2 PROFINET IO in SIPROTEC
2.7 Process Alarm
45SIPROTEC 4, Communication Module PROFINET IO, Communication Profile
C53000-L1840-C360-1, Edition 08.2012
2.7 Process Alarm
Process alarms in PROFINET IO use the RTA mechanism (Real Time Alarm) and are only sent as indication
ON or as indication RAISING.
The SIPROTEC device offers one process alarm which is named Summary Process Alarm.
An alarm is issued when the value of at least one indication of the SIPROTEC device linked with the alarm
changes.
When parameterizing the IO controller, it can be decided for each SIPROTEC indication sent via PROFINET IO
whether the indication is assigned to the process alarm Summary Process Alarm or not (see Figure 2-14 and
Figure 2-15).
Using process alarms provides the advantage that these alarms can be analyzed like an interrupt in the PLC
(Programmable Logic Controller) with assigned alarm blocks, thereby reducing the response to indication
changes (see Chapter 3.3.2.5).
If more than one indication was assigned to the process alarm Summary Process Alarm, an alarm means
that the value of one or more assigned indications has changed.
If several indications, which are combined to form the process alarm Summary Process Alarm, change
virtually simultaneously in the SIPROTEC device, the following applies:
1. If a change of the first indication is detected, an alarm is sent immediately.
2. The IO controller processes and acknowledges the PROFINET IO alarm. During this time, no second
process alarm is possible via PROFINET IO.
3. Further indication changes that can cause a process alarm are stored internally.
4. When the running alarm processing has been terminated and another alarm is present in the EN100, this
alarm is output by the IO device. This alarm can contain up to 3 stored indications.
The process alarm telegram contains alarm information consisting of a header plus additional alarm
information. User-specific data are transmitted in the additional alarm information. The additional alarm
information for the process alarm Summary Process Alarm contains the identifications and time stamps of up
to 3 indications which trigger the alarm. The same structure as for the event list data transmission is used here,
see Chapter 2.6.1.
If the additional alarm information contains several indications, these indications belong to the same IO module.
The process alarm Summary Process Alarm is always identified as follows:
• Slot = slot of the IO module to which the indication triggering the alarm is assigned
• Subslot = 1
• Structure ID = 200 as source
There is only this one process alarm for the PROFINET IO implementation for SIPROTEC devices.
If the SIPROTEC device does not communicate with the IO controller, no process alarm is processed and no
indication changes are stored for the process alarm.
com_profinet-io_profile_us.book Page 45 Friday, August 17, 2012 1:40 PM
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