Different texts for a measuring point can be configured in the CFC which can be displayed in the process screen or in the alarm list in runtime.
The screenshots shown in this entry depict a scenario where "kg" is to appear as the unit for a measuring point in the process screen. The unit can be specified in the dialog box "Properties - Input/Outputs" in the CFC.
The "Unit" entry field for a block I/O only appears if the I/O possesses the attribute "S7_unit". The attributes are allocated during the programming of a block, although they can also be allocated or modified afterwards. You can find notes on this in the PCS 7 Online Help under "Configuration - Engineering System > Implementing the PCS 7 Configuration > Creating the Master Data Library > Adapting Blocks > How to Modify Attributes of the Block I/Os".
During OS compilation, the texts are transferred from the CFC into the OS text library.
Internal "text reference"-type tags are additionally created in the WinCC Tag Management during OS compilation for texts which appear in the process screen (e.g. unit, identifier or comment).
These text reference-type tags contain the text ID of the Text Library as the starting value.
The text reference-type tags are used to display Text Library texts in the screen.
It is advantageous to know the circumstances under which texts, which are configured in the CFC, are transferred to the OS Text Library.
||New entry in the OS Text Library|
A new entry is only added to the Text Library during compilation if the text doesn't already exist in the library.
The following conditions govern internal decisions on whether or not texts already exist in the Text Library:
- "Language for Display Devices"
The check on whether or not a text already exists in the Text Library is performed in accordance with the default language for display devices selected in the SIMATIC Manager. You can call up the dialog box for specifying the default language for display devices in the SIMATIC Manager with the menu command "Options > Language for Display Devices...".
- Upper/lower-case lettering is irrelevant
Texts in the CFC which only differ from texts in the Text Library in terms of one, more or all of the letters in the texts are deemed to already exist. They are not inserted into the Text Library as new entries.
||No new entry in the OS Text Library|
If the requirements for the conditions described in line 1 are not met, two different scenarios may arise:
- Change to an existing entry in the Text Library
The existing entry in the Text Library is only changed for the default language for display devices set in the SIMATIC Manager. Should the text which is configured in the CFC only differ from an entry in the Text Library in terms of upper/lower-case lettering, a change is made.
The situation can arise where an existing text is changed in the Text Library during OS compilation. If the text was originally created using the OS Project Editor, the change is undone again the next time the OS Project Editor is run.
- The Text Library is not changed
The existing entry in the Text Library is not changed.
A number of factors dictate which of the two scenarios occur, e.g.
- the order in which the relevant blocks have been inserted into the CFC
- whether the OS compilation is performed in its entirety or in respect of changes.
Entry ID 26248773 describes how this can be affected directly.