Receiving CANbus data from external devices

[thusharag]

hi,
I tried to receive CANBUS data from an external relay (Woodward MFR2) to a MIAC. But some data comes. but very difficult to filter the data. such as difficult to read exact CAN IDs. I have attached here the transmission details of the external device. Could you please help me to read them out?

regards,

thushara.

[dazz]

Hi thrusharag
I dont have a miac but can you post your flowchart, sign up to the v4 or 5 forums link in my sig, this will allow others to see what version of flowcode you use and also will enable people to see how far you have got with your flowchart, and you will then get more help

Regards
Dazz

[thusharag]

hi,
actually I have done only a sample flowchart according to the normal way by using normal CAN (not extended CAN -CAN2). because I use this CAN normally to communicate with my HMIs in my projects successfully. But I cannot understand for this special application which one should I use. So please follow the above details of the requirement and guide me by which (CAN or CAN2) and how the flow chart should be.
Anyway I will put this in FLOWCODE 5 forum also.

thanks in advance,

Best regards,
thushara

[LeighM]

Hi Thushara

It looks like the device is sending out data on a single CAN ID of 0x320 (plus “item number”)
So looks like a standard frame 11 bit identifier.
Presumably the CAN ID can be configured on the device by changing its “item number”.

All data is then output on this CAN ID, but split across multiple messages.
Of the 8 data bytes available, byte 0 contains 0xdd, byte 1 contains the MUX number that tells you which section of data is contained in the remaining 6 bytes (or 3 data words).
So each “Telegram” message is made up of multiple words, so is sent 3 words at a time in each CAN message, where the MUX number tells you the part number.

So when the MUX number is 0 the data that follows contains words 1, 2 and 3, when the MUX number is 1 the data contains words 4, 5 and 6 and so on.
So to say get the “Bus bar frequency” you would need to read the word value in bytes 6 and 7 when the MUX value in byte 1 is equal to 4.
(Although that might be MUX = 3, because the table starts at MUX = 1, but the formula in the appendix starts at MUX = 0 for Line = 1 so that is a bit confusing)

That’s how I read these documents.
Hope that might be of some help.
Regards.
Leigh

[thusharag]

Hi LeighM,

Yes the way you thought is correct. I did it and now its working perfectly. Thanks a lot for the support.

Thanks again,

thushara.

[LeighM]

Thanks for letting us know it worked.
Leigh