From the help menu on CScape here is what it is says:
The history log provides an entry for each transition of an alarm state (history of Changes). The history log length is limited to 128 entries (256 entries for OCS 451/551/651 and is stored in non-volatile memory. Entries are only cleared at program download or through operator intervention. Once the log becomes filled, the least current entry is deleted when a new alarm event occurs. Noted that re-occurring alarms can quickly fill the history log. Entries contained in the history log show alarm transitions to the following alarm state:
ALM – Alarm went active
Optionally, the following alarm states can also be logged and shown if checked in the alarm configuration:
ACK – Active alarm was acknowledged by operator.
CLR – Active alarm was cleared by operator.
RTN – Alarm returned to inactive without being acknowledged.
Note that transitions from either ACK or RTN to CLR are not logged.
Why not just let the buffer fill up? You will always see the history of the last actions.
Regards,
