OB (OB 82) if it
exists. If it does not exist, then the CPU ignores the error.