The Arinc 429 avionic serial data systems: Key characteristics

29 December, 2016

 

The ARINC 429 and the MIL-STD-1553 data busses have a wide range of applications in military avionic systems.( arinc 429 tutorial and products, mil std 1553 tutorial and products ). These two serial data systems are optimized to provide quality communication of data and commands in avionic circuits and devices. Although the two avionic data busses have many characteristics in common, they also have some differences. In addition, they have lower speeds as compared to other serial data standards such as SAS and PCI-Express. SAS and PCI-Express are mostly used for communications in personal computers and other applications where short distances are involved.

Architecture of the ARINC 429 differential bus

This serial data bus uses twisted pair wires for transmission and reception of data and commands. The twisted pair wires of this self-clocking serial data bus have balanced differential signals. The peak-to-peak output voltage of this differential pair is 10 volts.  On the other hand, the MIL-STD-1553 utilizes dual redundant pairs. The transmitter of this balanced differential pair allows a peak-to-peak voltage of between 18 and 27 volts.

Capturing and decoding signals

The ARINC 429 and the MIL-STD-1553 serial data busses are optimized to allow easy capturing and viewing of signals. The moderate edge rates allow engineers to capture signals using ordinary oscilloscopes. This characteristic also enables engineers to display, decode, and interpret signals with ease. It also helps to reduce human errors when testing and troubleshooting avionic circuits and devices.

Signal characterization

An oscilloscope user can obtain information about the operation of an avionic system by examining the decoded signal. To confirm that a circuit or a device is operating as expected, many signal acquisitions should be examined. In some cases, the required information can be obtained by observing a long signal acquisition. Such signal examinations enable engineers to identify problems in military avionic circuits and devices.

 Testing systems that use avionic serial data busses

Engineers can obtain important attributes of a data stream using an ordinary oscilloscope. The oscilloscope also allows the user to zoom the parts of the signal containing properties of interest. Most scopes also allow users to generate tables. A signal can be characterized by examining the details of the data generated by an oscilloscope.

It is crucial to identify all the potential problems that can affect the performance of an avionic system. To achieve that, it is important to test both the system and the devices used in the communication of data and commands. When testing an ARINC 429 avionic system using an oscilloscope, it is important to examine all the details of the captured signal. Key signal attributes that can provide important information about an avionic circuit or device include parity, data value, status, message, and so on depending on the features of the testing equipment being used.

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