oscilloscope recommendation

[MaxXx]

Hello,

I am trying to find an oscilloscope that can record two channels simultaneously with 300MHz Bandwidth, 1GS/s, and 250Mpoints/s for each channel. I already have PXI1033 and PXIe-1073 chasses in the lab and I have looked at the PXI-5154 and 5153 and I know that they can continuously acquire and stream data to the computer with labview. I'm wondering if these modules will be able to continuously stream data to the computers at the equivalent rate of 250M points/s for each channel? The computer we have is about 4 yrs old Dell Vostro 420 workstation with intel core2duo ~3ghz, 2gb DDR2 800mhz memory and runs winXP. I hope this is fast enough to accept continuous stream of data from PXIe chassis equivalent to 250Mpoints/s for each channel.

Max

[Nathan-P]

First, I'm not sure what you mean by needing 1G S/s and 250Mpoints/s per channel.  These are conflicting specs.  It seems that since you only need two channels, then you will need a total of 500Ms/s, which with the PXI-5154, is 500 MB/s (8-bit samples).

With the PXI-1033, it has an integraded MXI system, which can only transfer 110 MB/s to the computer: 

https://www.ni.com/en-us/support/model.pxi-1033.html

The PXIe-1073 has a maximum transfer/bandwidth of 250 MB/s.

Both of these chassis would be insufficient to maintain the data throughput you require.  

You can find more information about data streaming here:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000kHVNSA2&l=en-US

You will need a MXI x4 to get the data rates you need. 

Now with the PXI-5154, it has two channels on it, which can sample in a "ping-pong" manner (multiplexed) at a max of 2 GS/s (1 GS/s per channel), which is 4x more than you need.  If you need the samples to be truely simultaneous, then you will need to have two cards, and have them syncronized.  

[MaxXx]

Thank you for your reply.

To clarify what I meant by 1GS/s and 250Mpoints/s per channel. When I look at oscilloscopes from other companies, for example the Tektronix DPO7054C, they provide the sampling rate, which is 5Gigasamples per second, which is how fast it can samples data from the input. They also provide the record length, which is 250Million points per second, which is how much it can store in memory. So when I try to get data from my experiment using the old oscilloscope, it can only acquire 10kpoints/s/channel, and I need higher resolution and longer time than that. The scope can not stream data to the computer continuously so there is a delay between obtaining data and outputting it to the computer.

In short, I'm just trying to find a module and chassis that can continuously stream data to the computer with at least 250Million points per second per channel without loosing or overwriting any of the data that is already in the module's memory.

Can I use that MXI-4 NI PXIe-PCIe8371 or NI PXIe-PCIe8381with my current chassis?

[Nathan-P]

Ok, for streaming applications, the record length isn't too much of a concern, as it just groups the data into chunks.  The NI-SCOPE driver includes an example LabVIEW program that shows how to stream data to disk.  The example is called "niScope EX Stream to Disk.vi".

Both of your existing Chassis have embedded MXI controllers, so no.  The MXI-express devices have two parts, a PXI anc PCI cards, the PXI card going into the controller slot of the chassis. (Slot 1)

I hope this helps.

[MaxXx]

I guess I will have to purchase a new chassis setup then, please help me see if this is correct setup.

Qty.   Model

1       NI PXIe-PCIe8381 Controller card

1       PXIe-1082 Chassis

1       PXI-5154 Digitizer Module

Do I need to purchase an embedded controller? or will that controller card be fast enough to stream data to my computer? Do you think I will have to setup a SATA RAID system on the computer in order to achieve fast write speed.

Thanks again!

[Nathan-P]

So, with your setup, it will try to stream 250MS/s from each channel on the PXI-5154. Which means that the module will need to stream 500 MB/s (8-bit samples).

Unfortunately, I just realized that the PXI devices cannot stream data at that rate. Since PXI devices use a PCI bus, the devices are limited to a max PCI bandwidth of 132 MB/s. On the PXIe-1082 chassis, all the hybrid slots share a PCI bus, which is connected to a PCIe x1 link. (All slots are also connected via a PCIe x4 link for PXIe cards)

Resources:
https://www.ni.com/en/support/downloads/instrument-drivers/instrument-bus-performance---making-sense...
https://www.ni.com/docs/en-US/bundle/pxie-1082-seri/resource/372752c.pdf (Page 1-6 has backplane diagram)

To get the streaming bandwidth, you will need a PXIe card connected to a slot with a x4 link. All the slots in the PXIe-1082 have that, so you will need a card like the PXIe-5162.

The NI PXIe-PCIe8381 would be fast enough to get the data to your remote controller (PC), but you will need enough RAM to buffer writing the data to disk. Like you mentioned, a faster disk setup would help, though you could setup the RAID in the chassis as well.

We also provide SATA RAID hardware that can connect to your system, like our In-Chassis RAID, or one that can write at 750 MB/s:
https://www.ni.com/en-us/shop/category/pxi-platform-completion-hardware.html?productId=118764
https://www.ni.com/en-us/support/model.hdd-8265.html

Do you need an Embedded Controller?

I want to note that using remote controllers may have difficulty connecting to a PXI chassis.  MXI-Express extends the PCI/PCIe bus, but some BIOS software is not able to enumerate the complete PCI/PCIe topology. (which supports a max of 255 cards/devices) Embedded Controllers have custom BIOS that allow the controller to enumerate the complete PCI/PCIe bus topology. To work with desktop and laptop PCs that do not have this capability, NI offers MXI-Express Compatibility Software. Just wanted you to be aware of this.

MXI-Express Compatibility Software:
https://www.ni.com/en/support/downloads/drivers/download.mxi-express-bios-compatibility.html

I hope this helps and is clear, if you would like more info please let me know.