What is CAN? Understanding CANdo and Real-World Solutions
- Uchi Embedded Solutions
- 14 hours ago
- 5 min read
Table of Contents
1. What is CAN?
5. Conclusion
What is CAN?
Imagine you are driving a modern car. Inside that vehicle, there are hundreds of electronic systems all talking to each other: the engine, brakes, transmission, dashboard, air conditioning, safety systems, and more. They all need to communicate quickly, reliably, and safely.
CAN (Controller Area Network) is the "language" these systems use to communicate.
Think of it like this: Instead of having separate wires running from every electronic system to every other system (which would be a chaotic mess of cables), CAN uses a single shared communication line where all these systems can send and receive messages. It is like a group chat, rather than individual phone calls.
Key Points About CAN:
Fast communication: Messages travel at speeds up to 1 million bits per second (1 Mbps)
Reliable: Built-in error detection and correction
Simple: Uses just 2 wires (CAN_H and CAN_L) plus ground
Prioritised: Important messages (like brakes) get priority over less critical ones
Universal: Used in cars, trucks, industrial machinery, medical devices, and robotics
Example: When you press the brake pedal, the brake ECU sends a CAN message that says "Brakes activated!" The ABS receives it and knows to adjust, the dashboard receives it and knows to light up the brake light, and the engine management receives it and knows to prepare for deceleration. All this happens in milliseconds on a single wire pair.
Problems Engineers Face Without CAN
Without proper CAN bus access and monitoring tools, engineers and technicians face real challenges:
1. Can't See What's Happening on the Bus
Modern vehicles have 80+ Electronic Control Units (ECUs) communicating constantly
Without visibility, engineers are "flying blind"—they don't know what messages are being sent, how often, or if there are errors
Debugging problems becomes guesswork instead of a data-driven investigation
2. Intermittent Issues Are Impossible to Track
A car might work fine in the garage but fail in real driving conditions
Engineers can't monitor live CAN data while driving or testing
This creates hours of unproductive troubleshooting
3. Hardware Integration Testing is Difficult
When building new ECUs or sensors, engineers need to test how their devices communicate with the rest of the vehicle
Without a CAN monitor, they can't verify messages are being sent correctly
Testing in the actual vehicle is expensive, time-consuming, and risky
4. Diagnostics Require Expensive Tools
Professional diagnostic scanners cost thousands of dollars
They are often locked into specific vehicle makes/models
Not accessible for hobbyists, students, or custom vehicle builders
Emergency roadside diagnostics are expensive
5. Can't Simulate or Replay Scenarios
If a fault occurs in the field, there's no easy way to reproduce it in the lab
Engineers can't test "what if" scenarios
Root cause analysis becomes a guessing game
6. Fault Isolation is Time-Consuming
Multiple ECUs communicating means problems could originate from many sources
Is it a sensor failure? A wiring problem? A software bug? A timing issue?
Without seeing the actual CAN messages, narrowing it down takes days or weeks
How CANdo Solves These Problems
CANdo is a simple and affordable USB-to-CAN adapter that provides engineers with complete visibility into CAN bus communication. It transforms your PC into a professional CAN bus analyser.
