This paper proposes a control scheme to coordinatethe DC voltage of converters in a HVDC grid using a Multi-agentSystem concept. Such interactions between agents, converters,and communication units are approached from a Cyber-PhysicalSystem (CPS) perspective. The Multi-agent based control schemetries to update the DC voltage set-points of the converters basedon local and neighboring information. The information exchangebetween the agents and communication delay tolerance of thecontrol scheme is studied by means of graph theory. The multiagentcontrol scheme has been implemented for a seven-terminalHVDC grid in a real time simulator and the impact ofcommunication delay on this distributed control approach hasbeen studied and is presented in the result.