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2 PROFINET IO in SIPROTEC
2.6 Event List
41
SIPROTEC 4, Communication Module PROFINET IO, Communication Profile
C53000-L1840-C360-1, Edition 08.2012
2.6
Event List
The event list is an autonomous ring buffer in the PROFINET IO communication module, in which value
changes (only single-point and double-point indications) are entered with a time stamp. These time stamps can
be transmitted via cyclic data exchange using the handshake method (read/acknowledge) described in
Chapter 2.6.3.
The event list is empty after an initial start or restart of the SIPROTEC device. Non-transmitted indications are
lost during initial start or restart of the SIPROTEC device.
Only such indications of the SIPROTEC device which are also included in the cyclic PROFINET IO telegram
in input direction are entered in the event list when values change. No entry is made for status changes and
command-sequence states.
The event list can contain a maximum of 500 entries. When adding a new entry to a full event list, the oldest
entry is deleted and the IO controller is notified of a buffer overflow with a bit in the handshake byte "Control_I"
in input direction.
The event list is not deleted when communication is interrupted. Entries for indication changes are still stored
and transmitted to the IO controller (including buffer overflow identification) after the communication connection
has been restored.
The event list entries are transmitted to the IO controller in the message blocks of the PROFINET IO telegram
and must be acknowledged by the IO controller (see Chapter 2.6.3).
The data types and the handshake mechanism used are proprietary, because PROFINET IO does not offer an
event list by default. The event lists handshake mechanism is a part of the cyclic data exchange.
In the GSDML file of the SIPROTEC devices, the event list is defined as an autonomous IO module, see
Chapter 2.4.
2.6.1
Input Direction
The following structure corresponds to the IO module
event list
, data in input direction, and the data area of
the
process alarm
Figure 2-19
Structure of the Event List, Input Direction (Read)
Control_I byte
7
6
5
4
3
2
1
0
Message -block
number
B
uf
fe
r ov
er
flow
Reserved = 0
Bit position
Meaning
Control_I byte
Reserved = 0
Message block #1
Message block #2
Message block #3
Byte offset = 0
Byte offset = 1
Start offset = 2
Start offset = 12
Start offset = 22
End offset = 31
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