CAT Data Link (CDL)

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ben.martins
Pico Staff Member
Pico Staff Member
Posts: 539
Joined: Tue May 16, 2017 1:02 pm

CAT Data Link (CDL)

Post by ben.martins »

Hi all,

Hope all are well?

Am after a little support from those working with Caterpillar products.

I've come across it before in the past surrounding the CDL network present on Caterpillar machinery. Most of the work is usually on J1939 which is fine as we have the amazing J1939 decoder, thank you software and decoding teams at Pico!

My problem is I'm struggling to get anything to decode it. At first glance it appears we are dealing with CAN especially as the packet structure looks the same. However, when adding rulers in we have very different voltage levels.
CDL CAN.png
For channel A we have a high 4V which appears to be pulled down to approx. 0.8V and for channel B a low 0.4 which is pulled up to 4V. The differential on this (B-A) sees the voltage swing from -4V to +3.3V.

Looking at the Baud rate, by using the time rulers on the smallest pulse in the message my frequency is around 62kHz (= 62kBaud).

However, creating a decoder with this baud rate nothing happens.

Therefore, I'm reaching out for a little help. Would anyone happen to know anything about the CAT CDL network? Baud rate, voltages etc. I'm certain we can decode it but there is something missing from the limited information I have available. I have attached the PSDATA file as well with the data along with a Math channel. May not need the math channel to decode with as both channel A & B are fairly clean signals as the engine wasn't running!

Any help would be gratefully appreciated.

Kind regards

Ben
Attachments
CAT 962 H CAN DATA AT OBD PORT IN CAB D E CDL 1 buffer.psdata
(12.58 MiB) Downloaded 246 times

Redmech
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Posts: 7
Joined: Wed Sep 07, 2022 3:08 am

Re: CAT Data Link (CDL)

Post by Redmech »

Ben,

I work around quite a few cat machines, I could hook my 4425A to a 966G next week most likely. I just fixed a D11R CDL issue, can wires were shorting to ground, watching the wave form in real time was so much faster than hunting for a rub spot.

Ross Dugan

ben.martins
Pico Staff Member
Pico Staff Member
Posts: 539
Joined: Tue May 16, 2017 1:02 pm

Re: CAT Data Link (CDL)

Post by ben.martins »

Hey Ross,

Great catch with the CDL issue and as you say being able to see the signal, especially with something like network, makes it little easier.

If you don't mind grabbing a capture for me that would be great. Would you have anything about this network you would be willing to share?

Thanks again.

Kind regards

Ben

Redmech
Newbie
Posts: 7
Joined: Wed Sep 07, 2022 3:08 am

Re: CAT Data Link (CDL)

Post by Redmech »

The repair on the D11 I had a short clip on video, in this one I was using my 2204A and not my 4425A, crawling around on large machines, sometimes I use the cheap scope if great accuracy and deep memory isn’t needed.

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