More imformation about "AI Convert" signal

[graduate student 44]

does anyone know anything about the "AI Convert" signal on pxi-4472? i read it somewhere that it generates a pulse whenever an A TO D is performed on board, so does that mean a pulse for each data sample?

[Stuart_G]

Yes...that is a good way to think of it. There are basically 2 clocks. There is your sample clock and your convert clock. The sample clock is the time you specify for an acquistion to occur in. So if you specify a sample clock of 100Hz then all of your samples from all of your channels will happen within 100Hz. The convert clock comes into play mostly when you have multiple channels in your acquistion. Say you have 2 channels and they must complete within the specified 100Hz. Your convert clock specifies when EACH channel goes and gets the data point from your A/D. In this case your convert clock wold be 200Hz. If you had 8 channels your convert clock would be 800Hz.

[graduate student 44]

that makes sense. thanks! i'm having 11 pxi-4472 boards, each with 8 channels on it, so 88 channels in all. i need to take a timestamp for each data sample, but only one timestamp for all 88 channels. so which signal should i monitor? the scanclock, or ai convert, or anything else?

[graduate student 44]

also, i tried to route "scanclk" and "AI Scan start" to an RTSI line, labview refuses to run. i then tried every other option as the signal name, labview doesn't seem to like it. is there anything i could do to output these two signals? thanks!

[Stuart_G]

I didn't read your original post close enough and didn't realize you were using DSA boards. I'm not sure where you saw reference to "convert clocks" for DSA because these boards are simultaneously sampled so you don't really have the notion of a convert clock. I would suggest what you probably really want to do is synchronize all of your boards and then take one timestamp. The only other alternative I could think of is to take a timestamp from each of the boards, however, I doubt this is what you really want to do. I haven't used DSA before so I'm not sure how you do the syncrhonization but searh on NI's website and you should be able to find an example for how this is done.

StuartG

[graduate student 44]

thanks a lot! i managed to route "AI Convert" to an RTSI line and things seem to work, except for another problem. geez, there is always something more coming!