Obix Driver Configuration

VOLTTRON’s uses Obix’s restful interface to facilitate communication.

This driver does not handle reading data from the history section of the interface. If the user wants data published from the management systems historical data use the Obix History Agent agent.

driver_config

There are three arguments for the driver_config section of the device configuration file:

• url - URL of the interface.
• username - User name for site..
• password - Password for username.

Here is an example device configuration file:

{
    "driver_config": {"url": "http://example.com/obix/config/Drivers/Obix/exports/",
                      "username": "username",
                      "password": "password"},
    "driver_type": "obix",
    "registry_config":"config://registry_configs/obix.csv",
    "interval":     30,
    "timezone": "UTC"
}

A sample Obix configuration file can be found in the VOLTTRON repository in examples/configurations/drivers/obix.config

Obix Registry Configuration File

The registry configuration file is a CSV file. Each row configures a point on the device.

The following columns are required for each row:

• Volttron Point Name - The name by which the platform and agents running on the platform will refer to this point. For instance, if the Volttron Point Name is HeatCall1 then an agent would use <device topic>/HeatCall1 to refer to the point when using the RPC interface of the actuator agent.
• Obix Point Name - Name of the point on the obix interface. Escaping of spaces and dashes for use with the interface is handled internaly.
• Obix Type - One of “bool”, “int”, or “real” without quotes.
• Units - Used for meta data when creating point information on the historian.
• Writable - Either “TRUE” or “FALSE”. Determines if the point can be written to. Only points labeled TRUE can be written to through the ActuatorAgent. This can be used to protect points that should not be accessed by the platform.

The following column is optional:

• Default Value - The default value for the point. When the point is reverted by an agent it will change back to this value. If this value is missing it will revert to the last known value not set by an agent.

Any additional columns will be ignored. It is common practice to include a Point Name or Reference Point Name to include the device documentation’s name for the point and Notes and Unit Details for additional information about a point.

The following is an example of a Obix registry confugration file:

Obix

Volttron Point Name	Obix Point Name	Obix Type	Units	Writable	Notes
CostEL	CostEL	real	dollar	FALSE	Precision: 2
CostELBB	CostELBB	real	dollar	FALSE	Precision: 2
CDHEnergyHeartbeat	CDHEnergyHeartbeat	real	null	FALSE
ThermalFollowing	ThermalFollowing	bool		FALSE
CDHTestThermFollow	CDHTestThermFollow	bool		FALSE
CollegeModeFromCDH	CollegeModeFromCDH	real	null	FALSE	Precision: 0, Min: 3.0, Max: 3.0
HospitalModeFromCDH	HospitalModeFromCDH	real	null	FALSE	Precision: 0, Min: 3.0, Max: 3.0
HomeModeFromCDH	HomeModeFromCDH	real	null	FALSE	Precision: 0, Min: 3.0, Max: 3.0
CostNG	CostNG	real	null	FALSE	Precision: 2
CollegeBaseloadSPFromCDH	CollegeBaseloadSPFromCDH	real	kilowatt	FALSE	Precision: 0
CollegeImportSPFromCDH	CollegeImportSPFromCDH	real	kilowatt	FALSE	Precision: 0
HospitalImportSPFromCDH	HospitalImportSPFromCDH	real	kilowatt	FALSE	Precision: 0
HospitalBaseloadSPFromCDH	HospitalBaseloadSPFromCDH	real	kilowatt	FALSE	Precision: 0
HomeImportSPFromCDH	HomeImportSPFromCDH	real	kilowatt	FALSE	Precision: 0
ThermalFollowingAlarm	ThermalFollowingAlarm	bool		FALSE

A sample Obix configuration can be found in the VOLTTRON repository in examples/configurations/drivers/obix.csv

Automatic Obix Configuration File Creation

A script that will automatically create both a device and register configuration file for a site is located in the repository at scripts/obix/get_obix_driver_config.py.

The utility is invoked with the command:

``python get_obix_driver_config.py <url> <registry_file> <driver_file> -u <username> -p <password> ``

If either the registry_file or driver_file is omitted the script will output those files to stdout.

If either the username or password arguments are left out the script will ask for them on the command line before proceeding.

The registry file produced by this script assumes that the Volttron Point Name and the Obix Point Name have the same value. Also, it is assumed that all points should be read only. Users are expected to fix this as appropriate.