Data storage

Data can be stored in IEEE4 or FP2 formats. The format is selected in the program instruction that outputs the data, such as Minimum() and Maximum().

Additionally, data can be stored in IEEE8 format when high precision is needed. For more information on double-precision math, watch an instructional video at: http://www.campbellsci.com/videos/double-precision .

While Float (IEEE 4 byte floating point) is used for variables and internal calculations, FP2 is adequate for most stored data. Campbell Scientific 2 byte floating point (FP2) provides 3 or 4 significant digits of resolution, and requires half the memory space as IEEE4 (2 bytes per value vs 4).

Resolution and range limits of FP2 data
Zero	Minimum magnitude	Maximum magnitude
0.000	±0.001	±7999.

The resolution of FP2 is reduced to 3 significant digits when the first (left most) digit is 8 or greater. Thus, it may be necessary to use IEEE4 output or an offset to maintain the desired resolution of a measurement. For example, if water level is to be measured and output to the nearest 0.01 foot, the level must be less than 80 feet for FP2 output to display the 0.01 foot increment. If the water level is expected to range from 50 to 90 feet the data could either be output in IEEE4 or could be offset by 20 feet (transforming the range to 30 to 70 feet).

FP2 decimal location
Absolute value	Decimal location
0 – 7.999	X.XXX
8 – 79.99	XX.XX
80 – 799.9	XXX.X
800 – 7999.	XXXX.