What are Handles and what can cause duplicates/ mismatches?

Issue

Getting duplicate Handle errors, how can these be fixed?

Product Line

Andover Continuum

Environment

All versions of Continuum

Cause

Duplicate handle errors can cause problems on sites.

Resolution

An SQL database gives every object a unique handle that is used internally to reference that object. If Continuum requests a value from say an Input point that has handle 1234, but that controller thinks handle 1234 may be say a TimeDate point then problems will ensue.

Every object in the DB has a unique handle, this includes all classes: points, programs, graphics, reports, schedules etc, etc.

Duplicate handles can be caused on sites where engineers use multiple databases during commissioning on new panels (maybe a Single User on their laptop), It can also be caused by importing dump files with handles created from other databases, or just from database corruption on the server from failures etc. It can also be caused by the use of an Infinity LSX280 see Lessons Learned #11088.

Usually reloading the controller will re-sync' the controller and all of its object handles back to the site database, but if DB has become corrupted where you should run the analyser and try to fixup (Clean) any issues or even have to manually delete the offending objects, running the Import Export Fixup utility (See Lessons Learned # 6190) followed by a controller reload can resolve problems, but worst case would be to revert to a backup DB if it is found to be corrupt.

So it is good to engineer a project all from a single DB and take care when importing dump files.