What CANdo Provides:
1. Real-Time Message Visibility
See every CAN message on the bus as it happens
View message IDs, data bytes, timestamps, and frequencies
Understand exactly what's being communicated between systems
2. Free Professional Analysis Software
The CANdo Application is completely FREE
Displays messages in an easy-to-read table format
Real-time updates, colour coding, and filtering options
No expensive software subscriptions
3. Message Logging and Playback
Record entire driving sessions or test scenarios
Save to files and analyse later offline
Replay recorded scenarios to reproduce bugs consistently
Export data to CSV for analysis in Excel or Python
4. Message Transmission for Testing
Send custom CAN messages to test how systems respond
Test multiple scenarios without needing the actual vehicle running
Verify new ECU designs work correctly with the rest of the system
5. Affordable Hardware
CANdo interface costs just a fraction of professional diagnostic tools
USB connection to any Windows PC (or Linux with SDK)
Works with any standard CAN bus at any baud rate
DB9 connector follows industry standard
6. Programmable Access via SDK
Write custom software tools in C, C++, Python, or other languages
Integrate CANdo into automated test systems
Build custom dashboards and monitoring applications
Integrate with ROS2 for robotics projects
Real-World Benefit Examples:
For Automotive Engineers:
Debug communication issues between ECUs without expensive dealership tools
Test new sensor integrations safely on the bench before vehicle installation
Monitor OBD2 CAN traffic from road tests and diagnose faults immediately
For Hobbyists and Makers:
Monitor custom vehicle modifications and integrations
Understand how modern vehicle systems work
Build aftermarket systems that communicate correctly with vehicle electronics
For Industrial Automation:
Monitor machinery communication networks in real-time
Troubleshoot equipment failures without shutting down production
Test new control systems before deployment
For Students and Educators:
Learn how CAN protocol works with real, affordable hardware
Hands-on experience with industrial communication standards
Build projects that integrate CAN communication
How to Use CANdo
Step 1: Get the Hardware
1. Purchase a CANdo Interface from suppliers
2. Plug it into a USB port on your Windows PC
3. Connect the DB9 connector to your CAN bus (CAN_H and CAN_L pins)
Step 2: Download and Install Software
2. Download CANdo Application (Windows, completely FREE)
3. Run the installer and complete the installation
4. Launch the application
Step 3: Configure and Start Monitoring
1. Set the CAN Bit Rate to match your bus:
Automotive: typically, 500 kbps
Industrial: typically, 250 kbps
Custom rates available (12.5 kbps to 1 Mbps)
2. Click the "Start CANdo" button
3. Watch messages arrive in real-time:
Each row shows: Time, Message ID, Data bytes, Count, Period
Messages update as they arrive on the bus
Scroll through hundreds of captured messages
Step 4: Analyse and Debug
View Live Traffic
See all messages being transmitted
Watch message frequency and data changes
Spot unusual patterns or errors
Filter Messages
Focus on specific message IDs
Hide noisy, less-important messages
Zoom in on the communication you care about
Transmit Test Messages
Create custom CAN messages
Set message ID, data bytes, and timing
Send once or repeatedly to test system responses
Verify systems react correctly
Log for Later Analysis
Record entire sessions
Save to file with timestamps
Replay to reproduce bugs consistently
Export to CSV for spreadsheet analysis
Example: Diagnosing a Real Problem
Scenario: A vehicle's dashboard warning light is flashing incorrectly.
Old way: Take it to a dealership, pay $150, wait a week, they might not even find it.
With CANdo:
1. Connect CANdo to the vehicle's CAN bus
2. See all messages in real-time
3. Filter to dashboard-related messages
4. Notice that a certain sensor message has bad data or timing
5. Transmit a corrected message to test if it fixes the warning light
6. Identify the problem in 30 minutes
7. Save logs as proof of the fix
Conclusion
CAN bus communication is the nervous system of modern vehicles and industrial machines. Without the ability to see what's happening on the CAN bus, engineers and technicians are essentially working blind.
CANdo solves this by providing:
Affordable hardware
Free professional software
Real-time visibility into all CAN messages
Recording and playback for reproducible debugging
Message transmission for testing and diagnostics
Programmable SDK for custom tools and automation
Whether you're an automotive engineer debugging production vehicles, a hobbyist working on vehicle modifications, an industrial technician maintaining machinery, or a roboticist building autonomous systems, CANdo gives you the visibility and control you need to work faster, smarter, and more reliably.
Next Steps:
1. Download the CANdo Application: https://www.cananalyser.co.uk/download.html
2. Read the User Guide: https://www.cananalyser.co.uk/download/CANdoAppUserGuide.pdf
3. Connect your first CAN bus and start monitoring!
Happy bus monitoring!
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