Message Timestamps

In the next sub-section a minimum viable schema is described. Note that the minimum viable schema doesn’t include a timestamp. It is recommended to add a timestamp to the JSON message if possible and an example of this is provided in the other described schemas.

If a timestamp is not included in the JSON message, DCH will append a timestamp, with the timestamp being the UTC time at which the message was retrieved from the broker by DCH. There may be a delay between the time the message arrives at the broker, and the time at which it is retrieved from the broker.

Another potential issue with timestamps is if the gateway is not synchronised with an NTP server (either directly or via the LAN). Gateway internal clocks will drift over time if not synchronised, and this drift will cause problems with some demand reduction DCH applications that monitor wholesale electricity spot pricing in addition to building point values.

NOTE: There is an issue with Tridium Jaces that could fail to synchronize with NTP servers. This is corrected in Niagara versions 4.10.2.52+. There is a Niagara Community forum posts titled “NTP not syncing automatically” that describes the issue.