Siemens SINUMERIK 828D Function Manual page 1109

You can rename your data blocks and change their properties, by clicking with the right mouse button in the
operation tree on the corresponding data block. Select "Properties". The "Properties data block" dialog box
opens. Here, you can change the name, block number and data class as well as add an author and comments.
Note
If you just want to rename your data block, click the right mouse button in the instruction tree
on the object you want to rename and chose "Rename".
You can also easily edit your data block in another program (e.g. Microsoft Excel).
Editing data blocks in the Programming Tool PLC828
To edit data blocks in the Programming Tool PLC828:
•In the navigation bar, click on the button "Data block".
• Select the "View" > "Data block" menu command.
• In the operation tree, double click on the button "Data block" and then on the data block to be edited:
Assigning addresses and initial values in the data block
You define the structure of the DB (the sequence of the individual DB variables) in the declaration view. Initial
values can be assigned to the variables of the data block that are saved with the data class or the project and
with which the actual values of the DBs are initialized when loaded into the CPU for the first time.
When you define a variable, you assign its name and data type. The default initial value is set to zero/OFF,
however, this can also be changed. You can optionally insert comments. The Programming Tool PLC828
automatically assigns the address. Each address is aligned by its size which means that gaps can occur.
Example:
The maximum size of a data block is limited (512 bytes), if it is exceeded the Programming Tool PLC828 marks
the excess variable addresses using a red wavy line. The Programming Tool PLC828 returns an error when
compiling the project.
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
P4: PLC for SINUMERIK 828D
14.3 Programming
1109