# Error in running 22mw with S-Fuction for OpenFAST in Matlab **URL:** \ **Category:** Controls\ **Created:** [July 9, 2025, 3:44pm UTC](https://forums.nlr.gov/t/error-in-running-22mw-with-s-fuction-for-openfast-in-matlab/9064 "2025-07-09T15:44:53Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Yongxiang.Lei](https://avatars.discourse-cdn.com/v4/letter/y/3ec8ea/32.png) [@Yongxiang.Lei](https://forums.nlr.gov/u/Yongxiang.Lei)\ **Post date:** [July 9, 2025, 3:44pm UTC](https://forums.nlr.gov/t/error-in-running-22mw-with-s-fuction-for-openfast-in-matlab/9064/1 "2025-07-09T15:44:53Z")
Hello, I am encounting an issue when I was using S-function to OpenFAST, the following error shows for the reading process. Did anyone meet this before. I would be so grateful if any suggestions are given. # Best regards, Yong Unable to perform assignment because the size of the left side is 1-by-7 and the size of the right side is 6-by-1. # Error in HD2Matlab\>ParseFASTTable (line 274) [Table(i,:),~,~,nextIndex] = sscanf(line,‘%f’,nc); ^^^^^^^^^^ Error in HD2Matlab (line 122) [DataOut.Joints] = ParseFASTTable(line, fid, NJoints); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Error in GetFASTPar\_Subfile (line 31) p = HD2Matlab(SubfileName,2); % get parameter data (2 header lines) ^^^^^^^^^^^^^^^^^^^^^^^^ Error in ReadWrite\_FAST (line 29) [HDP, HDFile] = GetFASTPar\_Subfile(FP, ‘HydroFile’, fast.FAST\_directory, fast.FAST\_directory,true); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Error in runFAST2 (line 42) [Param,Cx] = ReadWrite\_FAST(fast); ^^^^^^^^^^^^^^^^^^^^ [this\_dir,~,~] = fileparts(mfilename(‘fullpath’)); % Compile FAST for use with simulink & mex using openfast docs fast.FAST\_SFuncDir = ‘C:\yongxiang\Code\windctrolcode22mw\IEA-22-280-RWT-main\OpenFAST\IEA-22-280-RWT-Monopile’; %%%% NEED FOR SIMULINK fast.FAST\_InputFile = ‘IEA-22-280-RWT-Monopile.fst’; % FAST input file (ext=.fst) fast.FAST\_directory = ‘C:\yongxiang\Code\windctrolcode22mw\IEA-22-280-RWT-main\OpenFAST\IEA-22-280-RWT-Monopile’; % Path to fst directory files % Simulink Parameters % Model %simu.SimModel = fullfile(this\_dir,‘Simulink’,‘ROSCO’); simu.SimModel = ‘WT’; % Script for loading parameters simu.ParamScript = fullfile(this\_dir,‘Utilities’,‘load\_ROSCO\_params’); %% Simulink Setup [ControlScriptPath,ControScript] = fileparts(simu.ParamScript); addpath(ControlScriptPath); addpath(fast.FAST\_SFuncDir); addpath(‘Utilities’) %% Read FAST Files & Load ROSCO Params from DISCON.IN [Param,Cx] = ReadWrite\_FAST(fast); % Simulation Parameters simu.TMax = Param.FP.Val{contains(Param.FP.Label,‘TMax’)}; simu.dt = Param.FP.Val{contains(Param.FP.Label,‘DT’)}; simu.wPA = 8.6; % Pitch actuator natural frequency, rad/sec simu.zetaPA = 0.707; % Pitch actuator damping ratio, unitless simu.PC\_MaxRat = 0.3; [R,F] = feval(ControScript,Param,simu); %% Premake OutList for Simulink OutList = {‘Time’}; OutList = [OutList; Param.IWP.OutList{1,1}; Param.EDP.OutList{1,1}; Param.ADP.OutList{1,1}; Param.SvDP.OutList{1,1}; ]; for iOut = 2:length(OutList) OutList{iOut} = OutList{iOut}(2:end-1); %strip "s end %% Exectute FAST % Using Simulink/S\_Func FAST\_InputFileName = [fast.FAST\_directory,filesep,fast.FAST\_InputFile]; TMax = simu.TMax; SimulinkModel = simu.SimModel; %%%Load the NN parameters warning off s\_dim = 3; % state dimension a\_dim = 3; % action dimension par\_memory\_all = ; controller\_update\_num = 200; % disp(update\_num); %controller\_update\_num = update\_num; init\_idx = 1; model = ‘WT’; load\_system(model); actor\_net\_path = [pwd, ‘\Networks\Actor\Actornet.mat’]; critic\_net\_path = [pwd, ‘\Networks\Critic\Criticnet.mat’]; % Actor\_net = importONNXNetwork([‘Networks\Actor\actor\_’,num2str(controller\_update\_num),‘.onnx’], ‘InputDataFormats’, ‘BC’, ‘OutputLayerType’, ‘regression’, ‘TargetNetwork’, ‘dlnetwork’); save(actor\_net\_path,‘Actor\_net’) set\_param([model,‘/PPO Controller/Actor’],‘NetworkFilePath’, actor\_net\_path) % Critic\_net = importONNXNetwork([‘Networks\Critic\critic\_’,num2str(controller\_update\_num),‘.onnx’], ‘InputDataFormats’, ‘BC’, ‘OutputLayerType’, ‘regression’, ‘TargetNetwork’, ‘dlnetwork’); save(critic\_net\_path,‘Critic\_net’) set\_param([model,‘/PPO Controller/Critic’],‘NetworkFilePath’, critic\_net\_path) Out = sim(SimulinkModel, ‘StopTime’, num2str(simu.TMax)); sigsOut = get(Out,‘sigsOut’); %internal control signals %% Get OutData SFuncOutStr = ‘.SFunc’; % Try text first, then binary [OutData,OutList] = ReadFASTtext([fast.FAST\_directory,filesep,fast.FAST\_InputFile(1:end-4),SFuncOutStr,‘.out’]); if isempty(OutData) [OutData,OutList] = ReadFASTbinary([fast.FAST\_directory,filesep,fast.FAST\_InputFile(1:end-4),SFuncOutStr,‘.outb’]); end % Dump data to structure for i = 1:length(OutList)-6 simout.