Siemens OP15, Equipment Manual, Page: 53 / 177

7-3
Manual OP5, OP15
( ) J31069-D0840-U001-A2-7618
The message buffer of the OP can store up to 256 events. Events are the:
arrival of a message,
acknowledgment of a message (alarm messages only),
departure of a message.
During configuration, you can define a remaining buffer space. When this
remain ing buffer space has been reached, an automatic overflow warning is
issued – for example,
EM remaining buffer
. This overflow warning is
a system message. Messages continue to be inserted into the buffer even after
the remaining buffer space has been reached.
A sub-category of the event message is the standby message. The standby
message is the event message number 0. It appears on the display when the
OP is operating at the message level and event or alarm messages are not
waiting. The standby message is stored in the firmware and contains the ver-
sion and the device type:
OP15/A Vx.xx
2 x 40 char. 5 mm char. height
Figure 7-1 Example of Standard Standby Message on OP15/A
Depending on the configuration, the standby message can be represented by
other text. It can contain the date and time but not variables.
7.1.1 Acknowledging Alarm Messages
Alarm messages have to be acknowledged on account of their priority. This
can be done automatically by the PLC or by the operator pressing the Ac-
knowledge key. The OP displays unacknowledged alarm messages in flashing
mode. The LED (ACK) assigned to the Acknowledge key also flashes.
If several alarm messages are waiting to be displayed, after one has been
acknowledged the next one is shown on the display, which similarly has to be
acknowledged.
If no more alarm messages are waiting to be displayed, the OP reverts to the
operating level from which it branched to the message level to display the
alarm messages.
Overflow warning
Standby message
Acknowledging
alarm messages
Message Handling