The different between PIL and SIL
Engineers developing embedded control algorithms and test code by executing it inside a simulation software e.g. PLECS, this approach is referred to as Software-in-the-loop (SIL).
The Processor-in-Loop (PIL) approach is executes the control algorithms on the real embedded hardware like TI DSP 28335, connecting to simulation software e.g. PLECS with a USB or ethernet connection.
A major advantage of PIL over SIL is that during PIL testing, actual compiled code is executed on the real MCU. This detects platform-specific software defects such as overflow conditions and casting errors.
Also, although PIL testing does not execute the control algorithms in true real-time, the control tasks do execute at the normal rate between two simulation steps.
Therefore, PIL simulation can be used to expose and analyze potential problems related to the multi-threaded execution of control algorithms, including jitter and resource corruption.