crio analog input problem

[souske]

Hello

I'm using crio with AO NI9263 and AI N9239 modules and trying to measure on AI what I'm sending on AO. The problem is that if I use FPGA I don't get any results. I've tested the modules using Scan Interface mode and there AO+AI works perfectly well. Does anyone know what can cause the problem?

Regards

Mikolaj

[MikeS81]

Hi Mikolaj,

where do you have problems? Do you still use the Scan Interface mode or did you write your own FPGA vi?

Mike

[souske]

Hi Mike

I have written an extremely simple fpga vi. I write to AO and read from AI. No matter what I write to AO on AI I always get 0 (zero). Simmilar vi executed in Scan Interface mode works fine.

Mikolaj

Message Edited by souske on 09-09-2008 11:55 AM

[MikeS81]

Hi Miloaj,

did you check you modules seperatly? Can you output something? Did you check if you have selected the correct mode? Did you download all functions to the fpga?

Mike

[souske]

Hi Mike

Yes to all  I even checked AO with a multimeter to make sure that something goes out.

Mikolaj

[MikeS81]

Hi Mikolaj,

so you have only problems with reading the AI?

Mike

[souske]

Yes.

Mikolaj

[JMota]

I'd bet the problem you are running into is that you are not writing to the digital Start channel for the 9239, which is only available on the FPGA. Note that the FPGA I/O Node for the 9239 AI channels is self-timed (based on the module's data rate configured).

The programming experience for the 9239 is similar to the 9233. Check this other thread where someone was running into the same problem

http://forums.ni.com/ni/board/message?board.id=280&message.id=4432&query.id=127789#M4432

Hope this helps.

[souske]

Thanks! That solved the problem. Examples for hardware are also a very nice thing. I completely forgot about them.

Regards

Mikolaj