Diagnostic Messages J1939

[triviper]

Does anyone have any information on how to handle multipacket responses to PGN 59904 requests (00EA0016) for information like DM1 and DM2 using the J1939 Transport Protocol? As outlined here: http://zone.ni.com/devzone/cda/epd/p/id/6215

I have an AU electronics SAE J1939 simulator module that is supposedly putting out multi-packed DM1 messages like this:

 

and I am sending and reading SOMETHING of a response to the special request PGN 59904 (00EA0016) using multiple software tools in LabVIEW and CompactRIO's and 9853 High Speed CAN modules (down to the FPGA level) yet I don’t receive but a fraction of the SPN’s (Suspect Parameter Numbers) or the FMI’s (Failure Mode Indicator) that I expect or what’s on the list shown.

I know this is a more advanced capability of CAN and J1939 instead of just reading engine parameters, but I already use the "Request" PGN (EA00) to get the engine hours from this simulator so I know the request works.

Is there something special I need to do to get and parse out multipacket information instead of just one parameter?

Thanks!!!

[Nick-C]

The J1939 Transport Protocol is not officially supported at this time, however I'd like to try and do my best to help you get down to the bottom of the problem. 

Have you started from any example, or have you built your entire VI from scratch? Based on what I looked at in the VI libraries and examples, those are coded for single packet reads/writes. Would it be possible for you to post the portion of code where you are reading the multi-packeted messages along with a screenshot or log of the data that you are receiving?

-Nick-

[triviper]

Nick,

Think I have it figured out, I was limiting my packets of DM1 messages (multi-packet message) to a 64 bits when it should have been ALL and can be much more than this. The simulator I have puts out approx, +250 bits for a multi-packet broadcast message (+37, 8 byte payloads) to get the info in the pickture I sent before.

As long as I sent the REQUEST correctly (FECA for DM1), this seems to work.

Thanks

[Nick-C]

Glad to hear you got everything worked out. If you have any other questions feel free to post them up and we'll see what we can do to help.

-Nick-

[Venki1988]

Does have any Information releated to DM1 message in J1939 protocol,Currently I am testing off road vechile Instrument Cluster So I need to Simulate the Diagnostics message DM1 on it.I am having SPN number , FMI Code but I don't have OC and CM.

Thanks

Venkateswaran V

[triviper]

Well I have not messed with the J1939 for a while but what I can tell you is getting ALL the DM1 and DM2 messages is pretty easy. If I recall correctly they are broadcast automatically, you just need to be able to decode the frames correctly. We used the CVT tools and the XNET database editor to parse the individual messages out.

65226 = FECA = 16697856 is the DM1 PGN

65227 = FECB = 16698112 is the DM2 PGN

dec = hex = w-00 ext

Here is a picture of how we parse the parameters in XNET.

If you still have problems contact David Harding (david.harding@intrepidspecialties.com). He is a former NI guy who trained us and now has his own company.

[triviper]

The problem is sometimes you have to REQUEST a specific peice of information or WRITE a value to the ECM..... Sometimes this is easy. Soemtimes not.

We were having fun with this as we were having to calculate Hydraulic HP based on RPM\shaft speed, then WRITE the value to FE05.

Al I can say about this is good luck.

We eventually got it (thanks to David Harding's experience) but we had to hack it way down at the FPGA level on the Compact RIO. 

[COwen314]

Venkateswaran,

DMC just released a set of J1939 drivers for LabVIEW that can handle requesting and parsing DM1 messages, among other things. You can find them here.

CO

[avanti05]

Hi , i want to implement DM2 for j1939 with infenion, i am not getting how to implement it. if is there any sample code . please help me