"Not Enough Memory" error message using PXI-8176 ETS Labview 8.2.1

[somit]

I am trying to acquire and save data using the ADC PXI-5105 card and the PXI-8176 embedded controller. Unfortunately the error message, "Error Message=Not enough memory to complete this operation", is displayed on the PXI monitor when attempting to acquire at least four seconds of data.

However, I do not get this message when I use the PXI-8196 embedded controller. In fact, I can acquire data for minutes using the PXI-5105 and PXI-8196.

I use the 8.2.1 ETS RT for both embedded controllers.

Is it possible that the PXI-8176 does not have the hardware requirements to accomplish my task? Should I tell my supervisor to replace the PXI-8176 with the PXI-8196?

My PXI-8176 has:

   1.2 GHz processor

   128MB RAM

My PXI-8196 has:

    2.0 GHz processor

    512MB RAM

Thanks.

FYI, I am acquiring data using the PXI-5105 card on 6 channels. Each channel is sampled at 1 Msamp/sec at 2 bytes per sample. Therefore, I acquire data at 12MB/sec.

[somit]

Update:

FYI, our PXI-8196 controller is equipped with 2GB of memory. I confirmed that the PXI-8176 only has 128MB.

Also, I forgot to add wait functions in my producer/consumer loops. The producer loop fetches data from the PXI-5105 and the consumer loop writes data to binary file.  Although the program still crashes using the PXI-8176, my best results occur when I use a 2ms wait for the producer and a 100us for the consumer.

[reggier]

Hello Somit,

The first thing you can do to troubleshoot this issue is watch the RT system manager to see if the memory actually does spike when the VI runs.  This will help explain more about where the error is coming from.

reggier

[Matthew_W]

 Hi Somit,

 Additionally, can you run the shipping examples for NI-SCOPE without a problem? What sampling rate, number of records and samples per record are you acquiring?

 Have a great afternoon,

 MatthewW
 Applications Engineer
 National Instruments

[somit]

Hello,

I used the RT System monitor to determine the memory loss. I also monitored loop counters for the ADC producer loop and the binary-writing consumer loop. The PXI-8176 could not write to disk fast enough. However, I have recently switched to the PXI-8196 and this situation has been resolved.

However, I have yet another issue that I need assistance on. We are trying to continuously acquire data on four channels at 5 MSPS (12-bits) using the PXI-5105 ADC card and the PXI-8196. The goal is to fetch data from the PXI ADC card and sent via TCP connection to a host laptop. The laptop will receive the TCP packets and write to binary accordingly.

I have two pairs of producer/consumer loops in my design. The first loop pair resides on the PXI-8196. It produces the ADC data and consumes the ADC data by sending TCP packets to the host laptop. The second loop pair resides on the host laptop. It produces the received TCP packets and consumes the TCP packets to binary file. This design works perfectly at 1 MSPS. However, it fails at 5 MSPS.

What should my inputs be to the frame size and timeout inputs to the NIScope acquisition VIs? Previously, I used "-1" for my timeout and "1000" samples for my frame size at 1 MSPS (four channels) which worked perfectly.

Thanks,

 --Somit

[somit]

To clarify, the error I receive when increasing to 5 MSPS is "buffer has been overwritten" error. I still have plenty of memory when this error occurs, although the memory is decreasing at some rate because my TCP consumer cannot keep up with the ADC producer.

[David S.]

Hi somit -

The buffer overwrite error means that you didn't fetch the data from the digitizer quickly enough, and the card's available memory overflowed.  You may be limiting the fetch rate by forcing all the fetched data directly into TCP packets.  I recommend monitoring your queue backlogs and digitizer fetch backlog to find the bottleneck.

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