Variant – OPC Unified Architecture

5.4.2.17 Variant

Variant values shall be encoded as a JSON object with the fields shown in Table 41.

Table 41 – JSON Object Definition for a Variant

Name	Description
UaType	The built-in type for the value contained in the Body (see Table 1) encoded as JSON number.
Value	If the value is a scalar, it is encoded using the rules for type specified for the Type. If the value is a one-dimensional array it is encoded as JSON array (see 5.4.5). Multi-dimensional arrays are encoded as a JSON array containing all elements. The mapping of a multidimensional array to a flat list is described in 5.2.2.16. The field is not encoded if the value is a NULL for nullable built-in types (see Table 1).
Dimensions	The dimensions of the array encoded as a JSON array of JSON numbers.

Name

Description

UaType

The built-in type for the value contained in the Body (see Table 1) encoded as JSON number.

Value

If the value is a scalar, it is encoded using the rules for type specified for the Type.

If the value is a one-dimensional array it is encoded as JSON array (see 5.4.5).

Multi-dimensional arrays are encoded as a JSON array containing all elements. The mapping of a multidimensional array to a flat list is described in 5.2.2.16.

The field is not encoded if the value is a NULL for nullable built-in types (see Table 1).

Dimensions

The dimensions of the array encoded as a JSON array of JSON numbers.

Encoders, when allowed by the DevelopmentPlatform, should write the UaType first. Decoders shall accept the UaType field in any position.