Network Basics

A Node needs to communicate over your site’s network to collect and share data. This happens using common protocols (languages that devices use to talk to each other), such as BACnet or Modbus. Understanding a few basics about networks and protocols helps in setting up and troubleshooting.

Questions for the site team / OT Contractor:

• “Can you confirm which network this device should connect to?”
• “Which protocol is in use here — BACnet, Modbus, or something else?”

Where do I install my node?

The Node must connect to the same network as the devices it needs to communicate with. Usually this means plugging into the building automation system’s control network, not just the general office Wi-Fi or guest network.

This could be:

• An open Ethernet port near the equipment
• A switch that connects back to your building network
• Or a specific location your IT team designates for new devices
• A virtual node that is “routed” to the correct network.

Asking IT:

• “Which network should I plug the Node into so it can reach the building devices?”
• “Do I need a dedicated port or VLAN for the Node?”
• “Where on our network should I connect this Node?”
• “Is there a specific port or switch that’s best for this device?”

What is a subnet?

A subnet is like a “neighborhood” inside your network. Devices in the same subnet can talk to each other directly. The Node needs to be in the same subnet as the devices it’s talking to, or IT will need to set up routing. If they’re in different subnets, traffic usually has to go through a router or firewall.

Asking IT:

• “What subnet are the building devices on, and can the Node be placed in the same one?”
• “If the Node is in a different subnet, can you set up routing so it can communicate?”

What if I have multiple networks?

Some sites have more than one network — for example, one for building automation systems, one for lighting systems, one for metering systems and another for corporate IT. The Node needs to be placed on the correct network for the devices it’s meant to communicate with. It is also possible to install multiple nodes on different networks and connect them in the Novant cloud.

Asking IT:

• “We have multiple networks — which one is the building automation system on?”
• “Should the Node be isolated on its own network, or join an existing one?”
• “Would it be easier to install a node per subnet?”
• “What routing can be done by the IT team? If it’s not available I could also install additional Virtual or Hardware nodes”

How do I tell if it’s BACnet, Modbus or X?

Different buildings use different protocols to let devices talk. BACnet and Modbus are the most common. Sometimes the system documentation or device labels will say which protocol is in use. If not, IT or your building automation team can confirm.

Asking the site team:

• “Is our building automation system using BACnet, Modbus, or another protocol?, specifically the controllers in the field”
• “Do you know if the devices are set to talk over IP or serial connections?”