No slave response using 8476

[Jwilson]

Hello, I am attempting to do LIN communication using the 8476 USB module. I am using VB .NET examples (LIN Master Send Header Frame and Receive) I repeatably get the error response 84 0 1 6 0 0 A, from the NI manual I know that this error Means "LIN bus error no reponse" using another manufactures LIN module I receive the proper response. I set my baud rate to 9600 in MAX and also in the application using ncSetAttributes function. I am not sure what I am overlooking.

Thanks JWilson

[Sammy Z · Accepted solution]

Dear JWilson,

Would you please take a screenshot of your error please, and post it?

Also, as a source of extra information, please look at the following discussion forum entry.

http://forums.ni.com/ni/board/message?board.id=30&thread.id=3614&view=by_date_ascending&page=1

Regards,

Sammy Z

[Jwilson]

SammyZ Thanks for the reply, Last night I was able to solve my issue, when I read the NI manual it said that I could use the software termination instead of the 1K master and 30K slave pull up resistors. With the software termination selected I was not able to get a response from the slave. When I added the pull up resistors I was able to communicate just fine. The documents say that with the software termination selected that the pull up resistors are not required, I did not have any success without the resistors.

PS. I believe that they are assuming that the slave transceiver has the standard 30K pull up, I was not able to verify that.

Thanks JWilson

[no slave response]

Hi,

I'm use the 8476 and as see a problem same too. I'm tried to add 30 K-Ohm resistor pull up between +bat pin and LIN pin, as it's same, I till don't receive any respomse from slave. Please advise.

Thank you and Regards,

Tom

[Jwilson]

Tom, please verify that you have both resistors and diodes connected as shown. That was the issue I had, made the attached drawing for reference. Hope this helps.

Thanks JWilson

[JB]

Sorry for chiming in about a month after your last message... However, I have just discovered a mistake in your schematics.

Extract from the LIN Protocol Specification (Revision 1.2 page 30) : 

The diode is mandatory to prevent an uncontrolled power-up of the device from the bus in case of a "loss of battery".

Therefore, the diodes must be reversed.

[Jwilson]

Thanks for the reply, when I referenced the drawing to make another cable I found the mistake on the diodes. Thanks again J Wilson

[K.M.R.]

Jwilson,

Where did you find VB.net examples for the USB-8476?  I downloaded the NI-CAN272.exe and installed it, but there was only source code for VB6.  I am in the process of migrating the VB6 code to VB.net, but it's not the easiest of tasks.  I have not purchased the 8476, just researching it for use in a project as the LIN Master.  Any information you can provide is greatly appreciated.

Thanks,

K.M.R.

[Adam G]

Hello K.M.R,

I am not sure where he would have got a VB.NET example. If you wish to use VB.NET so you will have to create a wrapper if you wish to use VB.NET.

Best Regards,

Adam G 

[K.M.R.]

I figured that would be the case.  It's too bad, the NI USB-8476 looks like a nice piece of hardware.  I just wish the source code was up-to-date.