Improvement of Data Acquisition Speed on Single Board RIO

[Sharter67]

Dear all

I am currently using the NI embedded software evaluation kit.

For AC voltage the board should provide 250kS/s sampling rate. Since I have 2 signals after the multiplexer, i should get at least 100kS/s for each channel.

I only need to acquire the data for a definite time. The use of an intern memory migth be the solution to keep the data. But is the Xilinx RAM memory fast enough to avoid the loss of data? Do you have some tips for the progammation?

Thanks!

[Marian_O]

Getting Started with CompactRIO - Logging Data to Disk

Hello Sharter67,

thank you for posting at the National Instruments Forum. The sbRIO (Single Board Reconfigurable Input/Output)-device does contain two systems:

- the FPGA

- the Real-Time Controller with LabVIEW Real-Time Operating System.

There are several options, to acquire analog data:

- the LabVIEW Scan Interface: no FPGA programming is necessary, all programming takes place inside the Real-Time Part of the project

- LabVIEW FPGA Programming

A good starting point is the new Getting Started Pages from National Instruments, please follow the steps for "CompactRIO". They explain the installation of the necessary hard- and software.

www.ni.com/gettingstarted

Then, you may use the following "Getting Started" for Analog Acquisition and streaming to "disk" (onboard flash RAM):

Getting Started with CompactRIO - Logging Data to Disk

http://zone.ni.com/devzone/cda/tut/p/id/11198

For FPGA progamming examples, consult the "LabVIEW Example Finder" (Help » Example Finder).

Navigate to:

"Hardware Input and Output » CompactRIO » Module Specific » Analog Input"

A simple Example is the "NI 9205 Basic IO.lvproj". It is important to change the Realtime-Controller and FPGA-Target in the Example Projects in order to successfully use them.

The procedure is explained here:

Moving Examples to Another FPGA Target

http://zone.ni.com/devzone/cda/tut/p/id/5075

I hope, that these information will help you to Getting Started with the Analog Acquisition at maximum Speedrate.

Have a great day

[Sharter67]

Thanks for this great tutorial!

(Getting Started with CompactRIO - Logging Data to Disk

http://zone.ni.com/devzone/cda/tut/p/id/11198)

I managed to go down to 16 microseconds for each channel... Shouldn't i reach 8 microseconds (2 analog inputs)?

I started to have a huge noise in the two signals. I think i should connect in differential mode, but how can i set this in LabVIEW?

Thanks for your help.

[Sharter67]

A precision: I found the RSE and NRSE mode in the module configuration... but why isn't there any differential mode???

Thanks

[Marian_O]

Hello Sharter,

which modules are you using? You found the type indicated on the front of the module (4 digits).

Best regards