Is the acknowlegment set by H/W or S/W?

[Eric Paulin]

Hello,

For the first card, the serial is BC9A72 and part number is 184272E-02.

For the second card, the serial is C814B8 and part number is 184272F-02.

The model of the computer is a Dell Inspiron 7000 with an Intel PII inside running Windows 98.

The device is a custom built Lithium-Metal-Polymer Battery using a 80C515C processor with a Phillips PCA82C250_SM CAN chipset.

We follow the CAN standards and requirements. The length of the cable is minimal, basically your CAN ports cable length plus a cable about 1 foot and a half in length coming from the device. With that distance being so small I've noticed that the network works with or without the resistors but I a
lways use them.

We work at a 100000 baud rate.

We've tried with another device and the same problem occurs. We've noticed that when the messages are sent at a slower rate from the device, and not at a slower baud rate, the messages are acknowledge by the NI-CAN card. I do think it's either the Ni-CAN card or Labview that is to slow to process the messages. We've already developped a smaller aplication using Visual Studio using the NI-CAN card and there were no problems found at all.

We haven't measured the resistance between the CAN_HIGH and CAN_LOW but it will be done to be sure that the problem isn't there.

We also changed the cables.

I think that's it for now.

Thank you

[Randy Solomonson]

It sounds like the program running on NI-CAN could be the problem. Does this program check for all errors and warnings in each VI? Try using the Bus Monitor program that ships with NI-CAN 1.5 and later. Feel free to attach a simplified version of the VI.

What are the minimum and maximum delays between the CAN messages? Also, is it possible to lower the baud rate to 125k? If so, does that change the results?

It sounds like we're getting closer to the cause of the problem.

Randy Solomonson
Application Engineer
National Instruments

[Eric Paulin]

Hello,

I do beleive that the software was the problem but I don't quite know why. We got two different kind of ways to communicate with our device and by using the other way it's as smooth has it can get. I'm going to look further more in the code when I'll have time but right now I need to move to my other projects. I think it's just the way that I configured the CAN bus in reception....Well quite frankly, I don't think I needed to set it up because it was already setup.

Thnaks for your hlep and time.

Eric Paulin

[Randy Solomonson]

Sure thing. It'd be great to know how I can duplicate this issue here, if it's necessary to investigate further.