The CAN bus has become the main control system application bus for new energy vehicles, military industry, aviation and other industries. ZLG Zhiyuan Electronics is committed to building a CAN bus safety guarantee system and shockingly released the CANDT conformance test system!
The CAN conformance test requires that all nodes in the CAN network of the vehicle meet the specification requirements of CAN bus nodes, reduce the difference of nodes in the CAN network, ensure the stability of the CAN network environment, and effectively improve the anti-interference ability of the CAN network.
Why conduct CAN conformance testing?
1. Vehicle CAN network architecture
With the development of the new energy automobile industry, the node evolution in the vehicle CAN network has become extremely complicated. Now there are as many as 60 CAN nodes in the new energy automobile, and the network evolution has become extremely complicated.
Complex CAN network of the vehicle
Two, the harm of CAN bus inconsistency
In a complex CAN network, the quality of each node is uneven, which will pose a greater safety hazard to the CAN bus network. Usually, the error of one of the nodes will affect the normal operation of the overall bus, and even lead to the paralysis of the overall bus.
Wrong judgment of explicit threshold level leads to vehicle network failure
Generally speaking, the mechanism of the CAN bus to determine the dominant recessive level is as follows: when the differential level is greater than 0.9V, it is the dominant level; when the differential level is less than 0.5V, it is the recessive level, which is between 05V and 0.9V It is an area of ​​uncertainty. But in the actual network, when a node in the CAN bus network is still judged as recessive when the differential level is 0.9V, a bit logic judgment error occurs, which causes the node to send out an error frame, and the bus falls into a network failure state.
Solution: For example, in the CAN network node admission stage, perform a dominant threshold test on each node, and use a voltage source to increase the differential voltage to 0.9V to ensure that all nodes can be judged as dominant at this differential voltage and stop Sending messages will reduce the occurrence of the bus failure problem and reduce the workload of CAN bus network debugging.
Therefore, in order to ensure the stability of the CAN bus, a CAN conformance test of the vehicle network must be carried out. As the overall designer of the CAN bus network, what are the contents of the CAN conformance test and how to ensure the stability of the CAN bus through the CAN conformance test?
3. CAN conformance test content and solutions
1. CAN conformance test content
In China, most OEMs have CAN bus network test specifications, which mainly include the physical layer, link layer, and application layer.
With so many test items, how is the current industry tested?
CAN conformance test content (excerpt)
2. CAN conformance test scheme
CAN conformance test tools include CAN cards, oscilloscopes, power supplies and other equipment. Current engineers mainly use CAN cards to collect message data manually and test waveforms through oscilloscopes to achieve the purpose of testing bit time, amplitude, and bit width. However, the efficiency of the test scheme is very low. Generally, it takes 10 hours or even 2 days to complete the overall CAN conformance test project, which wastes a lot of research and development costs.
Manual test framework construction
ZLG Zhiyuan Electronics is committed to building a CAN bus safety guarantee system, and shockingly releases the CANDT conformance test system!
The CANDT conformance test system can automatically complete CAN node physical layer, link layer and application layer conformance tests. It is the only instrument in the current CAN bus test field that can perform complete physical layer automated tests and export reports. It is designed to promote automobiles The CAN bus has developed steadily in many fields such as electronics, military industry, and rail transit, and a CAN bus safety guarantee system has been constructed to ensure CAN network interconnection and interoperability.
In addition, the test report output by CANDT based on the test results can be used as a basis for judging access to the CAN network, greatly reducing the workload of the host factory in the network debugging link, and ensuring the stability of the overall CAN network environment.
ZLG Zhiyuan Electronics has focused on CAN bus failure test analysis for many years, and has been committed to building a CAN bus safety guarantee system to ensure CAN bus interconnection!
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