PCI-CAN/2 problems

[aworld]

Hello guys, i have problems by using PCI-CAN/2 with my PC.

Before i use PCI-CAN, i used USB 8473 CAN to connect the can port of my microcontroller, it works all right.

But now when i use PCI-CAN, there comes the problem. The data transmitted is not same as when i use USB-CAN, which means when i send the same data, but i received different data with these two devices.

 This becomes very strange, what am i missing ?

The point is when i use USB CAN. it works all right, but when i use PCI-CAN, it seems to be all wrong.

Hardware information :  both CAN device are from NI, i have connect 120 om resistor on CAN_H and CAN_L on microcontroller. The RS232 Cable max lenght is 1 M. I didn't put 120 om resistor on the PC side. Later i try connect my can port directly on the PC without any cable, it shows the same result.   Then i think the problem might be my PCI-CAN, then i try another PCI-CAN, it gives me the same unstable confused strange result again.

Programming tools : CVI.

Thanks...

[O_Proulx]

Hello aworld,

The first thing we should look at is termination.  Your network should be terminated at both ends with a 120 Ohm resistor, which means that you should have one on the PC side.  You can look at this knowledgebase for more information on termination.

What baudrate are you using?  Do you have a High-Speed PCI-CAN card?  Are you using extended arbitration IDs in your program?

A great debugging tool is NI-Spy.  This will enable you to look at all the NI-CAN driver calls.  It can be a great tool to use when seeing wrong data.  You could compare the NI-SPY capture of the USB-CAN with the one from the PCI-CAN card.  

Have a great day!

[aworld]

Hello aworld,

Hello, O.Proulx

Thanks for your advice, i am using PXI-8430 PCI-CAN/2, this card is high speed card, the Baudrate i am using is 1 Mbs/s, i am not using extended arbitration IDs in my program.

I think i will try to add two 120 ohm resistor on both side at the moment, and let you know about the result after i finish the testing.

Thanks a lot.

 

Aworld