I came across the following text in the Power and Grounding section of the CHARM documentation:
"CHARM extender cables DO NOT extend the shield bar from one group of baseplates to the next. ... If extender cables are used and shielded signal cables are located on baseplates on both sides of the extender cables, separate shield cables must be connected to the CG bar from each set of baseplates."
PIN 5 of the cables are connected to the shield bar. You shouldn't have to run separate cables!
Travis, I heard from our DeltaV team that this note in the Quick Start Guide is to assure a good shield ground will always be maintained.