User`s guide

4 Verification
Your starting point in developing a plant/controller system is to model
the system a s two subsystems in closed-loop s imulation. As your design
progresses, you can use Simulink software external mode with standard
Real-Time Workshop software processors (such as GR T or ER T) to help you
model the control system separately from the plant.
However, these simulation techniques do not help you account for restrictions
and requirements imposed by the hardware, such as limited memory
resources, or behavior of process or-s pec ific optimized code. W hen you finally
reach the stage of deploying controller code on the processor hardw a re, y ou
may need to make extensive adjustments to the controller system. After you
make these adjustments, your deployed system may diverge significantly from
the original model. Such discrepancies can create difficulties if you need to
return to the original model and change it.
PIL cosim ulation addresses these issues by providing a n intermediate
stage between simulation and deployment. In a PIL cosimulation, the
processor participates fully in the simulation loop — hence the term
processor-in-the-loop.
Definitions
4-4