NI USB-8473 versus NI PCI-CAN (series 1)

[Automan]

Hello.

I have to develop an application with multi-rate periodic frames by using the NI USB-8473 interface. As it will take a while for NI to deliver it to us we have decided to start development with an old NI PCI-CAN (Series 1) interface. As far as I could understand both interfaces use NI-CAN and because of that no modification will be necessary for the USB-8473. Is that really so? By looking at the hardware of the PCI card I could see a lot of electronics that eventually would not be the same as in the small USB module, I mean, maybe the last doesn't have a processor inside and no hardware managed periodic frames could be possible as in the PCI card. I hope it is not the case.

Thanks. 

[herosphro]

Automan,

If you are using the Frame API for NI-CAN in your current test code then the program should port over fine.  The NI USB CAN devices don't support CAN Objects so we can't use the Channel API and there are a couple Frame API functions that won't work either.  If for some reason you really want to use the Channel API on the USB-CAN device you can look into the conversion library that NI provides, however this library doesn't always work perfectly. 

Simply put, I would recommend trying to build your program using the Frame API and then it will transfer easily onto the NI USB-8473.

[Automan]

Hello John, thanks for the answer.

I was planning to start my application based on the "Hardware Input and Output > CAN > Frame API > General > CAN Transmit - periodic.vi" example found with the NI Example Finder, but according to you the NI-CAN VIs ncWriteObj.vi or ncConfigCANObj.vi will not work with the USB-8473.

In this case it seems all I have to work with is the ncWriteNet.vi and ncWriteNetMult.vi and the timing will have to be managed by timed loops for example. It is a lot more work to do than using ncWriteObj.vi as it seems the timing is managed in hardware in this case. Please correct me if I am wrong.

In my application I have to send 19 extended CAN messages (29 bits IDs) with periods ranging from 10 to 100ms. Is there any example on sending periodic frames with the USB-8473?

[Bangalore100]

Hi.

Is it possible to transmit periodic frames (33ms periodicity) using NI CAN USB 8473 series? I am using the Frame API's, as Channel API's are not supported for the USB interface.

I use Visual C as the programming language.