Belden 934 692-001, Technical Manual, Page: 48 / 64

Diagnostic properties of the modules
48
7.7 Alarm and error messages of
LioN-P/-R modules via PROFINET
Technical manual LioN-P/ -R PROFINET
Release 1.2 02/2016
7.7 Alarm and error messages of LioN-P/-R
modules via PROFINET
If both LioN-P/-R modules detect an error condition, an alarm message will
be triggered. The modules support diagnostic alarms. Diagnostic alarms are
triggered in case of peripheral faults such as overload, short-circuit, and
undervoltage.
An alarm is triggered in case of an incoming event (such as sensor short-
circuit) as well as an outgoing event.
The evaluation of the alarms depends on the PROFINET I/O controller used.
7.7.1 Alarm evaluation in STEP 7
In STEP 7 the user program execution is interrupted through the triggering of
a diagnostic alarm, and a diagnostic block is called. The following blocks are
used:
Initial information on the cause of the error and error type is already delivered
based on the OB called and its start information. You can receive more
detailed information about the error event in the error OB by calling SFB 54
RALRM (read supplementary alarm information). For this, SFB 54 must be
called in every error OB.
If the error OB called does not exist in the CPU, the CPU goes into the STOP
operating state.
It is also possible to call a diagnostic data record using its data record number
with the system function block SFB 52 “RDREC” in OB 1.
Note
Alarm and error messages are only transmitted via PROFINET when the
parameter for diagnostics is activated in the configuration of the modules in
the control system.
Cause of the alarm OB call
Peripheral error (short-circuit, overload, wire
breakage, undervoltage of an I/O module) OB B2
Complete failure of the system OB B6