On Fri, Feb 21, 2025 at 05:57 AM, Carlo wrote:

The point is that, by removing both the independent current source I1 and the G-source Ghot from the overall topology, the topology check realizes that there is the series/string of R:U1:cool and R:U1:load resistors (connecting node N001 with U1:HB passing through the intermediate node U1:HA) that are actually disconnected from the rest of the circuit. Therefore the topology check complains that U1:HB node is floating and connected to the (controlled) current source G:U1:HOT.

Thinking again about it, I realized that the "topology check routine" throws a warning complaining that there is a cut-set made of (independent or controlled) current sources only.

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In this specific circuit, as you pointed out, it isn't a problem at all since the G-controlled source within the subckt actually implements/realizes just a non-linear resistor.

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Carlo.

The Windows error code 0xc0000409 is a software exception error that can occur when an application is installed incorrectly

So, does this mean the Windows service account does not know what LTspice is, or where to find it?

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Sorry, I don't know snakes.

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Andy

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I believe I am doing this

Thank you, the application is clearly installed correctly though because it works when not running as a service

On Thu, Feb 27, 2025 at 11:15 AM, Jeff Kayzerman wrote:

Yes it is a windows error, something about a stack buffer overrun, not sure what to make of that. The message "Simulation failed with status code <status code>" Is my code in the except block of the python program. There is no log file that gets created from LTspice.

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You'll need to launch the python LTspice subprocess in the context of the target user and target schematic source folder.

On Thu, Feb 27, 2025 at 09:26 AM, Andy I wrote:

Of course it should not have made any difference whatsoever.

I think it would make a difference because the solver has to determine additional unknowns with more capacitors, namely the current through each individual capacitor. There are no additional nodes, but there are more branches. This may be enough to make the matrix numerically unsolvable.

Yes it is a windows error, something about a stack buffer overrun, not sure what to make of that. The message "Simulation failed with status code <status code>" Is my code in the except block of the python program. There is no log file that gets created from LTspice.

On Thu, Feb 27, 2025 at 10:57 AM, Andy I wrote:

Oh...I would think they would fix that in this version

It's been around for a very long time.? A decade or two?? I think there would be no reason for them to pick up on that one particular thing that has been there for so many years, unless somebody nagged them about it in 2025.

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Andy

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Yes...its minor and cosmetic.

But if it were me I would have fixed it a long time ago.

On Thu, Feb 27, 2025 at 10:31 AM, Jeff Kayzerman wrote:

I tried putting all the symbols under the same folder as the simulation. Let me try to better describe what I am doing.

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A python service is polling an AWS message queue for incoming instructions to run a job. The message has the location of a simulation file in AWS S3. Python pulls the .asc file and kicks off LTspice with the provided command line interface using this line of code?

process = await asyncio.create_subprocess_exec(LTSPICE_PATH, "-b", "-run", solverFlag, fpath, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE)

*NOTE* -b for batch mode, no interactive gui

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That code kicks off LTspice as an async process. I have a callback function which runs when the process finishes that zips up the output files and places them back into AWS S3. The user is then emailed the status of their job and the location of their files.

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All of this works great!

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What isn't working is when I try to run this process as a windows service. The python is running properly but kicking off LTspice results in this error code 3221226505 so I get an email saying "Simulation failed with status code 3221226505".

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Since there is no descriptive error message I have no idea why everything works fine when I run it while I'm logged in but it won't run as a background service. I need it to run as a background service because the server won't let a user stay logged in indefinitely.

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Suggestion..

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Create a batch or command file and run a command within it, so it gets the windows environment variables while running as a service.

Redirect the results to a file. It might be telling....

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Oh...I would think they would fix that in this version

It's been around for a very long time.? A decade or two?? I think there would be no reason for them to pick up on that one particular thing that has been there for so many years, unless somebody nagged them about it in 2025.

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Andy

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On Thu, Feb 27, 2025 at 01:31 PM, Jeff Kayzerman wrote:

What isn't working is when I try to run this process as a windows service. The python is running properly but kicking off LTspice results in this error code 3221226505 so I get an email saying "Simulation failed with status code 3221226505".

Presumably that is a Windows status code.? I think it did not come from LTspice, but it might mean Windows is telling you that LTspice did not exit happily.

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Can you find what that error code means, if it's from Windows?

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It's curious that the message states "Simulation failed ...".? Where did that word "Simulation" come from?

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Did LTspice create a .LOG file?? What does it say?

