Technical data

Glossary
Software
464 System Manual, 07/2009, C79000-G8976-C222-07
WinCC buffer
Message and archive processing can be assigned to the ST7cc tags. If this is the case,
individual messages or archive data are generated in ST7cc, that are transferred over the
ODK interface to Alarm Logging or Tag Logging for further processing.
The results of processing an ST7cc tag can, however, accrue faster than they can be
accepted by WinCC. The WinCC buffer takes the WinCC jobs from the ST7cc processing
and therefore separates the asynchronous procedures of job creation and job processing.
WinCC channel DLL
To allow WinCC to communicate with the widest variety of data sources (programmable
controllers, ST7cc servers etc.), various communications drivers are used.
A communications driver is a C++ DLL that communicates with the data manager over an
interface known as the channel API that is specified by the data manager. The WinCC tags
are supplied with process values over the communications driver.
WinCC tag
WinCC tags are central elements to allow process values to be accessed. Within a WinCC
project, they have a unique name and a data type. A WinCC tag is assigned to a logical
connection that specifies which channel supplies the process values of the tags and over
which connection.
For the WinCC tags whose data sources are the ST7 tags, the channel DLL is the
connection over which the ST7cc server supplies the process values.
The WinCC tags required for ST7cc can be generated with ST7cc Config.
WinCC Tag Logging (Runtime)
Tag Logging is used to receive data from running processes and to prepare it for display and
archiving. The data formats and the acquisition times and archiving times can be set as
required.
WinCC Tag Logging is 'computer time'-oriented and [ ] not intended for the arrival of data
with a delay offset as is the case with SINAUT ST7. This means that the ST7cc server must
make certain archiving preparations for WinCC. The ST7cc server transfers the values to be
archived to Tag Logging over the ODK interface. This ensures the chronological
arrangement of the archive values even if process data is delivered by the ST7 stations, for
example, with an offset of an hour.
WinCC tag management
WinCC tag management covers all WinCC tags.
WinCC Tag Management
Each element (in other words, every tag) used in WinCC is collected in Tag Management
and managed there.