Question on XREF attribute for parent/child schematic symbols

[tcoppens84SWP]

Round 2 of my rapid-fire quession session:

1. When you link, for example, a parent CB symbol (HCB1) to a child CB symbol (HCB2), is there supposed to be a value entered into the XREF attribute for the parent? Currently my child symbols are the only ones with values entered into XREF. 

2. How is the XREF attribute itself used in ACADE functions when it comes to tagging parent/child devices? Does it only exist to visually display the xref in the drawing?

3. Are the dashed link lines there purely as a visual indicator, or do they have a functionality beyond that? Do I need to AELINK the child to a parent AND assign a parent in the "Insert/Edit Child Component" window? 

4. Is there a way to view all parent/child relationships in a project? I keep getting an error saying the number of parent/child associations has exceeded the symbol's limit, and I want to see where all the children are.

[rhesusminus · Accepted solution]

1. No.
2. For child symbols, it'll show a cross-reference back to the parent symbol. For the parent symbol it specifies the location/rotation of the  cross-reference "MTEXT", pointing to the child symbols.
3. They are used for commands like scoot, when you have multi-phase components, and you scoot one of them. You'll be asked if you want to scoot the linked symbols as well. If you link parent/child symbols, it's used to show that these objects are "mechanically linked together". Some other symbols, like shielded cables, are also linked together with this functionality.
4. You can always try the surfer. It should show all parent/child/one-line/panel references to your device..

[Icemanau]

1 - When you link a child block to a parent block, the parent block is supposed to have the XREF attribute updated.

However, if it is linked by the Link Components tool, to another child component the entire XREF is changed to invisible  so you don't see it.

2 - The only use for the XREF is to provide the user a visual link on printouts. There is no in program usage.

3 - Again there is no usage apart from suppressing most of the attributes of the child blocks and some on the parent block. It's generally used when child components are next to the parent like the 2nd/3rd poles of 3 pole breakers. You do NOT have to link the blocks using the Link Component tool, especially if the child block is not close to the parent.

The Parent/Child associations are what is used to link the blocks in the scratch database.

4 - The Surf command will bring up a list of Parent/Child blocks throughout the project  but only what item you select. You can even go to the various list items using the tool, no matter what dwg page it's on. I don't think there is any tool or report that will create a list of all the components with Parent/Child associations.

Regards Brad

[tcoppens84SWP]

Okay, thanks, this clears some things up. I see now that the XREF attribute is basically just a note for humans that says, "The other part is at this location," with no other functionality. I forgot how useful the SURF command is for this type of troubleshooting.

Follow up question:

When the value of the TAG2 attribute of a child symbol matches the value of the TAG1 attribute of a parent symbol, is that what causes ACADE to associate them as such? Or is there more to it than that?

[rhesusminus]

That is correct. If the combination of INST/LOC/TAG matches, it's different symbols/functions of the same device.