Unable to run OpenFAST example problems using Simulink

[madhuri-seeram]

Dear Sir,
I am trying to run the OpenFAST example problems Run_OpenLoop.m and Test01_SIG,m files. I am getting the following message and Errors.

Run_OpenLoop

---

OpenFAST

Copyright (C) 2023 National Renewable Energy Laboratory
Copyright (C) 2023 Envision Energy USA LTD

This program is licensed under Apache License Version 2.0 and comes with ABSOLUTELY NO WARRANTY.
See the "LICENSE" file distributed with this software for details.

---

OpenFAST-v3.4.1-dirty
Compile Info:

• Compiler: Intel(R) Fortran Compiler 2021
• Architecture: 64 bit
• Precision: single
• OpenMP: No
• Date: Apr 12 2023
• Time: 13:57:40
  Execution Info:
• Date: 07/29/2026
• Time: 13:21:52+0530

OpenFAST input file heading:
FAST Certification Test #6: AOC 15/50 with many DOFs with gen start, loss of grid, and
tip-brake shutdown. Many parameters are pure fiction.

OpenFAST completed.

Error using [Run_OpenLoop](matlab:matlab.lang.internal.introspective.errorDocCallback('Run_OpenLoop', 'D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_OpenLoop.m', 15)) ([line 15](matlab: opentoline('D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_OpenLoop.m',15,0)))
Error reported by S-function 'FAST_SFunc' in 'OpenLoop/FAST Nonlinear Wind Turbine/S-Function':
FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:Invalid numerical input for file
"D:\openfast-main\openfast-main\glue-codes\reg_tests\r-test\glue-codes\openfast\AOC_WSt\AOC_WSt.fst" occurred while trying
to read CompServo.

Run_Test01_SIG

---

OpenFAST

Copyright (C) 2023 National Renewable Energy Laboratory
Copyright (C) 2023 Envision Energy USA LTD

This program is licensed under Apache License Version 2.0 and comes with ABSOLUTELY NO WARRANTY.
See the "LICENSE" file distributed with this software for details.

---

OpenFAST-v3.4.1-dirty
Compile Info:

• Compiler: Intel(R) Fortran Compiler 2021
• Architecture: 64 bit
• Precision: single
• OpenMP: No
• Date: Apr 12 2023
• Time: 13:57:40
  Execution Info:
• Date: 07/29/2026
• Time: 13:22:27+0530

OpenFAST input file heading:
FAST Certification Test #1: AWT-27CR2 with many DOFs with fixed yaw error and steady wind

OpenFAST completed.

Error using [Run_Test01_SIG](matlab:matlab.lang.internal.introspective.errorDocCallback('Run_Test01_SIG', 'D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m', 42)) ([line 42](matlab: opentoline('D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m',42,0)))
Error due to multiple causes.
Caused by:
Error using [Run_Test01_SIG](matlab:matlab.lang.internal.introspective.errorDocCallback('Run_Test01_SIG', 'D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m', 42)) ([line 42](matlab: opentoline('D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m',42,0)))
Error reported by S-function 'FAST_SFunc' in 'Test01_SIG/FAST Nonlinear Wind Turbine/S-Function':
FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:Invalid numerical input for file
"D:\openfast-main\openfast-main\glue-codes\reg_tests\r-test\glue-codes\openfast\AWT_YFix_WSt\AWT_YFix_WSt.fst" occurred
while trying to read CompServo.
Error using [Run_Test01_SIG](matlab:matlab.lang.internal.introspective.errorDocCallback('Run_Test01_SIG', 'D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m', 42)) ([line 42](matlab: opentoline('D:\openfast-main\openfast-main\glue-codes\simulink\examples\Run_Test01_SIG.m',42,0)))
The expression: u(strcmpi('LSSGagVxa',OutList))
in 'Test01_SIG/Fcn'
has a syntax error

Please help me

[jjonkman]

Dear @madhuri-seeram,

Regarding the error, "Invalid numerical input ... while trying to read ..." , it sounds like your input file is not formatted for the version of OpenFAST you are using. You can always enable the Echo option to debug issues associated with input file processing.

Regarding the error about the "expression ... has a syntax error", does ElastoDyn ouptut LSSGagVxa exist in your ElastoDyn OutList?

