Storage locations of logs (RT Unified) - WinCC Unified

Introduction

You adapt the main database storage locations for tag and alarm logging in the Runtime settings of the HMI device. Different options are available depending on the HMI device.

For Unified PCs, you have the option of storing the storage location in the "WinCC Unified Configuration" tool under "Archive Settings".

Note Default setting for the database storage location The storage location "Default" is configured as default setting in the Runtime settings and in the "Logs" editor. If you do not change these options, the database is saved according to the setting in the "WinCC Unified Configuration" tool.

Note No support of network drives Network drives are not supported as storage location for databases. Do not select a network drive when configuring the location of the databases.

Note No support of relative path names If an unsupported path is specified as the storage location for logs, it can cause an internal error when loading the project. Relative path names are not supported.

Storage location of a log

You adjust the storage location of the main database of the tag logs and alarm logs in the Runtime settings of the HMI device.

The following options are available depending on the HMI device:

When you define a storage location in the Runtime settings of the HMI device, and thus enable logging, you can specify the database storage location for individual tag and alarm logs in the "Logs" editor under "Storage medium".

It must be ensured that the "WCCILScsService" service user under which Runtime is running has read and write rights to the directory in which the logs are stored. You have the following options here:

• Configure the directory for the logs with the "WinCC Unified - Configuration" tool and configure the storage of logs in this directory or its subdirectories in the engineering system.

• In the engineering system, configure the storage of logs in directories for which no restriction of the access rights is configured in the operating system. However, this means that the logs are then not protected from access by third parties.

Note If you want to access a large number of log values within a short time, it is advisable to set the maximum memory of the SQL server to at least 4 GB in the "WinCC Unified – Configuration" tool.

Changing the storage location of the main database

Note Data loss when changing the location of the main database If you have already saved data in a log and then change the location of the main database and reload the project, you can no longer access the already logged data in Runtime. Changing the location of individual logs in the "Logs" editor is possible without data loss as long as the location of the main database remains unchanged.

In the following cases, access to already logged data is lost:

• Unified PC:

  • If you use the storage medium "Standard" as the storage location of the main database in the Runtime settings of the Unified PC and change the storage location of the databases in the Werkzeug "WinCC Unified - Configuration" tool

  • If you use the storage medium "Local" as the storage location of the main database in the Runtime settings of the Unified PC and change the folder

  • If you change the file path of the log in the file system of the Unified PC, e.g. rename folders with a file explorer

• Unified Comfort Panel:

  • If you change the storage medium or folder of the main database location in the Runtime settings of the Unified Comfort Panel

  • If you change the file path of the log on the external storage medium, e.g. rename folders with a file explorer

Naming conventions

The log names must be unique in an HMI device. Even if different storage locations are selected for different logs, the log name must be unique.

Syntax examples for storage locations

Location of local file system on the Unified PC:

• <C:\My_File_Folder\My_Archives\Machine_1>: Saves the log on the local hard disk drive "C:" in the subdirectory "My_File_Folder\My_Archives\Machine_1"

Memory card storage location on the Unified Comfort Panel:

• </media/simatic/data-storage /My_Archives/TagLogs>: Saves the log in the subdirectory "My_Archives\TagLogs"

File name

The segments are stored according to the syntax <Unique name of the Runtime project>_<Abbreviation of the logging service>_<System ID>_<Start date of the segment>_<Start time of the segment (UTC)> for example, as follows:

• Microsoft SQL: "HMI_RT_1_TLG200_20201106_135307.mdf" and "HMI_RT_1_TLG200_20201106_135307_log.ldf"

• SQLite: "HMI_RT_1_TLG200_20201106_135307.db3"

The backup files of the segments are stored with the syntax <Unique name of the Runtime project>_<Abbreviation of the logging service>_<System ID>_<Start date of the segment>_<Start time of the segment (UTC)> under the configured path, for example as follows:

• "HMI_RT_1_TLG200_20201106_135307.bak"

• "HMI_RT_1_TLG200_20201106_135307_diff.bak"

  The file with the extension "_diff.bak" is created when the backup was already created and value changes occurred later, for example, by manually adding values.

External storage medium

You have the option of saving the logs on an external storage medium. To avoid the loss of data, the storage medium must be properly removed.

	Notice
Data loss due to improper removal of the storage medium When the storage medium is not removed correctly, logging is interrupted. As soon as you connect a storage medium and restart Runtime, logging can be continued with existing databases. Data that occur between improper removal of the storage medium and the start of Runtime are not logged.

The procedure for ejecting the storage medium differs depending on the HMI device:

• Unified Comfort: You use the system function "EjectStorageMedium".

• Unified PC: Eject the storage medium using the PC operating system.

Next, you remove the storage medium and connect a different storage medium.

Data that occurs during the change process are written to a buffer. Logging is continued in a new segment after the change has been completed.

Logs on different storage media

Note Storage medium for Unified Comfort The storage location of the main database of a logging type and the configured storage medium of all associated logs must be identical.

Storage location for archives during simulation

The configuration of the storage location in the project is ignored during the simulation.

During the simulation the storage location specified is used in the "WinCC Unified Configuration" tool under "Archive settings".

Tag persistency

In Runtime, you have the option of specifying tag persistency for internal tags. A separate database, in which the last values of the persistent tags are stored, is used for tag persistency.

When the databases for data logs or alarm logs and the database for tag persistency are stored on the same storage medium and the medium is changed while Runtime is running, tag persistency can be affected.

Note Use different storage media for tag persistency and logging.

Parameter set types

With Unified Comfort, you have the option of saving parameter set types on external storage media.

When the databases for data logs or alarm logs and the parameter set types are stored on the same storage medium and the medium is changed while Runtime is running, the parameter set types can be affected.

Note Use different storage media for parameter set types and logging.