Lost Sync with System Clock – Resetting Control Engine in Niagara R2 Enterprise Server

[Product_Support]

Issue

Enterprise Server displays repeated warning messages:

Lost Sync with system clock - resetting control engine

Product Line

TAC IA Series

Environment

• Niagara R2 Enterprise Server
• UNC-520, UNC-410 controllers

Cause

The warning occurs due to incorrect or inconsistent time synchronization settings between the Enterprise Server and UNCs. This can result from:

• Improper serverEnabled or clientEnabled configuration
• Missing or incomplete time protocol server entries
• Tight clientResetTolerance values

Resolution

Verify and adjust the following settings:

Enterprise Server (ES):

• serverEnabled = true if syncing with UNC
• clientEnabled = true if ES gets time from an internet or site server; otherwise set to false
• clientResetTolerance: Default is 30 sec (too tight). Set to 60 sec or more (enter value in seconds)
• timeProtocolServer*: If clientEnabled = true, all three slots must contain a time server address. If only one server is used, repeat the same address in all slots. No blank slots allowed

UNCs (TimeSyncService):

• serverEnabled = false
• clientEnabled = true
• clientResetTolerance: Same as ES (≥60 sec)
• timeProtocolServer*: Same rule as ES
• Reboot the UNC after making changes