Do Not Enable Authentication in Niagara R2 LonWorks Service with MNL Controllers on LON Trunk

[Product_Support]

Issue

Enabling Authentication in a Niagara R2 station’s LonWorks service when MNL controllers are on the LON trunk under a UNC can disable LON communications to the controllers, possibly permanently.

Product Line

TAC IA Series

Environment

• Niagara R2
• MNL Controllers

Cause

When Authentication is enabled in the LonWorks service without proper commissioning, MNL controllers can enter one of two states:

1. Recoverable Mode – Authentication enabled but controllers not commissioned with Authentication.
2. Permanent Hard Offline Mode – Authentication cleared via service pin, then recommissioned incorrectly, making the controller unrecoverable.

Resolution

• Do NOT enable Authentication when MNL controllers are present on the LON trunk.
• If Authentication was enabled:
  • Use the service pin method to clear controller authentication (refer to WorkPlace Tech Tool 4.0 Engineering Guide, p. 602).
  • Attempt recovery using NodeUtil to access and modify memory. Contact Product Support for detailed instructions.
• If the controller was recommissioned after clearing authentication, it will be permanently offline and cannot be recovered.