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Comment Out a Schematic

Thread Summary

The user seeks a method to comment out a hierarchical schematic in LTspice to store text notes and unused circuit snippets without affecting the netlist. The final answer suggests using a dummy subcircuit or changing the Prefix to 'X' and using a non-functional subcircuit. Accompanying answers propose shorting all pins of components, using jumpers, or creating non-simulatable symbols with the same names as real symbols in a separate directory.
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Category: Software
Product Number: LTspice 26.0.1
Software Version: LTspice 26.0.1

Hello All:

Is there a way to comment out a schematic?
I have a hierarchical schematic design, a dozen pages and 4 levels of hierarchy.
That all works just fine.

I want to create another page to place on my top level schematic.
This page will store text notes, unused circuit snippets.
One copy of each C, D, Q, R, etc...
So it is easy to see that there are 17 different values of resistor in the project.
If one value can be found that is acceptable, I would copy it to it's destination.
If one value can't be found that is acceptable, I would create a new resistor and value, then copy it to it's desired position.
Now I can later easily see that there are 18 different values of resistor in the project.

LTspice must not attempt to netlist that notes schematic.
Can it be done?

Parents
  • Hi  ,

    Great, thanks. This example will help. Was just talking to the devs about this. Obviously, not a new request.

    mike

  • Hi  ,

    It appears to me that some code character could be used to mean "ignore this schematic named NOTES".
    Like !NOTES or \NOTES or #NOTES or )NOTES instead of XNOTES to cause LTspice to ignore that schematic.

    Hmmm, probably not using as one would netlist line characters, but using LTspice's hierarchy would be possible.

    mike

  • Hello Michael

    I have tried the semicolon comment character ; on the Prefix line.
    It does this in the net list ";§XNOTES 0"

    Although after setting Prefix to ; one can no longer open the schematic and the schematic is still not ignored.

    Using the comment character on any of the other lines works.
    Setting InstName to XNOTES; will cause anything on any or all of the following lines to be ignored as a comment.

    All for now

  • Hi  ,

    Yes, I see. I was able to test out your setup. I first had to change the Q1 and D2 values as I got an error for missing model. 

    In my test run, your Notes device subcircuit is netlisted, but, of course, does nothing.

    I "commented out" your XSomeCircuit by jumping it in the main schematic. I tried commenting it out within the subcircuit, but LTspice did not like that. When the main is run, it is also netlisted, but does nothing.

    Nevertheless…

    Would you agree: Ideally, one would be able to choose Edit > Comment Out, and then point to, or marquee over, components, and those components would be not netlisted, or, they would be netlisted as comments. Or, they would be shorted somehow.

    I have tried the semicolon comment character ; on the Prefix line.
    It does this in the net list ";§XNOTES 0"

    Hmmm. 

    mike

  • Would you agree: Ideally, one would be able to choose Edit > Comment Out, and then point to, or marquee over, components, and those components would be not netlisted

    Yes and no.
    I had not envisioned components directly, I foresee many more complications with commenting out, for instance, a 14-pin chip, or a diode that supplies power to many devices.

    I had envisioned commenting out a schematic, like my notes schematic.
    The ability to comment out some things or anything, using "EDIT > Comment Out" is highly desired.

    I have a hierarchical schematic world that contains many pages/layers.
    An entire page may contain circuits that are optional to the project as a whole.
    Now, I must delete that entire page and simulate to verify if recent changes have ruined the ability for that functionality to removed without error.
    I also must remember to NOT close the parent page or I lose the ability to Ctrl-Z the deleted page back into existence.

    Resistors have to be set to 1G to get them out of the way, and then, lets see, what was that value that resistor used to be?

    Of course a "commented out" entity would have to be easily recognizable as being "comment out".

    All for now.

  • Of course a "commented out" entity would have to be easily recognizable as being "comment out".

    Yes, of course. :-)

    mike

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