How do I find my BACnet points list?
There are four routes, easiest first: ask your controls contractor
for the submittal documents, export a points list from your building management
system's front end, scan the network with a BACnet discovery tool, or read the
Object_List property from each controller directly. Scanning is the
only one that is guaranteed to reflect what is actually on the network today
rather than what was installed on paper.
1. Ask the controls contractor
The company that installed or maintains the building automation system normally holds a points list as part of the project submittals, often as a spreadsheet. This is the fastest route when it works. Two caveats: the document describes the design, not necessarily the installed system, and it goes stale the first time anyone adds a VAV box.
2. Export from the BMS front end
Most head-end software — Niagara, Metasys, Desigo, EBI, and the rest — can export a point list or a database report. Look for a report, export, or database view rather than the graphics pages. This gives you what the head-end knows about, which is usually a curated subset: points nobody mapped into the front end will be missing.
3. Scan the network
A discovery tool broadcasts a BACnet Who-Is message and lists every device that answers, then reads each device's object list. This is the only method that reflects reality, including the controllers nobody documented.
You need three things:
- A device on the same IP subnet as the controllers, or a BBMD configured to forward broadcasts to you.
- UDP port 47808 (0xBAC0) reachable and not blocked. Some sites move devices to 47809–47817 to separate networks on one wire.
- Permission. Scanning a building network is a read-only operation, but it is still someone's production control system.
Easy BACnet does this from an Android phone: connect to the building's network, tap Scan for Devices, and it discovers the devices, reads every point on each one, and exports the whole thing as a CSV attached to an email. That is usually faster than getting a laptop onto a controls VLAN.
4. Read Object_List directly
If you are writing your own tooling: every BACnet device object exposes the
Object_List property (property identifier 76), which enumerates every
object on that device. Read index 0 first to get the count, then read each index
in turn, then read Object_Name (77) and Present_Value
(85) for each object you care about.
Two practical warnings. Some inexpensive gateways cannot serve
Object_List one index at a time and need the whole array requested in
a single read. And a controller with hundreds of objects will return a list too
large for one packet, which requires segmentation support in your client.
If the scan finds nothing
That is common and usually a network problem rather than a BACnet problem. See why can't I find my BACnet devices.