Common Questions

How does the PCIe-8371 (part number 194591x-02) differ from the PCIe-8371 (part number 199994x-01)?

Besides the physical weight and size reduction, there is now a front panel LED that indicates link status, as shown in the LED Status Descriptions of MXI-Express x4 Products table. The smaller size allows the PCIe-8371 to fit in systems requiring a low-profile card when used with the low-profile front bracket included with the card.

You may see a small performance increase and/or reduced latency in most applications, but otherwise there is no functional difference.

What connectors do the NI MXI-Express x4 copper cables use?

The NI MXI-Express x4 copper cables use x4 PCI Express connectors. For more information about these connectors, visit Molex at www.molex.com and search for x4 PCIe iPass.

How many PXI bus segments can I connect together with MXI-Express x4?

The PCI specification allows up to 255 bus segments. MXI-Express x4 does not limit this number, but the maximum number of bus segments allowed can be BIOS or operating system dependent. Also, a computer may already have several PCI bus segments internally, and the MXI-Express x4 link also has multiple PCI buses internally. Every PCI Express device has at least one bus segment, though it has more if it includes a bridge or switch.

Will my PC work with MXI-Express x4 products?

It depends on the robustness of your PC BIOS. In most cases, the BIOS can enumerate the bridge resources that the MXI products require for operation, especially for smaller MXI system configurations. For more information, refer to the NI Developer Zone article Tips to Help You Successfully Use NI MXI-Express Controllers at ni.com/zone.

What is the maximum MXI-Express x4 copper cable length?

The maximum length for a MXI-Express x4 copper cable is 7 m. National Instruments offers 3 m and 7 m copper cables. Refer to the Cabling section for more information.

What are some improvements from MXI-3 and MXI-4 to MXI-Express x4?

MXI-Express x4 incorporates the latest technology to include:

• Support for PCI Express slots.
• Support for PXI Express and CompactPCI Express chassis.
• Improved error correction and handling for noisy or harsh environments.
• Improved mechanical connectivity and performance.
• Support for two chassis from a single card in the host PC.

Can I connect a MXI-3, MXI-4, and MXI-Express x4 board directly?

No. MXI-3, MXI-4, and MXI-Express x4 boards use different cable connectors and cannot be connected. Also, the board-to-board communication protocols differ.

Can I use a MXI-3, MXI-4, and MXI-Express x4 kit in the same multichassis PXI system?

Yes. You can mix different MXI kits to connect multiple PXI and PXI Express chassis. As mentioned above, an individual MXI-3 or MXI-4 board cannot cable directly to a MXI-Express x4 board.

MXI-3 and MXI-4 systems require a specific boot ordering. Is this a requirement with MXI-Express x4?

Yes. When you use MXI-Express x4, the PCI bus still requires you to power-on secondary PXI/PXI Express chassis before powering on the host PC.

With MXI-3 and several chassis connected in series (daisy chain configuration), you are required to power-on the chassis in order starting with the chassis at the end of the chain and move towards the host controller. With MXI-Express x4, multiple chassis are connected in parallel. You can power them on in any order, but you must power on the host PC last.

For more details, refer to the Powering On the MXI-Express x4 System section.

Which operating systems do MXI-Express x4 products support?

Most operating systems recognize MXI-Express x4 as a collection of PCI-to-PCI bridges. It should have CompactPCI Express support automatically with most systems such as Windows, Macintosh OS X, Linux, and Solaris. Full PXI Express functionality requires PXI Platform Services software. Refer to the Software Installation and Configuration section for more information.

What software does my MXI-Express x4 kit require?

For Windows and LabVIEW RT, the required software is included as part of the PXI Platform Services software included with your kit. The software for your MXI-Express x4 controller enhances the product, allowing you to view information about the organization of your PXI Express system, gain access to the PXI Express chassis’ trigger routing capabilities, and programmatically retrieve data about the chassis and modules you have installed.

For a list of operating systems PXI Platform Services supports, refer to KnowledgeBase 53399AQ7, PXI Platform Services Operating System Support, on ni.com.

If PXI Platform Services does not support your operating system, you still can use MXI-Express x4 as a PCI Express expansion solution. However, this solution does not support features such as chassis and controller identification, trigger routing, and slot detection.

MXI-3 required optimization software. Does MXI-Express x4 require the same?

No. The MXI-Express x4 hardware performs necessary optimization automatically.