Thanks for explaining your process!
In thinking about what would be the best move forward to “decoding” some of the usefull PGN’s, some questions came to mind. Mostly, what would be the right standard part to buy to start off.
First, what are we looking for? During the hackaton these came up as the most relevant:
- Motor RPM
- PTO RPM
- Fuel usage (this one is likely proprietary?)
- Hitch angle/height
- Speed (can also be done by gps?)
The sheet you pointed to (J1939 Digital Annex) actually seems to be automotive oriented, as you probably know. I have read somewhere that quite a few of the common PGN’s were copied to the ISO 11783 standard as each engine has a RPM etc. From your comments I understand that this file contains at least a few of the definitions we need to convert the messages. Is this correct? (from your own experiences of working with the sheet?) Would we be better of buying this sheet instead of one of the ISO 11783 parts?
Regarding the ISO 11783, you pointed to part 3.
Am I correct to understand that this part also contains definitions like you have in the J1939 sheet?
Or is that a different part, perhaps part 7 or 8?
In studying what PGN’s and SPN’s are, another question came up.
On the ISOBUS Website I found a data dictionary.
I noticed there are definitions for the same PGN with a different SPN. Does that mean we need both the PGN and SPN to match a similar signal to its previous occurence?
Wikipedia seems to suggest something similar: PGN’s and SPN’s