A frame output stream session transmits an arbitrary sequence of frame values using a single stream. The frame values are not limited to a single frame—they can transmit any frame.

The data passed to Write is an array of frame values, each of which transmits as soon as possible. Frames transmit sequentially (one after another).

As with frame input stream sessions, you can create more than one frame output stream session for a given interface.

The frame values for this mode are stored in a queue, such that every value provided is transmitted.

Frame Output Stream Example

In this example CAN database, frame C is a cyclic frame that transmits on the network once every 2.0 ms. Frame E is an event-driven frame that uses a transmit time (minimum interval) of 2.5 ms.

Each frame contains two signals, one in the first byte and another in the second byte.

The following figure shows a timeline of a frame transfer on the CAN network. Each frame contains its name (C or E), followed by the value of its two signals. The timeline begins with a single call to Write.

The following figure shows the data provided to the single call to Write. Each frame is displayed with CAN-specific elements. To understand the data returned from Write function, refer to information on the format of raw frame data. The array provides values for frames C and E.

Assuming the Auto Start? property uses the default of True, each session starts within the call to Write. All frame values transmit immediately, using the same sequence as the array.

Although frame C and E specify a slower timing in the database, the frame output stream mode disregards this timing and transmits the frame values in quick succession.

Within each frame values, this example uses an invalid timestamp value (0). This is acceptable, because each frame value timestamp is ignored for this mode.

Although frame C is specified in the database as a cyclic frame, this mode does not repeat its transmit. Unlike the frame output queued mode, the frame output stream mode does not use CAN frame properties from the database.