Generation rate or onboard memory

[Mystogan]

Hi,

im trying to generate digital signal with pxie 6544. I read in datasheet, that this device has onboard memory size 1Mbit/channel. In the other part of the datasheet, it says, maximum data rate per channel is SDR: 100Mbps or 400MB/s typical data streaming rates (I guess this rate means I can use all 32 channels with maximum rates 100MHz to generate signal).

I can use either 4byte or 2byte data for generation. But I dont think it would let me have bigger buffer size, right? 

Is there any ways I can generate signal somehow without using onboard memory size?

[Thomas_Just]

Hi Mystogan,

please find some information about streaming here:

Streaming

http://zone.ni.com/reference/en-XX/help/370524L-01/nisignal_generators_help/5442_streaming/

I think this handles your problem of generating waveforms that are too large to fit in the onboard memory.

[Mystogan]

Hi Thomas,

thanks for your suggestion. But seems I cant use DMA with my 6544 device. Moreover, it seems I dont have enough time to "update" my signal on the fly.

I got error "the data being written cannot keep up with the output". I assume, the device cant wait for my signal update.

Basically I'm using the example "Continuous generation - Stream from memory example.vi".

regards,

Yan.

[Mystogan]

Hi,

I have Digital Waveform Editor (DWE) installed and I think I should be able to split my generation into smaller pieces, save them in multi HWS files. 

But I dont know how to import&generate multiple HWS files.

I'm wondering how do people stream very large data with HSDIO. There are examples using TDMS but looks quite complicated.

I think DWE would help me to simplify the generation and data split.

[deppSu]

TDMS is of ease of use and has high IO performance. It's very popular to do streaming of measurement data with TDMS. The examples inside LabVIEW will be good start to get to know TDMS.

[Mystogan]

Hi,

I've tried to use TDMS to stream my signals, but seems its still too slow for HSDIO board? I'm confused with HSDIO streaming examples in forum, they are configuring some stuffs which I dont have.

This is what I did to try to stream my TDMS, which is included in zip file (1M samples).

*My mistake, actually I need to build 40M samples data instead of 1M. But still, this is somehow doesnt work.

[Mystogan]

sorry, wrong file.

[deppSu]

Hi, do you mean that the IO speed of TDMS Read doesn't satisfy your application? If that's the case, I think first we should figure out what's your desired file IO read speed of your application. The next step is to see what's the maximum throughput to use TDMS on your platform. LabVIEW have a bunch of example File IO benchmark VIs (you can find them by using "benchmark“ as the keyword to search), you can play with these VIs and see if they can satisfy your application.

[Mystogan]

Hi,

I've tried to look for "benchmark" examples in LV. I got the examples for read and write: TDMS advanced sync read speed test.vi. And the result tells me the MB/s speed of data read and write. 

I dont see any helps related with my application :S

[deppSu]

According to your former post "seems its still too slow for HSDIO board", does it mean the performance of TDMS Read dosen't satisfy your application?