In RT-LAB, what's the difference between Normal, Accelerator, and Real-Time execution?

Q&A
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1

Hi,
I’m new to RT-LAB. Can someone explain when I should use Simulink Normal mode, Accelerator mode, and Real-Time execution?
Thanks!

2

:green_circle: Simulink Normal Mode
What it is: Standard Simulink desktop simulation — no code generation, no real-time constraints.

When to use it:

Model development and debugging

Verifying math/logic before compiling

Quick “does my model even run?” sanity checks

Key traits: Slow (variable-step or fixed-step offline), full Simulink debugging tools available, no OPAL-RT hardware needed.

:yellow_circle: Accelerator Mode
What it is: Simulink generates C code from your model and runs it as a compiled MEX on your desktop — still offline, but much faster.

When to use it:

Long batch simulations where Normal mode is too slow

Validating model behavior at fixed time-step before going real-time

Catching code-generation issues early (some blocks behave differently once compiled)

Key traits: 5–50× faster than Normal mode, still non-real-time, runs on your PC, good intermediate step before RT execution.

:red_circle: Real-Time Execution (RT-LAB)
What it is: RT-LAB compiles your model, deploys it to an OPAL-RT target (e.g., OP4610, OP5700), and executes it under hard real-time constraints at your chosen time-step (e.g., 10–50 µs).

When to use it:

Hardware-in-the-loop (HIL) testing with physical controllers

Closed-loop testing requiring deterministic timing

Validating controller firmware against a plant model in real time

Key traits: Deterministic execution, I/O synchronization with physical hardware, requires OPAL-RT target, overruns = errors.

3

Thanks PFA007!
That clears things up.
The comparison between the three modes makes it much easier to understand when to use each one.