This primitive DataType defines a value which can be represented by decimal number in string. Lexical representation of the string conforms to W3C XML Schema Definition Language (XSD) 1.1 Part 2: DataTypes.
Table 16 - DecimalString Definition
Subtype of the String defined in OPC 10000-3
OPC UA Applications may have the responsibility to encode / decode the DecimalString to an appropriate data type which is supported by the application’s platform. The DecimalString is a numeric string with an optional sign and decimal point.