Possibility of continuous data logging at 60 Msample/s by (Ni PCI-5105)?

[bilal khan]

Is continuous data logging at 60 Msample/s (Ni PCI-5105) onto hard drive possible? What configuration will be required that of PC, Ni Data acquisition card (on board memory size), application software LabVIEW?

[John_P1]

Hi bilal khan,

Streaming continuously at 60 MHz should be possible on the 5105 provided you are only using a single channel--anything more would be pushing the practical limit of the PCI bus.  I would take a look at the NI-SCOPE Stream to Disk Using Win32 File IO example.  You would need to use an niScope property node to set the Binary Sample Width to 8 (Acquisition >> Binary Sample Width).  You would lose 4 bits of precision, but 60 MB/s would be more sustainable than 120 MB/s.

On the hardware side of things, even 60 MB/s is pushing the limit of most hard drives--you may be able to get by with a fast 3.5" SATA, but I would recommend a RAID-0 setup to be safe.  The following link contains a few hard drive benchmarks and tips for streaming:

Streaming Data to and from Disk

Since we are talking about continuous streaming, the on-board memory of the scope should not be much of a factor provided it allows enough of a buffer such that samples are not overwritten.  The 16 MB option will probably be sufficient, but you might consider the 128 MB option to be on the safe side.  The rate that your code fetches samples from the board is going to be entirely system dependant so I can't confirm that the 16 MB option would work in all cases.

If you are looking at purchasing a new system, I'd like to point out that we currently offer two PXIe scopes that can stream at much higher rates:

• PXIe-5622 -- typically used with RF applications, this board offers 16-bit precision at 150 MHz on a single channel
• PXIe-5122 -- this board offers 2 channels at 100 MHz, 14-bit precision

Of course, you would need a PXI Express chassis and controller for these options.  You would be able to use our 12-drive or 4-drive PXIe Raid Arrays--we have achieved rates of up to 600 MB/s on these systems.  This would be significantly more expensive than purchasing a single board--I just wanted to point out that we do offer complete streaming solutions.  See the following link for more info on benchmarks achieved with such systems:

High Speed Data Streaming: Programming and Benchmarks

To summarize, the 5105 is capable of streaming 60 MHz on a single channel, but you will run into issues with the PCI bus if trying to acquire at rates much faster than that.  If you wanted to extend the application to more channels or higher rates, you might consider looking into a PXI Express system.

-John