Is PXI Express backwards compatible with PXI?
Yes. PXI Express maintains both software and hardware compatibility with PXI peripheral modules.
Software: PCI Express uses the same OS and driver model as PCI, resulting in complete software compatibility between PCI-based systems (such as PXI) and PCI Express-based systems (such as PXI Express). This software compatibility is ensured by the PCI-SIG, a group composed of member companies who are committed to the development and enhancement of the PCI and PCI Express standards.
Hardware: PXI Express chassis provide hybrid peripheral slots that accept PXI Express peripheral modules and hybrid slot-compatible PXI peripheral modules. These peripheral slots deliver signaling for PCI and PCI Express.
Can I use my existing code written for previous PXI systems?
Yes. PXI Express maintains complete software compatibility with PXI. Software compatibility includes operating systems such as Windows 7 and Linux®, application software such as Microsoft Office and NI LabVIEW, and user code such as LabVIEW VIs and C++ projects.
What is a PXI Express hybrid slot?
PXI Express chassis have two kinds of peripheral slots: PXI peripheral slots and PXI Express hybrid peripheral slots. The PXI hybrid peripheral slots, shown in Figure 3, can accept either PXI Express peripheral modules, 32-bit CompactPCI boards, or hybrid slot-compatible PXI modules.
Figure 3. A PXI Express hybrid slot accepts PXI Express peripheral modules, 32-bit CompactPCI boards, and hybrid slot-compatible PXI modules.
What is a hybrid slot-compatible PXI module?
National Instruments PXI modules that do not include a J2 connector are already hybrid slot-compatible. For NI modules that do include the J2 connector, you must replace that physical connector to achieve compatibility with PXI Express hybrid peripheral slots. As shown in Steps 1 through 3 below, the J2 connector is removed and replaced with the smaller eHM connector (XJ4). You can still use the resulting hybrid slot-compatible module in existing PXI peripheral slots.
Step 1. Select a PXI peripheral module that you would like to modify.
Step 2. Depopulate the J2 connector.
Step 3. Populate the eHM (XJ4) connector.
Figure 4. Connector Modification of a PCI-Based PXI Module for Hybrid Slot Compatibility
For modified NI modules, only the backplane connectors are replaced; the rest of the module remains unchanged. This modification takes advantage of the fact that the lower portion of the J2 connector is largely unused in 32-bit PXI modules, with the exception of its use in local bus.
What is going to happen to my existing PXI equipment?
You can use existing PXI peripheral modules in PXI Express chassis that have hybrid slots and in PXI chassis. Because the PXI Express specification offers a feature set enhancement and not a replacement for PXI, National Instruments and others will continue to develop and sell PXI controllers, chassis, and modules based on PCI signaling.
To use existing PXI peripheral modules in a National Instruments PXI Express chassis, simply insert the module into one of the several PXI peripheral slots. If the existing equipment does not have a J2 connector, you also can place the module in a hybrid slot. If there are more existing PXI modules that have J2 connectors than there are PXI slots available, you can send the remaining PXI modules to National Instruments to be made hybrid slot-compatible for a nominal fee.
Can I send in my National Instruments PXI modules to make them hybrid slot-compatible?
No, NI no longer offers this service because all current NI manufactured PXI boards come with a pre-installed XJ4, so the service is obsolete. We recommend getting in touch with your sales representative to negotiate the acquisition of the newer version of the non-hybrid module.
Will future PXI modules from NI be natively hybrid slot-compatible?
Yes. National Instruments now incorporates the smaller eHM connector on most of its PXI modules that previously used the J2 connector. As a result, you may use these modules in either existing PXI peripheral slots or PXI Express hybrid peripheral slots. Again, not all existing modules are made hybrid slot-compatible. For example, legacy products such as E Series data acquisition modules cannot transition to the new connector.