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Since there is no descriptive error message I have no idea why everything works fine when I run it while I'm logged in but it won't run as a background service. I need it to run as a background service because the server won't let a user stay logged in indefinitely.

I am unfamiliar with running programs in a Windows background service.? Is it possible that a background service does not "see" itself with a normal default directory?? Is it a mirror of the right directory, including all contents?? What about its environment variables?? Does it see the LTspice .ini file too?

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I'm assuming that everything works now that you moved all the symbols (and models too?) into the same folder with the schematic, when run normally.? I think that is what you said.

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Andy

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Yes, I read all the advice and started out with a very low value for CSHUNT, but ended up with 5pF in order to get convergence. However, this was BEFORE I added the LT1375. Rather than a proper SMPS I was initially working with a switched load on the PTC, and then a Heath-Robinson arrangement of switches and pulse generators set up to do something SMPS-like in the simplest possible way, because the regulator I'm actually using (MCP16331T-E/CH) doesn't appear to have a SPICE model. So 5pF was not unreasonable. If I had stuck with 1e-15 I would still be tearing my hair out. However, having made some progress and achieved something that didn't look completely wrong, I then went on a search for something a bit like a MCP16331T-E/CH that had a model, in order to move a little closer to reality. I was not surprised to find I now had convergence problems again, but this time no matter what I did I either got no convergence at all, or LTSpice slowed to a crawl. But with CSHUNT removed and the timebase shift, I now have all six SMPS's working with the PTC in place, and I can see that it should pass the formal inrush current test by a significant margin, even though strictly speaking it doesn't have to (if the customer asks you to jump a hurdle, and doing so wont kill you, you jump the hurdle). Apart from the capacitor oddity, the model is now stable against changes. And yes, when I replaced one big capacitor with several capacitors in parallel I used ideal capacitors, not capacitors with parasitics. I might try again now I've made various changes.

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Regarding voltage/current sources, I gave the voltage source a series resistor. From what I've read, LTSpice will convert such voltage source to the equivalent current source before modelling commences, so I didn't do that manually.

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On Thu, Feb 27, 2025 at 10:42 AM, Andy I wrote:

Sorry, I misunderstood:

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On Thu, Feb 27, 2025 at 01:25 PM, eetech00 wrote:

The "LT" characters get an overbar.

That is not a new bug in 24.1.4.? The fact that the schematic editor displays it with the overbar, that is.? It has "always" worked that way, I think ever since LTspice had that feature that preceding anything with an underscore (under certain conditions that you listed) causes it to display in the schematic editor with an overbar.

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Oh...I would think they would fix that in this version

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But the command executes correctly, right?? Or does v24.1.4 mess that up too?

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The command works right, just looks weird.

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Yes, it is a bit annoying that the underscore always causes the word after it to have the overbar when seen in the schematic editor.? I took it as a relatively minor annoyance.

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Anyway, I think nothing about this has changed in version 24.1.4.

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Andy

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Ok

On Thu, Feb 27, 2025 at 10:31 AM, Andy I wrote:

Does it work to put the filenames in quotes?? As a temporary workaround.

Hi Andy

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No...it doesn't seem to matter.

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I also discovered if the statement is changed to a comment, the behavior is the same.

Sorry, I misunderstood:

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On Thu, Feb 27, 2025 at 01:25 PM, eetech00 wrote:

The "LT" characters get an overbar.

That is not a new bug in 24.1.4.? The fact that the schematic editor displays it with the overbar, that is.? It has "always" worked that way, I think ever since LTspice had that feature that preceding anything with an underscore (under certain conditions that you listed) causes it to display in the schematic editor with an overbar.

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But the command executes correctly, right?? Or does v24.1.4 mess that up too?

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Yes, it is a bit annoying that the underscore always causes the word after it to have the overbar when seen in the schematic editor.? I took it as a relatively minor annoyance.

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Anyway, I think nothing about this has changed in version 24.1.4.

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Andy

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I tried putting all the symbols under the same folder as the simulation. Let me try to better describe what I am doing.

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A python service is polling an AWS message queue for incoming instructions to run a job. The message has the location of a simulation file in AWS S3. Python pulls the .asc file and kicks off LTspice with the provided command line interface using this line of code?

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Andy

If I add .inc/.lib statement on schematic:

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.inc file(3)_LT.txt

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It is converted to:

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.inc file(3)(overbar)LT.txt

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The "LT" characters get an overbar.

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Seems if a parenth, bracket, curly brace is preceded by an underscore, the followed text gets an overbar.