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CAN BUS telemetry problem
Posted: Wed Apr 05, 2017 6:29 pm
by Acelotte
Hello
Recently I'm trying to read and write some parameter from ECU (EM40) via CAN bus. However, I cannot find any value displayed in the panel. Since I set all the "Mask" zeros in CAN RX Setup, the ECU shall receive CAN bus message with any ID. But it seems I got nothing in GWv4.
CAN bus settings
speed 500khz
CAN ID style 11/29bits
A problem is that I just power up the ECU without any sensors connection. Is this possible to course CAN telemetry failure?
I tested my CAN reading writing program (based on a Atmel board) and I'm sure its OK thus it becomes more strange.
Many thanks!
Re: CAN BUS telemetry problem
Posted: Thu Apr 06, 2017 7:53 am
by RickS
The CAN Telemetry Setup panel look to be set up OK but without looking at the transmitted CAN bus with a 'sniffer' (like P-CAN) it is hard to tell whether the EM40 is sending any data... You can also test if the bus is active with an oscilloscope, if you don't have the interrogation software.
Regarding the RX, you will need to specify the arbitration codes that you want to read into the EM40, in the 'ID' box for each of the 4 messages that you want to receive. In beta test at the moment, we are running GWv4 with the 'Mask' option removed as it has no purpose now. See attachment as an example (add your own codes!)....
Re: CAN BUS telemetry problem
Posted: Thu Apr 06, 2017 9:37 am
by Acelotte
Thank you for your reply. I'll retry this test as your instruction. Many thanks.
Re: CAN BUS telemetry problem
Posted: Thu Apr 06, 2017 10:31 am
by RickS
I have noticed, that in you CAN Tx panel, you have not specified a CAN arbitration code to put your selected parameters on. On the right hand side of the panel, there is an option 'CAN ID'. You should put a different code in here for each of the three messages that this ECU transmits....
In the attached example, a code of 0x400 is specified for 'Message 1', so 'Message 2' could be 0x401 and 'Message 3' could be 0x402.
The Help tab in GWv4 has a very good section on setting up the CAN telemetry. Take a look as it will explain it in greater detail than I can do here..!
Re: CAN BUS telemetry problem
Posted: Thu May 11, 2017 3:55 pm
by Acelotte
Thanks for your kind help. What you've mentioned is of importance. Besides, I'd like to add that the CAN bus telemetry works only when the "CAN Telemetry" parameter in "Option selection list" is "ON". That's what I didn't realize before. Hope this experience can help others.
Re: CAN BUS telemetry problem
Posted: Tue May 16, 2017 7:59 am
by RickS
No problem and pleased that it helped you and hopefully others.
Regards, RickS