Electronics > Altium Designer

Problem with sheet refernce in altium


I am new to altium and don't have much experience using sheet references.

I have a circuit that is repeated 15 times that each take a unique input from an external source. Instead of drawing the circuit 15 times, I put it on a sheet. the sheet had 2 bidirectional inputs and 2 bidirectional outputs.

I then used a sheet reference block for each of the 15 unique inputs.

I think there is a problem when I annotate because for all 15 blocks i get several errors along the lines of the following:

[Error]   BAL2.SchDoc   Compiler   Net NetR37_CH0_1 has only one pin (Pin R37-1)   

R37 is a series resistor with one of the inputs to the block.

Is this caused by an annotation issue? is the compiler confused that the circuit is repeating 15 times? I though i used the sheet references properly so i am not sure what is going on here...

You are doing a multi-channel hierarchical design, so those settings must be correctly set it to work properly.
In schematic, go to Project->Project options-> Multi channel and Project->Project options-> Options, and see if this two is setup correctly.
Basically the schematic, hierarchically needs to assign different designators to the 15 components, otherwise nothing will work properly. On the lower left corner of the schematic you should see 15 tabs of the same circuit.
I don't recall all the settings as this was years ago when I last used it.

Have you looked at the docs? https://www.altium.com/documentation/altium-designer/multi-sheet-and-multi-channel-design-ad?version=18.1

There are a few different ways to do multichannel designs like this, if you can show a screenshot of your sheet instances, how they're connected, and your multichannel options that would be helpful.  A screenshot of R37 and any other components that are mentioned in the error messages would also be good.

The error you reference doesn't seem to indicate an annotation problem but a connectivity problem.  Well, I guess it could be a connectivity problem caused by an annotation problem, but it's hard to say.  Are all of the errors you're getting "Net ___ has only one pin"?  Are there any errors referencing sheet entries/ports? Or any sheet entries/ports that show red squiggly lines?

Also sometimes altium gets a little stupid about names. A lot of functionality relies on the names of things, including the way it resolves references to objects, and there are certain patterns of intermediate names it creates to keep track of connectivity (and other references-by-name necessary to achieve the 'A' in EDA) while compiling the project. Occasionally a user's naming scheme isn't digestible to the compiler, because it resembles one of those internal patterns and it gets confused. The whole thing is rife with problems like this, where when you really try to automate things using the built in tools there are tons of traps, limitations, and just plain bugs all over the place because of how fragile it is.

So you might just need to fiddle with how you've named things and the annotation settings and see if it starts working.


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