WinCC/Audit is for monitoring changes in operator activities in runtime operation as well as for recording project changes at the engineering stage. The system records all the change data in a secure database known as the Audit Trail. You can view the Audit Trail using the Audit Viewer. The Audit Viewer enables the user to display, query, filter, print and export the following audit trails:
-Audit trail databases from SIMATIC WinCC V6.x on the basis of the option WinCC /Audit
-Audit trail files from SIMATIC WinCC flexible on the basis of the option WinCC flexible /Audit
-Data- and Alarm Log files with checksum (from WinCC flexible 2008)
Additionally, the Audit Viewer - via the "Data Validity Indicator" - supplies information on whether modifications have been made to the WinCC flexible audit trail file after its creation date.