In this brief video demonstration, ACE IoT and Doug Plumley, Software Architect at Dartmouth College, explore Dartmouth’s BACnet networks using Grasshopper, a powerful tool for understanding the operational technology (OT) landscape in buildings—and the open-source foundation of ACE Sentinel.
The Network Is the Problem (and the Opportunity)
The OT networks connecting HVAC, metering, and other systems deployed in buildings are often invisible to the teams who rely on them. The lack of visibility makes troubleshooting difficult and resolving issues even harder. When you can’t see how things are connected—or whether they’re connected at all—it becomes nearly impossible to manage your BAS infrastructure with confidence.
That’s where tools like Grasshopper come in.
Grasshopper visualize BACnet/IP and Field Bus networks in real time. It provides illustrations of where and how devices are connected to the network and to each other. Facilities management (FM) teams can use Grasshopper to identify duplicate addresses and/or routing conflicts. Leveraging knowledge graph technology, FM teams can store snapshots of their building’s network and easily identify what’s changed since yesterday, last week or last month. For Doug Plumley, Grasshopper’s “point-in-time snapshots” reveal both expected behaviors and anomalies that might otherwise go unnoticed.
Watch the Walkthrough
In the walkthrough, Doug highlights specific examples from Dartmouth’s campus environment: duplicate devices appearing on multiple networks, routing loops caused by misconfigured IP routers, and how side-by-side visual comparisons of network states from different days help identify changes and pinpoint who made them. This ability to “diff” a network, as Doug puts it, has resolved more than a few finger-pointing moments across the teams working on Dartmouth’s campus.
From Open Source to Enterprise-Ready
While the walkthrough focuses on Grasshopper, the tool is more than a one-off utility. It’s the open-source foundation for ACE Sentinel, ACE IoT’s enterprise-ready BACnet network diagnostics and visibility product.
Doug puts it simply:
“It lets you reason about the network and the changes to the network in a way that substantially shortens the time to fix issues.”
Sentinel expands on Grasshopper with managed deployments, an enhanced interface, and seamless integration with ACE Aerodrome and the SkyHook gateway. Indeed, the combination of ACE Sentinel and an Independent Data Layer (IDL) solution from ACE IoT means that FM teams have powerful new diagnostic tools designed to enable both proactive monitoring (like alerts for new or disappearing devices) and passive visibility (like real-time traffic snapshots and long-term change tracking).
A Shared Visual Language
One of the most compelling outcomes Doug describes is how Grasshopper has helped bridge the communication gap between Dartmouth’s facilities and IT teams.
“You now have the ability to point at something and reason about it with them.”
By providing a shared visual representation of both BACnet/IP and Field Bus networks, tools like Grasshopper and Sentinel make more concrete abstract infrastructure that is difficult to grasp using spreadsheets. Using Grasshopper or Sentinel, OT teams see the devices and segments they know. IT teams recognize the routers and IP structures they’re used to. And both OT and IT teams can meet in the middle—looking at the same screen, speaking the same language.
Open, Accessible, and Built to Grow
Doug also touches on why the open-source nature of Grasshopper matters: it’s permissively licensed, extensible, and backed by a real-world deployment. That means technologists who want to build on the tool—or simply validate their own systems—can get started right away. The full agent code is available on GitHub, alongside documentation and data export options like CSV-based asset registries and graph files in Turtle format.
For commissioning agents and engineers, facilities managers, campus operators, and anyone involved in large capital projects, Doug is clear:
“The use cases you can layer on top of having a knowledge graph like this are kind of limitless.”
See It for Yourself
We invite you to watch the walkthrough and see how network transparency helps Dartmouth—and how the same principles power ACE Sentinel. Whether you’re trying to validate system readiness, resolve communication issues, or align your teams, it all starts with increased observability of your networks. (And stay tuned: a full Flight Logs episode featuring a deeper dive with Doug is coming soon!)
