Q: We connected both Encore 61000 and HDPQ DataNode connected to PQView during our demo to Singapore Power Grid. The 61000 showed events timestamped in UTC, but HDPQ-DN showed in local time.
The event timestamps come from the monitor’s clock setting, but are shown in local time?
How is local time calculated, from the UTC offset in the monitor, of from the UTC offset in the PQDMS computer?
A: The 61000, HDPQ, the ESS and the PQDMS ALL operate in UTC – all time stamps are managed and stored in UTC only. This is not to say that you can’t set a monitor with the wrong time.
Time zone information is applied by the ESS and PQView components at display time. A global time zone is applied by the ESS to all monitors. In PQView the per/site (aka monitor) UTC offset and DST values are applied.
Time zone information in the monitors is NOT used by the ESS or the PQDMS since all data recorded by the monitor is timestamped in UTC. I don’t recall if the 61000 even has time zone information; the HDPQ-DN, which runs essentially the same firmware as the HDPQ, does have timezone information that can be used to format time values in local time; however, like the 61000 the HDPQ clocks are set to UTC and all data is recorded in UTC.