Best regards,

[madhuri-seeram]

I have downloaded openfast 5.0.0 version. How I should enable the Echo option.
I the problem is with the numerical value 1 in CompServo command of .fst input file. How to resolve the issue

[madhuri-seeram]

Dear Sir, I used the power shell to run the opefast files. I am getting the similar kind of problem even in powershell with CompServo numerical input in the *.fst input file. Almost all the input files are giving similar kind of error. Please find the screenshot below. [image: image.png]

…

On Wed, 29 Jul 2026 at 21:11, jjonkman ***@***.***> wrote: *jjonkman* left a comment (OpenFAST/openfast#3404) <#3404 (comment)> Dear @madhuri-seeram <https://github.com/madhuri-seeram>, Regarding the error, "Invalid numerical input ... while trying to read ..." , it sounds like your input file is not formatted for the version of OpenFAST you are using. You can always enable the Echo option to debug issues associated with input file processing. Regarding the error about the "expression ... has a syntax error", does ElastoDyn ouptut LSSGagVxa exist in your ElastoDyn OutList? Best regards, — Reply to this email directly, view it on GitHub <#3404?email_source=notifications&email_token=AUBALZ6GJCXIEQFRLJ4U6CD5HILMHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJSGAYTENRYG4Y2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-5120126871>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AUBALZ6HPWXBMYVYSJPYIID5HILMHAVCNFSNUABEKJSXA33TNF2G64TZHM3DOMBWHE3TKNR3JFZXG5LFHM2TAMBWHA3DEOJVG2QXMAQ> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AUBALZ3SDVM7OLQUJ6H2ODL5HILMHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJSGAYTENRYG4Y2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJKTGN5XXIZLSL5UW64Y> and Android <https://github.com/notifications/mobile/android/AUBALZ7V2RYQHWQ3G24PXCD5HILMHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJSGAYTENRYG4Y2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLTGN5XXIZLSL5QW4ZDSN5UWI>. Download it today! You are receiving this because you were mentioned.Message ID: ***@***.***>

[jjonkman]

Dear @madhuri-seeram,

Such an error is almost always caused by the use of input files that are not formatted for the version of OpenFAST you are using. I'm sure the error is not associated with the setting of CompServo itself, but likely there is a line added or missing above it. Enabling the Echo option should help you figure out how OpenFAST is interpreting your input file. And you can always see how the input files change with each release of OpenFAST in the following documentation on OpenFAST readthedocs: https://openfast.readthedocs.io/en/main/source/user/api_change.html. If you are starting fresh, I would ensure you use the OpenFAST executable and r-test tagged for the same release version.

Best regards,

[madhuri-seeram]

Dear Sir,

In version 5.0.0, I couldn't find openfast_x64.exe in the assets. So, I followed the following procedure.

I have downloaded the build/bin folders from "https://github.com/sido28/OpenFAST-build-folder-/tree/main" and the OpenFast software is of version 5.0.0. I am following the steps given in "https://hal.science/hal-04858231v1/file/OpenFAST_En.pdf" to use the MATLAB simulink. Is the build/bin and openfast versions are not the release of same version?. If not please let me know how to install and execute the examples either using power shell or MATLAB simulink.

I have tried to run the files using echo on option in the matlab input file, Run_OpenLoop.m as followes. Even, I am getting the same error as earlier.

echo on
FAST_InputFileName = '../../../reg_tests/r-test/glue-codes/openfast/AOC_WSt/AOC_WSt.fst';

[jjonkman]

Dear @madhuri-seeram,

NLR no longer provides 32-bit assets, so, the precompiled Windows executable of OpenFAST in the v5 release is simply called OpenFAST.exe. You can download that, as well as the precompiled OpenFAST mex function (FAST_SFunc.mexw64) and library (OpenFAST-Simulink.dll) for MATLAB/Simulink here: https://github.com/OpenFAST/openfast/releases/tag/v5.0.0.

NLR-provided documentation for installing and compiling OpenFAST is provided here: https://openfast.readthedocs.io/en/main/source/install/index.html. On Windows, I would say that the use of Visual Studio with Intel Fortran (all free) is simplest: https://openfast.readthedocs.io/en/main/source/install/install_vs_windows.html.

Best regards,

[andrew-platt]

For simulink, there is a small issue you will need to work around. See #3332