Interface States

Stopped

The interface always exists, because it represents the communication controller of the NI-XNET hardware product port. This physical port is wired to a cable that connects to one or more remote ECUs.

The NI-XNET interface initially powers on in the Stopped state. In the Stopped state, the interface does not communicate on its port.

While the interface is stopped, you can change properties specific to the interface. These properties are contained within the Session Node (LabVIEW) or in the Session Property Interface Properties. When more than one session exists for a given interface, the Interface category properties provide shared access to the interface configuration. For example, if you set an interface property using one session, then get that same property using a second session, the returned value reflects the change.

Properties that you change in the interface are not saved from one execution of your application to another. When the last session for an interface is cleared, the interface properties are restored to defaults.

Started

In the Started state, the interface is started, but it is waiting for the associated communication controller to complete its integration with the network.

This state is transitory in nature, in that your application does not control transition out of the Started state. For CAN and LIN, integration with the network occurs in a few bit times, so the transition is effectively from Stopped to Communicating. For FlexRay, integration with the network entails synchronization with global FlexRay time, which can take as long as hundreds of milliseconds.

Communicating

In the Communicating state, the interface is communicating on the network. One or more communicating sessions can use the interface to receive and/or transmit frame values.

The interface remains in the Communicating state as long as communication is feasible. For information about how the interface transitions in and out of this state, refer to "Comm State Communicating" and "Comm State Not Communicating" sections of Interface Transitions in this help.

In LabVIEW, the Communicating state behaves differently for Ethernet as compared to other XNET protocols (e.g., CAN). For more information, refer to the Ethernet Operational Status property in the NI-XNET API reference.