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Reference Designator Problem

Question asked by alexb0 on Jul 9, 2018
Latest reply on Jul 16, 2018 by phiet

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Hi all,

I really need an explaination about the reference designator as shown in this topic: https://support.mentor.com/en/product/852852099/knowledge-base/MG80631

1) Why for some components, there is this problem and for others, there is no problem? For the moment I have this problem only for CAPACITOR...

2) I followed the topic in the goal to change the ref des.

- For the first capacitor on my design, no problem with the 2 methods.

- For a second reference, it's impossible for me to change the ref des of this capacitor... I deleted the "C?" on the symbol editor, package with "Delete local data, then rebuild all local lib data" but the ref des still "U145" instead of "C145".

Thanks for information.

Regards,

Alex

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alexb0 Jul 12, 2018 2:39 AM
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No one ever had this problem?
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phiet @ alexb0 on Jul 12, 2018 6:44 AM
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No, because we have matching Ref Designator properties on components and Prefix in Library ... We don't use mix

[quote] It is best to have the Ref Designator property on your symbols correspond to the Reference des prefix as set for a partition in Library Manager. As an example, capacitors that have a C? Ref Designator property value should have a Reference des prefix of C in Library Manager for the capacitors part partition.[quote]
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alexb0 Jul 12, 2018 8:39 AM
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The problem is there is a matching between our symbol property and the prefix in part definition.
I really have no idea where the prefix "U" comes from (for this component)...
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phiet Jul 12, 2018 8:53 AM
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is it possible that there's mismatch before and it's now corrected ?
in that case, that U became "block value" and cannot be overwritten...
in such case, delete the actual value and repackage (with update PDB and delete/update local lib option) should take care of this.
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alexb0 Jul 12, 2018 11:16 PM
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Hi phiet,

is it possible that there's mismatch before and it's now corrected ?
in that case, that U became "block value" and cannot be overwritten...

Indeed, that is true but I tried to delete the value and repackage with Update properties in first, no result and then I deleted again the value and repackage with delete local librairy but not works for this component.

Info: I had another capacitor with the same problem, as I said in my first message (case 2), but it works for this one so I don't know why it works sometimes and sometimes not...

Thanks

Alex
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phiet @ alexb0 on Jul 13, 2018 5:20 AM
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I reread your first message.You only deleted the C? value in the symbol. In fact, you think have also to delete the existing value of the Ref Designator in the schematic and repackage and do not forget to check the option "update PDB properties on symbol". This worked for us.
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phiet Jul 13, 2018 5:22 AM
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btw, are 2 capacitors same part number ?
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alexb0 Jul 13, 2018 6:13 AM
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Indeed, I forgot to write that I also deleted the instance value in the schematic...
I just made a short video of my problem. I created a new project with only one capacitor.

1) I deleted the "C?" definition in the symbol:
2) Part definition of the capa:

3) See the video (GIF) of packaging.

Info 1: In the video, I tried without the "Update PDB properties on symbol" but I also tried with this option, same result.
Info 2: As I said, this problem occurs only with some part references, not all... The symbol is the same beetween of of these capa.

Thanks

Alex
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phiet @ alexb0 on Jul 13, 2018 6:23 AM
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In the video, you do not have :"update PDB properties on symbol" checked .
Also, it will be interesting to see properties panel when you add you cap...
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alexb0 Jul 13, 2018 6:28 AM
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Yes, but I also tried with this option (Info 1) but nothing has changed.
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cesario_espiritu Jul 13, 2018 10:55 AM
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To fix it permanently, it should start from Lib.
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robert_davies @ cesario_espiritu on Jul 16, 2018 4:04 AM
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I would suggest you remove all of the property values of ? as they are unnecessary, if you switch on Place holders in the symbol editor you will be able to see where the values will appear during packaging and back-annotation. As to the REFDES, you can leave that as C? Once you have made the changes perform a symbol update in the schematic.
Re-run packaging using the Update local library data with newer central library data.
If it doen't fix the problem then provide a screenshot of the Ref Designator property in the Properties pane so we can see the symbol, block and instance values clearly.
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alexb0 Jul 16, 2018 12:15 AM
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To fix it permanently, it should start from Lib.
Can you explain with more details please?
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alexb0 Jul 16, 2018 5:03 AM
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Hi Robert,
The only property we put on our symbols is the RefDes (C? for capa, R? for resistor...).
Info: I made a new project with only one capa.
1) I rerun a packaging with "Update local library data" and "Only Extract Missing Library Data": The Ref Des stays at U1
2) I rerun a packaging with "Update local library data" and "Delete local data, then rebuilt all local lib data": The Ref Des stays at U1

Here, a screenshot of my component. The "C?" in the symbol defition was deleted in the goal to try the phiet suggestion.

Alex
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phiet Jul 16, 2018 5:39 AM
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Robert,
I wonder if it could it get the U from databook's field ?
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