Siemens simatic hmi op7, Руководство по эксплуатации оборудования

Страница: 70 / 196

7-12
Equipment Manual OP7, OP17
Release 04/99
7.4 Deleting Messages
All message events for event and alarm messages are automatically stored in
the event message buffer or alarm message buffer respectively. Each of these
buffers has space for up to 256 events. To prevent a buffer overflow, event
and alarm messages must be deleted from their buffers.
Message events from the event message buffer or alarm message buffer are
deleted
automatically when buffer overflow occurs
by means of the appropriate standard screen.
System messages are deleted automatically only when the buffer overflows.
7.4.1 Deleting alarm message and event message buffers upon buffer
overflow
When the specified remaining buffer capacity for the alarm and event mes-
sage buffers is reached, an overflow warning is output by default. Output of
this overflow warning can be activated and deactivated online via the corre-
sponding standard screen:
Alarms Overflow
Events Overflow
If the alarm or event message buffer has insufficient space to accept any
more message events, message events are automatically deleted until the spe-
cified remaining buffer capacity is reached. Deletion is carried out in the fol-
lowing order:
The oldest departed messages.
For departed event messages, the message events ’arrival’ and ’departure’
are deleted. For departed alarm messages, the message events ’arrival’,
departure’ and ’acknowledged’ are deleted.
Queued messages.
If there is still insufficient space for new events, the oldest queued mes-
sages are deleted in the case of event messages.
In the case of alarm messages, deletion is carried out in the following or-
der:
Acknowledged alarm messages yet to depart
Unacknowledged alarm messages that have already departed
Unacknowledged alarm messages yet to depart.
If “Printout Overflow” has been configured and a printer is connected to the
OP and switched on, a forced printout of all deleted messages is initiated.
Purpose
Overflow warning
Deleting upon
buffer overflow
Automatic printout