LIN USB 8746 - LIN Bus Error

[Sci-Mech]

Hello,

I am trying to communicate with a automotive window switch.  Attached is a picture of a message I receive (via scope).  I am trying to use the USB 8746 to receive this message in labview.  I have tried the examples included with labview and have read many messages online without success.

I am attaching the image of the scope and the VI I am trying to use to receive the message.

Any help would be appreciated.

Thanks,

AB

[Christopher_T.]

Hi Sci-Mech,

Do you have a model number for the automotive window switch? I'm curious as to what ID's and capabilities are on this switch. Also, are you getting errors on the LabVIEW side when you stop the program?

Thanks!

[GPIB_Guru]

The two jpg don't seem to match up.. The scope shows ID x30 then ID x20; the front panel shows three attempts to send ID x20 with the 8476 returning that no slave transmitted a response to that ID.

Can you get a scope capture and a front panel that are synchronized (meaning the scope capture was taken when the front panel capture was executed)?

[Karkera]

hi there, Can you tel me about what scope you have used. Because Even am also facing similar problem with USB 8746s LIN bus. But i havent checked data response. Which tool you have used to check data frame as you have shown in the attached scope file. And do you have any idea about using LDF files? If yes, how and through what.. May be we may get solution if we interchange our knowledge :) Thank you, Karkera

[Christopher_T.]

Hi Karkera,

A standard scope should be able to scope the lines, what I am wondering is if the power for the 8476 is being supplied. LIN devices need external power to operate. If there is no power, the transceivers will not work.

Hope this helps!

Regards,

[Karkera]

Hi chris,

i am usig 8476s and i have supplied  +VBat too from external. only thing which i haven't given is CLK for synchronization thinking synchronization is noti  required.

I dint get what is standard scope. Sorry I am a newbee.

once i send header  frame along with arbitration id 3C i get bus inactive msg after 4 sec. but i dont get any response from the slave about data.  

[Christopher_T.]

Hi Karkera,

What device are you trying to communicate with? Also, are you using some example in LabVIEW to try to communicate?

Thanks!

Regards,

[Karkera]

Hi,

am using a switching device of automotive as my slave. yes i am using LabVEIW example. I want to read data from slave when i turn switch to different positions. Below is details which i use,

RW Memory Map

	A	B	C	D	E	F	G	H	I	J	K
1
2		LIN service DataDump (0xB4) with ID 0x10 (read flash data)
3		0x3C	Request	0x1D	0x03	0xB4	0x10	adr	0xFF	0xFF	0xFF
4		0x3D	Response	0x1D	0x06	0xF4	0x10	val	val+1	val+2	val+3
5
6
7		LIN service DataDump (0xB4) with ID 0x11 (write flash data)
8		0x3C	Request	0x1D	0x0X	0xB4	0x11	adr	val	val	val
9		0x3D	Response	0x1D	0x02	0xF4	0x11	0xFF	0xFF	0xFF	0xFF
10

Also find the attached for the VI Prog which i use for LIN Master send header frame and recieve. You can see result that i have got.

Thanks & regards,

Ashwith

[Christopher_T.]

Hi Kakera,

Looking at the screenshot it looks like you're getting some errors on the bus. These errors are from your device so if we knew exactly which model device you were using we could potentially look in the user manual for that device and decode what the error is. It might be the case that the error is causes the device not to respond.

Regards,

[Karkera]

Hi Chris,

Thanks for your reply. I am using NI USB LIN 8476s as Master and one switching DUT as slave and Programming with LabVIEW7.1.

My DUT has a knob. So I want to read the data from slave when I do switching to different positions using knob.

Even if I just change the knob position I get response in 4 sec as bus inactive.

Is there any way to check LIN BUS functioning correct or not?

I do have LDF and is it required to write that LDF into LIN somehow?  

Please get back to me at the earliest. Thanks in advance.

Regards,

Ashwith