upgrading PXIe controllers for Windows 11/RT Linux compatibility

[mvsiva]

Hi,

I currently have the following PXI components

1. PXIe 1078 chassis with PXIe 8135 controller
2. PXIe 1071 chassis with PXIe 8115 controller
3. 2x PXIe6363 MIO cards used interchangeably with the two systems above
4. 5x PXIe4331 strain modules used interchangeably with the two systems above

I am operating both systems in RT mode and use NI VeriStand.

Both the 8115 and 8135 controllers are not compatible with RT Linux and are running Pharlap. Therefore, the highest version of LabVIEW I can use is LabVIEW 2020 SP1 and VeriStand 2020, since later versions do not support Pharlap. 

In addition, my institution is transitioning to Windows 11 in the next few months, and these LabVIEW and VeriStand versions are not compatible with Windows 11.

I am therefore looking to upgrade my PXI controllers. Using this tool, https://www.ni.com/en/support/documentation/compatibility/21/ni-hardware-and-operating-system-compat..., I found the following.

1. PXIe 8115 and PXIe8135 controllers are compatible with neither RT Linux nor Windows 11
2. PXIe1078 and PXIe1071 chassis are compatible with both RT Linux and Windows 11
3. The PXIe 6363 and PXIe 4331 modules are also compatible with both RT Linux and Windows 11

I am therefore thinking along the lines of keeping my two chassis and modules and upgrading just the controllers to PXIe 8822 or PXIe 8842.

The following are my questions.

1. With the PXI advisor, I was able to configure a system with either the PXIe 8822 or PXIe 8842 controller with a 1071 chassis, so I am guessing they are compatible. However, I didn't find the 1078 chassis in the advisor. Are the 8822 and 8842 controllers compatible with the 1071 and 1078 chassis?
2. Is there a risk of running into compatibility or support/service issues in the near future, say in the next 5 years if I kept the old chassis? My hesitation to upgrade the chassis as well is (1) of course budget constraints and (2) most of the new chassis seem to have many more expansion slots, and I am unlikely to expand to the degree of using that many slots.

Thank you.

Siva

[santo_13 · Accepted solution]

All that you need to check for Controller-Chassis compatibility is whether the chassis has slot 1 for controller (some are MXI or Thunderbolt only) and whether both are of the same PXI version (PXI-PXI or PXIe-PXIe).

Another key functional attribute to look for is the bandwidth supported by the Chassis and the Controller, you will be limited to the lower of the two. This is important when you're streaming large data from several slots.

Discontinued hardware may not show up in the PXI config advisor.

PXI consortium maintains the specs for PXI and PXIe to enable cross-vendor compatibility of products, as long as the chassis/slot PXI version and the controller/card PXI version matches, it should work.

[mvsiva]

Thank you, Santosh,

That is very helpful. I have a follow-up that is not really NI-related but on PXIe link speed.

The chassis list bandwidth in GB/s, the controllers specify PCI express link speed. This is GT/s. This Wikipedia page https://en.wikipedia.org/wiki/PCI_Express has a mapping - for example 2.5GT/s with x1 configuration is 250MB/s and with x16 configuration is 4GB/s. The 8822 controller for example is 2.5GT/s and seems to support x4 and x8 configurations (not sure what this means). The specification is in this table https://www.ni.com/docs/en-US/bundle/pxie-8822-specifications/page/overview.html. Does that mean the maximum bandwidth of this controller is 2GB/s?

Thank you.

Siva

[santo_13]

Side topic, for some PXIe cards there are certain cooling requirements, making them less performant on older chassis with lesser slot cooling and called out in the specifications but none of such sort for the controller.

[mvsiva]

Thank you. That is helpful to keep in mind as well. Also, is my understanding of the bandwidth (chassis vs controller) in my previous question correct?

[santo_13]

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@mvsiva wrote:

Thank you, Santosh,

That is very helpful. I have a follow-up that is not really NI-related but on PXIe link speed.

The chassis list bandwidth in GB/s, the controllers specify PCI express link speed. This is GT/s. This Wikipedia page https://en.wikipedia.org/wiki/PCI_Express has a mapping - for example 2.5GT/s with x1 configuration is 250MB/s and with x16 configuration is 4GB/s. The 8822 controller for example is 2.5GT/s and seems to support x4 and x8 configurations (not sure what this means). The specification is in this table https://www.ni.com/docs/en-US/bundle/pxie-8822-specifications/page/overview.html. Does that mean the maximum bandwidth of this controller is 2GB/s?

Thank you.

Siva

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This article provides a better overview of the speeds.

https://www.taborelec.com/Understanding-PXI-and-PXIe-instrumentation

I will have to research more to give you a better answer.

[mvsiva]

That actually answers almost all my questions. Only remaining question is what determines how many lanes - the 8822 specs for example say 4 times x4 and 2 times 8 lanes. Is that determined by the number of slots used?

[ZYOng · Accepted solution]

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@mvsiva wrote:

That actually answers almost all my questions. Only remaining question is what determines how many lanes - the 8822 specs for example say 4 times x4 and 2 times 8 lanes. Is that determined by the number of slots used?

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That depends on the backplane architecture of your chassis. Search for the keyword "backplane" in the user manual of your chassis and you can see how the links and bandwidth are distributed to each slot.

Generally speaking, you don't have to worry about the bandwidth if you are not that doing high-speed streaming. VeriStand works on hardware timed single-point mode and does not require high throughput.

[mvsiva]

Thank you. That answers all of my questions.