When an RTDS Simulator consists of three or more NovaCor chassis or previous-generation racks, a special purpose hub – referred to as a Global Bus Hub (GBH) – is required to exchange synchronization signals between each chassis or rack.
An RTDS Simulator consisting of a single chassis or rack operates independently and a two-chassis/rack RTDS Simulator can operate by making a direct connection between the two chassis/racks. For RTDS Simulators with 3 chassis/racks or more, each chassis/rack connects to the GBH using a fibre optic Tx/Rx cable. The GBH is accessible from the rear of the cubicle. GBH communication is separate from the Ethernet communication used to exchange information between the RTDS Simulator and the host workstation.
The Global Bus Hub is often located in a special auxiliary cubicle with the IRC Switch and Ethernet Switch.
The GBH allows up to 144 NovaCor chassis to be driven from one common timestep clock.