The waveforms of the disturbance recorder analog channels and the states of the disturbance recorder binary channels are constantly recorded into the history memory of the recorder. The percentage of the data duration preceding the triggering, that is, the pre-trigger time, can be adjusted with the Pre-trg length parameter. The duration of the data following the triggering, that is, the post-trigger time, is the difference between the recording length and the pre-trigger time. Changing the pre-trigger time resets the history data and the current recording under collection.