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Considerations When Using the NI PXI-4461 or NI PXI-4462

Updated Nov 30, 2023

Reported In


  • PXI-4461
  • PXI-4462
  • PXI-4472
  • PXI-4472B

Issue Details

The NI 4461 and 4462 sound and vibration modules are offered in both standard PXI and PXI Express-ready (PXIe-ready) versions. What is the difference between the versions and are there any caveats in compatibility?


The PXIe-ready (hybrid-slot compatible) 4461/2 devices have slightly less functionality regarding only synchronization schemes in comparison with a standard PXI 4461/2 devices. The PXIe-ready 4461/2 device had to make room for new connector pins used in hybrid PXI/PXI Express chassis, so some pins were removed from the connector.

Standard PXI 4461/2 devices can be synchronized with either of two methods: Clk10 or PXI Star Trigger. The Clk10 method uses the 10 MHz clock in the PXI backplane as the base clock. The PXI Star Trigger method requires one 4461/2 to route its clock to the others as the base clock for synchronization. In either case, the synchronization results (drift, phase shift, etc.) are identical. With the PXIe-ready devices, the PXI Star Trigger pin does not exist. Thus, the PXI Star Trigger method of synchronization is not possible in PXIe-ready 4461/2 devices.

One additional consideration is synchronization with a 447x device (PXI-4472 or PXI-4472B). The 447x devices are only capable of synchronization with the PXI Star Trigger. Thus, if you want to synchronize a 447x device with a 4461/2 device, you will need to use the standard PXI 4461/2 devices, which have the PXI Star Trigger pin. In addition, 447x devices are not PXIe-ready (hybrid-slot compatible), so they cannot be used in hybrid PXI/PXI Express chassis.

In general, NI recommends that customers continue to buy the standard PXI 4461/2 devices unless you are also using PXI Express modules and/or a PXI/PXI Express hybrid chassis.

Additional Information

Frequently Asked Questions

Q: Can I synchronize the full backplane PXI-4461/2 with hybrid-slot compatible PXI-4461/2 modules?

Yes. By default, DAQmx Channel Expansion uses reference clock (Clk10) synchronization. This synchronization method is not affected with the hybrid compatible modules. The hybrid-compatible modules will look different (they have different connectors) but they will operate identically.

Q: Did the device bundled with the Sound and Vibration Toolkit include the hybrid-slot compatible module or the standard PXI module?
The Sound and Vibration Toolkit bundles with the PXI-4461 or PXI-4462 included the hybrid-slot compatible module. The part number for these products has stayed the same but the bundle kit was changed to include the hybrid-slot compatible PXI-4461/2.

Q: How do I synchronize PXI-447x and PXI-4461/2 devices?
PXI-447x and 4461/2 devices can only be synchronized using the PXI Star Trigger method. This line is not available in the hybrid-slot compatible 4461/2 modules, so you must use the standard PXI 4461/2 devices with 447x devices. The 447x modules are not hybrid-slot compatible.

Q: Can I use the PXI-447x in a PXIe Chassis?
The PXI-447x can be used in the PXIe-1062 and PXIe-1065 chassis. These chassis have standard PXI slots that the modules can plug into. However, the star trigger lines on these chassis can only be driven by the PXI Express timing slot. This means you can not synchronize the PXI-447x modules installed in a PXIe chassis. Please use a standard PXI chassis to synchronize your PXI 447x modules.

Q: Are the PCI-4461/2 devices affected by this change?
These devices continue to use RTSI connections for synchronization and therefore are unaffected.

Additional Details: PXIe-Ready (Hybrid Slot-Compatible) Modules

The hybrid slot-compatible PXI-4461/2 modules can be used in PXI slots, CompactPCI slots, and hybrid slots. The PXI Systems Alliance specifies hybrid slot-compatible PXI modules to use modified slot connectors to mechanically fit in both PXI slots and hybrid slots. This mechanical change:
  • Provides compatibility to past, current, and future PXI chassis
  • Maintains existing product specifications
  • Requires no software changes (application or driver)
  • Maintains speed and capability of all PXI communication (PXI Express signaling is not provided)
Hybrid slot-compatible PXI modules do not include the pins used for PXI Star Trigger synchronization. The PXI Star Trigger is only one method of synchronizing multiple PXI-4461/2 devices. The Clk10 synchronization method for multiple PXI-4461/2 devices is not affected and continues to be available for both standard PXI and hybrid slot-compatible form factors. In applications where synchronization using the Star Trigger is necessary, for example synchronizing 4461/2 devices to 447x devices, please use the standard PXI form factor 4461/2 modules.