Siemens SIMATIC S7-400 Reference Manual page 22

Structure of a CPU 41x
Type of
Fault/Error
•
Priority class Priority class is called, but the
error corresponding OB is not available.
•
In the case of an SFB call: The
instance DB is missing or defective.
•
Error during the updating of the
process image
•
Failure of a Power failure in an expansion rack
•
rack/station
Failure of a DP line
•
Failure of a coupling line: missing or
defective IM, interrupted line)
•
Communication Status information cannot be entered in
error DB
•
Incorrect frame identifier
•
Frame length error
•
Error in the structure of the global data
message
•
DB access error
•
Cancel Nesting depth exceeded for
processing synchronous errors
•
Too many nested block calls (B
stack)
•
Error allocating local data
Programming Error in the machine code or in the user
error program:
•
BCD conversion error
•
Range length error
•
Range error
•
Alignment error
•
Write error
•
Timer number error
•
Counter number error
•
Block number error
•
Block not loaded
MC7 code error Error in the compiled user program (e.g.
impermissible OP code or jump over the
end of the block)
Loss of clock Clock was lost either because an OB
61 to 64 was not start due to higher
priorities or because additional
asynchronous bus loads suppressed
the bus clock.
There are also test and information functions available in each CPU that you can
call up with STEP 7.
1-10
Cause of Fault Response of the Operating
System
OB 85 call
If the OB is not loaded: The CPU
goes into STOP mode.
OB 86 call
If the OB is not loaded: The CPU
goes into STOP mode.
OB 87 call
If the OB is not loaded: The CPU
goes into STOP mode.
Call OB 88
If the OB is not loaded: The CPU
goes into STOP mode.
OB 121 call
If the OB is not loaded: The CPU
goes into STOP mode.
CPU goes into STOP mode.
Reboot or memory reset required.
Call OB 61..64 at the next pulse.
Automation System S7-400 CPU Specifications
Error LED
INTF
EXTF
EXTF
INTF
INTF
INTF
INTF
INTF
EXTF
A5E00165965-01