Re: More syntax issues with 24.1.x
On Tue, Mar 4, 2025 at 12:06 PM, Tony Casey wrote:
I have many testjigs that import digitised datasheet characteristic curves. An example of this would be:
.subckt IB_400u 1 2 3 4
R1 3 4 1G
B1 1 2 I=table(V(3,4)
.inc BC848B_Ic_Vce_400u.inc
+)
The file BC848B_Ic_Vce_400u.inc is a simple table:
+, 0, 0
+, 0.033713692946058194, 0.0037373737373737337
+, 0.07139456405596434, 0.007119195585620269
+, 0.09937242651150191, 0.01031229370884544
+, 0.11993258152246877, 0.014095645315621533
etc.
Yes, this won't work anymore. Prior versions pre-process the input and replace the .include line with the contents of the included file and then parse everything all over again. 24.1 is very different, it doesn't accept a top-level directive in the middle of something.
But you don't actually need such general behavior, all you want is to load data from another file, and that's certainly useful. How about extending the table syntax:
?
B1 1 2 I=table(V(3,4), "BC848B_Ic_Vce_400u.inc")
?
This would be easy to do. You'd still have to modify your netlists, though.
This issue seems to be related to the previously reported issue with nested .STEP directives of the form:
.step param A? 0 10 1
+ param B list 1 2 5 10
..where the 2nd line is failing with 24.1.x. Example schematic uploaded: LTspice_24.1_Step_problem.
?
This should work and does work for me if I try, but you obviously have a case where it doesn't. Unfortunately, you uploaded the wrong file. I'd appreciate a netlist or schematic.
?
Best Regards,
Mathias
?
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More syntax issues with 24.1.x
I have many testjigs that import digitised datasheet characteristic
curves. An example of this would be:
.subckt IB_400u 1 2 3
4
R1 3 4 1G
B1 1 2 I=table(V(3,4)
.inc BC848B_Ic_Vce_400u.inc
+)
This is used with a G-source called IB_400u, which in this case is
the? Ic vs. Vce characteristic of a transistor, i.e.:
XG1 C 0 C 0 IB_400u
The file BC848B_Ic_Vce_400u.inc is a simple table:
+, 0, 0
+, 0.033713692946058194, 0.0037373737373737337
+, 0.07139456405596434, 0.007119195585620269
+, 0.09937242651150191, 0.01031229370884544
+, 0.11993258152246877, 0.014095645315621533
etc.
This has always worked since LTspiceIV.
With 24.1.4, it no longer works. Apparently, the new syntax
checker works line by line, therefore the line:
B1 1 2
I=table(V(3,4)
..will fail due to unbalanced parentheses. There seems to be no
workaround that I have yet been able to figure, as the .inc
directive must appear at the start of a line.
I have uploaded example schematic to illustrate this issue: OP_Characteristic_rounding.
This issue seems to be related to the previously reported issue
with nested .STEP directives of the form:
.step param A? 0
10 1
+ param B list 1 2 5 10
..where the 2nd line is failing with 24.1.x. Example schematic
uploaded: LTspice_24.1_Step_problem.
--
Regards,
Tony
|
On 03/03/2025 18:28, Mathias Born via
groups.io wrote:
On Mon, Mar 3, 2025 at 06:02 PM, Tony Casey wrote:
It turns out that numeric models of "0" are rejected
as invalid in all versions of LTspice, including 24.1.4, even
though it is ultimately converted to a string. So the .STEP'ed
parameter list can't start at 0.
--
Regards,
Tony
That should not be the case. There is no special treatment of
the number zero. Can you provide a test case that proves a
problem? Works just fine over here.
I have uploaded an example schematic that shows 3 options for
stepping MOSFET models: Stepping_Models_pre-V24.1_workaround.
Option 1: works only in 24.1
Option 2: works in all versions
Option 3: fails completely in 24.1; fails 1st step, but works for
2nd step in pre-24.1
--
Tony
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Re: Can LTspice XVII and LTspice 24 Be Installed On the Same Win 10 Machine?
