dsHPEEVENTSEQERR -- WARNING: Out of sequence events discovered in hrc_evt1.fits.
# hrc_process_events (CIAO): The following error occurred 2482 times: dsHPEEVENTSEQERR -- WARNING: Out of sequence events discovered in hrc_evt1.fits.
There are occasional events that appear in the telemetry stream with time tags that make them seem to have occurred out-of-sequence. One special case where this occurs has been documented (see the Out-of-sequence HRC Time Tags memo); other occurrences are most likely to be caused by hiccups in the HRC or by double-bit errors in telemetry (single-bit errors are corrected).
This warning may be ignored in most cases, as long as the number of events flagged as out-of-sequence is a small fraction of the total number of events in the file. For example:
unix% dmlist hrc_evt1.fits counts 798768
and
>>> 2482 * 100 / 798768 0.3107285219237626
Since there are 798768 events in the file, the 2482 that were flagged as out-of-sequence make up just 0.31% of the total events.