How to Identify BACnet Instance Numbers in Niagara R2 UNC-520

[Product_Support]

Issue

When adding more BACnet objects to a Niagara R2 UNC-520, users need a way to generate a report listing all BACnet object instance numbers currently in use.

Product Line

TAC IA Series

Environment

Niagara R2 all versions

Cause

Niagara R2 does not provide a built-in feature or report to list BACnet instance numbers assigned to objects in a UNC.

Resolution

The only available method is to manually search the station’s XML configuration file for the term instanceNumber.

Steps:

1. Locate the station XML file on the UNC.
2. Open the file using a text editor.
3. Search for the keyword:

   instanceNumber
   

4. Review the results to identify all BACnet object instance numbers currently assigned.

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Best Practices for BACnet Instance Numbers

• Use Unique IDs Across the Network
  Ensure each BACnet object has a unique instance number to avoid conflicts during device discovery.
• Follow a Logical Numbering Scheme
  Assign ranges per device type or location (e.g., 1000–1999 for AHUs, 2000–2999 for VAVs).
• Document Assigned Ranges
  Maintain a central record of instance number ranges for all devices in the project.
• Avoid Overlapping Ranges
  When adding new devices, verify that the chosen range does not overlap with existing assignments.
• Plan for Future Expansion
  Reserve gaps in numbering for anticipated future devices or points.