On 03/03/2025 23:32, Jim wrote:
I currently
have LTspice 17.1.14 installed on my Windows 10 computer.? Can the
latest version of LTspice 24 be installed without uninstalling
LTspice 17?
All you have to do is to change the installation location, from:
C:\Program Files\ADI\LTspice\
..which is the default, to:
C:\Program Files\ADI\LTspice 24.1\
LTspice 24.1 will become the default application for opening files,
but you can choose XVII from the Desktop link, or Task Bar if you
make a copy there.
--
Regards,
Tony
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Re: Can LTspice XVII and LTspice 24 Be Installed On the Same Win 10 Machine?
Hello Jim,
When you install 24, the installer will change all pointers in the registry.
After installation double-clicking any .asc, .asy, .net, .plt etc... will cause 24 to open.
?
Therefrom, the only way to use 17 will be to start it manually and throw your .asc, .asy, .net, .plt etc...? file onto it or use its open menu.
?
Also, I would make a copy of the 17 directory? from "Program Files" or where ever it is to somewhere safe in case Murphy's Law causes 24 to install on top of 17.
The copy of 17 can be put back anywhere if the original 17 gets clobbered by the 24 install.
Where ever 17 is stored it will run from there without issue by double-clicking the 17 .exe or via a shortcut to the 17 .exe.
17 will continue to use all the same library storage paths that it used to.
?
As for libraries, both 17 and 24 use "C:\Users\<user>\AppData\Local\LTspice\lib" to store the ADI supplied libraries.
Installing 24 will fully erase "C:\Users\<user>\AppData\Local\LTspice\lib" before installing all of ADI's latest stuff that comes with 24.
If you have your 3rd party library stuff also stored in "C:\Users\<user>\AppData\Local\LTspice\lib", as many have done in the past, make a copy of "C:\Users\<user>\AppData\Local\LTspice\lib" before installing 24.
You can sort out what models etc... you wish to keep and, where to store it going forward, after 24 is installed, because you made a complete copy of it.
?
All for now
?
?
Sent:?Monday, March 03, 2025 at 5:32 PM
From:?"Jim via groups.io" <jrteig@...>
To:[email protected]
Subject:?[LTspice] Can LTspice XVII and LTspice 24 Be Installed On the Same Win 10 Machine?
I currently have LTspice 17.1.14 installed on my Windows 10 computer.? Can the latest version of LTspice 24 be installed without uninstalling LTspice 17?
?
Thanks
|
Re: Can LTspice XVII and LTspice 24 Be Installed On the Same Win 10 Machine?
Yes. Some people have even more versions on
the same computer.? XVII and 24 store their working files in
different places on your computer. Don't be tempted to make any
changes to files held within Program Files.
On 2025-03-03 22:32, Jim wrote:
I currently have LTspice 17.1.14 installed on my Windows 10
computer.? Can the latest version of LTspice 24 be installed
without uninstalling LTspice 17?
?
Thanks
--
OOO - Own Opinions only
If something is true:
* as far as we know - it's science
*for certain - it's mathematics
*unquestionably - it's religion
|
Can LTspice XVII and LTspice 24 Be Installed On the Same Win 10 Machine?
I currently have LTspice 17.1.14 installed on my Windows 10 computer.? Can the latest version of LTspice 24 be installed without uninstalling LTspice 17?
?
Thanks
|
Re: LTspice 24.1.4 - Limit function
Since limit() always has been implemented this way with if() functions, convergence isn't affected because there is no change.
Unfortunately it also means your efforts were in vain.
?
Best Regards,
Mathias
?
On Mon, Mar 3, 2025 at 10:36 PM, eetech00 wrote:
Hi Mathias
?
In the past, I always tried to avoid if() statements to prevent convergence issues, and often used LIMIT to wrap if() statements.
So I was concerned on how this re-write would affect convergence.
