CAN Bus Data Acquisition: Understanding, Logging and Analyzing Vehicle Communications

In today’s vehicles, the CAN bus (Controller Area Network) sits at the heart of the electronic architecture. With electrification, driving automation and the growing number of onboard ECUs, the explosion of vehicle-generated data has become a major engineering challenge.

Every drive generates millions of CAN frames carrying critical data on speed, voltage, temperature, driver inputs and subsystem status. In this context, CAN data acquisition has become a key step throughout development, testing and validation. From prototyping to track testing, capturing and decoding these data streams helps ensure vehicle safety, reliability and performance. Drawing on its expertise in automotive engineering and embedded systems, DUNASYS designs custom hardware and software solutions to help OEMs and suppliers take full control of their CAN networks.

Key Takeaways

• CAN data acquisition involves collecting and analyzing the communications exchanged between a vehicle’s ECUs.
• The CAN bus is the most widely used communication protocol in the automotive industry.
• CAN data is essential for diagnostics, ECU validation, ADAS and embedded software development.
• CAN data loggers record CAN frames for real-time or post-processing analysis.
• The rise of connected vehicles and software-defined vehicles (SDVs) makes data acquisition solutions more important than ever.

What Is CAN Bus Data Acquisition?

CAN data acquisition is the process of capturing, measuring and recording the electrical and digital signals that travel across an automotive CAN network.

The CAN bus protocol, standardized for several decades, allows ECUs to communicate with each other without complex point-to-point wiring. Every module connected to the network sends and receives messages in the form of CAN frames.

Acquisition involves collecting this data, converting raw values into readable physical values using database description files (such as DBC files), then analyzing them in real time or in post-processing.

How Does the CAN Bus Work?

CAN Architecture

The CAN network is based on a differential two-wire bus architecture. This design provides strong immunity to electromagnetic noise and high reliability in the demanding environment of a vehicle.

ECUs

Each ECU acts as a node on the network. It includes a CAN controller and a transceiver to send digital data or listen to messages broadcast on the bus.

CAN Frames

CAN communication uses message-based addressing, built on the message identifier rather than the sender’s address. A standard frame contains the ID, control bits, a data field and an error-checking code (CRC).

Real-Time Communication

The protocol uses non-destructive bitwise arbitration. High-priority messages immediately take precedence over lower-priority ones, ensuring real-time processing.

CAN FD

A major evolution of the standard, CAN FD (Flexible Data-Rate) addresses growing bandwidth needs. It increases the data field from 8 to 64 bytes and raises the bit rate during the data phase of the frame.

Why Perform CAN Data Acquisition?

• Vehicle validation: Verify on a test bench or in real-world driving that subsystems respond in line with operational requirements.
• Automotive diagnostics: Quickly identify failures, read diagnostic trouble codes (DTCs) and analyze bus traffic during intermittent faults with CAN diagnostics.
• Performance analysis: Measure vehicle dynamics, energy consumption or battery thermal efficiency.
• Embedded software development: Validate ECU control algorithms by monitoring internal variables transmitted on the bus.
• ADAS testing: Track interactions between trajectory, braking and driver assistance ECUs.

What Equipment Do You Need for CAN Data Acquisition?

A complete acquisition system relies on a well-matched hardware and software chain.

Data Logger

A CAN data logger is a standalone recorder installed directly in the vehicle. It continuously captures and stores frames on high-capacity storage media, even without an operator present.

CAN Interfaces

A hardware interface (PC-to-CAN via USB, Ethernet or Wi-Fi) connects the vehicle network to a computer for measurement or architecture validation.

Signal Conditioning and Sensors

To combine CAN measurements with external physical data, signal conditioners and transducers are often required. They handle filtering and electrical isolation to convert analog signals into digital data fed back onto the bus.

Analysis Software and Visualization Tools

Post-processing software provides real-time display, plotting, frequency analysis and graphical visualization of different signal types.

To meet these needs, DUNASYS offers advanced tools from its product range, including Dunalog data loggers and DUANACAN communication interfaces.

CAN Data Acquisition and ECU Validation

In ECU testing and functional validation, monitoring communication buses is essential. CAN logging makes it possible to verify timing compliance, calculate bus load and detect occasional message loss.

Combined with environment simulation methods, acquisition allows the rest of the vehicle to be simulated (restbus simulation), so a single ECU can be tested in isolation and its responses analyzed in detail.

CAN Data Acquisition for ADAS

Advanced driver assistance systems (ADAS) rely on collecting and processing massive volumes of heterogeneous data:

• Cameras: Provide visual detection of lane markings and obstacles.
• Radar: Transmits the distance and relative speed of surrounding objects.
• Sensor fusion: Combines the various sensor streams to reconstruct the vehicle’s overall environment.
• Assisted driving: Sends critical steering or braking commands over CAN FD or Ethernet.

CAN data acquisition synchronizes these data streams at high sampling rates to validate how quickly decision algorithms respond.

CAN Bus and the Software-Defined Vehicle (SDV)

The emergence of software-defined vehicles is reshaping the E/E architecture around more powerful zonal and central computers.

In this transition, data volumes are skyrocketing. Although Automotive Ethernet is playing a growing role for high-bandwidth applications, CAN and CAN FD remain essential for real-time subnetworks and actuators. Multi-network data acquisition is more than ever the cornerstone of software-defined vehicle development.

Challenges of CAN Data Acquisition

• Data volume: Managing gigabytes of raw data recorded during test campaigns lasting several weeks.
• Synchronization: Achieving precise time alignment between CAN buses, video, Ethernet and analog measurement data.
• Real-time performance: Processing, filtering noise and analyzing alerts at high rates without losing frames.
• Cybersecurity: Ensuring the integrity and confidentiality of data during remote collection, in line with automotive cybersecurity requirements.
• Multi-network analysis: Correlating CAN, CAN FD, LIN, FlexRay and Ethernet streams simultaneously.

How DUNASYS Supports Your CAN Data Acquisition Projects

As a specialist in automotive engineering, embedded systems and telematics, DUNASYS supports you end to end in optimizing and deploying your CAN data acquisition chains.

From dedicated hardware, such as our Dunadiag test units and Dunalog data loggers, to custom software development, our expert teams tackle your most complex challenges. We offer technical assistance services and full support for your needs through our custom project offering.