Question about the description file.

Mozgolom · September 10, 2021, 9:53pm

Some data is present in the can bus in the same frame, for example with can id 06E1. The first 3 bytes indicate which data (which parameter) and the next 2 bytes are the parameter value. So all the data is transmitted with the same CAN id in bytes 4 and 5. The difference is only in bytes 1, 2 and 3. This is the name of the parameter. How to describe such variables in the description file?

realdashdev · September 13, 2021, 5:07am

I think you are referring to ‘Composite ID’ support. It is supported and described here:

https://github.com/janimm/RealDash-extras/blob/master/RealDash-CAN/realdash-can-description-file.md

Mozgolom · September 14, 2021, 8:10pm

For example, the frames look like this:
7e9 05 62 2C 7A ХХ ХХ 00 00. 62 2C 7A - this is the data ID (byte 1, byte 2, byte 3), and XX XX - this is the data (byte 4, byte 5). This is the variable 1.
7e9 05 62 2D 08 ХХ ХХ 00 00. 62 2D 08 - this is the data ID, (byte 1, byte 2, byte 3) and XX XX - this is the data (byte 4, byte 5). This is the variable 2. And so on.

So, always the data I need is in a frame with the same id 7E9. The offset is also the same and is equal to 3. The data length is also the same and is equal to 2 bytes. The data is always in bytes 4 and 5, but depending on the contents of bytes 1, 2 and 3 refer to different parameters. How can I describe such data?

realdashdev · September 15, 2021, 9:06am

7e9 05 62 2C 7A ХХ ХХ 00 00. 62 2C 7A - this is the data ID (byte 1, byte 2, byte 3), and XX XX - this is the data (byte 4, byte 5). This is the variable 1.
7e9 05 62 2D 08 ХХ ХХ 00 00. 62 2D 08 - this is the data ID, (byte 1, byte 2, byte 3) and XX XX - this is the data (byte 4, byte 5). This is the variable 2. And so on.

Declare each composite ID frame separately in XML file:

<frame id="0x7e9:0x05622C,0,3">
    <value name="variable 1" offset="3" length="2"></value>
</frame>
<frame id="0x7e9:0x05622D,0,3">
    <value name="variable 2" offset="3" length="2"></value>
</frame>

Mozgolom · September 17, 2021, 6:41pm

I tried it like this

And like this Nothing is working.

realdashdev · September 20, 2021, 2:48pm

You cant have two values with same name ‘variable1’.

Mozgolom · September 20, 2021, 4:54pm

The real names of the variables are different.

realdashdev · September 21, 2021, 6:07am

If you just add a text gauge and link it to your variable, do you see any value there? This is a bit difficult to troubleshoot without having the same hardware, sorry

Mozgolom · September 21, 2021, 4:57pm

I have created both text sensors and indicators at the same time, but they do not show anything.

Mozgolom · September 21, 2021, 6:23pm

So, which syntax is correct?

Or

realdashdev · September 22, 2021, 6:10am

Oh, man I’m sorry. I gave you wrong examples on previous post (fixed them now). The correct format is

CAN_ID:COMPOSITE_ID,COMPOSITE_ID_OFFSET,COMPOSITE_ID_LENGTH

CAN_ID: the frame CAN ID.
COMPOSITE_ID: Composite ID that is read from frame data.
COMPOSITE_ID_OFFSET: Offset (in bytes) where Composite ID is in frame data.
COMPOSITE_ID_LENGTH: Length (in bytes) of the Composite ID in frame data.

Example:

<frame id="0x7e9:0x05622C,0,3">
    <value name="variable 1" offset="3" length="2"></value>
</frame>
<frame id="0x7e9:0x05622D,0,3">
    <value name="variable 2" offset="3" length="2"></value>
</frame>

Mozgolom · September 22, 2021, 9:42pm

It still doesn’t work. The parameters are present in the can bus, but RealDash doesn’t see them.

realdashdev · September 23, 2021, 5:09am

Sorry to hear that. Without being able to test on actual device there is nothing much more I can do to help you. I know that especially Link ECU users are using RD Composite ID system successfully, so the system should work.

Mozgolom · September 26, 2021, 10:09pm

Maybe there is some other way to see such data in RealDash? Without using composite ID. By the way, does the frequency of updating the parameter in the can bus matter?

realdashdev · September 27, 2021, 5:35am

You can use the CAN monitor option and highlight the interesting byte to see how its value changes when you have turn signal on.

The frequency on which data is sent to CAN bus only affects how fast the updates to RealDash are. Otherwise it should not have any effect on interpreting the data.

Mozgolom · October 6, 2021, 9:41pm

That is my frame.

But it does't work. Where is the mistake?

realdashdev · October 7, 2021, 7:26am

At least based on your screenshot your composite id on XML does not match on what you have on CAN monitor.

I’m sorry, but its next to impossible to remotely trying to troubleshoot this sort of issues

Mozgolom · October 7, 2021, 7:34am

Bytes 3 and 4 are constantly changing. These are identifiers. Bytes 5 и 6 these are DATA

nfrenay · January 31, 2023, 12:33am

@Mozgolom: were you able to fix your issue? I have the same problem. Posted here: https://www.realdash.net/forum/viewtopic.php?t=1866

Thanks.