FieldClassify()

Use FieldClassify() to attach a user-defined classification code to a data field in the table definition metadata. This gives cloud applications extra information that can be used to interpret and provide more details about field values.

Syntax

FieldClassify (Class_Code)

• Class_Code {String} = A string that can contain any code, tag, or text schema that you want your cloud application to interpret.

CampbellCloud uses hexadecimal classification codes, but that is only one implementation method. Other cloud platforms may choose different formats and define their own schema.

CampbellCloud Example

The Classification code is used to define metadata such as:

CampbellCloud Code	Classification	Subclassification	Units	Abbreviation	Aggregate Type
01010105	Temperature	Air Temperature	Degrees Celsius	°C	Sample

An example classification reference is available at campbell-m2i.xyz/classifications.

CRBasic Example

Important

• Use one FieldClassify() per table output processing instruction (e.g., Sample, Average, Totalize).

• When repetitions (reps) are used, FieldClassify() takes a single string containing a comma-separated list of values one for each field.

Single Field Example:

DataTable (Air_Temperature,1,-1)
  DataInterval (0,5,Sec,10)
  Sample (1,air_temperature_C,IEEE4)
  FieldClassify("&H01000105")
EndTable

Multi-Field Example:

DataTable (HygroVUE10,1,-1)
  DataInterval (0,5,Sec,10)
  Sample (4,HygroVUE10,IEEE4)
  FieldClassify ("&H01010101,&H02010101,&H01020101,&H0C060302")
EndTable

FieldClassify() Output

FieldClassify() adds a class value to each field definition in the data table metadata topic.

In the single-field example, the code assigned to air_temperature_C appears in the field’s class entry in the metadata JSON output. In the metadata JSON output, FieldClassify("&H01000105") appears as decimal value 16777477.

Example Output

Subscribe cs/v2/metadata/ABCD-EFGH-1234/metadata/Air_Temperature

{
  "fields": {
    "key": [
      "type",
      "settable",
      "size",
      "class",
      "stream"
    ],
    "definitions": {
      "air_temperature_C": [
        "xsd:float",
        false,
        1,
        16777477,
        -1
      ]
    }
  }
}

When a cloud environment receives this classification code, it is the responsibility of that cloud application to interpret the value and decide what action to take. FieldClassify() provides the metadata, but the meaning and behavior of the code are defined by the receiving system.