Datalogger Memory Mode selection will only appear when Linear sampling mode is selected. When using a datalogger in Linear Mode, there is a choice of Continuous Logging (wrap around) 
or Slate Logging 
.
Compressed Linear, Event Based and Schedule sampling modes can only use the Slate Mode option.
In Continuous Logging, the new log is started at the end of any previous log and continues logging, eventually recording over the first logged data. As one of the download options is to 'Append Data', Continuous Logging can be a preferred choice when logging long-term (see Section 5.1.2).
In Slate Logging, the new log is also started at the end of any previous log, but will stop recording after 40,000 readings (or up to 120,000 readings), so that the beginning of the current log will not be written over.
Figure 4-10 Datalogger Memory Mode
