Partitioned environment for Programmable Controller in safety applications

Use of Programmable Controllers (PLC) in safety-critical applications is gaining importance as a pre-qualified development platform to reduce Verification and Validation (V &V) effort. It has been observed, in practice, that most of the safety-critical functions are fairly simple and is achieved by only a small fraction of a large safety-critical software. This motivates the development of a partitioned operating environment for PLC, so that less critical components of the large safety-critical software can be partitioned from those, which are actually performing safety-critical functions. It will facilitate less rigorous V &V for less critical modules to get necessary approval for safety-critical system from regulatory authorities. This work addresses some issues in a Partitioned-PLC development towards improved schedulability bound, yet offering simplicity in implementation.