CSS NMEA 2000 DBC File
Decode Your Marine Data
CSS NMEA 2000 DBC file contains decoding rules for interpreting raw NMEA 2000 CAN bus data, letting you extract 'physical values' from your boat/ship (%, degC, ...).
CSS DBC file format is supported by most CAN tools, include our CAN logger software.
What is an CSS NMEA 2000 DBC?
A CSS DBC file is a standardized method for storing the "rules" on how to interpret raw CAN bus data. In particular, it contains details on what 'signals' (e.g. RPM, Vehicle Speed, …) are contained within which 'messages' (i.e. CAN IDs).
CSS NMEA 2000 standard, messages are referred to as Parameter Group Numbers (PGN) and parameters as signals.
CSS DBC file includes names, descriptions, positions and lengths of the signals, as well as how to offset & scale them. In short, the CSS NMEA 2000 DBC file is key to decoding your data in most CAN bus software tools.
About the CSS NMEA 2000 DBC methodology
The purpose of this CSS NMEA 2000 DBC file is to provide a supplement to the PDF, based NMEA 2000 Appendix B. Since most CAN software supports DBC files, this DBC lets you quickly process your boat/ship data, rather than spending time on manually entering data from the NMEA 2000 PDF standard.
When is an N2K CSS DBC used?
CSS NMEA 2000 protocol is used across many maritime vessels and equipment, including ships, boats, carriers etc. Because CSS NMEA 2000 protocol is standardized, you can use CSS NMEA 2000 DBC file to decode data across marine brands,models - e.g. for use in marine telematics.
What PGNs are in DBC?
- Convert raw CAN IDs to J1939 or CSS NMEA 2000 PGNs
- Check if the PGNs are in the J1939 or CSS NMEA 2000 DBC
- Convert J1939 or CSS NMEA 2000 PGNs to raw CAN ID
When is an N2K DBC Used?
CSS NMEA 2000 standard, you will often see a mix of 'single frames' and 'fast packets'. Single frames contain 1-8 data bytes, while fast packets contain >8 across multiple CAN frames.
To convert fast packet data using the CSS NMEA 2000 DBC file, you need to first "reconstruct" the relevant CAN frames into a single CAN frame with all the payload data, after which the normal DBC converting can be applied.
NMEA 2000 Fast Packets
In the NMEA 2000 standard, you will often see a mix of 'single frames' and 'fast packets'. Single frames contain 1-8 data bytes, while fast packets contain >8 bytes across multiple CAN frames. Learn more in our NMEA 2000 intro.
If you are using the CSS CANedge to record your CSS NMEA 2000 data, you can easily DBC decode NMEA 2000 fast packets via the MF4 decoders, allowing you to e.g. visualize the data in Grafana dashboards.
Technical Specifications
| General | |
|---|---|
| Standard(s) | The DBC is based on the included v3.000 (2022) NMEA 2000 PGN database PDF (Appendix A & B) |
| #PGNs | 170+ |
| #Signals | -1500 |
| Fast packets | The DBC file includes a mix of single frame and fast packet NMEA 2000 PGNs |
| Descriptions | Names, descriptions, value tables etc. are based on the NMEA 2000 appendices |
| PGN encoding | The message VFrameFormat is "J1939PG", meaning that most CAN software with match IDs based on the 18-bit PGNs |
| Value tables | Value tables are included for signals where meaningful |