EGD Flat


Type
'egdflat'

This block is used to source raw data from any number of EGD exchanges and transform the data into flat JSON format. Its configuration fields are as follows:


Field	Type	Required	Default
transport_addr	String	yes
data_map	Object	yes
log_level	String		'off'
log_name	String
egress	Object	no

Transport Address (transport_addr)

The host address where EGD messages are expected to be received. It is recommended to keep this field set as "127.0.0.1" unless multicast is used. The transport_addr can be specified as either of the following:

"transport_addr":"egd://<ip address>"
"transport_addr":"egd://<FQDN>"

Data Map (data_map)

The data_map field determines which EGD exchanges to subscribe to and how to convert their data to flat JSON format. The data_map follows the following format:

"data_map": {
    "<EGD Node Reference>": [
        {<Data Map Object>},
        {<Data Map Object>}
    ],
    "<EGD Node Reference>": [
        {<Data Map Object>},
        {<Data Map Object>}
    ]
}

The format for EGD Node Reference is production_id/exchange_id/sig_major/sig_minor. The

Data Map Objects

have the following fields:


Field	Type	Required
alias	String	yes
bit_offset	Integer	yes
type	String	yes

Alias (alias) - The alias field of the data_map determines the name of the requested value that should mean something to the target application. Examples are “temperature”, “pressure”, etc.
Bit Offset (bit_offset) - The bit_offset field determines what bit offset into the EGD page to start retrieving the value from. The EGD producer has a described data layout that can be retrieved from a controller or workstation via the EGD HTTP configuration API. Refer to the EGD protocol docs to learn more about the Production Data Unit format.
Type (type) - The type field of the data_map defines the type of data to pull from the EGD page. This value will determine how many bytes after the bit_offset are accessed and how to combine the bytes to form the requested type. Its possible values are as follows:
- 'int8'
- 'uint8'
- 'int16'
- 'uint16'
- 'int32'
- 'uint32'
- 'int64'
- 'uint64'
- 'float'
- 'double'
- 'string'
- 'datetime'
- 'time'

Log Level (log_level)

Configures the logger for the EGD client used internally to the block, can be any of the following (case insensitive):

off (default)
critical
err
warn
info
debug

Log Name (log_name): Used in the log file to associate statements with the block. If omitted, the block name is used for the log name.

Egress (egress)

Used to change the EGD output or egress formats.


Field	Type	Applicable to	Default	Description
Output Format	String		`flat_json`	Format of the JSON file output by the adapter into other blocks. Valid entries: `flat_json` `time_series`
Batch Interval	Integer		30 seconds	Amount of time (in milliseconds) the batcher will hold or accumulate data before generating a message. Upon sending data, the internal state is reset and emptied.
Maximum Number of Datapoints	Integer		1	The maximum number of data values the batcher will hold, per tag, over a batching interval. This functions as a very simple filtering step that helps control CPU usage.
Attributes	String	time_series	empty block	Attributes are dependent on the Output Format value.
Timestamp From	String		`source`	Configures how the output timestamp values are set. Valid entries: host (the adapter will use the local time in its output) source (the adapter will use the timestamp from the EGDsource in its output, unless that time is 0, in which case it will use the local time)

Flat_json Output Example:

"egress": {
        "output_format": "flat_json",
        "timestamp_from": 1
    }

Time_series Output Example:

"egress": {
        "output_format": "time_series",
        "batch_interval": 30000,
        "max_num_datapoints": 1,
        "attributes": {},
        "timestamp_from": 1
    }

Example Output Data (Flat JSON)

{
    "timestamp": "1504739531776",
    "data": {
        "temperature": {
            "val": 15,
            "type": "int16"
        },
        "pressure": {
            "val": 16.2,
            "type": "float"
        }
    }
}

Example EGD Flat Config Block

"egd_source_block": {
    "type": "egdflat",
    "config": {
        "transport_addr": "egd://localhost",
        "data_map": {
            "4026531967/150/0/0": [
                {
                    "alias": "sine01",
                    "bit_offset": 1056,
                    "type": "double"
                }
            ],
            "5126541937/151/2/1": [
                {
                    "alias": "valve_on",
                    "bit_offset": 8,
                    "type": "int8"
                },
                {
                    "alias": "valve_status",
                    "bit_offset": 16,
                    "type": "string"
                }
            ]
        },
        "log_level": "info",
        "log_name": "egd_source_flat",
        "options": {
            "foo": "bar"
        }
    }
}