?
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Re: LTspice 24.1.4 - Limit function
On Sun, Mar 2, 2025 at 11:44 PM, Mathias Born wrote:
One of the exciting new features of LTspice 24.1 (which is the best thing since the invention of sliced bread :-) is that it compiles the math expressions of behavioral sources into highly optimized machine code matching the host machine. In this process, the limit() function is decomposed into more primitive operations to allow the optimizer to "see through it". It's the result of this decomposition that you see in the expanded netlist.
Performance measurements have shown that this new approach consistently cuts the time spent for behavioral source down to 50% (!)
?
Best Regards,
Mathias
?
Hi Mathias
?
In the past, I always tried to avoid if() statements to prevent convergence issues, and often used LIMIT to wrap if() statements.
So I was concerned on how this re-write would affect convergence.
?
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Mathias, ok will take a look at this
?
Larry
|
If you consult the help on the topic of sub-circuit instantiation (LTspice Simulator -> Circuit Elements -> X. Subcircuit) you'll see that this is indeed possible.
?
Best Regards,
Mathias
?
On Mon, Mar 3, 2025 at 08:16 PM, larryg wrote:
I understand you can step .model files but can you step two mosfets that use the .subckt
?
Larry
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Re: PWL with REPEAT/ENDREPEAT fails with zero start time and negative amplitudes.
On the contrary. LTspice works just fine, better than ever. The error is in your contradicting PWL numbers, as the error message says. The help contains a detailed example for this.
If in doubt, write down the final sequence of value pairs you expect from the program.
?
Best Regards,
Mathias
?
On Mon, Mar 3, 2025 at 08:49 PM, bwolfe58 wrote:
There appears to be a bug in LTspice Version 24.1 that is still present in V.24.1.4. The Repeat/EndRepeat directive in some PWL source directives throughs an error.
See my uploaded example file PWL_Example1A.asc
?
ERROR MESSAGE:
net(3): Conflict: Last value differs from first value.
V2 out2 0 PWL repeat for 3 (0 0 1m 5 2m 5 2.5m -1 3m -1 4m 2 4.5m 2) endrepeat
? ? ? ? ? ? ? ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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PWL with REPEAT/ENDREPEAT fails with zero start time and negative amplitudes.
There appears to be a bug in LTspice Version 24.1 that is still present in V.24.1.4. The Repeat/EndRepeat directive in some PWL source directives throughs an error.
See my uploaded example file PWL_Example1A.asc
?
ERROR MESSAGE:
net(3): Conflict: Last value differs from first value.
V2 out2 0 PWL repeat for 3 (0 0 1m 5 2m 5 2.5m -1 3m -1 4m 2 4.5m 2) endrepeat
? ? ? ? ? ? ? ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
I understand you can step .model files but can you step two mosfets that use the .subckt
?
Larry
|
On Mon, Mar 3, 2025 at 06:02 PM, Tony Casey wrote:
It turns out that numeric models of "0" are rejected as invalid in all versions of LTspice, including 24.1.4, even though it is ultimately converted to a string. So the .STEP'ed parameter list can't start at 0.
--
Regards,
Tony
That should not be the case. There is no special treatment of the number zero. Can you provide a test case that proves a problem? Works just fine over here.
?
Best Regards,
Mathias
|
Re: LTspice vs ngspice 12AU7 tube amplifier transient analysis
On Mon, Mar 3, 2025 at 05:32 AM, Carlo wrote:
I'm not sure whether this is the right place to ask about the difference seen in tube amplifier's transient analysis between LTspice and ngspice.
Depending on what those differences are, it might or might not be ideal to ask here.? There are not a lot of group members here who use both programs, but there are a few.? Some?have asked LTspice/ngspice questions here before, sometimes but not always with much response.
?
Do you think LTspice's or ngspice's results are wrong?
Are you aware of the differences between LTspice and other SPICE programs?? Some of them include inductor series resistance, and waveform compression.? If making comparisons, are you sure the conditions were the same?
