Which technology is a building automation control networking platform designed for distributed control across devices?

• A. BACnet
• B. Modbus RTU
• C. LonWorks
• D. Modbus TCP

Answer: (C)

A system designed for distributed control across many devices means each device on the network can run its own control logic and communicate its state and commands to others, creating a coordinated network rather than a single central controller. LonWorks is built as a complete networking platform for exactly that kind of distributed control. It uses the LonTalk protocol to let a wide range of devices—HVAC, lighting, sensors, actuators, and other controllers—interact, share data, and execute local control decisions while still working together as a cohesive building automation system. The platform provides not only the communication scheme but also the tools and device models that enable multi-vendor interoperability and scalable, decentralized control across the building.

By contrast, BACnet is primarily a data-exchange standard that enables interoperability between different building systems, which is crucial for integration but doesn’t per se define a single distributed-control architecture. Modbus RTU and Modbus TCP are simpler, more linear protocols focused on client-server or master-slave data access, and they don’t inherently embody the distributed intelligence across many devices that LonWorks is designed to provide.