simulink-configure-real-time-model

Configure Simulink Real-Time Models

Prepare an existing Simulink model to build as a Simulink Real-Time application — configuring it consistently with the selected target platform, solver requirements, and Simulink Real-Time build options.

Release compatibility: Designed and validated for MATLAB R2026a and later. Earlier releases differ in APIs, system target files, and workflows — use that release's product documentation instead.

When to Use

• Setting up a Simulink model for Simulink Real-Time, or preparing it before slbuild
• Selecting or correcting the system target file (STF/TLC), including models on grt.tlc or ert.tlc
• Reviewing or setting fixed-step solver options for real-time execution while preserving the model's intended dynamics and sample-time behavior
• Configuring model parameters for a selected Speedgoat target computer or compatible Linux device — toolchain details, or Simulink Real-Time options (log level, polling mode, max file log runs, GCC -ffast-math)
• Handling errors about incompatible target platforms or missing target platform selection
• Running Upgrade Advisor for an older Simulink Real-Time model

When NOT to Use

If the task crosses one of these lines, load the named skill before writing that code, then come back.

• Defining or editing a target (IP, credentials, TargetSettings, addTarget), RTOS update, network/SSH setup, or troubleshooting a target that will not connect → simulink-configure-real-time-target. Selecting an already-defined target and calling connect(tg) with the user's consent stays in this skill (Step 1).
• slbuild, tg.load, tg.start, tg.stop, tg.Stimulation → simulink-run-real-time-application
• Capturing signal values during a run (slrealtime.Instrument, file log, SDI, MATLAB callbacks) → simulink-instrument-real-time-application
• Test-pointing or canvas-badging signals (set_param(port, 'TestPoint', ...), markSignalForStreaming) → simulink-instrument-real-time-application (setup-phase ops, not this skill)
• Editing model structure (blocks, connections), or desktop simulation with sim or parsim

STF values — do not hard-code; call getSTFName(tg) and let the installed support package decide. Never use slrealtime.tlc for Speedgoat hardware in R2026a+. When tg is unreachable, see references/disconnected-workflow.md; for which value each support package resolves to, see references/stf-by-target.md.

Prerequisites

• MATLAB R2026a or newer
• Simulink Real-Time installed (ver lists "Simulink Real-Time")
• A relevant support package installed for the target hardware:
  • Speedgoat hardware → Speedgoat Add-On (provides speedgoat.tlc for standard targets and speedgoat_aarch64.tlc for Speedgoat Pulse)
  • Linux x86-64 devices → Embedded Coder Support Package for Real-Time Linux (requires Embedded Coder and provides slrtlinux_x64.tlc)
• Model is loaded in Simulink (load_system or open_system)
• Read references/api-reference.md before writing code. It lists the only APIs and model configuration parameters this skill uses; do not invent variants.

Workflow

Step	What	Detail
1	Choose the target — ask before connecting	below
2	Load the model	below
3	Inspect the existing configuration	below
4	Check for a referenced config set	below
5	Run Upgrade Advisor when the model is legacy	references/upgrade-advisor.md
6	Configure for the target platform (default path)	below
7	Resolve the STF manually (fallback only)	references/stf-by-target.md
8	Configure solver settings	below
9	Preserve user intent around stop time	below
10	Configure Simulink Real-Time options	references/slrt-options.md, references/compiler-options.md
11	Validate product and add-on assumptions	below
12	Validate configuration before saving	below
13	Run update diagram (ask first)	below
14	Save only after the user agrees	below

No reachable target at any point → references/disconnected-workflow.md.

1. Choose the Target — Ask Before Connecting

Never call connect(tg) without user consent, and never pick a target on the user's behalf. Even if only one target is defined, surface it and confirm.

1. User named a target (e.g., "configure for target sg") — tg = slrealtime("sg"), then ask permission before connect(tg).
2. User did not name a target — list getTargetNames(slrealtime.Targets) and ask which one to use. If only one exists, still confirm.
3. No targets are defined, and the user described their hardware — give the best STF guess from that description (Speedgoat → speedgoat.tlc unless it is a Speedgoat Pulse; Speedgoat Pulse → speedgoat_aarch64.tlc; Real-Time Linux x86-64 → slrtlinux_x64.tlc) and recommend defining a target with simulink-configure-real-time-target for more accurate results. If they proceed without one, follow references/disconnected-workflow.md instead of getSTFName.
4. No target is reachable and the user has not described their hardware — stop before any SystemTargetFile write. Name the options (Speedgoat / Speedgoat Add-On, including the Pulse exception; Real-Time Linux x86-64 / Embedded Coder Support Package for Real-Time Linux), ask which applies, then load simulink-configure-real-time-target to define the target. Do not resolve this gate from installed products — see the Never list.

