User-Specific Diagnostics With Siemens Step 7; User-Specific Diagnostics With Siemens Step - Festo CPX-FB33 Manual

3. Diagnostics

3.5.3 User-specific diagnostics with Siemens STEP 7

Control Module
system
Siemens OB 82
STEP 7
OB 86
SFB 54
RALRM
Tab. 3/10: Intended use (significance) of the organisation blocks OB 82 and OB 86 as
well as the function block SFB 54
Festo P.BE-CPX-PNIO-EN en 1407c English
The diagnostics for PROFINET are supported in STEP 7 by
organisation blocks (OBs) and function blocks (FBs). OBs and
FBs consist of individual function instructions and thus form
special program modules, so-called Instruction Lists (IL)
which can be integrated into user-specific programs.
Organisation blocks start in response to a malfunction or a
device-related diagnosis and are used thereby for localisation
of the source of the error, while function blocks read the dia-
gnostics of the bus node and write to a data range of the user
program (see example in Fig. 3/3).
In this way, the system-specific diagnostics are individually
integrated in comprehensive, higher-order diagnostics sys-
tems.
The following OBs and FBs can typically be used for dia-
gnostics purposes: OB 82, OB 86 and SFB 54 (see Tab. 3/10).
Meaning
Starts as reaction to a device-related
diagnosis
Starts as reaction to failure of an I/O device
or the network
Receives an alarm and the associated
information from an I/O device and provides
this information as an output parameter
Detail information
– Siemens
Reference manual
"System and standard
functions for
S7-300/400"
– PROFIBUS/PROFINET
Guidelines with
respect to function
blocks
3-19