Emulation/simulation of PLC networks with the S3F network simulator

Programmable Logic Controllers (PLCs) are devices frequently used in industrial control systems with tight real time constraints on operations. Using emulation and/or simulation to evaluate the behavior of a network of PLCs is difficult because of the lack of tools that accurately mimic the real-time behavior of such networks. This paper addresses this issue by showing how to tightly integrate instances of a PLC emulator Awlsim with the network simulator S3F, in such a way that emulations and simulation are advancing synchronously in virtual time. We demonstrate fidelity of the approach in capturing the operating behaviour of a PLC network under varied network conditions and stress levels.