Rockwell Automation T8xxx Application Note Trusted Intelligent Online Updates - Manual (Page 21)

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AN-T80009 Trusted
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Intelligent Online Updates
Issue 4 Nov 08 AN-T80009 21
1.13. Other issues
The following paragraphs are a collation of queries answered and issues reported with online updates.
1.13.1. Toolset upgrade to 3.51
To upgrade the Toolset from 3.46 workbench to 3.51 workbench, first uninstall the existing Toolset and
then install the new version. After an upgrade of the Toolset from build 3.46 to 3.51, the application
must be recompiled. The new Toolset can then be used to online-update the application.
1.13.2. Virtual boards
If a module I/O connection board is changed from virtual to real in the I/O connection table, the module
will not be activated if the new compilation is loaded through an update. The IOU manager will allow
the update to proceed using a normal update. Changes to the I/O connection boards and equipments
cannot be made online.
1.13.3. Unused local variables
Adding a local variable that is not used in its scope does not add that variable to the data dictionary. In
other words, if you add a local variable, but do not use it, the code that is produced is as if you had
never defined that variable. In a similar fashion, deleting a local variable that was never used does not
change the code either. The IOU manager will be unaware of this variable from the compiled code and
will therefore not report its addition or deletion.
1.13.4. Baseline version
If a system has an application loaded with IOU enabled, this version will remain as the baseline for the
next update (the ‘target snapshot’ described in section 1.5.1). Therefore all changes made to the
application since that load will be taken into account for the next update recipe.
1.13.5. Instance data limit exceeded
It is possible for the internal numbering of function block local variables (‘instance data’) to go over a
limit after which the IOU manager is unable to parse them. The instance data numbering is similar to
the internal naming convention for temporary variables. Every time function blocks are affected by a
logic change, the instance data number is always incremented. The IOU manager is unable to handle
instance data with a number over 9999. The result is that even if no change is made, the IOU manager
will perform an online update because it cannot pair up the instance data before and after. All function
blocks which cannot be paired will lose their internal states.
The limit of 9999 data points applies to each program (each program has its own numbered list). The
numbers can be inspected in the <program>.lsf file after compilation. The workaround is as follows:
1. Open the function block diagram program (FBD)
2. Edit->Select All
3. Edit->Cut
4. Save and Close the FBD
5. Open the FBD
6. Edit->Paste
7. Save and Close the FBD
8. Compile the project