Dataflow examples

Single asynchronous value signal and single domain signal

The following example demonstrates the sequence of packet buffers needed to initialize packet streaming and transmit two samples of an asynchronous value signal.

  1. Data descriptor changed event packet for value signal

    Generic header

    Header size

    0x0C

    Packet buffer type code

    0x00 (event)

    Packet streaming protocol version

    0x00

    Flags

    0x00

    Signal numeric ID

    0x00000001

    Payload size

    0x0000026B

    Payload

    		 
    {
  "__type": "EventPacket",
  "id": "DATA_DESCRIPTOR_CHANGED",
  "params": {
    "__type": "Dict",
    "values": [
      {
        "key": "DataDescriptor",
        "value": {
          "__type": "DataDescriptor",
          "name": "Value",
          "sampleType": 2,
          "dimensions": [],
          "rule": {
            "__type": "DataRule",
            "ruleType": 3,
            "params": {
              "__type": "Dict",
              "values": []
            }
          },
          "origin": "",
          "metadata": {
            "__type": "Dict",
            "values": []
          },
          "structFields": []
        }
      },
      {
        "key": "DomainDataDescriptor",
        "value": {
          "__type": "DataDescriptor",
          "name": "Domain",
          "sampleType": 9,
          "dimensions": [],
          "rule": {
            "__type": "DataRule",
            "ruleType": 3,
            "params": {
              "__type": "Dict",
              "values": []
            }
          },
          "origin": "",
          "metadata": {
            "__type": "Dict",
            "values": []
          },
          "structFields": []
        }
      }
    ]
  }
}

  2. Data descriptor changed event packet for domain signal

    Generic header

    Header size

    0x0C

    Packet buffer type code

    0x00 (event)

    Packet streaming protocol version

    0x00

    Flags

    0x00

    Signal numeric ID

    0x00000002

    Payload size

    0x0000018F

    Payload

    		 
    {
  "__type": "EventPacket",
  "id": "DATA_DESCRIPTOR_CHANGED",
  "params": {
    "__type": "Dict",
    "values": [
      {
        "key": "DataDescriptor",
        "value": {
          "__type": "DataDescriptor",
          "name": "Domain",
          "sampleType": 9,
          "dimensions": [],
          "rule": {
            "__type": "DataRule",
            "ruleType": 3,
            "params": {
              "__type": "Dict",
              "values": []
            }
          },
          "origin": "",
          "metadata": {
            "__type": "Dict",
            "values": []
          },
          "structFields": []
        }
      },
      {
        "key": "DomainDataDescriptor",
        "value": null
      }
    ]
  }
}

  3. Value signal data packet (with release flag)

    Generic header

    Header size

    0x2C

    Packet buffer type code

    0x01 (data)

    Packet streaming protocol version

    0x00

    Flags

    0x01 (Release packet)

    Signal numeric ID

    0x00000001

    Payload size

    0x00000010

    Extra header

    Packet ID

    0x0000000000000010

    Domain packet ID

    0x0000000000000012

    Sample count

    0x0000000000000002

    Packet offset

    0x0000000000000000

    Payload

    1.445e14, -3.78e-4

  4. Domain signal data packet explicit without offset (with release flag)

    Generic header

    Header size

    0x2C

    Packet buffer type code

    0x01 (data)

    Packet streaming protocol version

    0x00

    Flags

    0x01 (Release packet)

    Signal numeric ID

    0x00000002

    Payload size

    0x00000010

    Extra header

    Packet ID

    0x0000000000000012

    Domain packet ID

    0x0000000000000000

    Sample count

    0x0000000000000002

    Packet offset

    0x0000000000000000

    Payload

    0x0000000000000001,0x0000000000000002