Integrating several MNB-300 controllers to a UNC-510. How can bias resistors be added to this MSTP trunk?

Issue

Integrating several MNB-300 controllers to a UNC-510.  Bias resistors are available on the UNC-520 but not the UNC-510.  How can bias resistors be added to this MSTP trunk?

Product Line

TAC I/A Series

Environment

Niagara R2 UNC-510

Cause

The UNC-510 was not designed to include built-in bias resistors for a BACnet MSTP trunk.

Resolution

The MNB-300 has built-in bias resistors that are disabled by default.  Remove the cover and enable them with the jumpers provided.  Keep in mind that no more than two sets of bias resistors are to be enabled for any MSTP trunk.  For more information, see the MicroNet BACnet Wiring, Networking, and Best Practices Guide (F-27360).