CAN Bus Frames and Diagnostics
Transmit and observe safe standard CAN frames on an isolated two-node bench.
Topology and objective
MCU + CAN controller/transceiver ↔ terminated twisted-pair bus ↔ second node/analyser.
Hardware and tools
- Supported development board
- USB data cable
- Current-limited supply
- Serial monitor and logic analyser when applicable
Security and RF safety
- Never inject frames into a vehicle or safety system.nUse proper transceivers, termination and isolation.nDisconnect power before resistance measurement.
Practical procedure
- Power off and wire CAN_H, CAN_L and common reference.nVerify termination resistance on the isolated bus.nSet matching bit rate.nTransmit a non-critical laboratory identifier.nObserve arbitration, acknowledgement and error counters.
Telemetry / payload
{"id":"0x123","extended":false,"dlc":4,"data":"01 02 03 04"}Starter code / config
Send only lab IDs on an isolated bench network.Expected results
| Checkpoint | Expected | Tool |
|---|---|---|
| Termination | Approximately 60 Ω across H/L with two 120 Ω ends | DMM, power offnFrame |
Troubleshooting
| Symptom | Check | Action |
|---|---|---|
| Bus-off | Check bit rate, wiring and termination | Remove fault then recover controllernNo ACK |
Local-only sandbox
Commands & telemetry simulator
Send command
Simulator ready. No network connection is used.