D.3.4 Header layout for DataSetMessages

A UADP DataSetMessage header shall consist of the following fields according to this header layout:

DataSetFlags1

DataSetFlags2

Additional remarks:

Field is encoded as a Variant

The following types of DataSetMessages (Data Key Frame, Data Delta Frame, Keep Alive, etc.) are supported

The DataSetMessage header layout is shown in Figure D.4.

Figure D.4 – UADP DataSetMessage header layout

Table D.7 shows the configuration for the DataSetMessage header.

Table D.7 – UADP DataSetMessage header layout
Name Type Description
DataSetFlags1Byte

Bit 0: Indicates whether this DataSetMessage is valid

Bit range 1-2: Field Encoding

00 - Variant
Bit 3: DataSetMessageSequenceNumber enabled = 1

Bit 4: Status enabled = 0

Bit 5: ConfigurationVersionMajorVersion enabled = 0

Bit 6: ConfigurationVersionMinorVersion enabled = 0

Bit 7: DataSetFlags2 enabled = 1

DataSetFlags2Byte

Bit range 0-3: UADP DataSetMessage type

Shall be 0000 for a Data Key Frame

Shall be 0001 for a Data Delta Frame

Shall be 0011 for a Keep Alive

Bit 4: Timestamp enabled = 0

Bit 5: PicoSeconds enabled = 0 (not included in the DataSetMessage header)

For a description of Data KeyFrame, Data Delta Frames and Keep Alive see OPC 10000-14.