cRIO-9233 manual specs max data rate=50kS/s. Is this per channel or aggregate?

[mdillon2218]

Page 14 of the cRIO-9233 manual specs max data rate=50kS/s. Is this per channel or aggregate for all 4 channels?

[Thierry_Debelle_NI]

The maximum sample rate of 50 kS/s is per channel. The cRIO 9233 module provides simultaneous sampling on all 4 channels (24-bit sigma-delta converters).

[mdmichael]

I have been experimenting with the cRIO-9233 using the sample program VC_ContAcq_IntClk. The sample rate is behaving as though it is an aggregate. I can sample 1 channel at 50kS/s, but when I try to sample 2 channels, I am only able to set the SR at 25000 S/s. If I select anything above that value, I get an error:

DAQmx Error: Onboard device memory overflow. Because of system and/or bus-bandwidth limitations, the driver could not read data from the device fast enough to keep up with the device throughput.

This error occured with the SR=25000.01. Sampling at 25000.0 works fine. Similarly, I am only able to sample at 16666.66 S/s for 3 channels, etc.

Here are the lines frpm the example code that sets the sample rate and voltage channels-

DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0:Dev1/ai1","",DAQmx_Val_Cfg_Default,-5.0,5.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",25000.1,DAQmx_Val_Rising,DAQmx_Val_ContSamps,25000));
This combination returns the error above.

DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0:Dev1/ai1","",DAQmx_Val_Cfg_Default,-5.0,5.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",25000.0,DAQmx_Val_Rising,DAQmx_Val_ContSamps,25000));
This combination works successfully.

Any information about what is happening here would be appreciated.

Mark

[GValdes]

Hi, Mark,

How are you interfacing with the cRIO-9233 using DAQmx? As far as I know, the only way of programming it is using LabVIEW FPGA. Could you please clarify this for me?

Thanks!

GValdes

[Thierry_Debelle_NI]

The cRIO-9233 is not supported by DAQmx. You have to use LabVIEW FPGA to use this module. The problem seen here is most likely due to transfer bandwidth issues. The module can acquire at 50 kS/s per channel (200 kS/s aggregate if using all four channels). The bottleneck is the data transfer path via the FPGA and LabVIEW RT.
NI is currently working on some example code that can greatly improve performance (you should be able, with this example, to get 50 kS/s on all 4 channels). If you have an immediate need you should contact Jack Arnold (jack.arnold@ni.com) who is the DSA/SMIO product support engineer.

Regards,

Thierry

[Kurt_Veggeberg]

The cRIO-9233 will be incorporated into a product called the USB-9233 with the release of NI-DAQmx and can be programmed in NI-DAQ. This was shown at the SAE NVH show and will sell for $1495.

It will also soon be incorported into another product called the cRIO-4408 with 2 cRIO-9233 modules. It will not be controlled via NI-DAQ. It will have a personality pre-loaded on the system and communication and data transfer is controlled by TCP/IP protocol for the NI cRIO-4408. An example of this communication in LabVIEW is included with the device.

[duncan carter]

Is there an anticipated date for the release of the USB-9233 and the required DAQmx version?

[Kurt_Veggeberg]

The USB-9233 is expected to be released in July with the release of NI-DAQmx 7.5. The part number will be 779365-01. With the Sound and Vibration Toolset it is 779366-01.