Siemens SINUMERIK 840D sl, Function Manual

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Detailed description
2.11 General conditions and NC-VAR_Selector
Basic logic functions: PLC basic program solution line (P3 sl)
94
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Alias name
The variable names provided can be up to 32 characters in length. To make variables clearly
identifiable in the data block to be generated, several ASCII characters are added to the
selected name. However, the STEP 7 compiler recognizes only 24 ASCII characters as an
unambiguous STEP 7 variable. Since it cannot be precluded that variable names can only be
differentiated by the last 8 character positions, ALIAS names are used for names, which are
too long. When a variable is selected, the length of the STEP7 name to be used is, therefore,
checked. If the name is longer than 24 characters, the user must enter an additional name,
which is then used as the alias.
In this case, the user must ensure that the alias name is unambiguous.
Alias input can always be activated by the user in the "Options" menu.
An alias name can then be entered every time a variable is transferred.
It is also possible to edit alias names at a later point in time by doubleclicking on the S7
variable name field. This action can also be undone under the "Edit" menu item.
Figure 2-25 Screen with complete list and selected variables
Scrolling
A scroll bar is displayed if it is not possible to display all variables in the window. The
remaining variables can be reached by scrolling (page up/down).