Understand license tag counts

While an InTouch application is running, tag handles are stored in a memory database. Each tag must be assigned a handle. Tag handles are initialized and used by WindowViewer, but never saved permanently to disk after the application stops.

InTouch HMI now supports unlimited tag count. This means that the run-time database can theoretically store unlimited tag count license, which includes both local tags and tags that reference a remote tag source. However, we have tested up to 300000 tag handles (300K) only.

An InTouch application can never have more simultaneously active tags than the available memory handles in this run-time database. Your InTouch license determines how many local and remote tags can be assigned handles within the run-time database.

Also, the maximum number of active tags in an application is restricted by the functional limits of the run-time database. The actual maximum tag count is less than the theoretical maximum tag handles. A set of constants is subtracted from the maximum potential tag count.

• The invalid tag handle bit is reserved to indicate if an invalid handle value occurs within the WindowViewer run-time database.

• InTouch version 10 includes 34 system tags, which cannot be replaced by user-defined tags. If you migrate a version 7.11 or earlier application to the current version of InTouch, the system tag count is 37.

• At configuration time, 4096 database handles are reserved to store placeholder tags. When you import windows, scripts, or symbols during configuration time, placeholder tags are assigned to this memory segment. During run time, all 4096 placeholder handles are available to be assigned to remote reference tags.

InTouch license options are based upon the maximum number of local and remote reference tags that can be used in an application.

If an InTouch tag license is for less than 60K tags, then a sticky tag licensing scheme is enforced. A sticky tag is a remote tag reference that is bound at run-time when WindowViewer receives a data change notification for the remote reference. WindowViewer updates remote tag references during run-time up to the maximum limit of the InTouch license. WindowViewer does not update any additional remote tag references beyond the license limit. WindowViewer does not decrement the remote reference tag count when a window is closed. Each remote reference tag count sticks while the application is running.

A single message appears when you exceed the maximum remote reference tag count of your InTouch license. After the license maximum is reached, the values associated with invalid remote reference tags are never updated in the application. You must stop and restart the application before you can open other windows that include one or more remote tag references that are not already associated with those counted against the license limit.

A license that permits 60K or more tags means that sticky tags are not enforced and there is no enforced limit to the number of tags or the combinations of local and remote tags that can be used within an InTouch application.

For example, using a 60K licence, the implementation limits for local and remote reference tags are:

• Total possible local tags

  61404 = 65535 – (4096 + 37 + 1)

• Total possible remote reference tags

  Maximum = 65535 – (37 + 1 + Number of Local Tags)

So, running an application with a 60K license, you are effectively trading a potential remote reference for every user-defined tag in the local tag database. You can never have less than 4096 possible remote reference tags available in a run-time configuration. For a license that permits 100000 tags, the Maximum = 100000 – (37 + 1 + Number of Local Tags)