Claas Isobus

[Klaudia Aricas]

Currentlythe tractor (Claas Xerion) is steered with a Trimble TMX-2050, and a Pro 700 display runs my CNH P series aircart through ISOBUS. The cart uses gps messages sent from the Trimble though the isobus in order to enable turn compensation on the aircart. It will not work feeding it nmea though the serial port on the back of the Pro 700.

Remember in j1939 a CAN ID is broken up into sub fields. PGNs only make sense in this context (in other words a CAN ID can be different with the same PGN, depending on the destination address). Inside a j1939 message is payload (up to 8 bytes), divided into fields according to a formal SPN specification, see below for a pdf.

@torriem I have been having a look at this topic and think I have 3 of the 4 messgaes working. I did notice this line in your decoder for the bigger PGN and I think its just a typo needs to be PGN = ID & 0x01FFFF00 (that will use the 17bits of the 18bit PGN) .

Your decoder / encoder works very well and the can wrapper is very nice too. I will change the way the the current setup works because its fine for a few messages but when you start doing too much on the ISOBUS between brands the wheels come off pretty quick. Scrapping the filters and just let everything in and filter the PGN will work better for that side of it.

Yes I like being able to filter on plain PGNs. Does make it easier, provided the MCU has enough horsepower to deal with all the messages, which Teensy certainly does. Hardware CAN filtering is nice because it only lets in some of the messages to the microcontroller so even an 8-bit arduino can work. But yes filtering is only on the whole CAN ID, so looking for a PGN is harder that way the way j1939 IDs are encoded.

I think I have 65267, 65256, 129029 working with corrected postion from AgOpen. When i get more time just need to finish 65254 (Date/Time). I do still need to test on a machine as I have only guessed in the office. Im not sure if you have parts to test or still ordering parts?

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