Predefined trace headers

Maintaned by the system (write-protected):

_tform_ Trace data format (integer)
_tnrec_ Number of records in multicomponent trace
_tdlen_ Trace data length (bytes)
_tsint_ Trace samling interval
_tnsam_ Number of samples in the trace

Not write-protected:

  lasttr Last trace flag (=1 for last trace in ensemble; else 0)
seqno Trace sequence number within a trace ensemble
timstrt Trace time start