Siemens SIMATIC S7 Configuration And Programming Manual page 48

Mode of Operation
This F application block reads the tag addressed by ADDR_INT and OFFS_INT of
the data type INT in an F-DB and applies it to the OUT output.
Via the ADDR_INT input, the start address of the area with tags of the data type
INT in an F-DB from which the tag will be read is transferred. The address offset in
this area is transferred via the OFFS_INT input.
The addresses transferred at the ADDR_INT or END_INT inputs must point to a
tag of the INT data type in an F-DB. There must only be tags of the INT data type
between the addresses ADDR_INT and END_INT. The ADDR_INT address must
be lower than the END_INT address. The transfer of the ADDR_INT and END_INT
addresses must be fully qualified as "DBx.DBWy" or in the corresponding symbolic
representation as in the example in Section 1.2.12. Transfers in other forms are not
permitted.
You will find examples of the parameter assignment of ADDR_INT, END_INT and
OFFS_INT in Section 1.2.12.
Diagnostic Result
The F application block checks whether the address of the tag addressed with
ADDR_INT and OFFS_INT is outside the address area defined by the addresses
ADDR_INT and END_INT. If this is the case, the F-CPU changes to STOP.
The following diagnostic event is then entered in the diagnostic buffer of the
F-CPU:
Event ID 16#75E2
Safety program: area length error
occurred in: F application block F_INT_RD
word access to F-DB
F-DB number: x
access address: y
previous operating mode: RUN
requested operating mode: STOP
internal error, event entering state
Note the following: When using STEP 7, ≤ V 5.2 + SP 1, the diagnostic event is
displayed only in hexadecimal without textual information. You then receive the
F-DB number in hexadecimal as additional information 1, the access address in
hexadecimal as additional information 3.
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Product Information for the S7 Distributed Safety, Configuring and Programming Manual
A5E00169432-02