AVTP Control Format (ACF) CAN Example

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The AVTP Control Format (ACF) provides the capability of sending CAN messages over a time-sensitive, AVB network. Use cases include the interconnection of different CAN buses over an Ethernet backbone.

ACF CAN Encode

This example VI demonstrates how to encode XNET CAN Frames into ACF Ethernet packets. Data can be sourced either from manually entered XNET CAN Frames or from a knob control which is converted into a signal as defined by the network database. The signal takes the form of a CAN Frame in this example, and the frame is then encoded into ACF Ethernet packets. The signal definition can be viewed in the NI-XNET Database Editor.

 

ACF CAN Decode

This example VI monitors the network for ACF packets and decodes them into XNET CAN Frames. The decoded data can be viewed as an array of XNET CAN Frames or (if the encode side was using a signal from the database) as a gauge indicator after converting the CAN Frame to signal data.

 

Packet Format

The parts of an ACF packet are shown below. An ACF packet can contain either a Time-Synchronous Control Format (TSCF) header or a Non Time-Synchronous Control Format (NTSCF) header if the messages are not timing sensitive. This example demonstrates use of the TSCF header.

 

After the header comes the ACF payload data, which is comprised of one or more arbitrary ACF messages, which may be of types other than CAN. The CAN ACF message is shown below. There is also an abbreviated version of the CAN ACF message which does not contain the message timestamp.

  For more information about ACF, refer to IEEE Std 1722-2016, available for purchase at www.ieee.org.

 The contents of the ZIP are shown below: