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Note: In version 1.3.2 the Length and SignificantDigits attributes were used to express the requirements for the receiving system.  In version 2.0 the meaning of the Length attribute remains the same for the text and string datatypes, but was changed for the numeric datatypes and became optional for all datatypes.  The SignificantDigits attribute was renamed to FractionDigitsremoved. If DataType=text or string and the Length attribute is provided, Length=N indicates that the receiving system be system be able to process and store all text string values of length less than or
equal to N. All characters are allowed in text string values.

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There are 3 datatypes available for floating-point values: decimal, float and double.  The The decimal datatype represents a subset of the real numbers, which can be represented by decimal numerals.  This This datatype should be used for items with floating-point values when the number of decimal places is known in advance. In this case, attribute FractionDigits should be used to define the maximum number of fractional digits, or digits after the decimal point. FractionDigits controls the size of the minimum difference between item values by restricting the values to numbers that are expressible as i x 10^-n where i and n are integers and 0 <= n <= FractionDigits. For the decimal  For the decimal datatype, Length=N means that the number of characters required to represent the full numeric value, including the decimal character, must be less than or equal to N.  For datatype decimal, the Length and FractionDigits attributes must both be present or both be absent.  

In case the number of decimal places is not known in advance or is not important, either float or double datatypes should be used. Both of them are patterned after the IEEE floating-point types. DataType=float corresponds to 4-byte single-precision floating-point type, with the basic value space consisting of the values m x 2^e, where m is an integer whose absolute value is less than 2²⁴, and e is an integer between -149 and 104, inclusive. DataType=double corresponds to 8-byte double-precision floating-point type, with the basic value space consisting of the values m x 2^e, where m is an integer whose absolute value is less than 2⁵³, and e is an integer between -1075 and 970, inclusive.

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