(OutList{i}) = OutData(:,i); end observation = squeeze(Out.observation)‘; % dim 6 action\_std = squeeze(Out.action\_std)’; % action 3 + logprob dim 4 epi\_memory = [observation, action\_std]; % dim 10 reward = Out.reward.Data; value = Out.value; epi\_rewards = [reward, value]; % dim 2 mu = squeeze(Out.mu)‘; sigma = squeeze(Out.sigma)’; epi\_act\_output = [mu, sigma]; % dim 6 reshape\_epi\_memory = epi\_memory(init\_idx:end, 1: s\_dim+a\_dim+1); % state & action\_sampled & logprob dim=7 reshape\_epi\_reward = epi\_rewards(init\_idx:end, :); % dim=2 reshape\_epi\_act\_output = epi\_act\_output(init\_idx:end, :); % dim=6 par\_memory = [reshape\_epi\_memory, reshape\_epi\_reward, reshape\_epi\_act\_output]; par\_memory\_all = [par\_memory\_all; par\_memory]; % disp(‘Simulation is over.’); save([‘Memories/par\_memory\_’,num2str(controller\_update\_num),‘.mat’], ‘par\_memory\_all’) ---
**Author:** ![Daniel.Zalkind](https://avatars.discourse-cdn.com/v4/letter/d/5daacb/32.png) [@Daniel.Zalkind](https://forums.nlr.gov/u/Daniel.Zalkind)\ **Post date:** [July 10, 2025, 3:10pm UTC](https://forums.nlr.gov/t/error-in-running-22mw-with-s-fuction-for-openfast-in-matlab/9064/2 "2025-07-10T15:10:31Z")
Hi, This appears to be an error in the matlab helper functions, rather than the S-function. These helper functions are no longer maintained in favor of openfast-io ([openfast/openfast\_io at main · OpenFAST/openfast · GitHub](https://github.com/OpenFAST/openfast/tree/main/openfast_io)). I think the error may become clear if you set a break point at 274 in `ParseFASTTable` and observe the line being read. If the OpenFAST model works from the command line, I would presume it works using the S-interface. I usually suggest starting with [the simple Simulink examples here](https://github.com/OpenFAST/openfast/tree/main/glue-codes/simulink/examples) and building the complexity. You may need to adapt the matlab tools so they work with the latest input structure of OpenFAST. I hope this helps. Best, Dan ---
**Author:** ![Yongxiang.Lei](https://avatars.discourse-cdn.com/v4/letter/y/3ec8ea/32.png) [@Yongxiang.Lei](https://forums.nlr.gov/u/Yongxiang.Lei)\ **Post date:** [July 17, 2025, 2:44pm UTC](https://forums.nlr.gov/t/error-in-running-22mw-with-s-fuction-for-openfast-in-matlab/9064/3 "2025-07-17T14:44:23Z")
Hi Daniel, Many thanks for your guidance. I would like to use **matlab S-Function to call the 22MW wind turbine** for testing control target. As you mentioned eariler, I use the simple Simulink examples to try, it runs completely. Then yet, when I changed the path to a 22mw .fst path, its gives me the error of invalid numerical input. ![image](https://europe1.discourse-cdn.com/nrel/original/2X/0/0982271257185d09718c7adb051a6d256433cada.png) Could you please help to look at? Best regards, Yong ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [July 17, 2025, 5:10pm UTC](https://forums.nlr.gov/t/error-in-running-22mw-with-s-fuction-for-openfast-in-matlab/9064/4 "2025-07-17T17:10:43Z")
Dear @Yongxiang.Lei, My guess is that your OpenFAST input file(s) for the IEA Wind 22-MW RWT are not compatible with the version of OpenFAST within Simulink (i.e., the OpenFAST S-Function) you are running. Input file changes with each release of OpenFAST are documented here: [4.1.2. API changes between versions — OpenFAST v4.1.1 documentation](https://openfast.readthedocs.io/en/main/source/user/api_change.html). And you can always enable the `Echo` option in OpenFAST input files to debug issues associated with input file processing. Best regards,