I logged some CAN BUS date from a power wheelchair, there are some IDs with two bytes (standard data), and others with four bytes(extended data), what's the different between them and does this mean the standard data IDs have higher priority?

another question is, I just moved one control handle, and why there are many CAN BUS ID changed date?
Please ref. to the picture attached.



Thanks for help.
Adam

 

The CAN Identifier Field is either 11 bits long or 29 bits long. The lowest numbered identifier has the highest priority. There is a bit in the message frame that tells you how long the identifier is. Without knowing anything about the protocol, there are no conclusions that you can draw from looking at the bus traffic. If the protocol is proprietary to the manufacturer you are plain SOL.

 

The CAN Identifier Field is either 11 bits long or 29 bits long. The lowest numbered identifier has the highest priority. There is a bit in the message frame that tells you how long the identifier is. Without knowing anything about the protocol, there are no conclusions that you can draw from looking at the bus traffic. If the protocol is proprietary to the manufacturer you are plain SOL.

Thanks,
You are right, they are using Serial communication protocol. So how can figurative out the which ID relative to the button pressed?

Best
Adam

 

Thanks,
You are right, they are using Serial communication protocol. So how can figurative out the which ID relative to the button pressed?

Best
Adam

I dunno. Without the secret decoder ring it will; be very difficult. Good Luck.

 

Thanks,
You are right, they are using Serial communication protocol. So how can figurative out the which ID relative to the button pressed?

Best
Adam

Normally to decode something like this you need a signal you control as a timed cleartext and a monitor of all signals generated using a regular pattern of the cleartext. You seem to have both with button and BUS monitor.

 

I just moved one control handle

Was that an on / off switch or is it showing varying positions of a potentiometer?

 

Was that an on / off switch or is it showing varying positions of a potentiometer?

Thank you.
It is a control PAD with both on / off switch and potentiometer joystick. The date I collected with the potentiometer joystick handle tilt only.

 

Normally to decode something like this you need a signal you control as a timed cleartext and a monitor of all signals generated using a regular pattern of the cleartext. You seem to have both with button and BUS monitor.

Thank you.
I am using a A1+ USB - CAN Adapter with a analyze tool named LM_CAN, can you tell more detail about the CAN BUS DATE analyze process?
Best

 

https://www.csselectronics.com/scre...g-can-bus-messages-with-wireshark/language/en

 

https://www.csselectronics.com/scre...g-can-bus-messages-with-wireshark/language/en

Thanks,
I'll check it out.

 

I used another interface and software got these date, why the date so long, seem it used Serial communication? but the Serial communication send 8 bytes each time. why?
Please see pictures and help.

TEXT:
08:49:57.648 -> FRAME:ID=524896627:LEN=73:0C:07:60:04:00:00:02:00:49:73:49:49:FF:FF:51:1E:07:00:00:01:59:07:00:00:0D:01:00:00:E8:03:00:00:00:00:00:00:C5:00:C4:00:C0:00:C1:00:C2:00:C6:00:01:00:00:2D:31:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

08:49:57.920 -> FRAME:ID=524896627:LEN=73:0C:07:60:04:00:00:02:00:49:73:49:49:FF:FF:4E:18:08:00:00:01:59:08:00:00:0D:01:00:00:E8:03:00:00:00:00:00:00:C5:00:C4:00:C0:00:C1:00:C2:00:C6:00:01:00:00:23:27:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

08:49:58.194 -> FRAME:ID=524896627:LEN=73:0C:07:60:04:00:00:02:00:49:73:49:49:FF:FF:4E:11:09:00:00:01:59:09:00:00:0D:01:00:00:E8:03:00:00:00:00:00:00:C5:00:C4:00:C0:00:C1:00:C2:00:C6:00:01:00:00:19:1D:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

08:49:58.432 -> FRAME:ID=524896627:LEN=73:0C:07:60:04:00:00:02:00:49:73:49:49:FF:FF:4E:0B:0A:00:00:01:58:0A:00:00:0D:01:00:00:E8:03:00:00:00:00:00:00:C5:00:C4:00:C0:00:C1:00:C2:00:C6:00:01:00:00:0F:13:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

Thanks.