Altium Designer Documentation

Upgraded Duplicate UID Correction

Modified by Jason Howie on Apr 11, 2017
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While they remain unnoticed in the background and rarely require user intervention, UIDs (Unique IDentifiers) values play a critical role in Altium Designer for differentiating design elements during synchronization, Net generation and Schematic-PCB component linking.

Unique IDs are automatically assigned to circuit elements (for example, components) when they are placed on a schematic sheet, and therefore provide a singular reference for that object, irrespective of changes to other component attributes. In some circumstances though, such as errors when importing a design, file corruption, a bug from previous software, or even an accidental change through manual entry, UIDs can be duplicated or go missing.

Duplicated component UIDs have been detected by the schematic compiler in previous versions of Altium Designer, which offered the ability to restore component UID differentiation through the Reset Component Unique IDs command. However, UIDs values are assigned to all design objects, from Ports through to Wires and independent Parameters, and UID duplication for those elements can create design errors.

To detect and correct possible UID duplication for all circuit elements, Altium Designer 15 introduces advanced UID detection for the schematic compiler and a new mechanism for automatic UID duplication correction.

Compiler UID detection

With this release Altium Designer’s schematic compiler now detects UID duplicates for design connectivity objects, including Ports, Sheets, Components, Component pins and parameters, etc. The compiler reports duplicate UID errors in the Messages panel, and these can be cross-probed and manually corrected by regenerating their UID as required.

Duplicate UIDs are now detected for the full range of design connectivity objects.

Note that the compiler does not detect duplicates of connectivity-independent UIDs, such as those for Parameter Sets for example. However, duplicates of these UID types are automatically corrected when a document is loaded – see Autocorrect on load information below.

To regenerate (reset) a UID for an individual object, click the Reset button associated with the Unique Id field in the object’s Properties dialog.

Manually regenerate an object's UID from its Properties dialog.

Correct multiple duplicated UIDs

To correct a number of duplicate or missing UniqueIDs in a single process, use the Tools » Convert » Reset Component Unique IDs command. This command now encompasses two processes, which are effectively performed in sequence:

  1. Duplicate UIDs are detected within the design and corrected by resetting (regenerating) the UID value for one of the objects in the duplicate pair.
  2. The UIDs for Parts and Sheet symbols are reset (regenerated).

Note that the command can be applied to the active schematic, all open schematics, or all schematics documents in the project.

Auto correction on load

With the exception of component UniqueIDs, duplicate UIDs are now automatically detected and corrected when a Schematic document is loaded in Altium Designer, thereby removing the need for user intervention.

The detection/correction process works through all UIDs in the design, including Set Parameters and parameter additions to Ports, Nets Labels, Directives, Sheets and so on. This correction is important for Parameter UIDs in particular, where duplicate UIDs can cause obscure Rule misbehavior and annotation errors in projects with Variants.

Automated UID correction removes the need for designers to track down duplicated UIDs that may not be detected by schematic compilation.

Components that have duplicate UIDs are not processed by the automatic correction on document load. Component UIDs are fundamental to design connectivity, and any duplicate UIDs (which are very unlikely to occur) are best resolved by intention when detected by the Compiler.

When any of the corrective measures have been applied to resolve duplicate UniqueIDs – individual, multiple or automated UID changes – the related Schematic-to-PCB links need be reinstated to maintain design connectivity.

Use the PCB editor’s Edit Component Links dialog to perform the required updates (Project » Component Links).

After UID changes, reinstate a design's Schematic-PCB component links.


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