CAN Comm setup (OBD-II)

[qorwkwkd20]

Hello, here to ask another question.

I am doing my own project to get a data from a car through OBD-II.

Car; Chevy Spark 2016,
Logger; SDL Sport.

Through OBD-II, what I want to log is just 2 things. RPM and speed.

From what I found; on C185 Motec Manager > New > OBD-II, there is already existing CAN comm setup for OBD so I mimic them. From the advice I got here before, I used ADL2 sport Motec Manager to make .CC7, which SDL Sport is able to read.

However, none of them - speed and RPM - did not work. Nothing recorded.
whole 3 weeks invested, but really can't find the answer...

But here is one thing I am doubting. On C185 Motec Manager > New > OBD-II > CAN Comm setup, it says;
Offset; 1 for ID; 410C(RPM), and click "Change" to go "Change Comms Channel" offset; 3 and length;2.

Since RPM uses 2 bytes, so the length 2 is correct,
but I am not really sure the offset value. Also why there is 2 different value for offset?

From what I know; I should hop 2 bytes to get the RPM only, so offset should be 2...?

What is the offset on the "identifier" and "change comms channel"? Are they different? What are they?

[David Ferguson]

Well, not sure what you know.

Do you know how OBD-II works (request / response)? If not, this is a very useful reference:

https://en.wikipedia.org/wiki/OBD-II_PIDs

Do you have the MoTeC documentation on how their OBD-II CAN templates works? Your MoTeC dealer should be able to help you by providing that document.

Are you receiving any CAN OBD-II data on the SDL currently? (ie, is the baud rate correct, wiring ok).

I would post the complete CAN templates (TX and RX) you are using instead of screen shots if you want help.

[qorwkwkd20]

Hello David,
Thanks for the reply.

Here is some answers what you asked.

Do I know how OBD-II works? ->
Probably. To get the data through OBD, I should request(Tx, 7DF CAN ID), and get a reply(Rx, 7E8 CAN ID). It is based on CAN protocol, consist of 8 bytes of CAN Data, first is number of byte it contains, 2nd for Mode (01 - show current data, Tx / 41- show current data, Rx), 3rd for PID, 4th to 7th actual data, 8th unused.

Do I have a Motec CAN comms Documentation? ->
No. The SDL Sport currently I am using is borrowed from my friend, so I think my friend would have the document you said.

Am I having any CAN OBD-II data on SDL? ->
I believe I am not. Not getting any data from OBD, since nothing was showing on the display. RPM and vehicle speed were '0'. I throttled, but nothing happens for RPM, I moved the car, nothing happens on vehicle speed. But gauge cluster on my car was showing right value.

Is my CAN Bus is okay? ->
Yes, I tried other CAN based sensor, it tells me right data.

Is my wiring okay? ->
Yes, the test from CAN based sensor, wiring is fine,

Is my pin okay? ->
Using proper OBD pins (6, 14) for chevy.

Is my baud rate okay? ->
However, the baud rate you mentioned, I believe it is not able to change on SDL Sport Dash Manager... Unlike C185 dash manager has 500kbps, 1Mbps, etc...

For the full template, please have a look at the image below. I have captured everything possible.

[qorwkwkd20]

And other captures

[qorwkwkd20]

Another capture

[David Ferguson]

I think you may be able to set the CAN baud rate in Online->Communications->Connection Setttings -- I don't have an SDL here to test with, but I seem to remember that there was a different method used to set the baud rate on the SDL/SDL3.