Input Filtering

Since the Control Interface interacts with different entities, such as Device Registries, Assignment Agents or Field level Devices the Control Interface can filter service specific static input values from the service callback function to set concrete instances for each. In case that such a value is provided, it replaces global instances, e.g., provided as Execution Engine class arguments, or dynamic behavior for the resource assignment. In case that a service receives an argument for an Assignment Agent and a Resource Assignment, the Assignment Agent is ignored and the resource provided with the Resource Assignment argument will be selected to execute the service.

Resources

To select a concrete resource to execute the scheduled service, a dispatcher must provide an Engine Struct ResourceAssignment through the list of input_parameters to the Service Started Callback. The Struct contains a single field job_resource of type string:

Struct ResourceAssignment{
    "job_resource":"string"
}

Capabilities

In case that a target resource is determined by the dynamic Resource Assignment behavior, the Execution Engine can restrict the resources returned from the Device Registry’s Filter_Agent method by providing service specific capabilities, which are matched against existing capabilities of the Field Level Devices. To consider such capability restrictions, a dispatcher must provide an Engine Struct ServiceName_Capabilities through the list of input_parameters to the Service Started Callback. Here, the ServiceName must correspond to the name argument of the Service started callback. The number of fields can be arbitrary, however, it must be considered that the Common Information Model restricts the types of capabilities to be matched. The name of each filed of such a ServiceName_Capabilities must correspond to the BrowseName of a Field Leve Device Server. The type of each struct field is a string, independent of whether the capability is numeric, boolean or string.

Struct ExampleService_Capabilities{
    "CapabilityName_1":"string",
    "CapabilityName_2":"string",
    ...
}

Assignment Agents

To set an Assignment Agent that replaces the Execution Engine’s default behavior, or a global Assignment Agent, a dispatcher must provide an Engine Struct AssignmentAgent through the list of input_parameters to the Service Started Callback. The Struct contains a single field agent of type string:

Struct AssignmentAgent{
    "agent":"string"
}

Device Registry

To set a Device Registry that replaces the Execution Engine’s global Device Registry, a dispatcher must provide an Engine Struct DeviceRegistry through the list of input_parameters to the Service Started Callback. The Struct contains a single field agent of type string:

Struct DeviceRegistry{
    "registry":"string"
}