Posted in 2024
Spying on a CANOpen bus
- 13 December 2024
CANOpen is a protocol stack that sits on top of a normal CANBus. Recently I found myself needing to monitor the traffic between 2 devices on a CANOpen network. Monitoring a CANbus by itself is easy to do with a little Python. Where I ran into difficulty was interpreting the raw CANbus frames into CANOpen messages. Here’s how I solved that.
Defining CANBus messages with a DBC file
- 03 December 2024
DBC files are a standard way to define the messages that will be transmitted over a raw CANBus. While working with this format I found it easy to find tools that could interpret, use, and generate DBC files. However I had a hard time finding resources to describe the format and schema of these files. This post describes some of the schema details I found the most helpful, many of which I had to learn by digging through the source code of tools that work with DBC files. Personally, I find examples the easiest way to learn/understand schema basics, so I’ll use that here while also describing the schema itself.