multiple PCIe-6363s in same computer

[cowenowner]

If I install 4 32 channel PCIe-6363 on the same computer (I found a Gigabyte motherboard with 5 PCIe slots), and acquired analog data at the full sampling rate (2 MS/s on each card) on all 128 (4x32)  inputs, would I be able to record all of that data onto a standard 3gb/sec hard drive, or would the system choke with that amount of throughput? Would there also be cooling or power problems with installing 4 PCIe_6363 cards on a single machine?

Thanks!

Stephen

[SamboNI · Accepted solution]

Hi Stephen,

Regarding the PCIe-6363 devices, it's important to realize that they can sample at 2 MS/s with one channel, but the multichannel rate is 1 MS/s, which is divided among all of the channels you are using in the task. This is because all 32 channels are multiplexed to a single analog-to-digital converter (ADC)

This behavior is true among all of our multifunction DAQ devices, with the exception of simultaneous sampling devices (such as the PXIe-6368), which sample each channel at 2 MS/s, as they each have their own analog to digital converter.

So you would be able to acquire on all 128 channels without a problem, but they would be at a rate of 1 MS/s / 32 channels = 31.25 kS/s per channel.

As for the total write-to-disk speed for 4 PCIe-6363s, this would be 4 devices * 1 MS/s  per device * 2 bytes/sample = 8 MB/s. Desktop hard drives can easily achieve this.

You'd want to connect them with a RTSI cable to make sure they all use the same sample clock and trigger at the same time. These devices adhere to the PCIe specification, and therefore you won't have any problems with power or cooling on that motherboard. They do not require any external power unless you need to source additional current on their +5 V line, in which case you'd use the motherboard's hard drive connector.

Does this answer your question? Do you actually need 2 MS/s on each channel? Let us know if you actually need 2 MS/s on every channel, and we can rework the math with the PXIe-6368 and discuss considerations.

Best regards,

Sam

Message Edited by SamboNI on 09-18-2009 05:06 PM