Technical data

Configuring Messages
16.1 The Message Concept
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 345
16.1.10 Differences Between Project-Oriented and CPU-Oriented Assignment of
Message Numbers
The table below lists the differences between project-oriented and CPU-oriented assignment of
message numbers:
Project oriented CPU oriented
Some of the message attributes and texts
depend on the used HMI unit and must be
configured display specific.
The assigned attributes and texts do not depend on the
HMI unit used, that is, there is no need to enter further
display devices or specify a display specific message for
this device.
Programs must be recompiled after they have
been copied.
Programs can be copied to other locations of a project and
to other projects (cross-project copying). However, the
program must be recompiled if only single blocks have
been copied.
When you subsequently change message type
data (texts and attributes), you must also modify
the instances.
If you subsequently change message type data (texts and
attributes), all changes are applied automatically to the
instances (Exception: you have previously changed the
data of the instance).
Texts can only be written on one line. Texts can be written on several lines.
For all message types (except WR_USMSG) up
to 2097151 messages per program can be
created.
Up to 8191 alarm_s messages can be created per program.
For all other message types (except WR_USMSG) up to
32767 messages per program can be created.
When you "Save As with Reorganization" of projects or
copy programs from the project-wide to the CPU-wide
message number concept, you should therefore make sure
that the maximum number of possible messages per
program is not exceeded in the CPU-wide message
number concept!