?
I think it should not hurt to ask here, as long as you do not expect good answers, and realize that there is some bias.
?
Andy
?
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On 03/03/2025 17:12, Andy I via
groups.io wrote:
Can LTspice24 (vers. 24.1.4) .STEP through non-numeric
parameter values?
?
If it can .STEP only through numeric parameter values, then
how does it eliminate the need to rename the models?
I think you missed the context of earlier messages. The numeric
.STEP'ed parameter is silently converted to a string as a
"workaround". To use this directly, still requires the AKO: syntax.
The new method of avoiding AKO: is:
M1 D G 0 0 {Model}
.step param M list 0 1
.param Model select(M,"BSP89","BSS145")
The problem with this is that the new select syntax is implicitly a
zero-based array, so the .STEP'ed parameter list must start at 0 and
increment by 1. If you tried to make this capable of also supporting
the old AKO method with pre-24.1.4, you'd have to change it to:
M1 D G 0 0 {M}
.step param M list 1 2
.model 1 AKO: BSP89
.model 2 AKO: BSS145
It turns out that numeric models of "0" are rejected as
invalid in all versions of LTspice, including 24.1.4, even though it
is ultimately converted to a string. So the .STEP'ed parameter list
can't start at 0.
However, a workaround for this is:
M1 D G 0 0 {M+1}
.step param M list 0 1
.model 1 AKO: BSP89
.model 2 AKO: BSS145
Are you keeping up?? :-)
--
Regards,
Tony
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Re: LTspice vs ngspice 12AU7 tube amplifier transient analysis
ngspice has its own mailing list.? It is still current as of 2025.? It is hosted on sourceforge.net.
?
There is one list for Users, one for Developers, and one for reporting Bugs.
?
Andy
?
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Re: Transferring opamps and other libraries
On Mon, Mar 3, 2025 at 07:36 AM, Carlos E. Mart¨ªnez wrote:
Of course I installed version 24.0, and I was talking indeed about the problems I was having when trying to run my sims with parts this version did not have in its library.
Carlos,
?
Yes I understand that.? But are they parts that CAME with the older version, or are they parts that YOU added to the previous version?
?
People often forget that they added models to their copy of LTspice, and later assume that everyone else has the same models as they do, and that LTspice "came that way", when it did not.? This is one of the reasons why adding your new parts to LTspice's own library is not a good idea.? By keeping added models physically separated from LTspice's own built-in library, it helps to enforce the fact that the model in question did not come with LTspice.? The simulation runs just fine either way, whether an added model is kept separate from LTspice's own library, or added to it.? But it helps YOU see and understand that it was something you added.
?
Is it too long ago for you to remember if you added those models, or if they came with LTspice?
?
Speaking about op-amps, I think LTspice only ever had op-amp models made by Linear Technology or Analog Devices (including companies it acquired).? Models for op-amps that were not made by either company, would not have come with any version of LTspice and must have been added by you.? Note that LTC/ADI second-sourced a few op-amps too.
?
Also, I can't say this with 100% certainty, but I am not aware of any op-amp models made by LTC/ADI and included with LTspice, which were later dropped.? If it was there years ago, I think it is still there.
?
Transistor models are different.? LTC and ADI did not make them.? (Matched pairs being an exception.? But they did not make the transistors that come in LTspice's transistor libraries.)
?
Andy
?
?
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On Mon, Mar 3, 2025 at 02:59 AM, Mathias Born wrote:
In LTspice 24.1.4, numeric parameters implicitely convert to strings. As a result, the old way of using numeric parameters as model names works again.
However, the new string type is better, because it eliminates the need to rename any models.
Can LTspice24 (vers. 24.1.4) .STEP through non-numeric parameter values?
?
If it can .STEP only through numeric parameter values, then how does it eliminate the need to rename the models?
?
Andy
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Tony Casey
eewiz
John Woodgate