Power electronics-based DC power systems are seen as one of the most promising solutions for the integration of storage systems and the exploitation of renewable energy sources. These systems can indeed rely on high performing controllable interfaces and data communication network. Moreover, to achieve cutting-edge features, such as resilience, flexibility, and upgradability, the choice of the zonal topology for such systems is mandatory. The zonal topology is certainly not a standard option and still needs quite a bit of study and testing campaigns. This is why this paper presents a Controller Hardware In the Loop (CHIL) open source platform to investigate the behavior of a zonal DC grid. Considering the availability of the physical controller of an industrial scale zonal distribution, this paper shows an emulation platform based on Linux Real Time Application Interface, managed by such controller. The platform has been presented in previous works, but here an order-reduction modeling option is discussed to further improve the real-time performance. The reduced-order model accuracy is proven by comparing the results with the experimental transients.