How CAN we identify unfamiliar CAN network protocols ?, Identify the can protocol

How CAN we identify unfamiliar CAN network protocols ?, Identify the can protocol

In the CAN network, data transmission and receiving of all nodes share a bus. In the face of an unknown multi-node CAN bus network, how CAN we accurately analyze the communication protocols between nodes?

1. CAN bus communication

Similar to 485, CAN-Bus communicates with each other in the form of a Bus. All CAN nodes are mounted on a pair of differential lines. However, the node in the CAN bus does not have the concept of master-slave. When the node has data to be uploaded, it CAN be sent independently and instantly. The advanced arbitration mechanism ensures that data does not conflict with each other.

CAN bus communication mode

2. CAN bus protocol analysis

Compared with the standard seven-layer communication model, the CAN bus CAN be divided into the physical layer, link layer, and application layer. Resolve the link layer to obtain the node ID. If you do link layer resolution for an unencrypted CAN bus, use the CAN Bus Interface Card (also known as the CAN box. These tools CAN be used to convert CAN communication to USB, PCI, and other communication methods. A professional bus analyzer is required for comprehensive analysis of the CAN bus. CANScope is a comprehensive set of CAN node testing and calibration, CAN Bus Fault Diagnosis and solution.

CAN bus packet capture tools and methods

Iii. Application of Multi-channel CAN cards

The above-mentioned bus protocol analysis is performed on the premise that there are few bus nodes and the node IDs are known. When faced with a network with unknown protocols, multiple nodes, and unknown node IDs, the first thing to do is to extract the packets from each CAN and identify each node ID.

Data separation and Extraction

If each node is taken out separately for testing, the original communication rules will inevitably be damaged. How can we find out a strange receiving and receiving protocol without disrupting the original communication? To do good, you must first sharpen your tools. You need a CAN card that CAN send and receive, transfer Multiple CAN data at the same time, USBCAN-8E-U is this test tool.

USBCAN-8E-U

The USBCAN-8E-U integrates 8-channel CAN-bus interface, each channel CAN do routing (forwarding) function. When identifying the node ID, you CAN connect the node to eight CAN interfaces at the same time, and then set up eight CAN communication free forwarding, to ensure that the original network communication rules are not damaged. Powerful PC software displays the CAN messages sent and received by each channel separately, so that data analysis is clear at a glance.

Multi-node CAN network analysis