Altium Designer Documentation

Enhanced Component Link Synchronization

Modified by Jason Howie on Apr 11, 2017

Each schematic component links to its PCB component via a Unique IDentifier (UID). By using a unique identifier, it means that the designators can become unsynchronized (perhaps by performing a PCB re-annotate a number of times), without any risk of the schematic and PCB becoming un-synchronizable.

The UID links the schematic component to the PCB component.

The UID is assigned to the schematic component when the part is placed on the sheet, then transferred to the PCB component when the design is first transferred from the schematic editor to the PCB editor. So far so good, there is no component linkage management that needs to be performed.

But if additional components are added to the schematic and an Update PCB performed, there is no longer a match between the set of schematic components and the set of PCB components, so the software will halt and warn that not all of the components are linked, and offer to match by designator instead. Previously, the only way to recover from this situation was to switch to the PCB editor and run the Project » Component Links command. This command opens the Edit Component Links dialog, which is the interface for managing UIDs. The designer would then match the UIDs and click Perform Update, the outcome being that the PCB UIDs would be updated if needed, so each matches the UID of their schematic part.

To simplify how the designer deals with this situation, this release introduces an automatic link resolution feature. Now when you perform an Update PCB and there are component UID mismatches, the following dialog appears:

If there are UIDs present on either side without a matching UID on the other side, this dialog appears.

Regardless of which button you click, the sequence of steps is the same. These steps include:

  1. Update the component links - if the Automatic button is clicked, this step is not displayed on screen. If the Manual button is clicked, the Edit Component Links dialog opens, where you must match any unmatched components and transfer them to the Matched Components side. Don't worry about new schematic components, they remain on the left side of the dialog and are added to the PCB as part of the ECO step. Once all possible matching has been done, the Perform Update button is clicked to assign matching UIDs to those newly matched components. If UIDs are changed, an Information dialog will report the details.
  2. Match any unmatched nets - If there are nets whose names do not match on both sides, the Match Manually dialog will appear next, reporting that some nets are not able to be matched (this dialog does not appear if all nets are matched). If you click Yes in the Match Manually dialog the Match Nets dialog will open, where you can manually match any unmatched schematic nets to unmatched PCB nets. If you choose to click No, then instead of you matching the differently named nets, the existing unmatched nets are removed from the PCB, and the new nets that do not currently exist on the PCB, are added.
  3. The Engineering Change Order dialog then opens, detailing all of the changes that must be made to synchronize the schematic and the PCB. Once these are executed, the schematic and PCB should be back in sync.


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