The paper describes the idea of design and implementation of Processor-in-the-loop (PIL) model of Automated Transportation Center (ATC) designed as a heavy laboratory operated by VSB-Technical University of Ostrava. It contains technical description of the real technology, the main concept of PIL model and its particular solution for ATC. As for means of design and implementation, the REX Control system was used as a real-time target running on ALIX system board that handles the software model of real technology while the real control system based on Simatic PLCs stays unchanged. The communication between PLCs and ALIX is provided by PROFINET protocol while all of the original I/O signals are re-mapped to match the PROFINET communication standard.