Skip to content

Part 5 : Runtime and Communication

Definitions

mtppy.part5.definitions.iec61131_data_types

Implementation of IEC-61131 Data Types.

mtppy.part5.definitions.w3c_xml_data_types

Conversion of MTP supported automation datatypes.

W3cXmlDataTypes(string_value, python_type, opcua_variant, converse_function)

Bases: Enum

Enumeration of W3C XML schema data types supported by MTP 2.0.

Each member of this enumeration maps a W3C XML schema data type to the corresponding Python type, the matching opcua.ua.VariantType and an optional conversion function used to cast Python values to the target representation when reading or writing MTP data items.

Fully Supported Attributes

BOOLEAN, BYTE, UNSIGNED_BYTE SHORT, UNSIGNED_SHORT INT, UNSIGNED_INT LONG, UNSIGNED_LONG FLOAT, DOUBLE STRING

Partially Supported Attributes

DATE, TIME, DATE_TIME ANY_URI, TOKEN

Initialize a W3cXmlDataTypes enum member.

Parameters:

Name Type Description Default
string_value str

The W3C XML schema name of the data type (e.g. "boolean", "unsignedInt", a.s.o).

 required
python_type type | None

The corresponding Python type (e.g. bool, int, float, and str). May be None for XML types without a direct Python equivalent (e.g. anyURI, token).

 required
opcua_variant VariantType | None

The corresponding opcua.ua.VariantType value. May be None for XML types without a direct OPC UA mapping.

 required
converse_function Callable[[ANY_TYPE], ANY_TYPE] | None

A callable used to cast or convert a Python value to the data type's expected Python representation. May be None for types that do not require an explicit conversion step.

 required

mtppy.part5.definitions.opcua_data_types

Definition of String Constants for OPCUA Data Types.

Mediator Communication Object for the Communication

mtppy.part5.communication_object.OPCUACommunicationObject(opcua_node_obj, node_id, variant_type=None)

Bases: CommunicationObject

Write DataItem values to an OPC UA node.

Values are wrapped in an opcua.ua.Variant before being passed to the node's set_value method.

Initialize an OPC UA communication object.

Parameters:

Name Type Description Default
opcua_node_obj Node

OPC UA node that receives written values.

 required
node_id str

OPC UA node identifier retained for diagnostics and model generation.

 required
variant_type VariantType | None

The OPC UA variant type the node was created with. When provided, values are written with this exact type so the node's value type stays consistent with its declared DataType. When None the type is inferred from the Python value.

 None