Niagara R2: Cisco Mediator BACnet Controller Cannot Write to Exposed Objects

[Product_Support]

Issue

A Cisco Mediator BACnet/IP controller connected to a Niagara R2 UNC can read exposed BACnet objects but cannot overwrite setpoints or issue commands.

Product Line

TAC IA Series

Environment

Niagara R2 all versions

Cause

The Niagara R2 station requires a specific BACnet user configuration to allow external BACnet devices to write values or send commands. Without this user, write requests are rejected.

Resolution

Create a special BACnet user in the Niagara R2 station:

1. Open the Niagara R2 station configuration.
2. Navigate to Security → Users.
3. Add a new user with the following properties:
   • User Type: BACnet
   • Assign appropriate permissions for writing to exposed objects.
4. Save and restart the station if required.

Refer to Tridium BACnet Integration Guide, pages 4-6 and 4-7, for detailed steps.