In this work, we present an architecture that was implemented for remote laboratories of control systems. The architecture is implemented in a laboratory inside the University and it needs only a local computer connected to the physical system the student will work with remotely. All the approach is based on free software, which eliminates the need of buying expensive licenses. In the paper, we detail the implementation of the architecture, and we present the comparison between the results of experimenting on-site and remotely with the physical systems to validate the approach.