Requirements and Installation

Requirements

WinCC OA version 3.12 or higher.

Installation

A normal installation of WinCC OA version 3.12 or higher is sufficient for using the identification caching.

The identification caching is deactivated by default. The identification caching writes the identification to the hard disc when a manager stops and reads it from the hard disc when a manager starts. In order to activate the identification caching, set the config entry useLocalIdentification = 1 in the [data] section of the config file.

The following config entries can be used for the identification caching.

Cached identification may not be shared among manager with different settings for "distributed" and "refuseCNS". If e.g. a manager using CNS, is using the cached identification of a manager not using CNS, it will not be aware that CNS should be used since the CNS settings were not configured. If those settings are changed for a manager using cached identification, the cache has to be removed before the manager is started.

Config Entries

Config Entry useLocalIdentification

Especially for slow connections (e.g. for remote UIs via modem connection) the start phase of a manager is very slow when the whole identification is transferred in bigger projects. To improve this, the identification is saved on the local computer. The identification caching is deactivated by default. To activate the identification caching, use the config entry useLocalIdentification in the config file. The entry can be used in the [data] section of the config file.

When the manager starts the first time, the identification is transferred by the Data Manager (since the files for the local identification were not created yet). When the manager runs, it processes changes. When the manager stops, it writes the current identification in the DpMsgTypeContainer.bin and DpMsgIdentification.bin files. These files are saved in the directory <proj_path>/data.

When a manager starts again (remote UI, Dist), it requests the changes of the identification from the Data manager.

Config Entry maxUpdateMsgCount for the Data and Dist Managers

Whenever the identification changes, the Data manager creates a notification message, for example, DP_MSG_MANIP_DP to notify about new or deleted data points, which are distributed via the Event manager to all managers running in this system and via the Dist manager to all other systems. A manager that receives such messages, updates the identification and increments the time stamp of that identification.

The Data and Dist managers buffer these messages. The Data manager buffers the messages for all systems, the Dist manager for the current system only.

If a manager requests “changes since a time stamp”, for example, a client from the Data manager or a Dist manager from a remote system, the Data manager or the remote Dist tries to satisfy the request by sending only the notification messages from the buffer. The messages are needed to update the identification i.e only the notification messages after the time stamp in the request are sent.

To avoid that the buffer grows indefinitely, the number of identification notification messages in the buffer is limited. The size can be adjusted via the config entry maxUpdateMsgCount in the [data] or [dist] section.

If the Data or Dist manager can’t satisfy the request by sending notification messages, i.e. the time stamp in the request is too old, the entire identification is sent instead.

Config entry updateStatusForHiddenSystems

If the one-way-dist is used, the dist manager is enabled to request the identification only from certain systems but still connect to all systems (see the config entry distSystemIds). Therefore, the systems or their managers still know if the partner system is connected or not. However, due to the lack of the identification, the system is not shown in the system overview panel and you cannot access the data points.

The config entry "updateStatusForHiddenSystems" can be used for systems that are not included in the distSystemIds list. With the updateStatusForHiddenSystems you activate the status updates for the identifications of these systems.

Several Managers on Client

If the identification caching should be used on a remote UI where several managers (UI, CTRL or API) are running, start the managers with the -num option.