The following Simulink Real-Time targets are defined on this machine: <name1>, <name2>, ... Which one should I configure <model> for? I will ask before connecting.

An authorized connect(tg) can still fail or block. Guard the call; when it fails, report err.identifier and the cause (never the raw error block) and switch to the disconnected fallback rather than retrying blindly or leaving the model half-configured.

2. Load the Model

Run load_system(model) and confirm with bdIsLoaded(model). If the model is not on the MATLAB path, locate it or ask the user to confirm the path before changing settings.

3. Inspect Existing Configuration

Read SystemTargetFile, SolverType, Solver, and FixedStep before changing anything, so the change can be explained before saving. Also read StopTime and the Simulink Real-Time options if the user asked about runtime duration, logging, polling mode, or compiler behavior.

A model already on a Simulink Real-Time family target file is not necessarily wrong — verify it against the selected target. A legacy target file (slrealtime.tlc, slrt.tlc, slrtert.tlc, xpctarget.tlc, xpctargetert.tlc) goes to Step 5 before any STF change. Step 5 does not depend on the target or the support package: run it even when Step 1 or Step 11 stops the STF write.

4. Check for External or Referenced Configuration Sets

cs = getActiveConfigSet(model);
usesConfigSetRef = isa(cs, "Simulink.ConfigSetRef");

A referenced config set can be shared by every model that references it. Do not silently detach or replace it — ask for explicit permission unless the user already requested that behavior.

5. Run Upgrade Advisor When Needed

Run upgradeadvisor(model) before any SystemTargetFile write when the model is legacy — created in an older release, reporting migration errors, or on one of the legacy target files above. references/upgrade-advisor.md has the trigger list, handling order, and the two valid check IDs. Warn the user that the advisor fixes may migrate or discard legacy settings; upgrade first, then configure, and never build from a legacy target file. The target-selection and support-package stops (Steps 1 and 11) gate the SystemTargetFile write, not Upgrade Advisor — run the advisor first, then ask.

6. Configure Model for Target Platform (Default Path)

Use this unless the user explicitly asked for manual STF control.

model = "myModel";
tg = slrealtime("targetName");
load_system(model);
try
    connect(tg); % only after the user approved this specific target name
    configureModelForTargetPlatform(tg, model);
catch err
    % Report err.identifier + cause; then use references/disconnected-workflow.md
end

It sets SystemTargetFile to the STF that getSTFName(tg) returns and switches SolverType to Fixed-step in one call. Do not also write SolverType, and do not call getSTFName(tg) first to "confirm" — that adds noise to the narrative.

It can prompt interactively. When it cannot resolve the platform it opens the modal Speedgoat Target Platform Selector, which blocks a non-interactive session. Call it only against a connected target whose platform resolves; otherwise take the disconnected fallback.

7. Resolve the System Target File (Manual Fallback Only)

Only when the user asked to drive SystemTargetFile themselves, or another workflow needs the STF string first: modelSTF = getSTFName(tg);, write it to SystemTargetFile, and verify before saving. Never hard-code an STF without going through the support-package question.

8. Configure Solver Settings

After Step 6, SolverType is already Fixed-step — skip it. After a manual or disconnected STF write, set SolverType to Fixed-step.

Set FixedStep only to a value the user gave; otherwise preserve the current value unless it is invalid. auto infers the fundamental sample time from the model. Solver choice depends on the model: FixedStepDiscrete for a fully discrete model, ode1/ode3/ode4 when continuous states are present, or FixedStepAuto to let Simulink choose.

Do not switch continuous to discrete dynamics, change solver order, or change the base rate as a silent cleanup — those change numerical behavior, real-time load, and test results. Involve the user when the tradeoff is not obvious; for structured regression checks, use testing-simulink-models.

9. Preserve User Intent Around Stop Time

Desktop StopTime does not govern target execution; runtime stop-time control (setStopTime(tg, ...), start(tg, "StopTime", ...)) belongs to simulink-run-real-time-application. Write model-level StopTime only when the user wants the saved model to carry that value, then verify the readback.

