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Data bottleneck concerns

I have the following configuration setup for my application; and I need help to understand that this configuration will work when put together without having data bottleneck down-streamed to my PC. The configuration is shown in the table below:

PXIe-1071  chassis Holds 5160 + 1209
PXIe-PCIe8381 PCI Express (x8 Gen 2) Control of PXI Express 
  1. Direct PC control of PXI Express systems
  2. 100 m maximum cable length with rugged latching connectors
  3. Sustained throughput of 3.2 GB/s per direction
  4. What's the PCIe rev on the mobo? What rev does this card support?
PXIe-1209 high-performance, 2-channel,
100 MHz Pulse Generator
MCX connectors for output and trigger syncs
PXIe-5160 500 MHz, 2.5 GS/s, 10-Bit, 2-ch, 64MB PXI Express Oscilloscope BNC inputs, 50 Ohms i/p impedance

 

  1. Chassis has a max throughput of 3 GB/s, while the 8381 cable has a max throughput of 3.2 GB/s. They each have their own maximum throughput. That being said, each slot of the chassis only has a maximum throughput of 1 GB/s each. (3 slots x 1 GB/s = 3 GB/s for the chassis). The 4th slot sends the data from the other 3 slots to your computer.
  2. 5160 is 2.5 GS/sec aggregate, so 1.25 GS/sec/Ch at @10 bit resolution.
    1. When they say aggregate, does it mean I can split 2 channels to run at 1.25 GS/sec?
    2. If I intend to use just single channel on 5160, can I run it at 2.5 GS/sec ?
    3. Will the chassis and 8381 PIXe-PCIe card be able to sustain all the data throughput to my host PC if I run the 5160 @ 1.25/GS/Sec/Ch or 2.5 GS/Sec on just one channel?

At the end of the day, having able to read in all the date seamlessly without any issues to the host PC is of utmost importance.

I would really appreciate on any advise over this technical question I have been facing.

NI System Configuration:
- NI PXIe-1071, 4-Slot 3U PXI Express Chassis , 1 GB/Slot throughput, Part Number: 781368-01
- NI PXIe-PCIe8381,x8 Gen2 MXI-Express for PXI Express Interface,3m, Part Number: 782522-01
- PXIe-5160 PXI Oscilloscope, 500 MHz, 10 bits, 2.5 GS/s, 2 Channels, 64 MB, Part Number: 782621-01
- Astronics PXIe-1209 2-Channel, 100 MHz PXI Pulse Generator, Part Number: 785033-01
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This page should help a little: http://www.ni.com/white-paper/10801/en/

 

You can't stream data off of the 5160 that fast since it has a PXI Express gen 1 x4 link to the backplane (1GB/s theoretical, more like 800MB/s realistically).

 

Usually you'll use scopes to capture data around a trigger event. The card will acquire the data to its internal DRAM bank, and you'll transfer that record to the host over the PCIe link.

 

Some math to consider:

  • 1.25MHz * 16bits = 2.5GB/s (way faster than the 5160s backplane link)

 

How much do you actually need to transfer back to the host? Can you acquire a record around a trigger event?

 

If you did select a setup that could stream this much data, how are you planning on processing it all? Do you need to save it all to disk?

 

http://www.ni.com/white-paper/13476/en/

http://www.ni.com/product-documentation/53547/en/

Craig H. | CLA CTA CLED | Applications Engineer | NI Employee 2012-2023
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How much do you actually need to transfer back to the host? Can you acquire a record around a trigger event?

>> Yes absolutely, that is what I intend to do: Acquire data only around a trigger. For instance, I will only have to use the scope to digitize the signal on 10000us period time frame.

 

If you did select a setup that could stream this much data, how are you planning on processing it all? Do you need to save it all to disk?

>> Based on my previous answer, if I only acquire data around a triggered event for a period of lets say 10000us, then yes I will stream it to an SSD (acts as a fast buffer to store data) and sequentially push it to a slower HDD if necessary for later processing.

 

 

Was I able to answer your questions?

NI System Configuration:
- NI PXIe-1071, 4-Slot 3U PXI Express Chassis , 1 GB/Slot throughput, Part Number: 781368-01
- NI PXIe-PCIe8381,x8 Gen2 MXI-Express for PXI Express Interface,3m, Part Number: 782522-01
- PXIe-5160 PXI Oscilloscope, 500 MHz, 10 bits, 2.5 GS/s, 2 Channels, 64 MB, Part Number: 782621-01
- Astronics PXIe-1209 2-Channel, 100 MHz PXI Pulse Generator, Part Number: 785033-01
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