cRio Data acquisition with PID and Host Monitoring

[maxoverclock]

I am using labview 8.20 and starting this app using the FPGA wizard.  I am setting up a test platform and am using the cRIO to control my system and collect data.  attached is my current code.  i have my inputs and output working and my host app is monitoring and controlling what it needs to.  i now need to add to PID controls and to save the information going in and out of my testbed.   my pid loops will be running faster and my host app runs at about 40ms.  what is the best way to save data at 1-2ms resolution.  is it better to hold everything in the cRIO memory and then convert it to engineering units and dump it to disk when the experiment is finished or is it better to transfer, convert and save as things are running? 

i dont'want to bog down my host app since i have to enter experiment parameter changes and need to monitor at no slower than i am already running....

i looked over http://zone.ni.com/devzone/cda/epd/p/id/3432 but it looks like it is pretty invoived to implement and am not sure if it is the best way. 

any help would be appreciated....

cheers

[.avi file]

Greetings!

      It appears on the RT side you are only viewing the data and not sending back any data down to the FPGA after any kind of analysis on the RT. Your PID is on the FPGA. Hence there is no need to convert the data in real-time.  You can send the binary data using RT FIFO's (shared variables and have RT FIFOs enabled) back to the host and do the conversion to engineering units on the windows side after the experiment. This is your best approach if you are doing continuous acquisition and loop control on the FPGA. You can choose to log data to cRIO memory in portions and then as it gets filled up you send it back to the windows side. Still all the conversion is done in the windows side.

Thanks and hope this helps
Best regards
Avi Harjani

 

[ZenerII]

Hi Max, I would be very interested in your experience and impressions of the FPGA Wizard.  We are continually looking for ways we can improve the Wizard, so if you have any feedback good or bad, please reply to this post or email me at mike.trimborn@ni.com

Thanks, Mike

[dbtestcon]

I have feedback on the FPGA wizard.   If you go back in to rerun the wizard on an existing .fwc it would be cool if it asked permission before it wrote over the existing VIs.  Being a dummy, I forgot to change the name of the "new" generated VIs and it blew away several hours of mods I had made to the existing VI. 

[NoahR]

Hi dbtestcon,

Thanks for the suggestion involving the FPGA Wizard.  If you would like to provide some feedback to us here at National Instruments, you can go to www.ni.com/contact and you will see a section entitled "Product Feedback" where you can submit your own feedback for any product suggestion that you may have.  We really appreciate any feedback that we get.  Thanks!

Noah R.