Compact RIO

[Emmanuel]

Hi,

I am using a compactRIO to measure voltages, currents and frequencies from a rig i built in order to simulate wind turbines.

Electrically the whole rig works quite well, the cRIO is used as well for system control (eg AnOutput to control variable frequency drives, and sets of digital outputs...)

My problem relate to the "storing of measurements". I read voltages from my generators with a couple of C9221 cards and i cannot do any data acquisition , i tried few examples

from the ni website regarding Fifo and DMA but none are working for me... I use the scan engine for some of the cards but I am using the FPGA for the C9221 cards.

Now, I probably started the whole data acquisition issue the wrong way !!!

Would you know any example which would apply to data acquisition from a C9221 card.

Any help is greatly appreciated...

Cheers

[Tim Erickson]

I would look at the data logging examples first. That is where I started.

1) If you need to log data continually:

Set up a real time FIFO. Put data into the FIFO in your data acquisition loop. Remove data from the FIFO and write it to a file in a separate loop. Log the data to a USB memory stick but you could also send the data to a host computer over Ethernet.

OR

2) If you need to collect data at a high rate for a short period of time and then save:

Set up a state maching that looks for a trigger. When the trigger is detected change states and to collect data for the preset time and then save.

I ended up using 2) above. We are looking at impact data resulting from the collision of two locomotives.

Edited August 10, 2009 by Tim Erickson

[Emmanuel]

Thanks very much Tim,

I will try this today.

cheers