10. Configure Simulink Real-Time Options

The Simulink Real-Time Options pane appears only after a Simulink Real-Time STF is selected. The five option names in references/api-reference.md are the only ones this skill names. Read an option's current value before writing it; if the active config set does not expose it, report the mismatch instead of writing. Enable UseGCCFastMath only on explicit request. Do not override target-managed toolchain, make-command, or target-language parameters. Dialog names and per-option guidance: references/slrt-options.md; custom compiler flags: references/compiler-options.md.

11. Validate Product and Add-On Assumptions

Before diagnosing STF errors, check v = ver; installedNames = string({v.Name}); for MATLAB, Simulink, Simulink Coder, and Simulink Real-Time. Speedgoat hardware also needs the Speedgoat Add-On for speedgoat.tlc and speedgoat_aarch64.tlc.

This check establishes capability, not intent — never use it to infer which hardware the user is targeting.

A missing support package stops this workflow. When the user has named their hardware and the add-on that provides its STF is not installed, name the exact STF value and the add-on, tell the user to install it and come back, and apply no partial configuration — see references/disconnected-workflow.md § Required support package absent.

12. Validate Configuration Before Saving

Read back SystemTargetFile, SolverType, Solver, and FixedStep. SolverType must be Fixed-step; if not, the configure calls did not take effect — do not save, diagnose first. With a target object available, compare the model's STF against getSTFName(tg); on a mismatch, do not save and report it.

13. Run Update Diagram

Ask permission, then run set_param(model, "SimulationCommand", "update"); — a lifecycle command, one of the few set_param forms this skill authorizes. On failure, report the diagnostic. Typical causes: variable-step solver settings, blocks unsupported for code generation, continuous states with an incompatible solver, missing sample times, invalid config-set references, missing support packages, or target-file callback failures.

14. Save Only After Successful Setup

Ask whether to save and wait for the answer before save_system(model). Saving first and asking afterward is not consent. For a dry run or inspection, do not save — return the planned changes.

Guardrails

Always:

• Derive the target file from a connected target when possible, preferring configureModelForTargetPlatform over getSTFName plus manual writes.
• Inspect and change the named model configuration parameters through the active environment's model-configuration capabilities; use the product APIs in references/api-reference.md for target-object, introspection, and lifecycle operations.
• Run Upgrade Advisor for legacy models, and set or preserve fixed-step behavior explicitly.
• Verify SystemTargetFile, SolverType, Solver, and FixedStep after changing configuration.

Ask first:

• Before calling connect(tg) — always confirm the specific target name, even if only one target is defined.
• Before reconfiguring a model already on a Simulink Real-Time family target file.
• Before changing a model with an external config set.
• Before applying Upgrade Advisor fixes that may alter model behavior.
• Before setting a fixed-step size when the intended base rate is unknown.
• Before enabling performance-affecting compiler options such as -ffast-math.
• Before running update diagram after configuration.

Never:

• Pick a target on the user's behalf or call connect(tg) without explicit permission for that specific target name. Even with a single defined target, list it and confirm.
• Treat installed products or support packages as evidence of the user's intended hardware. ver output, a present Speedgoat Add-On, and a clean speedgoat.version establish capability only. Never write SystemTargetFile on the strength of an installed-support probe when the user has not stated their target family — propose and wait instead.
• Save the model before the user has agreed to it. Ask, then wait for the answer, then save_system. Applying changes and announcing "the model has been saved" alongside a request for confirmation reverses the gate.
• Invent function names, property names, or parameter values that do not appear in references/api-reference.md, this skill's examples, or its reference files. If a form is not shown, do not use it — for example, hard-coding slrealtime.tlc for a Speedgoat target, or calling tg.setSTF(...).
• Invent internal check IDs for Upgrade Advisor. The only valid Simulink Real-Time check IDs are mathworks.design.slrealtimeUpgrades and mathworks.design.slrealtimeLoggingUpgrades. For anything else, open the advisor with upgradeadvisor(model) and tell the user which categories to run.
• Change solver type, solver, or fixed-step size without preserving model intent.
• Build the model in this skill unless the user explicitly asks for setup plus build.

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Copyright 2026 The MathWorks, Inc.

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