1. First-in, First-out (FIFO). In this mode the logger continues to take readings when its memory is full (to make room, it discards the oldest reading every time it adds a new one). Thus, the memory will contain a "sliding window" of information.
2. Stop When Full. Simply enough, The logger stops recording when its memory is full.
You can also set the time interval at which your logger saves readings using TrendReader 2 software. The sample rate you select will apply to all enabled channels. At a sample rate of eight seconds, one reading is taken every eight seconds and saved to memory.
As you slow the sample rate the logger begins to average readings before saving them to memory. To do this the logger takes a reading every eight seconds, but instead of transferring this directly to the logger’s memory, it stores the readings in a buffer (a temporary memory) where it is retained until the sampling interval is over.