What DM-TS-B Is
DM-TS-B (Device Management-Time Synchronization-B) is the BACnet Interoperability Building Block (BIBB) for a device that accepts TimeSynchronization: a time master sends the current local time and the device sets its clock from it. The UTC counterpart, accepting UTCTimeSynchronization, comes from the related DM-UTC-B.
Why It Matters on the Restart Path
A device that just restarted has a clock that may be wrong, stopped, or reset to a default epoch, depending on whether it has a real-time clock backed by battery or supercapacitor. DM-TS-B is what lets that device recover a correct clock after a restart rather than running schedules, trend timestamps, and alarm times against the wrong time until the next scheduled broadcast happens to arrive. The full restart-recovery picture covers where this fits.
What It Requires
| Piece | What it does |
|---|---|
| Receiving TimeSynchronization | Sets the device’s local-time clock from the broadcast |
| Applying the update correctly | Distinguishes a routine periodic sync from a post-restart clock recovery, since a device coming back from a coldstart has more reason to trust an incoming sync than one that has been running steadily |
Where You Meet It in the Field
Any controller whose Schedule has to fire at the right moment, whose Trend Log needs comparable timestamps across devices, or whose alarms need to correlate across a site depends on DM-TS-B being implemented correctly, not just claimed.
What Chipkin Provides
The CAS BACnet Stack supports DM-TS-B today: the device receives TimeSynchronization and UTCTimeSynchronization and updates its clock. The CAS BACnet Stack 6.x release is targeting a post-restart time-sync path where the device requests time from a configured master after a coldstart instead of waiting for the next outbound broadcast. Talk to us about your specific clock-recovery scenario.