If an events has been flagged by as trailing event, all related pattern parameters are NULL and PHA_CTI and PI are NULL, to indicate that these events should be ignored.
All four PAT parameters are combined into a PAT_ID (Int16), PAT_SEQ (Int8, completely used to store values 1...198) and PATTERN (Int8) column which are part of the PPS product `EPIC pn calibrated event list'.
